Lawn mower

Abstract

To provide a mower that achieves an ideal mowing load control technology in accordance with a unique ability such as a character, taste, or habit of a user, and is excellent in safety and stability, for a beginner, unskilled person, elderly person, or woman who uses a small sulky mower mainly not regularly.SOLUTION: In a sulky mower configured to have an electronic control HST, a mowing travel load fluctuation is detected by an engine speed fluctuation, the detection is read by a control unit, and the electronic control HST is controlled to control the speed so as to stabilize mowing work.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present invention mainly relates to small riding-type mowers or similar lawn mowers, and relates to improvements in the traveling safety and workability thereof. [Background Art]

[0002] Conventionally, almost all small riding mowers popular in Japan are of the four-wheel rear-wheel drive-front-wheel steering type. This is common as a drive steering system, there are also four-wheel drive types designed for uneven terrain, and crawler drive types which are less common than wheel drive types. Furthermore, as is the case with most other agricultural machinery, HST (Hydro Static Transmission) is used for traveling speed control in most mowers. Conventionally, the adjustment shaft of this HST is rotated by operating a single lever to control traveling speed and forward / reverse movement. At present, as control technology becomes more sophisticated year by year, with the electronic control of HST, we have entered an era where higher safety and improved workability are required. [Patent Document 1] Japanese Patent Laid-Open No. 2018-196354 [Patent Document 2] Japanese Patent Laid-Open No. 2020-000158 [Patent Document 3] Japanese Patent Laid-Open No. 2008-290512 [Patent Document 4] Japanese Patent Application No. 2022-009789 [Disclosure of the Invention] [Problem to be Solved by the Invention]

[0003] The applicant previously developed an electronically controlled HST for small riding lawnmowers (Patent Document 4). This application aims to fully utilize its superior performance and ideally realize cutting load control technology, which has been attempted in various ways in the past. Conventional technology prioritizes work efficiency and productivity (i.e., machine performance priority), and the operator is largely left out of the picture (Patent Documents 1 and 2). Fifteen years ago, when electronic control technology was still weak, the applicant also attempted to improve workability and safety by mechanically controlling the HST (Patent Document 4), but this too was a technology-oriented approach prioritizing machine performance, and its market reception was not very good. In the first place, only highly skilled professionals can achieve the highest performance and efficiency of the machine, and most people who use the machine are beginners, inexperienced people, the elderly, and women who use it irregularly. This is especially true for the general-purpose small machines that the applicant supplies to the general market. Optimal control tailored to the individual abilities of each person, as seen in recent AI control, was completely absent in the conventional approach that prioritized machine performance alone. This invention distinguishes itself from the engineer-oriented approach that often prioritizes performance in developing new technologies. Instead, it aims to provide a grass trimmer that offers superior safety and stability by providing assistance tailored to each user, and by realizing a cutting load control technology that responds to the unique abilities of each user, including their personality, preferences, and habits. [Means for solving the problem]

[0004] To solve the above problems, the present invention provides a small riding lawnmower equipped with an engine or motor, a pair of left and right steering front wheels and drive rear wheels or drive front wheels or drive front and rear wheels or drive tracks, and a cutting unit located in the center or front of the machine body, using an HST (Hydro Static Transmission) for the drive transmission mechanism, and connecting an actuator to the swashplate adjustment shaft (trunnion shaft) on the hydraulic pump side of the HST, The actuator's rotation is adjusted by changing the rotational speed or stroke speed, and a means for detecting the lever rotation position using a rotation sensor is provided in the HST lever mechanism, and furthermore, a means for detecting the swash plate adjustment shaft rotation position using a rotation sensor is provided in the rotation drive mechanism of the swash plate adjustment shaft by the actuator, and the control unit controls the rotation or stroke of the actuator so that the swash plate adjustment shaft position is at a speed corresponding to the rotational position of the HST lever. It was configured as an electronically controlled HST with shift-by-wire control.

