JPH0653462B2 - Vehicle drive device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a vehicle drive device.

(Prior Art) A vehicle in which the front wheels of the large diameter wheels are the main driving wheels, the rear wheels of the small diameter wheels are the auxiliary driving wheels, and the rear wheels can be steered in conjunction with the steering wheel is It is widely used for the front-mounted type that is equipped with the working machine.

In this type of vehicle, since the turning radii of the front wheels and the rear wheels are different when turning, if the front and rear wheels are in a driving state, the rear wheels serve as a brake for the front wheels, and the rear wheels are steered. Therefore, the turning radius could not be reduced. Also, because the rear wheel side is a brake, the rear wheel slips on the ground,
If it is a lawn or the like, it has a drawback of damaging the lawn.

Therefore, a manually operated clutch is installed in the power transmission system of the rear wheels and the power to the rear wheels is cut off by manual operation of the clutch when turning, or a one-way clutch is installed in the power transmission system of the rear wheels. However, a one-way clutch that automatically disengages when turning is provided.

(Problems to be Solved by the Invention) The former manual operation type clutch has a drawback that the operator needs to operate the clutch each time the vehicle turns, which makes the operation very complicated.

With the latter one-way clutch, there is no problem when turning in forward traveling, but the one-way clutch does not function during reverse traveling, and the vehicle will turn with the front and rear wheels still driven. It had a large turning radius and had the drawback of damaging the lawn.

In view of the above-mentioned conventional problems, the present invention enables a smooth turning motion even when moving forward and backward, and always travels with the driving force of the main drive wheels, and when a slight slip occurs on the main drive wheels. It is an object of the present invention to allow the vehicle to travel by the driving force of the main drive wheels and the auxiliary drive wheels.

(Means for Solving Problems) In order to achieve the above-mentioned object, the present invention takes the following means. That is, a feature of the present invention is that a pair of left and right main drive wheels and a pair of left and right auxiliary drive wheels are arranged in front of and behind the vehicle body, and the distance between the left and right auxiliary drive wheels is between the left and right main drive wheels. The distance is smaller than the distance, the outer diameter of the main drive wheels is larger than the outer diameter of the auxiliary drive wheels, the auxiliary drive wheels are steering wheels, and the main drive wheel side end portion of the vehicle body is provided. Mower is attached to
A main power transmission system and a sub power transmission system for transmitting power to each drive wheel are respectively provided so that the peripheral speed of the main drive wheel becomes higher than that of the sub drive wheel, and these power transmission systems are provided via a north pin differential. It is connected to the drive source.

(Operation) According to the present invention, during traveling, the main drive wheels are driven through the north pin differential and the manual force transmission system, and the auxiliary drive wheels are idled by the north pin differential. To run.

When the main drive wheels slip, the auxiliary drive wheels are driven through the north pin differential and the auxiliary power transmission system, and the vehicle travels by the driving force of the main and auxiliary drive wheels.

The main drive wheel bears the weight of the car body and the mower, but since the main drive wheel has a larger diameter than the auxiliary drive wheel, the ground contact pressure becomes small and the lawn is not damaged.

Further, since the auxiliary driving wheels, which are steered wheels, have a narrow wheel distance, a large turning angle can be obtained and a turning radius can be reduced.

(Example) Hereinafter, the present invention will be described in detail with reference to the illustrated example.
1 to 3, reference numeral 1 denotes a vehicle body, which is a member 2 such as a square tubular member.
Is assembled into a rectangular frame shape. In this vehicle body 1, an engine (drive source) 3 and a hydrostatic transmission 4 are arranged side by side in the center of the front and rear, and a pair of left and right large front wheels are provided in the front through front wheels 5. A (main drive wheel) 6 is suspended, and a pair of left and right rear wheels (auxiliary drive wheels) 9 are suspended at the rear through a rear axle 8 of a rear wheel drive device 7. The engine 3 is supported by the vehicle body 1 via a vibration isolator, and the crankshaft 10 protruding forward from the engine 3 has a traveling pulley 11 and a PT.
An O pulley 12 is provided. A radiator 13, a cooling fan 14, and an oil cooler 15 are arranged behind the engine 3.

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. Behind the transmission 4, there is a power transmission device inside.
A transmission case 21 incorporating 20 is mounted vertically so as to project downward.

As shown in FIG. 4, the power transmission device 20 includes a front wheel power transmission system (main power transmission system) 22 and a rear wheel power transmission system (sub power transmission system).
23, north pin differential 24, front wheel clutch 25, rear wheel clutch
26, speed increasing mechanism 27, etc. North pin diff
24 has a differential case 29 with a gear 28, which is rotatably supported by the transmission case 21 by front and rear bearings 30 and 31, and the gear 28 is a gear fixed to the output shaft 32 of the transmission 4. 33 bite.

