JPH0644845B2 - Front mount mower drive steering device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a drive steering device for a front mount mower.

(Prior Art) In a front mount mower having a mower in front of a vehicle body, conventionally, a so-called Ackermann type steering system in which four front and rear wheels are drive wheels and left and right rear wheels can be steered around a kingpin There are things that take.

(Problems to be solved by the invention) With this type of vehicle, the turning radius at the time of turning becomes large despite steering with the rear wheels, and when cutting the grass around the standing tree, the work is There was a drawback that made it difficult. Further, since the front and rear wheels are used as the driving wheels, there is a drawback in that when the vehicle turns, slippage occurs on the rear wheel side by the turning radius difference between the front and rear wheels, thereby damaging the lawn or the like.

In view of these problems, the present invention has an object to improve turning performance by enabling turning with a small radius without causing wheel slippage or the like.

(Means for Solving the Problems) As a means for solving the problem, the present invention provides a vehicle body 1 having a pair of left and right front wheels 6 and 9 at the front and rear portions thereof, and a mower 70 at the front thereof, within the width of the left and right front wheels 6. The engine 3 is arranged between the front and rear wheels 6, 9 and closer to the front wheel 6, and the pair of left and right rear wheels 9 is connected to the rear wheel.
It is arranged at the rear end of the vehicle body 1 so that it can be steered about the center of the vertical axis in the center of the 9 and the front wheel 6 idles and the rear wheel 9 is driven when turning.

(Operation) When the rear wheels 9 are steered during turning, the front axle 5 and the rear axle 8
It is possible to turn with the intersection on the extension line of and as the turning center O. At this time, if the steering angle is large, the turning radius between the front wheel 6 and the rear wheel 9 is large, but the front wheel 6 is idling and the rear wheel 9
Since only the front wheel 6 is driven, there is no slippage on the front wheel 6 side due to the difference in radius, and smooth turning is possible.

When the rear wheels 9 are steered to near 90 degrees, the left and right front wheels 6 rotate in opposite directions because the rear wheels 9 move laterally, and the center portion between the left and right front wheels 6 turns as O '. it can.

(Embodiment) The present invention will be described in detail below with reference to the embodiments of the drawings.
1 to 3, a vehicle body 1 is a member 2 such as a square tubular member.
Is assembled into a rectangular frame shape. The vehicle body 1 includes an engine 3 and a hydrostatic transmission 4 arranged side by side in the center of the front and rear, and a pair of left and right front wheels 6 through a front axle 5 in the front.
Is rotatably suspended, and a pair of left and right rear wheels 9 are suspended at the rear via a rear axle 8 of a rear wheel drive device 7. The engine 3 is supported by the vehicle body 1 through a vibration isolator, and a crankshaft 10 protruding forward from the engine 3 is provided with a traveling pulley 11 and a PTO pulley 12. In addition,
Behind the engine 3, a radiator 13, a cooling fan 14,
An oil cooler 15 is arranged.

The transmission 4 is supported by the vehicle body 1 via a vibration-proof material, and the input shaft 16 protruding forward from the transmission 4 has a belt.
A pulley 18 that interlocks with a traveling pulley 11 of the crankshaft 10 via 17 and a cooling fan 19 that blows air to the transmission 4 are provided. As shown in FIG. 4, on the rear side of the transmission 4, a transmission case 24 having an output shaft 20 and a transmission shaft 23 that is interlocked via gears 21 and 22 is mounted. Is parallel to the output shaft 20 and protrudes rearward from the transmission case 24.

Reference numeral 25 denotes a front PTO shaft, which is rotatably supported by a bearing case 26 attached to the lower front end of the vehicle body 1 so as to be located below the front axle 5 on the front side of the transmission 4. The shaft 25 is interlocked with the PTO pulley 12 via a pulley 27 and a belt 28.

The rear wheel drive device 7 is supported by a frame-shaped rear frame 29 that projects rearward from the rear end of the vehicle body 1. As shown in FIGS. 4 and 5, the rear wheel drive device 7 is constructed by incorporating a gear transmission mechanism in an upper case 30, an inner cylinder 31, an outer cylinder 32 and a lower case 33. The upper case 30 is attached to the rear frame 29 via a pair of left and right mounting portions 34. The upper case 30 has an input shaft 35, a bevel pinion shaft 36, and a bevel gear that links these.
37,38 are assembled. The input shaft 35 is projected from the upper case 30 diagonally forward in the left-right direction, and is connected to the transmission shaft 23 via a universal joint 39 at the front end.

