JP6863339B2 - Riding lawn mower - Google Patents

Description

The present invention relates to a riding lawn mower equipped with a mower that performs lawn mowing work, and more particularly to dust removal of a dust net of a radiator.

In a riding lawn mower having a radiator fan that sucks in outside air through the radiator's dust net, there is a configuration in which the radiator fan is periodically reversed to blow off the dust stuck in the dust net and ensure that the outside air is introduced (for example, patent). Document 1).

Further, there is a configuration in which a water temperature sensor for detecting the radiator cooling water temperature is provided, and the radiator fan is automatically reversed when the water temperature sensor exceeds the set water temperature while the combine is not working (for example, Patent Document 2).

JP-A-2007-9825 Japanese Unexamined Patent Publication No. 2001-41038

In particular, in Patent Document 2 described above, when the water temperature sensor rises to a preset temperature, the radiator fan is automatically reversed to eliminate clogging of the dust net. It is also premised that it is not working.

Therefore, clogging due to reversal is attempted based on the temperature of the radiator cooling water, and if the cooling water temperature does not rise or fall properly, the reversal is unexpectedly performed, and instead, the radiator fan switching mechanism is used. There is a risk of impairing durability. In addition, there is a problem that consideration is not given to dealing with clogging during normal work.

In view of the above problems, it is an object of the present invention to improve the durability of the electric motor for driving the radiator fan and to effectively remove dust from the dust net.

The present invention has taken the following technical measures to solve the above problems.

The invention according to claim 1 includes an engine 4, a radiator 43, and a radiator fan 44 driven by an electric motor 48. The electric motor 48 is configured to be capable of forward / reverse switching, and the radiator fan 44 is configured in advance. In a riding lawn mower configured to switch to a set forward rotation time ts or a preset reverse rotation time tr.
A water temperature sensor 55 for detecting the cooling water temperature T of the radiator 43 is provided, and when the cooling water temperature T does not reach the preset water temperature T1, the reverse interlocking of the radiator fan 44 is regulated.
The cooling water temperature is detected at predetermined time intervals, and when the water temperature this time is lower than the previously detected water temperature, the counting of the normal rotation time is stopped.
When the current water quality is equal to or higher than the previous detected water temperature, the normal rotation time is counted.
When the forward rotation time accumulated by counting reaches the preset normal rotation time ts, the radiator fan 44 switches to the reverse rotation, and when the preset reverse rotation time tr is reached, the radiator fan 44 switches to the normal rotation.
The invention according to claim 2 comprises a mower 5 for mowing grass grass having a cutting blade 4 in front of the front wheels 2 and 2 of the traveling vehicle body 1 in the invention according to claim 1.
The radiator fan 44 is configured to switch in reverse when the mower 5 is raised by the work equipment elevating position detection sensor 57 that detects the elevating position of the mower 5.
The pre-reverse stop time for stopping the radiator fan 44 for a predetermined time before the normal rotation and the pre-reverse stop time for stopping for a predetermined time before the normal rotation after the reverse rotation are set.
The invention according to claim 3 is the invention according to claim 1 or 2, wherein the cooling water temperature T exceeds a preset overheat warning temperature T2 or exceeds the overheat warning temperature T2 and is preset. An alarm is output when the determination time is reached, and the alarm output is regulated or the warning determination time is extended during the reversal of the radiator fan 44.
The invention according to claim 4 is the invention according to claim 2 or 3, wherein the engine 4 is mounted on the vehicle body 1 in the front-rear direction, and a cooling fan 52 is provided in front of the engine 4.
The radiator 43 and the radiator fan 44 are provided on either the left or right side of the vehicle body 1.
The radiator fan 44 is arranged on the side of the cooling fan 52 in a state where the axis of the fan shaft 45 is orthogonal to the front-rear direction of the vehicle body 1.
The stop time before reverse rotation and the stop time before forward rotation were set differently.
First invention relating to the present invention includes an engine 4, a radiator 43, a radiator fan 44 driven by an electric motor 48, the electric motor 48 is configured to be forward-reverse switching, the radiator fan 44 in advance In a riding lawn mowing machine configured to switch to a set forward rotation time ts or a preset reverse rotation time tr, a water temperature sensor 55 for detecting the cooling water temperature T of the radiator 43 is provided, and the cooling water temperature T is set to a preset water temperature T1. When it does not reach the limit, the reversal interlocking of the radiator fan 44 is regulated.

