JP2005095071A - Lawn mower - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lawn mower designed to inform a relevant operator of the result of detecting that a grass bag is full without installing any exclusive sensor, thus preventing trouble such as an engine stall despite being of miniature and inexpensive type. <P>SOLUTION: The lawn mower works as follows: The engine output, more specifically the OPrate is estimated based on engine target rotation rate NED and throttle opening θTH (S12), and when the estimated OPrate exceeds a specified value( 80% ), it is judged that the grass bag is full with cut grass (S14), and at the same time, an operator is informed of the judgement by lighting a relevant information lamp (S20). <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a lawn mower.

  Generally, a lawn mower is equipped with a grass bag, and the lawn mowing blade is collected there. When the grass bag is full of cut grass, rotational resistance is generated in the blade, and the load on the engine that drives the blade increases. For this reason, in a lawnmower in which the engine speed is adjusted by a mechanical governor, the engine speed decreases, and the operator can know that the glass bag is full.

  On the other hand, in a lawn mower equipped with a so-called electronic governor that adjusts the engine speed by opening and closing the throttle valve with an actuator, the throttle is opened so as to maintain the target speed even when the engine load increases. Since the engine speed is adjusted, the engine speed does not decrease, and the operator cannot know that the glass bag is full. If the operation is continued while the glass bag is full, an excessive load is applied to the engine, resulting in a problem such as stalling or clogged grass between the blade and the housing that houses the blade.

Therefore, for example, in the technique described in Patent Document 1, an optical sensor is attached in the vicinity of the opening of the glass back, and it is determined that the glass back is full when the vicinity of the opening is shielded by the collected grass. The operator is informed by a buzzer or a lamp. The lawn mower according to Patent Document 1 is a riding lawn mower.
Japanese Patent Laid-Open No. 5-76232

  However, when a dedicated sensor for detecting that the glass bag is full as described above is provided, there is a problem that a space for mounting the sensor is required and the cost increases. In particular, in a non-ride type lawn mower that is required to be small and inexpensive, such a problem is remarkable and it is difficult to provide a dedicated sensor.

  Accordingly, an object of the present invention is to solve the above-mentioned problems, and without detecting a dedicated sensor, it detects that the glass bag is full and notifies the operator, so that the engine stall is achieved while being small and inexpensive. The purpose of the present invention is to provide a lawnmower that prevents the occurrence of problems such as these.

  In order to solve the above-described object, according to claim 1, an actuator for opening and closing an engine throttle valve mounted on a lawn mower is provided so that the engine speed becomes a preset target speed. In a lawn mower that controls the driving of the actuator and collects on a grass bag mounted with grass cut by a blade driven by the engine, throttle opening detecting means for detecting the opening of the throttle valve; Engine output estimating means for estimating the output of the engine based on the detected throttle opening and the target rotational speed, and determining that the glass back is full when the estimated engine output exceeds a predetermined value A glass back full judging means for notifying the operator when it is judged that the glass back is full It was configured with and.

  According to a second aspect of the present invention, the notifying means is composed of a display device, and the display device is arranged at a site that falls within the field of view when the worker is performing lawn mowing work.

  In the lawn mower according to claim 1, the throttle opening detecting means for detecting the opening of the throttle valve, and the engine output for estimating the output of the engine based on the detected throttle opening and the target rotational speed. An estimation means, a glass back full determination means for determining that the glass back is full when the estimated engine output exceeds a predetermined value, and an operator when the glass back is determined to be full The notification means for notifying is provided, so that it is possible to detect that the glass back is full and notify the operator without providing a dedicated sensor, and thus the engine is small and inexpensive. It is possible to prevent problems such as stalls.

  Further, in the lawn mower according to claim 2, the notifying means is composed of a display device, and the display device is arranged at a site that falls within the field of view when the worker is performing the lawn mowing work. In addition to the above-described effects, the operator can surely recognize that the glass bag is full, and thus can more effectively prevent problems such as engine stall. . In addition, since the operator can recognize that the glass bag is full without taking his eyes off the cutting position, workability can be improved.