The bevel pinion shaft 36 is provided in the up-down direction, and an inner cylinder 31 is attached to the lower side of the upper case 30 concentrically with the bevel pinion shaft 36 by a bolt 40 so as to project downward. The inner cylinder 31 has a large diameter portion 41 and a small diameter portion 42 vertically, and a bevel gear 38 is rotatably supported on the upper end of the large diameter portion 41 via a bearing 43A. The outer cylinder 32 is a bush 43 on the inner cylinder 31,
It is rotatably fitted through a bearing 44 and the like, and is retained by a retaining ring 45 at the lower end of the inner cylinder 31 so that it cannot be pulled out downward. The lower case 33 incorporates a rear wheel differential device 46, is attached to the lower end of the outer cylinder 32 with bolts 47, and bearing cases 48 are attached to the left and right sides of the lower case 33 with bolts. The rear wheel differential device 46 is supported by a bearing case 48 via a bearing 49, and its bevel gear 50 is engaged with the bevel pinion 51 at the lower end of the bevel pinion shaft 36. Rear axle 8 protruding left and right from the rear wheel differential device 46
Is supported by a bearing case 48 via a bearing 52, and a rear wheel 9 is attached to an outer end of the rear axle case 48. The rear wheels 9 are provided in the vicinity of the lower case 33 so that the bearing case 48 fits substantially inside the tire rim 53.The tread between the left and right rear wheels 9 is approximately the same as the tread between the left and right front wheels 6. It is about 1/3.

At the upper end of the outer tube 32, as shown in FIGS. 4 and 5,
A sprocket 55 for steering is provided near the upper portion of the rear wheel 9 via a flange portion 54 extending outward. The sprocket 55 is divided into two in the circumferential direction, and each of them is detachably attached to the flange portion 54 with a bolt 56.

Reference numeral 57 denotes a hydraulic cylinder for steering, which is attached to the lower rear of the rear frame 29. The both ends of a piston rod 58 protruding from the hydraulic cylinder 57 to the left and right are connected to both ends of a chain 59 wound around a sprocket 55. Has been done. Therefore, when the piston rod 58 of the hydraulic cylinder 57 reciprocates in the left-right direction, the outer cylinder 32 is inserted through the chain 59 and the sprocket 55.
By turning around 31, the rear wheel 9 can be steered within a range of approximately ± 90 degrees. In addition, 60 is a guide sprocket,
The sprocket 55 is supported by the rear frame 29 on both sides of the rear of the sprocket 55 so as to secure the wrapping of the chain 59 on the 55.

Reference numeral 61 is a step support frame projecting forward from the vehicle body 1, 62 is a step plate mounted on the step support frame 61, 63 is a handle post, and 64 is a steering handle. A control unit 65 for steering controls the hydraulic cylinder 57 in conjunction with the handle 64. 66 is the car body 1
The floor cover attached to the cover covers the pulleys 11 and 12, etc. 67 is a driver's seat, 68 is a front wheel fan, and 69 is a safety frame.

A mower 70 is provided with three discs 73 that rotate around the vertical axis 72 on the lower side of the mower deck 71. A cutter 74 is pivotally attached to each of the discs 73 so that the cutter 73 is rotated by the rotation of the discs 73. It is designed to cut grass. Mower deck
71 has a gauge wheel 75 for adjusting the height of cutting and other rim gauges 76, and two links projecting forward from the vehicle body 1.
It is attached to the vehicle body 1 by 77 and can be moved up and down by expanding and contracting the hydraulic cylinder 78. Each disk 73 has a front PTO shaft.
It is rotationally driven by the power transmitted from 25 through the universal joint shaft 79.

80 is a grass collection container, which is arranged on the rear frame 29, and this grass collection container 80 is attached to a column 81 standing on the rear part of the vehicle body 1. The grass container 80 is made of punching metal, steel, or the like. 82 is a duct, 70 more
This is for feeding the grass clippings obtained in step 1 into the grass collection container 80. The duct 82 is connected to the center of the rear part of the mower deck 71, and is connected to the grass container 80 from below the front axle 5 and behind one front wheel 6. 83 is a fuel tank.

In the above structure, during mowing work, power from the crankshaft 10 of the engine 3 is used to drive the PTO pulley 12 and the belt 2
8, each disk 73 of the mower 70 is rotationally driven via the front PTO shaft 25 and the universal joint shaft 79, and is cut by the cutter 74. Then, the cut grass is sent to the grass collecting container 80 through the duct 82 and collected in the grass collecting container 80.