[0005] Furthermore, a means for detecting rotational speed is provided in the engine or motor section, and fluctuations in the grass-cutting load are detected by the fluctuations in rotational speed. The HST lever mechanism or HST foot pedal mechanism is equipped with a means for detecting the rotational position of the lever or pedal using a rotation sensor, and the throttle lever mechanism is also equipped with a means for detecting the rotational position of the lever using a rotation sensor. The control unit reads the engine speed set by the operator during grass cutting, i.e., the throttle lever rotational position, and the working travel speed, i.e., the HST lever or pedal rotational position, each time, and when the engine speed decreases due to increased cutting load,The HST was controlled to immediately return to the set engine speed, thus controlling the speed. The system provides assistance tailored to each worker, and the AI ​​controls the mowing load according to each worker's unique abilities, such as their motor skills, physical condition, personality, preferences, and habits. We made it possible to perform stable work cruises. [Effects of the Invention]

[0006] The present invention has the following effects as a result of the above-described means.

[0007] By controlling the grass-cutting speed according to the cutting load and further adjusting it to suit each individual operator, the grass trimmer becomes easy for anyone to operate, improving both work efficiency and safety during operation.

[0008] Because the machine learns and controls itself to suit each individual operator, it becomes more familiar to the operator as it is used over time, resulting in improved work efficiency and safety during operation. [Best Mode for Carrying Out the Invention]

[0009] In work assistance control that adapts to the grass cutting situation, detecting the cutting load becomes a problem. Ideally, the rotational torque fluctuations of the cutting blade should be detected, but the aim of this invention is not to increase the efficiency of the machine's operation, but to allow the operator to cruise with a sense of stability and security. Therefore, although it is an indirect detection, engine speed detection was used. This is because fluctuations in engine speed directly affect the operator's hearing and sense of touch. Although it is not a precise detection of the cutting load, the working travel speed is slower than the movement speed, so it is almost equivalent and sufficient. [Example 1]

[0010] A first embodiment of the present invention will be described based on the attached drawings. Figure 1 is a left perspective view of an embodiment of the wheeled lawnmower of the present invention, Figure 2 is a left side view and a top view thereof, Figure 3 is a plan perspective view of the drive mechanism, Figure 4 shows details of the motor drive mechanism of the HST adjustment shaft, and Figure 5 shows details of the HST lever mechanism. The drive transmission 4 is the top-of-the-line model among the applicant's wheeled lawnmowers and is a four-wheel drive model (Figure 4). The speed adjustment HST 5 is directly connected to it, and the adjustment shaft motor 53 that rotates its adjustment shaft 52 is also fixed to the drive transmission 4 with a highly rigid bracket (not shown). A rotational adjustment shaft arm 521 is fixed to the HST adjustment shaft 52 side, and a motor arm 531 is fixed to the adjustment shaft motor 53 side, and these arms are rotatably connected by an adjustment shaft link 522 including a buffer spring, forming a three-bar linkage configuration, and the rotation of the adjustment shaft is controlled by the motor (Figure 4).

[0011] An arm extends from the adjustment shaft arm 521, which is rotatably connected to the sensor arm b523. The rotational displacement of the adjustment shaft is transmitted to the rotation axis of the HST adjustment shaft rotation sensor S2, which is fixed to the sensor arm b523. The sensor sends the rotational displacement signal to the control unit 9 (Figures 1 and 3). The control operation is performed by operating the adjustment shaft motor 53 so that it matches the value of the adjustment shaft rotation sensor S2 set by the control unit 9.

[0012] The HST lever 51, which operates the HST, is pivotally supported on an operating pivot shaft by fixing a pulley and pulley brake 514 and an HST lever arm 511 to it so as to be able to rotate freely (Figure 5). During operation, the pulley brake engages and the HST lever 51 stops at the rotational operating position (i.e., maintaining the operating speed). When the brake pedal 54 is operated, or when the travel clutch is disengaged (although this embodiment is not present in this invention), the pulley brake is released and the lever returns to the neutral position by spring, resetting it. This mechanism is simpler than a joystick that uses an electromagnetic brake or motor, and is widely used in agricultural machinery, construction machinery, etc. that use HSTs.

