JP3652173B2 - Riding lawn mower - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a riding lawn mower equipped with a mower in the front part of a vehicle body. Specifically, the left and right drive includes a continuously variable transmission mechanism that can rotate forward and backward for each left and right drive wheel, and can turn on the spot. The present invention relates to a riding lawn mower configured to steer at a speed difference.
[0002]
[Prior art]
As this type of riding lawn mower, there is one previously proposed in Japanese Patent Application No. 10-248987. It includes a pair of left and right driving rear wheels, a pair of left and right driven steering wheels, and a mower arranged between the front and rear wheels of the driving rear wheels and the steering front wheels, and an HST for each of the left and right rear wheels. It is constructed with a speed difference steering type in which the front wheel follows the steering depending on the speed difference between the left and right rear wheels, and can turn on the spot by reversing the left and right rear wheels forward and backward. is there.
[0003]
[Problems to be solved by the invention]
In the proposed technique, since the radiator is arranged further behind the engine arranged behind the rear wheel, the radiator is the rearmost part in the hood, which is the rearmost end of the vehicle body. Therefore, when performing a pivot turn that turns with one rear wheel as a fulcrum or a small turn such as the in-situ turn described above, the bonnet that protrudes rearward is hit relatively hard against an obstacle such as a wall or a tree. In some cases, the radiator, which is a weak component, is easily damaged.
[0004]
Also, since the engine is generally supported in an anti-vibration manner, the engine and the transmission are structured to be axially transmitted through a pair of universal joints. Relatively arranged at a certain distance. Therefore, although the means for positioning the heavy engine in front of the light radiator is a preferable means for easily concentrating the mass, the bonnet protrudes backward to make it compact. In addition to being difficult, when the engine was increased in size, such as by replacing it with a diesel engine, the bonnet was further enlarged and the balance of the appearance was liable to deteriorate, leaving room for improvement.
[0005]
The present invention is a speed differential riding type lawn mower with a mission and mower in front of the rear wheels and an engine behind, improving the collision resistance at the rear end of the vehicle body when turning, etc., and downsizing the bonnet In addition, the purpose is to realize an improvement in the front-to-back balance.
[0006]
[Means for Solving the Problems]
[Configuration of Claim 1]
According to a first aspect of the present invention, in a riding-type lawn mower, a transmission case including a continuously variable transmission mechanism that is provided with a mower in a fuselage having front steering wheels and a pair of left and right driving rear wheels and capable of rotating forward and reverse is provided. In front of the vehicle axle and in a position overlapping the driving rear wheel in a side view with respect to the fuselage, a driving seat is arranged above the transmission case and in front of the axle of the driving rear wheel, An engine is arranged on the rear side of the axle, and the power of the engine is configured to be transmitted to the continuously variable transmission mechanism provided for each driving rear wheel,
It is characterized in that it is disposed within a space in the front-rear direction between the transmission case and the front portion comprising the driver seat and the engine .
[0007]
[Effects of the structure of claim 1]
According to the structure of Claims 1-5, since the radiator was arrange | positioned at the engine front side, the rearmost end part in a bonnet becomes an engine main body. Therefore, even if a collision occurs to the extent that the rear end of the bonnet is deformed, the excess impact is received by the relatively strong engine body. Unless it is a substantial collision, the bonnet is damaged. However, functional damage such as collapse of the radiator and the engine cylinder does not occur first.
[0008]
As described above, the shaft transmission structure with the universal joint requires a certain amount of longitudinal distance between the engine and the transmission case, so it is possible to place a radiator at the longitudinal distance, The bonnet can be made compact compared to the conventional arrangement where the radiator is placed in front of the engine, such as being able to be arranged at the front and rear positions that are not much different from the conventional ones, or rather downsizing.
[0010]
[Configuration of Claim 2]
A second invention is characterized in that, in the first invention, the radiator is located on or substantially on the axis of the drive wheel.
[0011]
[Operational effects of the configuration of claim 2]
As a transmission means from the engine to the transmission case, the transmission shaft connected to the crankshaft protrudes forward from the engine. However, the above-described proposed technique has a space on the transmission shaft. Therefore, if the radiator disposed at a relatively high position as compared with the engine is disposed on the space, that is, on the shaft of the drive wheel, or substantially on the shaft, the amount of rearward protrusion of the bonnet of the radiator can be shortened. it can.