When traveling, the power from the engine 3 is shifted to an appropriate speed by the transmission 4, and then transmitted to the input shaft 35 of the rear wheel drive device 7 via the gears 21 and 22, the transmission shaft 23, and the universal joint 39, and thereafter. The wheel drive device 7 drives the rear wheels 9. Then, the vehicle is driven by the driving force of the rear wheels 9. That is, in the rear wheel drive device 7, the power is transmitted from the rear wheel diff device 46 to the rear wheel diff device 46 via the input shaft 35, the bevel gears 37, 38, the bevel pinion shaft 36, the bevel pinion 51, and the bevel gear 50. The rear wheels 9 are driven via the left and right rear axles 8.

When the handle 64 is operated during steering, the hydraulic cylinder 57 is actuated in the left-right direction via the control unit 65, and the piston rod 58 rotates the outer cylinder 32 side around the inner cylinder 31 via the chain 59 and the sprocket 55. The rear wheel 9 turns in the steering direction around the vertical axis while the driving state is maintained. By steering the rear wheels 9 in this way, it is possible to steer with a small steering angle, and therefore it is very convenient for work around trees and the like. In addition, because the tread of the rear wheel 9 is small, the steering angle can be made sufficiently large despite turning the rear axle 8 itself around the vertical axis and steering, and within a range of ± 90 degrees. Can be steered.

When the rear wheels 9 are steered to the steering angle α during turning, as shown in FIG. 6, turning can be performed with the intersection point on the extension line of the front axle 5 and the rear axle 8 as the turning center O. At this time, front wheel 6 and rear wheel 9
Although the turning radius with and becomes l <L, the front wheel 6 is idling,
Since only the rear wheels 9 are driven, the front wheels are
There is no slippage on the 6 side, and it can turn smoothly.

When the rear wheels 9 are steered to nearly 90 degrees, the rear wheels 9 move laterally, so the left and right front wheels 6 rotate in opposite directions, and the center portion between the left and right front wheels 6 turns around the turning center O '. it can. Therefore, it is possible to make a sharp turn with a small radius by making the left and right front wheels 6 idle and steering the rear wheels 9 while driving them, which is very convenient for the mowing work by the mower 70 in front of the vehicle body 1. is there.

(Effect of the Invention) According to the present invention, the pair of left and right rear wheels 9 are steered wheels that are steered about the longitudinal axis at the center between the rear wheels 9, and the front wheels 6 are idle and the rear wheels 9 are rotated. When the vehicle turns, it turns around an extension line of the front axle or a point on the front axle. It is possible to turn, the turning performance is significantly improved, and it is very convenient for the work of cutting around the standing trees by the mower 70 provided in front of the vehicle body 1. Especially the left and right front wheels
Since the engine 3 is arranged within the width of 6 and closer to the front wheel 6 between the front and rear wheels 6 and 9, and the mower 70 is located in front of the vehicle body 1, there is an effect that stability in turning is good. .

Further, when turning, the rear wheel 9 travels around an extension of the front axle or a point on the front axle, but at this time, if the rear part of the vehicle body projects rearward more than the rear wheel,
In the case where the mower is provided in the front of the vehicle body, attention cannot be paid to the rear part of the vehicle body, and there is a risk that something is caught in the projecting portion and the vehicle body or the hooked object is damaged. Since the rear wheels 9 are arranged at the rear end of the vehicle body 1 so that the rear wheels 9 can be steered around the longitudinal axis at the center between the rear wheels 9, there is no need to hook anything on the rear portion of the vehicle body 1. .

[Brief description of drawings]

The drawings show one embodiment of the present invention. FIG. 1 is an overall plan view, FIG. 2 is a side view of the same, FIG. 3 is a front view of the same section, and FIG. 4 is a rear wheel transmission system. FIG. 5 is a sectional view of the rear wheel drive system, and FIG. 1 ... Body, 3 ... Engine, 4 ... Transmission, 5 ...
Front axle, 6 ... front wheel, 7 ... rear wheel drive, 8 ... rear axle, 9 ... rear wheel, 70 ... mower.

Claims (1)

[Claims] 1. A pair of front and rear wheels 6, 9 on the front and rear of the vehicle body 1.
In a vehicle equipped with a mower 70 in the front, the engine 3 is arranged within the width of the left and right front wheels 6 and close to the front wheel 6 between the front and rear wheels 6, 9 and the pair of left and right rear wheels 9 is placed between the rear wheels 9. The front mount mower is characterized in that it is arranged at the rear end of the vehicle body 1 so that it can be steered around the center of the vertical axis in the center, and that the front wheels 6 rotate and the rear wheels 9 are driven when turning. Drive steering system.