When the dustproof function of the radiator 43 becomes clogged, the cooling water temperature rises, but when this water temperature does not rise predeterminedly, it is not in the clogged state. Therefore, by restricting the reversal of the radiator fan 44, unnecessary reversing operation is suppressed. it can.

Second invention relating to the present invention, in the first invention relating to the present invention, before the shutdown time reversed for stopping a predetermined time before the forward rotation of the radiator fan 44, a predetermined time is stopped before forward after reverse Set the stop time before normal rotation.

If the rotation direction is suddenly changed without setting the stop time, the load applied to the electric motor 48 becomes large, but by setting the stop time, the load is suppressed and the durability deterioration of the electric motor 48 is suppressed.

Third invention related to the present invention, in the first or second invention relating to the present invention, beyond the coolant temperature T or exceeds the overheat warning temperature T2 previously set the overheat warning temperature T2 and preset When the warning determination time is reached, an alarm is output, and the alarm output is regulated or the warning determination time is extended during the reversal of the radiator fan 44.

With this configuration, the cooling water temperature tends to rise during the reversal of the radiator fan 44, but since the alarm output is regulated or the warning determination time is extended, it is possible to reduce the decrease in work efficiency due to work interruption.

A fourth invention relating to the present invention, in the second or third invention related to the present invention, equipped with an engine 4 to the vehicle body 1, a cooling fan 52 in front of or behind the engine 4, the vehicle body 1 A radiator 43 and a radiator fan 44 were provided on either the left or right side, and the stop time before reverse rotation and the stop time before forward rotation were set differently.

Since the radiator fan 44 is affected by the air blown by the cooling fan 53 of the engine 4 that constantly rotates while the engine 4 is operating, the time required to stop the radiator fan 44 differs between normal rotation and reverse rotation. Therefore, by setting the stop time before reverse rotation and the stop time before forward rotation at different times, it is possible to set appropriate stop times for each.

According to the present invention, it is possible to effectively remove dust from the radiator portion while improving the durability of the electric motor that drives the radiator fan.

It is a side view of a riding lawn mower. It is a left oblique rear perspective view of a riding lawn mower with the collector removed. It is the right oblique rear view view which removed the bumper of the riding lawn mower of FIG. It is a rear view of a riding lawn mower. It is a plan view of a car body. It is a perspective view of a radiator and its vicinity. It is a control block diagram. It is a flowchart. It is a time chart. It is a flowchart. It is a flowchart. It is a flowchart. It is a flowchart.

Hereinafter, embodiments according to the present invention will be described in detail with reference to the drawings.

A side view of the riding lawn mower 1 of this embodiment is shown in FIG.

For turf mowing, the front and rear wheels of the traveling vehicle body 1 are provided with front wheels 2 and 2 and rear wheels 3 and 3, respectively, and a cutting blade 4 is provided below the front portion of the vehicle body 1 and in front of the front wheels 2 and 2. A mower 5 is provided to form a so-called front mower. A steering column 7 is erected on the floor 6 above the front portion of the vehicle body 1, and a steering handle 8 is provided on the upper portion of the column 7. A driver's seat 9 is provided behind the steering wheel 8.

The frame configuration of the vehicle body 1 will be described in detail. From the front side, the traveling transmission (for example, HST) and the mower 5 are driven by receiving the power of the floor frame 10 supporting the floor 6 and the driver's seat 9 and the engine 11. A transmission case 12 that houses the transmission system, a safety guard frame 13 fixed to the upper part of the transmission case 12, a pair of left and right side frames 14L, 14R, etc. that are connected to the lower end of the transmission case 12 and support the engine 11 and the like. Consists of.

The floor frame 10 is formed in a U-shape in a plan view on the front side, and is provided at the front portion to support the column 7 and at the rear portion to support operation boxes such as the driver's seat 9 and various levers. Is connected to the left and right side surfaces 13L and 13R of the safety guard frame 13 in a superposed state. The left and right support columns 15L and 15R of the safety guard 15 are connected to the left and right side surfaces 13L and 13R of the safety guard frame 13, and the upper ends of the left and right support columns 15L and 15R are connected by the head frame 15H. L-shaped case connecting portions 13aL and 13aR are provided on the lower left and right sides of the safety guard frame 13, and are fixedly connected to the upper surface and the rear surface of the transmission case 12 to obtain a strong rigid body structure. ..