[0012]
Therefore, as the bonnet rear end position is moved forward, the possibility of collision with the obstacle at the rear end of the bonnet during a small turn is reduced, and even if the engine becomes larger due to diesel or large displacement, the above proposal Compared to technical ones, there is an advantage that the engine can be increased in size without increasing the rearward projecting amount of the bonnet, such as preventing the rearward projecting amount of the bonnet from changing.
[0013]
[Configuration of Claim 3]
The third invention is characterized in that, in the first or second invention, a radiator projected area in the front-rear direction is larger than a projected area in the front-rear direction of the engine.
[0014]
[Effects of the structure of claim 3]
According to the configuration of the third aspect, the size of the cross-sectional shape of the bonnet can be made smaller at the rear part than at the front part of the bonnet. As a result, the front-rear balance and the shape balance are improved. In addition, the heat dissipation area of the radiator can be made sufficiently large, and good engine cooling performance can be obtained.
[0015]
[Composition of Claim 4]
A fourth invention is characterized in that, in the first to third inventions, the driver's seat is arranged on the continuously variable transmission mechanism and at a position near the front of the radiator.
[0016]
[Operational effect of the configuration of claim 4]
According to the configuration of claim 4, the driving seat that is substantially L-shaped in a side view is disposed in front of the radiator and on the continuously variable transmission mechanism, so that the radiator is disposed after the backrest, and The continuously variable transmission mechanisms are located close to each other under the seating section, and a wasteful space can be left or a small number of parts can be centrally arranged, and the driver's seat can be moved closer to the drive wheels in the front-rear direction. In addition, the phenomenon that the driver's seat is swung during a small turn such as turning on the spot can be suppressed.
[0017]
In other words, the driver's seat can be placed close to the turning center, and it can be placed exactly in the space formed by the radiator and continuously variable transmission mechanism. A new body layout can be adopted.
[0018]
[Configuration of Claim 5]
According to a fifth invention, in the first to fourth inventions, the continuously variable transmission mechanism capable of forward / reverse rotation is constituted by HST, an HST fan for cooling the HST is provided, and suction to the HST fan is performed from below the radiator. A partition member is provided for the purpose.
[0019]
[Operational effect of the configuration of claim 5]
By making the continuously variable transmission mechanism capable of forward / reverse rotation HST, acceleration / deceleration and forward / reverse rotation can be performed smoothly, and the cooling air is sucked from the lower part of the radiator, so that the exhaust heat of the radiator is taken into the HST. Can be avoided. That is, there is an advantage that the HST can be efficiently cooled with no or little influence of the exhaust heat of the radiator, although the HST fan and the radiator are arranged relatively close to each other.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 and FIG. 2 show a riding lawn mower in which a mower is arranged mid-mounted on the lower abdomen between the front and rear wheels, 1 is equipped with a pair of left and right follow steering wheels, and 2 is equipped with a pair of left and right Drive rear wheels, 3 is an engine, 4 is a transmission case , 5 is a mower, 6 is a driver's seat, 7 is a lifting link mechanism for hanging the mower 5, and F is a body frame. This lawn mower is provided with an HST (an example of a continuously variable transmission mechanism capable of forward / reverse rotation) 8 for each of the left and right rear wheels 2, 2. It is configured as a speed difference steering type that follows the steering.
[0023]
As shown in FIGS. 7 and 8, the vehicle body frame F includes a rear frame 11 that supports a diesel-type, water-cooled engine 3 and a transmission case 4, and a front frame 12 that suspends the mower 5. An upper frame 13 that supports the driver's seat 6 is connected and integrated with the frame f. The rear frame 11 includes a pair of left and right plate frame members 9, 9, a rear end horizontal frame 14 that connects them at the rear end, and an intermediate horizontal frame 15 that connects the front and rear.
