JPH10252849A - Belt type continuously variable transmission for traveling car - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a temperature rise in a belt, and improve its durability by forming a drive shaft being the input shaft side of a belt type continuously variable transmission in a hollow shape, and sending a cooling wind in a belt case from an inflow port of an end part of this shaft. SOLUTION: A hollow circular tube-shaped shaft is used as a drive shaft 52, and its rear end (an end part on the side unconnected to an output shaft 50 of an engine E) is projected backward from a rear surface of a belt case 54, and an inflow passage 52a is formed to flow external air in the drive shaft 52. An arm 87 is arranged on the rear end of the drive shaft 52, and an outer periphery of a fan 88 is fixed to its end part. A cooling wind is forcibly sent in the inflow passage 52a along a guide plate 89 by rotating a fan 88 by driving the drive shaft 52. The cooling wind is delivered in a split pulley 60 from a delivery hole 52b of an end part of the inflow passage 52a, and directly cools a CVT belt 62 wound round the split pulley 60. The cooling wind cooling the CVT belt 62 comes outside of the belt case 54 from an exhaust port 54a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a belt-type continuously variable transmission for continuously changing the output of an engine of a work vehicle.

[0002]

2. Description of the Related Art Conventionally, the output of an engine is input into a transmission case, and the driving force is transmitted to the front and rear axle cases via the transmission case, while the PTO shaft supported at the rear of the transmission case is driven. And the power was transmitted to the working machine. A technique for transmitting the output of the engine to a transmission case via a belt-type continuously variable transmission has also been known. In the belt-type continuously variable transmission, a drive shaft for inputting the output of an engine and a driven shaft for transmitting power to a transmission case are pivotally supported, and split shaft split pulleys are fixed to each shaft. The width of the groove is changed, the effective diameter wound around the split pulley of the belt is changed, the driven shaft is steplessly driven, the gear type reduction device in the transmission case is simplified, and the impact during shifting is reduced. Was eliminated.

[0003]

However, in the conventional belt-type continuously variable transmission, the groove width of the split pulley is changed to change the effective diameter around which the belt is wound. At the time of change, the belt slipped on the split pulley, the friction between the split pulley and the belt increased, and the belt instantly became hot. Although the cooling air is sucked from one side and exhausted from the other side of the case, the split pulley and the belt are not directly cooled, cooling is insufficient, and the belt is driven at a high temperature. In this case, the belt is deteriorated to shorten the service life.

[0004]

The problem to be solved by the present invention is as described above. Next, means for solving the problem will be described. That is, in a traveling vehicle having a belt-type continuously variable transmission that continuously changes the power, a drive shaft on the input shaft side is formed in a hollow shape, and an inflow hole for introducing cooling air from an end of the drive shaft is formed. The cooling air is blown into the belt case. In addition, an inflow hole of the drive shaft is formed to a position where the split pulley is pivotally supported, and a discharge hole for discharging cooling air is radially opened in a groove of the split pulley.

[0005]

Next, an embodiment of the present invention will be described. FIG. 1 is an overall side view of a rice transplanter having a seedling table folding mechanism, FIG. 2 is a plan view of the same, FIG. 3 is a side sectional view of a belt cover for supporting a hollow drive shaft of the present invention, and FIG. Is a partial side view partially sectional view of another embodiment for sending cooling air to a hollow drive shaft, FIG. 5 is a partial side view sectional view of a hollow drive shaft, and FIG. 6 is a front view showing a support structure of a belt cover. FIGS. 7 and 8 are side and partial cross-sectional views, FIG. 8 is a partial front cross-sectional view showing a belt cover support structure, FIG. 9 is a partial cross-sectional view of an input side split pulley, and FIG. FIG. 11 is a diagram showing an operation configuration of the belt-type continuously variable transmission, and FIG. 12 is a partial cross-sectional view showing a support configuration of the traveling speed change lever.