The transmission case 12 is a part of the frame structure of the vehicle body 1 as described above, and the transmission endless bands and gears to the front wheels 2 and 2 are installed at the left and right ends of the transmission case 12. The traveling transmission cases 12aL and 12aR are mounted so that they can be transmitted.

The left and right side frames 14L and 14R are connected and fixed to the lower part of the transmission case 12. The side frames 14L and 14R extend rearward, and swash plates 14E and 14E for mounting an engine are formed in the middle of the front and rear portions so that the engine 11 can be supported in a vibration-proof manner. A rear axle case 16 is provided on the rear end side of the side frames 14L and 14R so as to be located above the side frames 14L and 14R. A rear wheel differential mechanism, left and right axles, a reduction gear mechanism, and the like are installed inside the rear axle case 16. The rear ends of the side frames 14L and 14R are connected and fixed by the left and right connecting members 14S.

The upper frame 17 is formed at a position slightly higher than the height of the engine 11, and the upper frame 17 is formed in a U shape in a plan view, and the curved portion is at the rear and the left and right front ends are connected to a nearby frame. Specifically, the front end portion is connected and fixed to a horizontal frame 19 that connects a pair of left and right vertical frames 18L and 18R whose lower end is fixed to the safety guard frame 13 and is vertically erected.

Next, the rear configuration of the frame structure of the vehicle body 1 will be described. Two vertical columns 20L and 20R for reinforcing are provided between the rear ends of the left and right side frames 14L and 14R and the upper frame 17. Ladder-shaped reinforcement is achieved by appropriately fixing and providing a number of horizontal rails 20H and 20H between the upper and lower sides of the vertical columns 20L and 20R.

The pan bar 21 is provided on the horizontal rail 20H arranged at a position slightly higher than the vertical center of the vertical columns 20L and 20R. Further, an air cleaner 31 is arranged inside the rear portion of the vehicle body 1.

As shown in FIG. 1, a collector 32 for accommodating cut grass is provided behind the safety guard 15 and above the upper frame 17 via an elevating mechanism. The elevating mechanism includes a parallel link elevating arm 33 and an elevating cylinder mechanism 34. One end is a collector frame on which the safety guard frames 13L and 13R supporting the safety guard 15 can be mounted, and the other end is a collector frame on which the collector 32 can be placed. It is connected to 35. The grass cut by the mower 5 is accommodated in the collector 32 via the bellows hose 36 and the duct 37 due to the blowing action of the blower (not shown). The duct 37 faces the inlet of the collector 32 so that the outlet of the duct 37 and the inlet of the collector 32 match when descending so as not to interfere with the ascending / descending operation of the collector 32, and the duct 37 can be easily separated from the inlet of the collector 32 when ascending. It is configured.

On the side surface of the vehicle body 1, an engine cover 40 that covers the side surface of the engine 11 is arranged, and a rear cover 41 is provided on the rear side of the vehicle body 1 so as to cover the vicinity of the upper part of the central sheet metal material 22 of the bumper 21. A battery case 42 for accommodating a battery is arranged on the left side surface of the vehicle body 1, and a radiator 43 is arranged on the right side surface of the vehicle body 1.

Next, the radiator 43 and the peripheral structure will be described with reference to FIG. The radiator 43 and the radiator fan 44 are provided on the vehicle body 1 with the fan shaft 45 axis orthogonal to the crankshaft on the front right side of the engine 11 in which the crankshaft (not shown) is arranged in the front-rear direction of the vehicle body 1. The bracket 46 that supports the radiator 43 body is formed in a U shape so as to surround the left and right sides (front and rear sides according to the vehicle body 1 standard) and the bottom, and the upper bracket 47 that connects the left and right bracket portions 46L and 46R is provided on the upper portion to be rigid. It is configured. The radiator 43 is supported by directly or indirectly connecting the left and right bracket portions 46L and 46R and the bracket 46 of the bottom bracket portion 46B to the side frame 14R and the upper frame 17. A shroud 44a of the radiator fan 44 is attached to the bracket 46, and an electric motor 48 capable of forward and reverse rotation is interlocked and connected to the fan shaft 45, and the electric motor 48 is fixed by a support arm 49 protruding from the radiator 43 main body side. doing.