  The best mode for carrying out the lawn mower according to the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 is a plan view of a lawnmower according to this embodiment. FIG. 2 is a side view of the lawn mower shown in FIG.

  1 and 2, reference numeral 10 denotes a lawn mower. The lawn mower 10 is a non-ride type self-propelled lawn mower provided with a total of four wheels, two front wheels 12F and two rear wheels 12R, and a handle bar 14. An engine 18 is mounted inside the engine cover 16 on the frame supported by the four wheels 12F and 12R. The engine 18 includes a recoil starter 20 and is manually started by an operator. A lamp unit 22 is disposed on the engine cover 16. As shown in FIG. 1, the lamp unit 22 includes a pilot lamp 22a and a glass back full notification lamp 22b.

  As shown in FIG. 2, the crankshaft 18 </ b> S of the engine 18 is connected to the rear wheel drive shaft 26 via the belt 24. The rear wheel drive shaft 26 is connected to the rear wheel 12R via a gear mechanism 28. A rear-wheel electromagnetic clutch 30 is disposed in the middle of the rear-wheel drive shaft 26 to intermittently transmit engine output to the rear wheels 12R.

  A lawn mowing blade 32 is attached to the tip of the crankshaft 18S. The blade 32 is a rotary blade having a substantially circular shape in plan view. Further, a blade electromagnetic clutch 34 is disposed between the blade 32 and the belt 24 in the crankshaft 18 </ b> S, and transmission of engine output to the blade 32 is interrupted.

  As shown in FIGS. 1 and 2, a glass back 36 is mounted on the rear portion of the lawn mower 10. The grass cut by the blade 32 is collected in the glass bag 36 by the action of the swirling flow generated by the rotation of the blade 32.

  A travel lever 38 is attached near the tip of the handlebar 14 described above. The travel lever 38 is rotatable around a shaft 38S (shown in FIG. 2). A travel switch 40 is disposed in the vicinity of the shaft 38S, and outputs an ON signal when the travel lever 38 is tilted forward in the traveling direction of the lawn mower 10 by an operator. A blade switch 42 is disposed on the travel lever 38. The blade switch 42 outputs an ON signal when pressed once by an operator, and ends the output of the ON signal when pressed again.

  FIG. 3 is an explanatory sectional view of the engine 18.

  The engine 18 includes one cylinder (cylinder) 46, and a piston 48 is accommodated therein so as to freely reciprocate. A combustion chamber 50 is formed between the head of the piston 48 and the cylinder wall surface, and an intake valve 52 and an exhaust valve 54 are disposed on the cylinder wall surface, and a space between the combustion chamber 50 and the intake path 56 or the exhaust path 58 is provided. Open and close. The engine 18 is specifically an air-cooled four-cycle single-cylinder OHV type internal combustion engine and has a displacement of 163 cc.

  The piston 48 is connected to the crankshaft 18S, and the crankshaft 18S is connected to the camshaft 60 through a gear. A flywheel 62 is attached to one end of the crankshaft 18 </ b> S, and the recoil starter 20 is attached to the front end side of the flywheel 62. Although not shown, the blade 32 is attached to the other end of the crankshaft 18S via the blade electromagnetic clutch 34 described above.

  A power generation coil (alternator) 64 is disposed inside the flywheel 62 to generate an alternating current. The alternating current generated by the power generation coil 64 is converted into direct current through a processing circuit (not shown), and then supplied as an operating power source to an ECU (described later), an ignition circuit (not shown), or the like.

  A throttle body 68 is disposed upstream of the intake passage 56. A throttle valve 70 is accommodated in the throttle body 68, and the throttle valve 70 is connected to an electric motor 72 (actuator, specifically, a stepping motor) via a throttle shaft and a reduction gear mechanism (both not shown). Further, a carburetor assembly (not shown) is provided on the upstream side of the throttle valve 70 in the throttle body 68. The carburetor assembly is connected to a fuel tank (indicated by reference numeral 76 in FIGS. 1 and 2), and injects gasoline fuel into the intake air in accordance with the opening degree of the throttle valve 70 to generate an air-fuel mixture. The generated air-fuel mixture is sucked into the combustion chamber 50 of the cylinder 46 through the throttle valve 70, the intake passage 56 and the intake valve 52.