[0006] First, an overall configuration of a riding rice transplanter will be described with reference to Figs. An engine E is mounted above a front part of a body frame 3 of a traveling vehicle 1 on which an operator or the like rides, a belt-type continuously variable transmission 51 is disposed behind the engine E, and a front axle case 5 is provided in front of a transmission case 4. The front case 6 is supported through the transmission case 4
A rear axle case 7 is connected to a rear portion of the vehicle, and the rear wheel 8 is supported by the rear axle case 7. The spare seedling table 10.1 is placed above the hood 9 covering the engine E.
0, the transmission case 4 and the like are covered by a vehicle body cover 2 on which an operator or the like rides through a step 11, a driver's seat 13 is mounted on the vehicle body cover 2, and the bonnet in front of the driver's seat 13 9 A steering handle 14 is provided at the rear.

The planting section 15 is composed of a seedling mounting table 16 for eight-row planting, a plurality of planting claws 17 and the like. The rotary case 21 is rotatably supported on the planting case 20 via a back and forth slidable, and the rotary case 21 that rotates at a constant speed in one direction is rotatable on the planting case 20. A pair of claw cases 22 are arranged at symmetrical positions, and planting claws 17 are fixedly attached to the tips of the claw cases 22.

Further, a supporting frame 24 is provided at the front of the planting case 20 via a rolling fulcrum shaft 23, and the supporting frame 24 is provided at the rear of the traveling vehicle 1 via a link mechanism 27 including a top link 25 and a lower link 26. And a lifting cylinder 28 for raising and lowering the planting section 15 via the link mechanism 27 is connected to the lower link 26. Then, at the same time as the front wheels 6.6 and the rear wheels 8.8 are driven to move, the seedlings for one plant are taken out from the seedling table 16 which can reciprocate slidably to the left and right by planting claws 17.
It is configured to perform seedling planting work continuously.

In the driving section where the driver's seat 13 and the like are installed, a traveling speed change lever 29, an auxiliary speed change lever 30 for planting up / down and work traveling speed change, a planting sensitivity adjusting lever 31, a main clutch pedal 32, a left and right brake pedal 33 are provided. 33, side clutch pedals 39 are disposed, a leveling center float 34 and a leveling side float 35 are disposed below the planting portion 15, and a fertilizer application for Yachijo is provided behind the driver's seat 13. A part 36 is provided.

As shown in FIG. 1 and FIG. 2, the multi-row seedling mounting table 16 is divided into two outermost left and right outer row seedling mounting tables to form divided seedling mounting tables 16a. The four rows are fixed-side seedling platforms 16b, and parallel folding mechanisms 37 are provided on the left and right ends of the fixed-side seedling platforms 16b.
The fixed seedling mounting table 16a is connected to the fixed seedling mounting table 16b via a parallel folding mechanism 37 so that the divided seedling mounting tables 16a can be folded substantially in parallel above the fixed seedling mounting table 16b.

Next, the power transmission configuration of the traveling vehicle 1 will be described. As shown in FIG. 3, the output shaft 50 of the engine E is transmitted to a belt-type continuously variable transmission 51 disposed behind the engine E, so that the power continuously variable is input into the transmission case 4. doing. In the belt-type continuously variable transmission 51, a drive shaft 52 and a driven shaft 53 having an axial center in the front-rear direction are supported in parallel in the left and right directions, and an output shaft 50 of the engine E is input to the drive shaft 52. The continuously variable power is transmitted to the transmission case 4 via the driven shaft 53.

Next, the support structure of the belt-type continuously variable transmission 51 will be described. The belt-type continuously variable transmission 51
Are mounted on the belt case 54. The belt case 54 is long in the left-right direction, as shown in FIGS.
The case is formed thin in the front-rear direction, and the side of the belt case 54 is supported by the left and right vehicle body frames 3 so as to have a low center of gravity.