On the outside of the radiator 43, a dustproof cover 50 formed by forming a punching metal or a net body having small small holes based on the bracket 46 and the upper bracket 47 in a box shape is arranged. Due to the normal rotation of the electric motor 48, the radiator fan 44 also rotates forward and sucks in the outside air. The outside air passes through the radiator 43 through the dustproof cover 50 and is introduced into the engine 11 portion inside the vehicle body 1.

In FIG. 5, the power of the engine 11 is transmitted to the HST 51 as a traveling transmission, and the output side rotation of the HST 51 can be changed to high or low by controlling the rotation of the trunnion shaft (not shown). The power of the HST 51 is transmitted to the front wheels 2 and 2 and the rear wheels 3 and 3 so that the vehicle body 1 can be driven. A cooling fan 52 that rotates by the driving force of the engine 11 and air-cools the engine 11 is arranged between the HST 51 and the engine 11. This is a positional relationship in which the radiator 43 is arranged on the side of the cooling fan 52.

Next, forward / reverse switching control by the electric motor 48 of the radiator fan 44 will be described. Operation signals of various switches and levers and detection signals from sensors are input to the controller C, and detection signals by the water temperature sensor 55 that detects the radiator water temperature are periodically input (FIG. 7). In the flowchart of FIG. 8, when the engine 11 of the passenger lawnmower is started, the electric motor 48 starts normal rotation and the radiator fan 44 rotates forward (S101, S102). Subsequently, it is determined whether or not the fan forward / reverse mode is selected, and when this fan forward / reverse mode is selected by turning on the non-figure mode setting switch or the like (S103), the controller C has a preset forward rotation time ts (for example,). 15 minutes) is started (S104), the normal rotation time ts has elapsed (S105), and the cooling water temperature T detected by the water temperature sensor 55 is compared with the preset water temperature T1 (for example, 95 ° C.) and detected. When the cooling water temperature T> the set water temperature T1 (S106), the radiator fan 44 is stopped and controlled (S107). The controller C outputs a reverse rotation switching signal to the electric motor 48, and the radiator fan 44 also reverses (S108). The controller C starts counting the preset reverse rotation time tr (for example, 2 seconds) (S109), and when the forward rotation time ts elapses, the electric motor 48 is stopped and output, and the radiator fan is stopped (S111).

After that, the radiator fan 44 repeats the forward rotation of the ts time and the reverse rotation of the tr time (S113).

As described above, by reversing the radiator fan 44 at regular intervals, the dust clogged in the dustproof cover 50 can be blown outward. The set reversal time tr is set to a very short time so as not to interfere with the radiator water cooling.

If the controller C determines in S106 that the detected cooling water temperature ≤ the set water temperature T1, the controller C returns to S102 and continues the normal rotation of the radiator fan 44. That is, it is presumed that the low detection cooling water temperature T of the water temperature sensor 55 means that the dustproof cover 50 is less clogged, and the stop signal and the reverse rotation command signal are not output to the electric motor 48 and the radiator fan 44. ing. Further, with this configuration, the chance of reversing the radiator fan 44 can be reduced, and the life of the device can be maintained for a long time.

Based on the time chart shown in FIG. 9, a supplementary explanation will be given while comparing with the basic pattern. While the engine 4 is being driven, the radiator fan 44 has a basic pattern of repeatedly executing time tr reversal (reversal 1, reversal 2, reversal 3 ...) every ts of forward rotation time. On the other hand, in the improved pattern 1 showing the embodiment described above, the cooling water temperature is monitored, the reversal command is received only when the set water temperature T1 is exceeded, and the radiator fan 44 can be reversed. In the illustrated example, at the time of reverse rotation 1 in the basic pattern 1, since the cooling water temperature has not reached the set water temperature T1, the reverse rotation command signal is regulated and not output, and the radiator fan 44 continues normal rotation and the next normal rotation. After the time ts, the cooling water temperature exceeds the set water temperature T1, and a reversal command signal is output (improved pattern 1).