The north pin differential 24 has a differential case 29 as shown in FIG.
A pair of differential output shafts 34 and 35, a drive ring 36, a cam ring 37, a pair of clutch rings 38 and 39, and a pair of differential hubs 4
0,41 and a pair of springs 42,43 are incorporated. The drive ring 36 is fixed to the differential case 29, and between the drive ring 36 and the pair of clutch rings 38, 39, square tooth engaging portions 44, 45 are formed as shown in FIG. The cam ring 37 is fixed to the inner circumference of the drive ring 36, and cam tooth portions 46, 47 are formed between the cam ring 37 and the pair of clutch rings 38, 39 as shown in FIG. . The clutch rings 38 and 39 are slidably fitted to the differential hubs 40 and 41, the differential hubs 40 and 41 are slidably fitted to the differential output shafts 34 and 35, respectively, and the clutch rings 38 and 39 are springs 42 and 43. It is biased toward the cam ring 37 side.

The front wheel power transmission system 22 includes an intermediate shaft 48, a front wheel drive shaft 19, and a differential output shaft 34, which are sequentially supported in parallel below the north pin differential 24.
And a gear 51 fixed to the intermediate shaft 48 and freely rotatable on the intermediate shaft 48, gears 51a, 52 fixed to the intermediate shaft 48 and the front wheel drive shaft 49 and meshing with each other. The front wheel drive shaft 49 extends below the transmission 4 and extends forward, and its front end is linked to the front wheel differential device 53. The gear 51 is freely rotatable on the intermediate shaft 48 and can be connected to and disconnected from the intermediate shaft 48 by the front wheel clutch 25. The front wheel clutch 25 is a friction type having a large number of discs 54 and can be connected and disconnected by a shifter 55.

The rear wheel power transmission system 23 has a transmission shaft 56 connected to the differential output shaft 35 via a shaft coupling. The speed increasing mechanism 27 is formed by engaging the gears 59 and 60 at both ends of the cylindrical shaft 58 rotatably fitted to the intermediate shaft 48 with the gear 28 fixed to the north pin differential 24 and the gear 61 loosely fitted to the differential output shaft 35. , Gears 28,59 and gear 6
At 0,61, the speed is increased. The gear 61 can be freely connected / disconnected to the differential output shaft 35 by the shifter 57 of the rear wheel clutch 26.

The front wheel differential device 53 is mounted on the lower side of the vehicle body 1 in front of the transmission 4 as shown in FIG. 1 and FIG.
It is provided so as to be largely deviated from one of the left and right central portions to one side. The front wheel differential device 53 is for driving the front wheels 6 with the power from the front wheel drive shaft 49 via the pair of left and right front axles 5. Since the front wheel differential device 53 is laterally offset, the front axle 5 on the major axis side is supported by the vehicle body 1 via the bearing 62. A PTO shaft 63 is inserted in the front-rear direction in the case of the front wheel differential device 53, and a belt is attached to the rear end of the PTO shaft 63.
A pulley 65 interlocking with the PTO pulley 12 via 64 is fixedly installed.

The rear wheel drive device 7 is supported by a frame-shaped rear frame 66 that projects rearward from the rear end of the vehicle body 1. As shown in FIGS. 8 and 9, the rear wheel drive device 7 is constructed by incorporating a gear transmission mechanism in an upper case 67, an inner cylinder 68, an outer cylinder 69 and a lower case 70. The upper case 67 is attached to the rear frame 66 via a pair of left and right mounting portions 71. The upper case 67 has an input shaft 72, a bevel pinion shaft 73, and a bevel gear that interlocks them.
74,75 are assembled. The input shaft 72 is projected from the upper case 67 in a diagonally forward direction in the left-right direction, and is connected to the transmission shaft 56 via a universal joint 76 at the front end. The front wheel power transmission system 22 including the front wheel differential device 53 and the rear wheel drive device 7
The rear wheel power transmission system 23 including the above is configured to transmit power such that the peripheral speed ratio between the front wheels 6 and the rear wheels 9 is about 1: 0.9.