  A throttle opening sensor 78 is disposed near the electric motor 72 and outputs a signal corresponding to the opening θTH of the throttle valve 70 (hereinafter referred to as “throttle opening”). A crank angle sensor 80 made of an electromagnetic pickup is disposed near the flywheel 64 and outputs a pulse signal at every predetermined crank angle.

  FIG. 4 is a block diagram schematically showing the operation of the lawn mower 10.

  As shown in FIG. 4, the outputs of the throttle opening sensor 78 and the crank angle sensor 80 are input to an ECU (electronic control unit) 82. The ECU 82 includes a microcomputer including a CPU, a ROM, a RAM, and a counter, and is disposed at an appropriate position of the lawn mower 10 as shown in FIG.

  The ECU 82 counts the output pulses of the crank angle sensor 80 and detects (calculates) the engine speed NE. The ECU 82 calculates an energization command value for the electric motor 72 based on the detected engine speed NE and the throttle opening θTH so that the engine speed NE matches the preset target speed NED, and The calculated energization command value is output to the electric motor 72 to control its drive.

  Further, a traveling instruction (ON signal) from the operator is input to the ECU 82 via the traveling switch 40, and a blade driving instruction (ON signal) from the operator is input via the blade switch 42. When a traveling instruction is input from the operator, the ECU 82 connects the rear wheel electromagnetic clutch 30 to transmit the rotational output of the engine 18 to the rear wheel 12R, thereby causing the lawnmower 10 to self-run. Further, when a blade driving instruction is input from an operator, the ECU 82 connects the blade electromagnetic clutch 34 to transmit the rotation output of the engine 18 to the blade 32, thereby rotating the blade 32 (making lawn mowing possible). ).

  Thus, the lawnmower 10 according to this embodiment opens and closes the throttle valve 70 by the electronically controlled throttle device (electronic governor) including the throttle body 68, the ECU 82, and various sensors, and the intake air amount of the engine 18 is increased. Is adjusted so that the engine speed NE becomes the target speed NED. Further, the rotational output of the engine 18 is transmitted to the rear wheel 12R via the rear wheel electromagnetic clutch 30, and the rear wheel 12R is driven to self-run, and the engine rotational output is transmitted to the blade via the blade electromagnetic clutch 34. 32, and the blade 32 is driven.

  Further, the ECU 82 lights a pilot lamp 22a indicating whether or not the lawnmower 10 is operating normally based on various inputs, and the glass back based on the detected throttle opening θTH and the target engine speed NED. It is determined whether or not 36 is full. When it is determined that 36 is full, the glass pack full notification lamp 22b is turned on.

  Next, the glass pack full detection operation of the lawn mower according to this embodiment will be described with reference to FIGS. FIG. 5 is a flowchart showing the operation. The illustrated program is executed in the ECU 82 every predetermined cycle (for example, 20 msec).

  Before continuing the description of the flowchart of FIG. 5, the outline of the operation will be described first. As described in the prior art, when the grass bag 36 is filled with the cut grass, rotational resistance is generated in the blade 32 that feeds the grass and the swirling flow (air) to the grass bag 36, and the load on the engine 18 increases. Accordingly, the throttle valve 70 is opened to maintain the target rotational speed NED, and the output of the engine 18 increases. Therefore, in this embodiment, the output OP of the engine 18 is estimated based on the target rotational speed NED and the throttle opening θTH, and it is determined whether or not the glass back 36 is full based on the estimated engine output OP. In addition, when it is determined that the glass back 36 is full, the glass back full notification lamp 22b is turned on to notify the operator.