Further, FIG. 10 shows an example of calculating the count time of the fan forward rotation time ts for the next reverse rotation command signal output after the reverse rotation command signal is output. Instead of starting the fixed normal rotation time ts immediately after the end of the reverse rotation as in the basic pattern and the improved pattern 1, the change in the cooling water temperature should be monitored to calculate the appropriate normal rotation time ts, that is, the reverse rotation of the radiator fan next time. By properly timing the command output and unnecessarily outputting the reverse command, the durability of the device is not impaired. When the fan forward / reverse switching control mode is selected and the reverse rotation time tr set in the reverse rotation state of the radiator fan 44 elapses during control execution (S201, 202) (S203, 204), the count of the reverse rotation time tr is stopped. , The reverse direction command output is also stopped (S205). Since the fan forward / reverse switching control is being executed, the radiator fan 44 switches to forward rotation, and the forward rotation time ts count is immediately started (S206). Here, the state of the cooling water temperature T is analyzed, and when the cooling water temperature T tends to decrease, the counting of the normal rotation time ts is stopped or interrupted (S207, 208). In the determination of the decreasing tendency in S207, the cooling water temperature is detected at predetermined short-time intervals, and it is determined that the cooling water temperature is decreasing when the water temperature of this time is lower than the previously detected water temperature. It is determined that there is no such thing. If there is no downward trend, the normal rotation time ts is continuously counted. The determination of S207 may be configured to always determine during the normal rotation of the radiator fan 44, and the determination target is various such that only the time when the radiator fan 44 is switched to the normal rotation is set as the determination target. Further, the decreasing tendency may be determined by observing the change in a long span comparing the water temperature at the time of the previous normal rotation switching and the current normal rotation switching. The count time is accumulated following S208 or S209, and when the cumulative count time exceeds the set ts (S210, S211), the radiator fan 44 is allowed to switch from forward rotation to reverse rotation (S212). Therefore, when the cooling water temperature shows a decreasing tendency, it is presumed that the cooling water circulation by the radiator 43 is properly performed, and by determining this decreasing tendency, the reverse operation of the radiator fan 44 can be postponed. As a result, the operation of the reversing mechanism of the radiator fan 44 is reduced, so that the durability of the device is not unnecessarily reduced.

In the time chart of FIG. 9, after switching from the radiator fan 44 reversal to the normal rotation of the improved pattern 1, when the decreasing tendency of the detected cooling water temperature is judged, the decreasing tendency occurs for a certain period (td). A reverse command of the radiator fan 44 is issued with a delay of dt (improved pattern 2).

During the selection of the fan forward / reverse switching control mode (S301), the load operation state may be taken into consideration (FIG. 11). That is, the load operation state is determined (S302), and when it is determined that the load operation state is determined, the fan forward / reverse switching control mode is executed (S303). Is executed (S304). Here, the means for determining the load operation state may be as follows.

That is, the load operation state is determined by the ON detection of the mower drive PTO switch 56 connected to the controller C and the Moor 5 descent detection by the work equipment elevating position detection sensor 57. Further, when the actual engine speed is the so-called rated speed state or a state close to the rated speed state, it can be determined as the load operation state. The controller C determines the difference between the engine set rotation speed and the actual engine rotation speed at the throttle operation position based on the actual engine speed from the engine rotation sensor 58 and the operation position of the throttle lever position sensor 59. If it is within the range of, the radiator fan 44 may be operated.

Next, the overheat warning based on the control of the cooling water temperature T will be described with reference to the flowchart of FIG. When the fan forward / reverse switching control mode is selected and the control is being executed (S401, 402), the cooling water temperature T exceeds the overheat warning temperature T2 and this state continues for a predetermined time (S403), an alarm is output. By the way, since the cooling water temperature tends to rise when the radiator fan 44 is in reverse rotation, the judgment of the alarm output is different from that in the normal rotation state of the radiator fan 44, and the warning judgment is made during reverse rotation. The time is set to be slightly longer than the standard time (S405, 406), and is set to the standard time during normal rotation (S406). Then, when each of these set times elapses, an alarm is output from the horn or the like (S407, 408). The alarm output may be turned off instead of the extension setting.

Further, in the configuration shown in FIG. 13, the mower work machine is raised due to a change of direction, release of grass, etc. during the moor work, and this timing is used to reverse the radiator fan 44. With this configuration, the radiator fan 44 is always in the normal rotation state during the work of lowering the moor, so that the radiator fan 44 does not reverse to the engine load state, so that the radiator 43 cooling effect is good. Keep in.