The bevel pinion shaft 73 is provided in the up-down direction as shown in FIG. 9, and an inner cylinder 68 is concentric with the bevel pinion shaft 73 below the upper case 67, and an inner cylinder 68 is bolt 77 so as to project downward.
Installed by. The inner cylinder 68 has a large diameter portion 78 and a small diameter portion 79.
And a vertical axis, and a bevel gear 75 is rotatably supported on the upper end of the large diameter portion 78 via a bearing 80. The outer cylinder 69 is the inner cylinder
It is rotatably fitted on the bush 68 via a bush 81, a bearing 82 and the like, and is retained by a retaining ring 83 at the lower end of the inner cylinder 68 so that it cannot be pulled out downward. The lower case 70 incorporates the rear wheel differential device 84, is attached to the lower end of the outer cylinder 69 by the port 85, and the bearing cases 86 are attached to the left and right sides of the lower case 70 with bolts. The rear wheel differential device 84 is supported by a bearing case 86 via a bearing 87, and its bevel gear 88 is meshed with a bevel pinion 89 at the lower end of the bevel pinion shaft 73. The rear axle 8 protruding left and right from the rear wheel differential device 84 is supported by a bearing case 86 via a bearing 89, and the rear wheel 9 is attached to the outer end of the rear axle 8. The rear wheel 9 is provided close to the lower case 70 so that the bearing case 86 fits substantially inside the tire rim 90.The tread between the left and right rear wheels 9 serves as a tread between the left and right front wheels 6. It is about 1/3.

At the upper end of the outer cylinder 69, as shown in FIGS. 8 and 9,
A sprocket 92 for steering is provided near the upper portion of the rear wheel 9 via a flange portion 91 extending outward. The sprocket 92 is detachably attached to the flange portion 91 with a bolt 93.

Reference numeral 94 denotes a hydraulic cylinder for steering, which is attached to the lower rear portion of the rear frame 66 as shown in FIGS.
Both ends of a piston rod 95 protruding right and left from 94 are connected to both ends of a chain 96 wound around a sprocket 92. Therefore, the piston rod 95 of the hydraulic cylinder 94
The left and right reciprocating motion of the chain 96, sprocket
The outer cylinder 69 rotates around the inner cylinder 68 via 92, and the rear wheel 9
It can be steered within 90 degrees. Reference numeral 97 denotes a guide sprocket, which is provided on both sides of the rear portion of the sprocket 92 so that the chain 96 can be wound around the sprocket 92.
Supported by.

As shown in FIGS. 8 and 9, the sprocket 92 is formed with a long hole 97 centered on the bevel pinion shaft 73, and the pin 99 at one end of the detection rod 98 is slidable in the long hole 97. Has been inserted. The other end of the detection rod 98 is attached to the vehicle body 1 through the pivot 10
It is connected to a lever 101 which is pivoted at 0. The elongated hole 97, the detection rod 98, the pin 99, the lever 101 and the like constitute a detection means 102 for detecting the steering angle of the rear wheel 9. The detecting means 102 disengages the front wheel clutch 25 and engages the rear wheel clutch 26 via the interlocking means 103 when the steering angle α of the rear wheels 9 (≉60 degrees) or more is reached. That is, the interlocking means 103 is a pivot as shown in FIGS. 8 and 10.
100 fixed to lever 104 to rod 105, lever 106,
It is connected to the shift forks 111,112 of each clutch 25,26 via the lever shaft 107, the ring 108, and the rods 109,110, and the shifters 55,5 are connected via the shift forks 111,112.
It is designed to operate 7. Lever 106 and link 10
8 is fixed to the lever shaft 107, and the shift forks 111,
112 is supported by lever shafts 113 and 114. The steering angle α is set to an angle when the turning center O is located near the outside of one side of the front wheel 6 as shown in FIG.

115 is a step support frame projecting forward from the vehicle body 1, 116
Is a step plate attached to this step support frame 115, 11
7 is a handle post and 118 is a steering handle.
119 is a control unit for steering, which is a steering wheel 118.
The hydraulic cylinder 94 is controlled in conjunction with the. 120 is a floor cover mounted on the vehicle body 1 and includes pulleys 11, 1
It is designed to cover 2 mag. 121 is a driver's seat, 122 is a front wheel fender, and 123 is a safety frame.

124 is the front mower, below the mower deck 125
Three disks 127 that rotate around the vertical axis 126 are provided, and a cutter 128 is pivotally attached to each disk 127 so that the disks 128 can be swung by the rotation of the disks 127. The mower deck 125 has a gauge wheel 129 for cutting height adjustment and other limit gauges 130, and
It is attached to the vehicle body 1 by two links 131 extending forward from the vehicle, and can be moved up and down by expanding and contracting the hydraulic cylinder 132.
In addition, each disk 127 is connected to the universal joint shaft 133 from the PTO shaft 63.
It is rotationally driven by the power transmitted via the.