[0024]
The front frame 12 is a front end horizontal frame that connects the square pipe member 10 bent to the front end of the left and right plate frame members 9 and 9 and the left and right front end portions thereof, bent in a front-opening U-shape in plan view. 16. The upper frame 13 straddles a pair of left and right rear vertical frames 18 and 18 erected from the plate frame member 9 in the front and rear direction in the vicinity of the rear axle 17, the front end of the plate frame member 9, and the rear end of the square pipe member 10. A pair of left and right front vertical frames 19, 19 erected in a state, a pair of left and right upper front and rear frames 20, 20 connecting the rear vertical frame 18 and the front vertical frame 19, and the upper horizontal frames 20, 20 are connected. The front and rear upper horizontal frames 21 and 22 are provided.
[0025]
A U-shaped plate bracket 53 facing downward in a side view is fixed to the front side of the front end horizontal frame 16. As shown in FIG. 3, the plate bracket 53 is made of a square pipe having front wheels 1 at the left and right ends. The front wheel support frame 54 is supported by a rolling fulcrum P that coincides with the left-right center C of the vehicle body in the left-right direction so that it can swing left and right. The rolling limit of the front wheels 1 and 1 is determined, for example, by contact between the front wheel support frame 54 and the plate bracket upper surface 53a, and can be freely rolled within a predetermined range. The front wheel 1 is configured as a caster wheel that is supported by a front wheel support frame 54 so as to be rotatable about a vertical rotation axis X via a support bracket 55.
[0026]
The engine 3 is supported by anti-vibration support by rubber mounts or the like at four front and rear, left and right brackets 23 projecting inwardly from the left and right plate frame members 9, and a suction type cooling fan 24 is provided at the front side of the engine 3. Before that, a radiator 25 is arranged. The radiator 25 is supported by a pair of left and right brackets 26 and 26 projecting inwardly from the left and right plate frame members 9. As shown in FIG. 6, the engine 3 and the transmission case 4 are disposed directly below the radiator 25. An interlocking transmission shaft 27 is disposed in the front-rear direction with a pair of universal joints (not shown). Although the radiator 25 is slightly deviated later in a side view, it is mounted at a position almost directly above the rear axle 17. Immediately before the radiator 25, a dustproof net 30 for preventing foreign matter suction is disposed.
[0027]
Since the radiator 25 is at a higher position than the engine 3 and the projected area in the front-rear direction is larger than the projected area in the front-rear direction of the engine 3, the muffler 28 is disposed on the engine 3. Regardless, the bonnet 29 is set in a shape that is rearwardly narrowed in both a plan view and a side view. In this case, the projected area of the engine 3 is that of the engine alone that does not include auxiliary equipment such as the muffler 28 and the fuel injection device (not shown).
[0028]
As shown in FIGS. 3 to 5, the transmission case 4 has a bifurcated shape in which a rear axle case 32 is bolted to both left and right sides of a transmission case 31 to which engine power is input. The mission case 31 is configured by integrally integrating the casing portions 31b and 31b of the HSTs 8 and 8 on the left and right sides of the input unit case 31a, respectively, and has a function of distributing the power input to the input shaft 33 to the left and right HSTs 8 and 8, And a PTO shaft 34 provided to protrude forward for driving the mower 5. The rear axle case 32 transmits the output of the HST 8 to the rear wheel 2 via a gear reduction mechanism (not shown), and the left and right rear axle cases 32, 32 are below the left and right plate frame members 9, 9. The transmission case 4 is mounted and supported on the rear frame 11 by bolting at a location straddling the recessed location.
The transmission case 31 and the driver's seat 6 are collectively referred to as a front part that is located on the front side of the axle of the driving rear wheel.
[0029]
As shown in FIGS. 1 and 2, the driver's seat 6 is mounted and supported on the upper frame 13, the fuel tank 35 is located below the rear wheel fender 50 on the left side, and the rear wheel fender 50 is located on the right side. And a pair of left and right speed change levers 37, 37 are installed upright on the front left and right sides of the driver's seat in a forward / backward swing operation type operated by the left and right hands, respectively. A space is provided between the back surface of the backrest 6a of the driver seat 6 and the front surface of the bonnet 29 so that the cooling air for the radiator can be taken in from the front end of the bonnet 29.