When shifting from the forward rotation to the reverse rotation of the radiator fan 44 in the above embodiment, the forward rotation output, the stop output, and the reverse rotation output are sequentially output to the electric motor 48. Further, when returning from the reverse rotation to the normal rotation, the stop output and the forward rotation output are sequentially output to the electric motor 48. Then, the stop time before reverse rotation due to the stop output after the forward rotation output is set to, for example, 8 seconds, the subsequent reverse rotation output time is set to 2 seconds, and the stop time before forward rotation due to the subsequent stop output is set to about 10 seconds, and the normal rotation output is set again. Transition. The reason for making a difference between the stop time before reverse rotation and the stop time before forward rotation due to the stop output is that the engine 4 cooling fan 52 exists in the vicinity of the radiator fan 44, and the influence of the cooling fan 52 affects the stop of the radiator fan 44. To do. The stop time before reverse rotation, the output time before reverse rotation, and the stop time before normal rotation may be configured so that the set times can be arbitrarily changed and adjusted.

In this way, by setting the pre-reverse stop time for stopping the electric motor 48 interlocking with the radiator fan 44 for a predetermined time before the reverse rotation and the pre-reverse stop time for stopping for a predetermined time before the normal rotation after the reverse rotation, the rotation is performed. When the direction is suddenly changed, the load applied to the electric motor 48 becomes large. Therefore, by stopping for a predetermined time before changing the rotation direction, the load applied to the electric motor 48 can be suppressed and the deterioration of the electric motor 48 can be suppressed.

Further, since the radiator fan 44 is affected by the air blown by the cooling fan that constantly rotates while the engine 1 is operating, the time required for stopping differs between the normal rotation and the reverse rotation. Therefore, by setting different times for the stop time before reverse rotation and the stop time before forward rotation, it is possible to set appropriate stop times for each.

4 Engine 43 Radiator 44 Radiator fan 48 Electric motor 52 Cooling fan 55 Water temperature sensor T Cooling water temperature T1 Set water temperature T2 Overheat warning temperature

Claims (4)

The engine (4), the radiator (43), and the radiator fan (44) driven by the electric motor (48) are provided, and the electric motor (48) is configured to be switchable between forward and reverse, and the radiator fan (44) is configured to be switchable. ) Is a riding lawn mower configured to switch to a preset forward rotation time (ts) or a preset reverse rotation time (tr).
A water temperature sensor (55) for detecting the cooling water temperature (T) of the radiator (43) is provided, and when the cooling water temperature (T) does not reach the preset water temperature (T1), the radiator fan (44) has a water temperature sensor (T1). It has a configuration that regulates reverse interlocking ,
The cooling water temperature is detected at predetermined time intervals, and when the water temperature this time is lower than the previously detected water temperature, the counting of the normal rotation time is stopped.
When the current water quality is equal to or higher than the previous detected water temperature, the normal rotation time is counted.
When the forward rotation time accumulated by counting reaches the preset normal rotation time (ts), the radiator fan (44) switches to the reverse rotation, and when the preset reverse rotation time (tr) is reached, the riding lawn mower switches to the normal rotation. Machine. A mower (5) for mowing grass with a cutting blade (4) in front of the front wheels (2, 2) of the traveling vehicle body (1) is provided.
The radiator fan (44) is configured to switch in reverse when the mower (5) is raised by the work equipment elevating position detection sensor (57) that detects the elevating position of the mower (5).
The riding lawnmower according to claim 1, wherein a pre-reverse stop time for stopping the radiator fan (44) for a predetermined time before the normal rotation and a pre-reverse stop time for stopping for a predetermined time before the normal rotation after the reverse rotation are set. The radiator fan (44) is configured to output an alarm when the cooling water temperature (T) exceeds the preset overheat warning temperature (T2) or exceeds the overheat warning temperature (T2) and reaches the preset warning determination time. The riding lawn mower according to claim 1 or 2, wherein the alarm output is regulated or the warning determination time is extended during the reversal of). The engine (4) is mounted on the vehicle body (1) in the front-rear direction, and a cooling fan (52) is provided in front of the engine (4).
The radiator (43) and the radiator fan (44) are provided on either the left or right side of the vehicle body (1).
The radiator fan (44) is arranged on the side of the cooling fan (52) in a state where the axis of the fan shaft (45) is orthogonal to the front-rear direction of the vehicle body (1).
The riding lawn mower according to claim 2 or 3, wherein the stop time before reverse rotation and the stop time before forward rotation are set differently.

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