That is, fixing plates 55 having a flat surface in the vertical direction are protruded laterally from the left and right side surfaces of the belt case 54, and an insertion hole 55a is opened at an end of the fixing plate 55. On the other hand, an inverted L-shaped stay 56 is fixed to the lower surface of the vehicle body frame 3 and a support plate 56a is formed vertically downward. A hole 56b having an axial center in the front-rear direction is formed in the support plate 56a. It is open. The belt case 5
In order to support the vehicle body 4 on the vehicle body frame 3, the insertion holes 55a of the fixing plate 55 and the holes 56b of the support plate 56a are aligned with each other.
The belt case 54 is supported by inserting a bolt 57 into the insertion hole 55a and the hole 56b and screwing a nut 58 to an end of the bolt 57 protruding rearward from the support plate 56a. When screwing with the bolt 57, the fixing plate 55
At a position between the rear surface and the front surface of the support plate 56a, a cylindrical cushioning member 59 formed by an elastic body such as rubber or resin is interposed,
The bolt 57 is passed through the inside of the cylindrical buffer member 59, and the fixing plate 55 is screwed to the support plate 56a.
Even if the left and right body frames 3, 3 are deformed, the belt case 54 is not deformed.

Next, the internal structure of the belt-type continuously variable transmission 51 will be described. As shown in FIG. 3, split pulleys 60 and 61 are arranged on the same plane in the belt case 54 on the drive shaft 52 and the driven shaft 53 which are supported by the belt case 54. The split pulley 60 fixed to the drive shaft 52 on the input side includes a fixed pulley 60a and a movable pulley 60b. A split pulley 61 composed of a fixed pulley 61a and a movable pulley 61b is disposed on the driven shaft 53 on the output side, and a CVT belt 62 is wound between the split pulley 61 and the split pulley 60. I have. The holding surfaces for holding the CVT belt 62 between the fixed pulleys 60a and 61a and the movable pulleys 60b and 61b of the split pulleys 60 and 61 are formed so as to be inclined from the inner peripheral side to the outer peripheral side, and the movable pulleys 60b and 61b slide. Operation
The effective radius for clamping the CVT belt 62 is changed.

The movable pulley 60b and the movable pulley 61b of the split pulley 60 and the split pulley 61 are slid in cooperation with the operation of the traveling speed change lever 29 via a cam mechanism or the like (not shown). As shown in FIG. 11, an operation shaft 63 protrudes outside the belt case 54, and
Reference numeral 3 denotes an operation of the traveling speed change lever 29. Further, a reduction mechanism for returning the movable pulleys 60b and 61b to the reduction position in cooperation with the operation of the main clutch pedal 32 is provided at an end of the operation shaft 63.

As shown in FIG. 11, a sliding shaft 65 which slides in conjunction with the main clutch pedal 32 is arranged on the same axis as the operating shaft 63. The sliding shaft 65 and the operating shaft 63 are connected to a woven brake 75 which is a friction type clutch mechanism.
Are connected so that they can be "joined" or "disconnected" by
In the “joined” state, the operating shaft 63 and the sliding shaft 65 are configured to rotate integrally.

The sliding shaft 65 is slidably pivotally supported by a support 66 standing upright from the body side. The support portion 66 includes a support plate 67 erected from the fuselage side, a cylinder 68 fixed to one side (belt case 54 side) of the support plate 66, and an end portion of the cylinder 68 on the belt case 54 side. The sliding shaft 65 is slidably pivotally supported by the pivoting member 69 in the middle of the sliding shaft 65.

The sliding shaft 6 inside the cylindrical body 68 of the support portion 66
A ring body 74 is externally fitted on the outer peripheral surface of the ring body 5.
A coil spring 73 is wound around the outer peripheral surface of the sliding shaft 65 between the support shaft 4 and the support plate 67, and the sliding shaft 65 is slid in a direction in which the sliding shaft 65 contacts the operating shaft 63. The operation shaft 63 is in the “joined” state.