[0013] One end of a link rod 512 is rotatably connected to the HST lever arm 511, and the other end is rotatably connected to the sensor arm a513. The HST lever rotation sensor S1, which is fixed to the sensor arm a513, rotates, and the rotation operation of the HST lever 51 is transmitted to the rotation sensor S1. The rotation sensor S1 transmits the operating position of the HST lever 51, i.e., the operator's speed setting value, to the control unit 9, sets the value of the HST adjustment shaft rotation sensor S2 to achieve that set speed, and drives the adjustment shaft motor 53 to that value (Figure 4).

[0014] The decision to use a three-bar linkage with a buffer spring in each bar, rather than a gear train drive, to rotate the HST adjustment shaft 52 with the adjustment shaft motor 53 was purely accidental during development. However, it provides a superior buffering effect against fluctuations in torque reaction force from the adjustment shaft resulting from changes in the grass-cutting load, which is not present in gear drive mechanisms (resulting in effects such as soft start, soft stop, soft acceleration, and soft deceleration). In summary, this electronically controlled HST with a shift-by-wire control configuration was developed by the applicant approximately 20 years after its initial conception (Patent Document 4).

[0015] Figure 6 shows details of the engine throttle lever mechanism. The upper figure shows a perspective view of the control pit, and the lower figure shows details of the throttle lever mechanism. A throttle lever arm 211 is fixed to one end of the throttle lever 21, which rotates the throttle wire 22 that adjusts the engine throttle, and rotates together with the lever. One end of a connecting rod 212 is rotatably connected to the arm 211, and the other end is rotatably connected to a sensor arm c213 fixed to the rotation axis of the throttle lever rotation sensor S3, so that the rotation angle of the throttle lever 21 is detected by the throttle lever rotation sensor S3. The reason why the detection rotation axis of the rotation sensor S3 is not directly connected to the rotation axis of the throttle lever 21 is to expand the rotation angle range of the lever (approximately 50°) to the full scale range range of the sensor (120°) for detection, thereby increasing the resolution as much as possible and improving the detection accuracy. The rotation angle detection mechanism of the HST lever is a similar mechanism to improve detection accuracy.

[0016] Figure 7 shows the engine speed detection state. Since the rectifier module 23, which is integrated with the regulator for charging the battery 8, is located outside the cover of the engine 9, detection is performed from this input side. Although simple, fluctuations in the cutting load immediately lead to fluctuations in the engine speed. Therefore, the operator can directly perceive changes in engine noise, cutting blade rotation noise, seat vibration, and the feel of the control levers, both aurally and physically. This allows for control that does not cause any discomfort to the operator's work operation. Although the detection of cutting blade rotation torque is indirect rather than direct, the purpose of this cutting load control is not to improve work performance, but to provide assistance that is appropriate for each operator, and this is actually more suitable for the control parameters.

[0017] The first embodiment of the cutting load control of the present invention will now be described with the above configuration. Generally, as with other agricultural implements, it is believed that the most efficient work can be performed by adjusting the acceleration and deceleration of the work travel speed according to the work load using the HST lever (in the case of manual operation) at maximum output (full throttle), and manufacturers have traditionally recommended this. However, although it feels like it's too late, only highly skilled professional operators are capable of such work, and most people rarely operate the machine to its full potential, instead using engine speeds that feel a bit scary and traveling speeds that feel about right to them. Most people use the machine irregularly before, after, or in between their main job, and often these operators are not their main workers (beginners, inexperienced operators, elderly people, women, etc.). The industry has known this for a long time. That is why most assist controls have been misguided, deviating from the essence of assisting and covering for the operator, by trying to enable even inexperienced operators to work at maximum performance.