  The output judgment method of the engine 18 will be specifically described. As shown in FIG. 6, the fully open output (100%) when the engine speed NE is the target speed NED (in this embodiment, 2900 rpm). ) Set the output lower by a predetermined rate than the full judgment point. In this embodiment, 80% of the fully open output (output generation rate 80%) is set as a full judgment point.

  FIG. 7 is a graph showing a characteristic of the throttle opening degree θTH with respect to the output occurrence rate OPrate when the engine speed NE is the target speed NED (2900 rpm). By searching the graph (map) shown in FIG. 7 based on the throttle opening θTH, the output generation rate OPrate (generally, the engine output OP) can be estimated, and the estimated output generation rate OPrate is It can be determined whether or not the full determination point (output occurrence rate 80%) is exceeded.

  The flow chart of FIG. 5 will be described based on the above. First, in S10, the throttle opening θTH is detected. In S12, the graph (map) shown in FIG. 7 is searched based on the throttle opening θTH, and the engine output OP, specifically, the output occurrence rate OPrate is estimated.

  Next, in S14, it is determined whether or not the estimated output occurrence rate OPrate exceeds 80%, that is, whether or not the glass bag 36 is full. When the result in S14 is negative and it is determined that the glass back 36 is not full, the process proceeds to S16 and the glass back full notification lamp 22b is turned off.

  On the other hand, when the result in S14 is affirmative and it is determined that the glass back 36 is full, the process then proceeds to S18 to determine whether or not the glass back 36 is continuously determined to be full for a predetermined time t1. . When this determination is affirmative in S14 (when it is determined that the glass back 36 is full), the counter is started by another program (not shown), and the count value reaches a predetermined time t1 (for example, 1 sec). This is done by checking whether or not.

  When the result in S18 is affirmative, the program proceeds to S20, and the glass back full notification lamp 22b is turned on to notify the operator. That is, the operator is prompted to interrupt the lawn mowing work and to process (remove) the lawn collected in the grass bag 36.

  On the other hand, when the result in S18 is negative, the glass back full notification lamp 22b is turned off in S16. This is because even if there is a temporary increase in the engine output OP (incidental increase due to fuel accumulation, etc.), this is mistaken as an increase in engine output (glassback 36 is full). This is to prevent the determination.

  Thus, in this embodiment, the engine output OP, more specifically, the output occurrence rate OPrate is estimated based on the target rotational speed NED of the engine 18 and the throttle opening θTH, and the estimated value is calculated. When the output occurrence rate OPrate exceeds a predetermined value (80%), it is determined that the grass back 36 is full of the cut grass, and when it is determined that the grass back 36 is full, the glass back full notification lamp 22b. Since it is configured so as to notify the worker by lighting up, it is possible to detect that the glass back 36 is full without providing a dedicated sensor, and to notify the worker, so that it is small and inexpensive. However, it is possible to prevent problems such as stalling of the engine 18 and clogging of the cut grass between the blade 32 and the housing that houses it. Yes.

  Further, since the glass back 36 is determined to be full when the estimated output occurrence rate OPrate exceeds a predetermined value (80%) for a predetermined time t1, the engine output is temporarily increased ( Unnecessary notification due to accidental rise due to fuel accumulation or the like can be prevented.

  Further, the glass back full notification lamp 22b is arranged on the upper portion of the engine cover 16. More specifically, as shown in FIG. Since it is configured to be placed in a part that enters the field of view (indicated by an angle α) when the lawn mowing operation is performed, the glass back 36 is shown. Can be surely recognized by the operator that the engine is full, and problems such as engine stall can be more effectively prevented. In addition, since the operator can recognize that the glass back 36 is full without taking his eyes off the cutting position, workability can be improved.