A one-way clutch 8 is provided on a sliding shaft 65 between the support portion 66 and the woven brake 75.
0 on the outer peripheral surface of the one-way clutch 80 to reduce the length of the lever operating rod 29a.
9 are connected. The traveling speed change lever 29 is shown in FIG.
As shown in FIG.
Is fastened, the end of the spring 81 is fixed to the machine body side, and a stopper 82 is disposed above the spring 81. When the traveling speed change lever 29 is tilted in the "joined" state of the woven brake 75, the sliding shaft 65 is rotated via the one-way clutch 80, and the operation shaft 63 is rotated by a fixed amount via the woven brake 75. The movable pulleys 60b and 61b of the split pulleys 60 and 61 are slid toward the speed increasing side. When the hand is released while the traveling speed change lever 29 is tilted, the traveling speed change lever 29 rotates according to the urging force of the spring 81 and returns to the neutral position where it is engaged with the stopper 82.
By 0, the operation shaft 63 and the sliding shaft 65 are fixed in a state of being rotated by a fixed amount, and are restricted from rotating to the deceleration side.

Therefore, when the speed of the driven shaft 53 is further increased by using the belt-type continuously variable transmission 51, the operation of tilting the traveling speed change lever 29 is repeated several times, so that the operation shaft 63 is stepwise. The movable pulley 6 is rotated
0b and 61b are further slid to the speed increasing side. Therefore,
The operation amount of the traveling speed change lever 29 can be shortened, and the length of the operation rod 29a of the traveling speed change lever 29 can be shortened.

A bent portion of an arm 71 formed in a "U" shape is pivotally supported on the upper side of the other side of the support plate 67 (on the side where the belt case 54 is not provided).
The lower end protrudes toward the end of the sliding shaft 65 and is in contact with an annular contact ring 70 fitted on the outer peripheral surface of the end of the sliding shaft 65. A wire 72 is fastened to the upper end of the arm 71, and the wire 72 is connected to the neutral main clutch pedal 32 at the “joined” position of the woven brake 75. Further, a wire 76 that is slid at the “disengaged” position where the main clutch pedal 32 is depressed is fastened to the outer peripheral surface of the operation shaft 63. The wire 76 is fastened to the upper position at the most decelerated position of the operating shaft 63, and the fastened operation has moved the fastened position downward as indicated by a two-dot chain line 76 'in the figure. When the main clutch pedal 32 is depressed, the wire 76 is pulled, and the operation shaft 63 is moved to the deceleration position.

When the driven shaft 53 is accelerated and the main clutch pedal 32 is depressed, the upper end of the arm 71 is pulled via the wire 72, and the arm 71 is moved in a two-dot chain line in FIG. 71 '
And the contact ring 70, which contacts the lower end of the arm 71, is moved integrally with the slide shaft 65 to the right side 65 'on the paper, and the woven brake 75 is cut to the "release" side where the brake is released. Has been replaced. At this time, the end of the other wire 76 interlocked with the main clutch pedal 32 is located below the rotation of the operation shaft 63, but when the main clutch pedal 32 is depressed, the wire 76
Is pulled, the operation shaft 63 is rotated to the maximum deceleration position without rotation being restricted by the one-way clutch 80, and the movable pulleys 60b and 61b can be slid to the deceleration side. The operation mechanism having this speed reduction mechanism is not limited to the belt-type continuously variable transmission 51, but may be an HST.
It can also be connected to a shaft that is linked to the trunnion arm of the transmission.

In the belt type continuously variable transmission 51, even if the movable pulley 60b of the split pulley 60 on the drive shaft 52 on the input shaft side is slid outward, the C
The VT belt 62 is wound at the minimum radius position of the split pulley 60, drives the drive shaft 52 at a low speed, and the power transmission to the drive shaft 52 is not cut off. Continuously variable transmission 51
Thus, a device having a clutch mechanism for cutting off the transmission of power to the driven shaft 53 has been required.