[0018] The intention of the present applicant is to draw a clear line from the conventional technology-oriented approach that prioritizes machine performance, provide assistance suitable for each individual worker, realize a cutting load control technology that adapts to each worker's unique characteristics including their kinesthetic sense, physical condition, personality, preferences and habits, and achieve ideal safety and stability. Load control technology is an essential technology for working machines such as mowers. Even if an unskilled worker intends to perform mowing work gently and stably, if they carelessly respond without paying attention to cutting load fluctuations caused by changes such as grass type, grass density and terrain, in the event of a sudden overload, the engine output will decrease, which can cause troubles such as grass entanglement on the cutting part 1, damage to the cutting part 1, engine stoppage due to stalling, and in the worst case damage to the power train, leading to work interruption and, in the worst case, making continued operation impossible (Fig. 9). Skilled workers constantly pay attention to forward conditions, engine noise, cutting blade rotation sound, machine body vibration and other factors to prevent such situations, subtly operate the HST lever (in the case of manual operation) to adjust the traveling speed, and perform operation to stabilize the noise and vibration, which relies on intuition gained from many years of work experience. Of course, beginners and unskilled workers do not have such intuition, so their operation naturally becomes awkward.

[0019] In the present invention's mowing load control, when the control ON condition is met, that is, when the operator raises the throttle lever 21 (= the value of the throttle lever rotation sensor S3 rises), sets the engine speed detected by the rectifier 23 to 1000 rpm or higher, and pushes the HST lever 51 forward (= the value of the HST lever rotation sensor S1 is forward), the control unit 9 reads and stores the setting value of the throttle lever rotation sensor S3, the engine speed at that time, and the travel speed (i.e., the value of the HST lever rotation sensor S1) at the start operation positions of the throttle lever 21 and HST lever 51 respectively, as the engine speed and work travel speed decided by the operator. When mowing work begins, the control unit 9 continues to continuously sample and monitor the engine speed with a moving average of approximately 0.2 seconds. If the mowing load becomes overloaded under any conditions and the engine speed decreases, the control unit 9 controls the HST 5 to reduce the travel speed until the engine speed reaches the level set by the operator. Once the engine speed increases after moving out of the overload range and into a light load state, the control unit 9 controls the HST5 to increase the working travel speed.

[0020] At this time, the speed control is limited to the speed set by the operator (HST lever rotation sensor S1 value), and even if the load becomes lighter than before the control, it will not exceed this set speed. This is because driving faster than the operator intends could cause anxiety to the operator. Naturally, in such cases the engine speed may increase slightly, but this is within the margin of error due to the slight load condition when the engine speed was set at the start of the work, and will not cause any discomfort to the operator. Basically, the engine speed is determined by the position of the throttle lever 21 (i.e., the amount the throttle wire 22 is pulled).

[0021] Incidentally, a decrease in engine speed does not only occur when the mowing load becomes excessive. It naturally also occurs when entering uneven terrain from level ground, or when climbing an uphill slope. However, in all these cases, the vehicle transitions to a more dangerous traveling state than the steady traveling state, and this control that decelerates the vehicle at such times also serves as safe traveling control. After escaping the dangerous area, the speed returns to the speed set by the operator via the HST lever 51. Conversely, considering that traveling under an excessive mowing load is also one type of dangerous traveling state, the present invention aims to achieve stable control of mowing load according to each operator's individual habits and preferences, and at the same time also provides safe traveling control adapted to each individual operator.

[0022] The above is the mowing load control technology conceived for beginners and unskilled operators that was developed earlier by the applicant using electronically controlled HST. This control is by no means a uniform one intended solely by designers; as beginners and unskilled operators perform more work and become accustomed to operation, it accommodates—depending on the individual—gradually increasing the engine speed and traveling speed, that is, it also accommodates increasing skill levels. Since the control unit 9 sequentially reads the operator's set values at the start of each work as described above, this also provides mowing load control adapted to the operator's skill level.