Reference numeral 134 denotes a grass collection container, which is arranged on the rear frame 66, and this grass collection container 134 is attached to a pillar 135 which is erected on the rear portion of the vehicle body 1. The grass container 134 is made of punching metal or the like. Reference numeral 136 is a duct for feeding the grass cut by the mower 124 to the grass container 134. The duct 136 is connected to the rear center of the mower deck 125 and extends from below the front axle 5 to one front wheel 6
It is connected to the grass container 134 via the rear of the. 137 is a fuel tank.

In the above configuration, during mowing work, power from the crankshaft 10 of the engine 3 is used to drive the PTO pulley 12 and the belt 6
4, each disk 127 of the mower 124 is rotationally driven through the PTO shaft 63 and the universal joint shaft 133, and the grass is cut by the cutter 128. Then, the cut grass is sent to the grass collecting container 134 through the duct 136 and collected in the grass collecting container 134.

During straight running, after shifting the power from the engine 3 to an appropriate speed with the transmission 4, the north pin differential 24, differential output shaft 34, gears 50, 51, front wheel clutch 25, intermediate shaft 48, gears 51a, 52, front wheel drive Power is transmitted to the left and right front wheels 6 via the shaft 49 and the front wheel differential device 53, and the vehicle travels by the driving force of the front wheels 6, which are large-diameter wheels, as indicated by arrows in FIG. At this time,
The rear wheel 9 is idling. In other words, the peripheral speed at which the rear wheels 9 are driven by the rear wheel power transmission system 23 is about 0.9 of that of the front wheels 6, so that the rear wheels 9 are driven in reverse at the peripheral speed adjusted with the front wheels 6 due to friction with the ground. Has been, therefore, North Pindiff
Since the rotational speed of the differential output shaft 35 of 24 becomes high, the clutch ring 39 is disengaged as shown in FIG. 12 by the cam teeth 45 between the cam ring 37 and the clutch ring 39, and as shown in FIG. Clutch ring 39 is disengaged from, and power is not transmitted to the differential output shaft 35 side.

If the front wheels 6 slip during straight running, the traveling speed decreases and the peripheral speed of the rear wheels 9 decreases. Then, when the peripheral speed of the rear wheel 9 becomes about 0.9, the clutch ring 39 is pressed by the spring 43 and slides to the drive ring 36 side, the square tooth engaging portion 45 engages, and the power is also applied to the differential output shaft 35 side. Transmitted. Therefore, the vehicle can travel by the driving force of the front wheels 6 and the rear wheels 9, and the slipping state of the front wheels 6 can be eliminated at an early stage. When the front wheels 6 are no longer slipping, the vehicle will be driven again only by driving the front wheels 6. In addition,
In the rear wheel drive device 7, the input shaft 72, the bevel gears 74, 75,
Bevel pinion shaft 73, bevel pinion 89, bevel gear
Power is transmitted to the rear wheel differential device 84 via 88, and the rear wheel 9 is driven via the rear axle 8.

When the handle 118 is operated during steering, the hydraulic cylinder 94 is operated in the left-right direction via the control unit 119, and the outer cylinder 69 side is rotated around the inner cylinder 68 via the piston rod 95, the chain 96, and the sprocket 92. The rear wheel 9 turns in the steering direction while keeping the idling state. Therefore, as shown in FIG. 14, it is possible to quickly turn despite the difference in the turning radii (r <R) of the front wheels 6 and the rear wheels 9 from the turning center O.

When the rear wheel 9 is within the predetermined steering angle α, only the pin 99 slides in the long hole 97 of the sprocket 92, and the detection rod 98
Etc. do not detect. When the rear wheel 9 becomes equal to or larger than the predetermined steering angle α and the turning center O is near the outside on one side of the front wheel 6 as shown in FIG. 15, the pin 99 engages with one end of the elongated hole 97, and the detection rod 98 is pulled so that lever 10
6. The link 108 rotates clockwise around the lever shaft 107 (indicated by arrow a in FIG. 10). As a result, the shift fork 111 rotates in the counterclockwise direction (indicated by the arrow b in FIG. 10) around the lever shaft 113 via the rod 109, the front wheel clutch 25 is disengaged, and the shift fork 112 moves via the rod 110. It rotates around the lever shaft 114 in the clockwise direction (indicated by arrow c in FIG. 10) to connect the rear wheel clutch 26. Therefore, the power to the front wheels 6 is cut off, and the front wheels 6 are idling. On the other hand, since the rear wheel clutch 26 is connected, the gears 28, 59, the cylinder shaft 58, the gear
Power is transmitted to the transmission shaft 56 via the speed increasing mechanism 27 of 60, 61, and the vehicle is turned by the driving force of the rear wheel 9. The speed increasing ratio of the speed increasing mechanism 27 is set so that the peripheral speed of the rear wheel 9 does not change much before and after the rear wheel clutch 26 is connected, and is about twice. At this time, the turning center O is near the outside on one side of the front wheel 6, so that the turning can be performed with a small radius.