  As described above, in the first embodiment of the present invention, the actuator (electric motor 72) for opening and closing the throttle valve (70) of the engine (18) mounted on the lawn mower (10) is provided, and the engine rotation The actuator (72) is controlled so that the number (NE) becomes a preset target rotational speed (NED), and grass cut by the blade (32) driven by the engine (18) is mounted. In the lawn mower (10) collecting in the grass bag (36), the throttle opening detection means for detecting the opening (θTH) of the throttle valve (70) (throttle opening sensor 78, S10 in the flowchart of FIG. 5) And the output (specifically, output generation) of the engine (18) based on the detected throttle opening (θTH) and the target rotational speed (NED). The engine output estimating means (ECU 82, S12 in the flowchart of FIG. 5) for estimating the rate OPrate) and the glass back (36) is full when the estimated engine output (OPrate) exceeds a predetermined value (80%). Glass back full determination means (ECU 82, S14 in the flowchart of FIG. 5) for determining that there is, and notification means (glass back) for notifying the operator (P) when it is determined that the glass back (36) is full. A full notification lamp 22b and S20) in the flowchart of FIG. 5 are provided.

  Further, the notifying means (22b) is composed of a display device (lamp), and the display device is arranged at a part that enters the visual field (α) when the worker (P) is performing the lawn mowing work. Configured.

  In the above description, when it is determined that the glass back 36 is full, the glass back full notification lamp 22b is turned on for visual notification, but a buzzer or the like is sounded for notification by voice. May be.

  Further, the attachment position of the glass back full notification lamp 22b may be near the rearmost part of the frame of the lawn mower 10 as shown in FIGS. 9 and 10, or as shown in FIGS. It may be the end of the handle bar 14 (the end near the worker P). That is, any part of the lawn mower 10 may be placed as long as it is within the field of view at the time of cropping.

  Further, although the stepping motor is used as the actuator for opening and closing the throttle valve 70, other actuators such as a DC motor and a rotary solenoid may be used.

It is a top view of the lawn mower which concerns on 1st Example of this invention. It is a side view of the lawn mower shown in FIG. FIG. 2 is an explanatory sectional view of the engine shown in FIG. 1. It is a block diagram which shows roughly operation | movement of the lawn mower shown in FIG. It is a flowchart of the glass back full detection operation | movement of the lawn mower shown in FIG. It is a graph which shows the characteristic of the engine speed with respect to the output of the engine shown in FIG. 6 is a graph showing the characteristics of the throttle opening with respect to the output occurrence rate estimated by the processing of the flowchart of FIG. It is explanatory drawing which shows the relationship between the arrangement position of the glass back full notification lamp shown in FIG. 1, and an operator's visual field. It is a top view similar to FIG. 1 which shows another example of the arrangement position of the glass back full notification lamp shown in FIG. It is explanatory drawing similar to FIG. 8 which shows the relationship between the arrangement position of the glass back full notification lamp | ramp shown in FIG. 9, and an operator's visual field. It is a top view similar to FIG. 1 which shows another example of the arrangement position of the glass back full notification lamp shown in FIG. It is explanatory drawing similar to FIG. 8 which shows the relationship between the arrangement position of the glass back full notification lamp shown in FIG. 11, and an operator's visual field.

Explanation of symbols

10 Lawn mower 18 Engine 22b Glass back full notification lamp (notification means, display device)
32 Blade 36 Glass back 70 Throttle valve 72 Electric motor (actuator)
78 Throttle opening sensor (throttle opening detecting means)
80 Crank angle sensor (engine speed detection means)
82 ECU (engine output estimating means, glass back full judging means)

Claims (2)

  An actuator for opening and closing the throttle valve of the engine mounted on the lawn mower, and controlling the drive of the actuator so that the engine speed becomes a preset target speed, and a blade driven by the engine In a lawn mower that collects grass cut with a cut grass, throttle opening detection means for detecting the opening of the throttle valve, and the engine based on the detected throttle opening and the target rotational speed Engine output estimating means for estimating the output of the glass back, glass back full judging means for judging that the glass back is full when the estimated engine output exceeds a predetermined value, and judging that the glass back is full Lawn mower characterized by comprising notifying means for notifying an operator when it is done . 2. The lawn according to claim 1, wherein the notifying means comprises a display device, and the display device is arranged at a site that falls within a field of view when the worker is performing lawn mowing work. Mower.

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