[0030]
On the right side of the driver's seat 6, a PTO clutch on / off lever (not shown) that interrupts power to the mower 5 and a hand accelerator lever (not shown) are provided. A lift lever 40 for moving the mower 5 up and down manually is provided on the right of the front of the driver seat 6, and a parking brake lever 41 is provided on the left side. A driving clutch lever (not shown) is disposed on the rear side of the driver seat 6.
[0031]
As shown in FIG. 6, the elevating link mechanism 7 is provided with a pair of left and right arms 44, 45 that are installed on the front frame 12 and the cutting blade housing 43, and interlocks the left and right rear arms 45, 45. A gear interlocking mechanism 47 that spans the rotation shaft 46 and the operation shaft 40 a of the elevating lever 40 is provided. That is, when the lifting lever 40 is swung upward, the mower 5 is lifted, and when the lifting lever 40 is swung downward, the mower 5 is lowered.
[0032]
As shown in FIG. 5, an HST fan 48 for cooling the HST 8 is provided, and a guide plate (an example of a partition member) 49 for sucking the HST fan 48 from below the radiator 25 is provided. is there. That is, the HST fans 48 for the left and right HSTs 8 and 8 are provided on the input shaft 33 of the mission case 31 , and a guide plate 49 that is lowered from the lower side of the radiator 25 is attached to be sucked from the lower space of the engine 3.
[0033]
That is, the HST 8 cooling air is sucked from the lower side of the engine 3 and the radiator 25 is sucked from the rear of the driver seat 6 and discharged from the rear surface of the hood 29. In addition, the provision of the guide plate 49 prevents mutual interference of exhaust heat.
[0034]
[Another embodiment]
As the continuously variable transmission mechanism 8 capable of forward and reverse rotation, there is a friction type continuously variable transmission mechanism (CVT) using a disk. A combination structure in which the belt continuously variable transmission and the forward / reverse switching mechanism are linked so that they can be operated in an interlocked manner and can be shifted by a single operation of a single lever or the like is also possible.
[Brief description of the drawings]
FIG. 1 is a side view of a riding lawn mower. FIG. 2 is a plan view of a riding lawn mower. FIG. 3 is a plan view showing a configuration of a lower part of a vehicle body. FIG. 5] Side view of a notch showing the structure of the rear part of the vehicle body. [Fig. 6] Enlarged side view of the main part showing the lifting structure of the mower. [Fig. 7] Side view showing the structure of the vehicle body frame. Plan view showing the structure 【Explanation of symbols】
1 Steering front wheel 2 Drive rear wheel 3 Engine 5 Moore 6 Driver's seat 8 Continuously variable transmission mechanism
17 Drive rear wheel axle 25 Radiator
31 Mission case 35 Fuel tank 36 Battery 48 HST fan 49 Partition member

Claims (5)

A transmission case that has a mower in a fuselage including front steering wheels and a pair of left and right drive rear wheels, and that houses a continuously variable transmission mechanism capable of forward and reverse rotation, is located in front of the axle of the drive rear wheels and is viewed from the side. In a position overlapping with the driving rear wheel, a driving seat is arranged in front of the axle of the driving rear wheel above the transmission case , an engine is arranged behind the axle of the driving rear wheel, Configured to transmit engine power to the continuously variable transmission mechanism provided for each driven rear wheel;
A radiator is disposed within a space in the front-rear direction between the engine case and the driver seat and the engine, and the radiator is disposed between the left and right driving rear wheels in plan view with respect to the fuselage. A riding lawn mower.   The riding lawn mower according to claim 1, wherein the radiator is located on or substantially on the axis of the drive wheel.   The riding lawn mower according to claim 1 or 2, wherein a front-rear direction projected area of the radiator is larger than a front-rear direction projected area of the engine.   The riding lawn mower according to any one of claims 1 to 3, wherein the driver's seat is arranged on the continuously variable transmission mechanism capable of forward and reverse rotation and at a position near the front of the radiator.   The continuously variable transmission mechanism capable of forward / reverse rotation is composed of HST, an HST fan for cooling the HST is provided, and a partition member is provided for sucking into the HST fan from below the radiator The riding lawn mower according to any one of claims 1 to 4.

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