[0023] As described above, the present invention has realized a mowing load control technology for beginners and unskilled operators that adapts to each individual's inherent characteristics including kinesthetic sense, physical condition, personality, preferences, and habits. Although various technologies have been attempted in the past, this is the first time that the original purpose of mowing load control—truly assisting and supporting the operator—has been achieved. This not only improves the safety and stability of mowing work, but also contributes to improving the operator's skill level. [Industrial Applicability]

[0024] The present invention can be used in all small and medium-sized riding work machines, such as small and medium-sized riding agricultural machinery and civil engineering construction machinery, for which traveling speed control is effective for adjusting work load. [Brief Description of the Drawings]

[0025] [Figure 1] FIG. 1 is a left perspective view of a wheel-type mower showing the first embodiment of the present application. [Figure 2]These are a left side view and a top view of a wheeled lawnmower showing the first embodiment of the present invention. [Figure 3] This is a plan perspective view showing the travel drive mechanism of the first embodiment of the present application. [Figure 4] This figure shows the HST motor control mechanism of the first embodiment of the present application. [Figure 5] This figure shows the HST lever mechanism of the first embodiment of the present application. [Figure 6] This figure shows the engine throttle lever mechanism of the first embodiment of the present application. [Figure 7] This figure shows the engine speed detection method of the first embodiment of the present application. [Figure 8] This figure shows the control block and control chart of the first embodiment of the present application. [Figure 9] This is an illustrative diagram showing the problems that the Smart Cruise invention aims to solve. [Explanation of Symbols]

[0026] 1 Reaping section 2 engines 3. Steering Wheel 4. Drive transmission 5 HST 6 Front wheels 7 Rear wheel 8 batteries 9 Control Unit 21 Throttle lever 22 Throttle cable 23 Rectifier 211 Throttle lever arm 212 Connecting Rods 213 Sensor Arm c 51 HST Lever 52 HST adjustment axis 53 Adjustable shaft motor 54 Brake pedal 511 HST Lever Arm 512 Link Rod 513 Sensor Arm a 514 Pulley & Pulley Brake 521 Adjustable shaft arm 522 Adjustable shaft link 523 Sensor Arm b 531 Motor Arm S1 HST lever rotation sensor S2 HST Adjustment Shaft Rotation Sensor S3 Throttle lever rotation sensor

Claims

[Claim 1] A small riding lawnmower equipped with an engine or motor, having a pair of steering front wheels and drive rear wheels or drive front wheels or drive front and rear wheels or drive tracks, and a cutting unit located in the center or front of the machine body, using an HST (Hydro Static Transmission) as the driving transmission mechanism, an actuator connected to the swashplate adjustment shaft (trunnion shaft) on the hydraulic pump side of the HST, and the rotation adjustment is controlled by the rotational speed or stroke speed of the actuator, a means for detecting the lever rotation position using a rotation sensor is provided in the HST lever mechanism or HST foot pedal mechanism, and further a means for detecting the swashplate adjustment shaft rotation position using a rotation sensor is provided in the rotation drive mechanism of the swashplate adjustment shaft by the actuator, and the rotation adjustment is controlled by the rotational speed or stroke speed of the actuator by a control unit so that the swashplate adjustment shaft position is at a speed corresponding to the rotation position of the HST lever or HST foot pedal, in an electronically controlled HST, This small riding lawnmower is equipped with a rotation sensor to detect the rotation position of the lever or pedal in the HST lever mechanism or HST foot pedal mechanism, and a rotation sensor to detect the rotation position of the lever in the throttle lever mechanism. The control unit reads the engine speed set by the operator during mowing, i.e., the throttle lever rotation position, and the working travel speed, i.e., the HST lever rotation position or HST foot pedal rotation position, each time the operation is performed. When the engine speed decreases due to increased mowing load, the HST is controlled to immediately return to the set engine speed, thereby controlling the speed. In other words, it provides assistance tailored to each operator, enabling AI control of the mowing load according to each operator's unique abilities such as motor skills, physical condition, personality, preferences, and habits, allowing each operator to cruise smoothly during operation.

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