When the steering angle α is steered to 90 degrees, the turning center O is located at the center between the left and right front wheels 6 as shown in FIG. 16, and the left and right front wheels 6 rotate in the opposite direction via the front wheel differential device 53. Therefore, it is possible to make a sharp turn around the turning center O.

Since the north pin differential 24 is used also when going straight or turning when traveling in reverse, the same function as in traveling forward and the same operation as described above are performed.

The detecting means 102 and the interlocking means 103 may be electrically configured, or only the front wheel clutch 25 may be interlocked with the interlocking means 103 and the rear wheel clutch 26 may be manually connected / disconnected.

The vehicle may have a relationship in which the front and back are opposite to those in FIG. The type of the clutches 25, 26 may be friction type, occlusion type, or hydraulic type.

The steering mechanism is an outer cylinder as shown in FIGS. 17 and 18.
Secure the upper and lower two sprockets 138 and 139 to the upper end of 69, and wrap the two chains 140 and 141 around it.
The end opposite to the piston rod 95 may be fixed to the sprockets 138 and 139 with metal fittings 142 and 143.

(Effect of the Invention) According to the present invention, the peripheral speed on the side of the main drive wheels 6 is made higher than the peripheral speed of the auxiliary drive wheels 9, and the power transmission system 2 for the angular drive wheels 6, 9
Since 2 and 23 are interlockingly connected to the drive source 3 side via the north pin differential 24, the north pin differential 24 can smoothly turn when moving forward and backward. Main drive wheel 6 and sub drive wheel 9
Since there is a difference in peripheral speed between the main drive wheel 6 and the main drive wheel 6, when the main drive wheel 6 slips slightly, the auxiliary drive wheel 9 is driven via the north pin differential 24.
The vehicle can travel by the driving force of the main drive wheels 6 and the auxiliary drive wheels 9. Further, the main drive wheel 6 bears the weight of the vehicle body 1 and the mower 124, but since the main drive wheel 6 has a larger diameter than the auxiliary drive wheel 6, the ground contact pressure becomes small and the lawn is not damaged. Further, since the wheel distance of the auxiliary drive wheel 9 which is a steered wheel is narrow, a large turning angle can be taken and the turning radius becomes small.

[Brief description of drawings]

The drawings show an embodiment of the present invention. FIG. 1 is an overall plan view, FIG. 2 is a side view thereof, FIG. 3 is a sectional front view thereof, and FIG. 4 is a sectional view of a power transmission device. FIG. 5 is a cross-sectional view of the north pin differential, FIG. 6 is a development view of an engaging portion of a drive ring and a clutch ring, FIG. 7 is a development view of an engaging portion of a cam ring and a clutch ring, and FIG. 8 is a rear wheel steering portion. A plan view of
FIG. 9 is a sectional view of the rear wheel drive unit, FIG. 10 is a plan view of the interlocking device, and FIGS. 11 and 12 are operation explanatory views of the north pin differential.
13 to 16 are explanatory views of the operation, FIG. 17 is a sectional side view of another steering mechanism, and FIG. 18 is a schematic perspective view of the same. 1 ... Car body, 3 ... Engine (drive source), 6 ... Front wheel (main drive wheel), 9 ... Rear wheel (sub drive wheel), 22 ... Front wheel power transmission system (main power transmission system), 23 ...... Rear wheel power transmission system (auxiliary power transmission system), 24 …… North pin differential, 25 …… Front wheel clutch, 27 …… Speed increasing mechanism, 102 …… Detecting means, 103 …… Interlocking means

Claims (1)

[Claims] 1. A pair of left and right main drive wheels (6) and a pair of left and right auxiliary drive wheels (9) are arranged in front of and behind the vehicle body (1), and the distance between the left and right auxiliary drive wheels (9) is left and right. Is smaller than the distance between the main drive wheels (6), and the outer diameter of the main drive wheels (6) is larger than the outer diameter of the auxiliary drive wheels (9). ) Is a steered wheel, and a mower (124) is attached to the main drive wheel (6) side end of the vehicle body (1), and the peripheral speed of the main drive wheel (6) is the auxiliary drive wheel (9). The main drive train (2) that transmits power to each drive wheel (6) (9)
2) and an auxiliary power transmission system (23) are respectively provided, and these power transmission systems (22) and (23) are interlockingly connected to the drive source (3) through the north pin differential (24). Travel drive.