Therefore, by making the sliding range of the movable pulley 60b of the split pulley 60 on the drive shaft 52 wider than the belt width, the transmission of the driving force to the CVT belt 62 by the split pulley 60 is cut off. . 9 and 1
As shown in FIG. 0, the engagement concave portion 60 is provided inside the inner peripheral surface of the boss portion of the fixed pulley 60a in which the drive shaft 52 is fitted.
c is formed, and an engagement recess 60d is formed inside the inner peripheral surface of the boss portion of the movable pulley 60b when slidably engaged with the drive shaft 52. The drive shaft 52 in the engagement recess 60c and the engagement recess 60d is formed to have a smaller outer diameter by one step, and a cylindrical collar 85 is loosely fitted on the outer peripheral surface at this position.

Therefore, when the movable pulley 60b is slid outward (in the deceleration direction), the effective diameter of the split pulley 60 is reduced, and when the movable pulley 60b is further slid outward, the CVT belt 62 is pinched by the split pulley 60. As shown in FIG. 10, the CVT belt 62 is wound around the outer peripheral surface of the collar 85 and the drive of the drive shaft 52 is stopped.
Power transmission to the driven shaft 53 can be cut off. Note that a pivot such as a bearing may be fitted instead of the collar 85 disposed on the drive shaft 52.

Next, the cooling configuration of the belt-type continuously variable transmission 51 according to the present invention will be described. As shown in FIG. 3, a hollow cylindrical shaft is used for the drive shaft 52, and the rear end of the drive shaft 52 (the output shaft 50) is used.
The end of the belt case 54 that is not connected to the rear side projects rearward from the rear surface of the belt case 54, and an inflow passage 52a through which external air flows into the drive shaft 52 is formed. The inflow channel 5
As shown in FIGS. 3 and 5, a plurality of discharges 2a are formed up to a position between the fixed pulley 60a and the movable pulley 60b of the split pulley 60, and communicate with the fixed pulley 60a and the movable pulley 60b. The holes 52b are radially opened in the radial direction of the drive shaft 52.

A fan 88 is used to blow cooling air into the inflow passage 52a of the drive shaft 52. At the rear end of the drive shaft 52, fixed arms 87 are fixedly mounted.
... The outer periphery of the fan 88 is fixedly provided at the end. The fan 88 is fixedly installed with the blowing direction toward the inflow path 52a, and the outer peripheral surface of the fan 88 and the fixed arms 87, 87,.
And a drive plate 5 protruding from the rear surface of the belt case 54.
A guide plate 89 is fixed to a cylindrical cover 91 on which the cover 2 is mounted.

An exhaust port 54a is opened below the split pulley 61 disposed on the driven shaft 53 of the belt case 54. An exhaust hose 92 is connected to the exhaust port 54a.

Therefore, when the drive shaft 52 is driven and the fan 88 is rotated, the cooling air generated by the fan 88 is fed to the inflow passage 52a along the guide plate 89, and the end of the inflow passage 52a. Discharge holes 52b
Cooling air is discharged into the split pulley 60, and the CVT belt 62 wound around the split pulley 60 is directly cooled.
Further, the cooling air that has cooled the CVT belt 62 is
3b, the cooling air is blown to the exhaust port 54b side along the CVT belt 62 as indicated by the arrow in FIG. 3, and the cooling efficiency of the CVT belt 62 is improved. You.

Further, instead of the fan 88, a suction hose 90 shown in FIG. 4 is fixed to the end of the cover 89 on which the drive shaft 52 is mounted, and the end of the suction hose 90 is used to cool the engine E. A configuration in which the cooling air is drawn from the cooling fan of the engine E by extending to a position near the cooling fan (not shown) may be employed.

When a coolant such as transmission oil is sealed in the belt case 54 of the belt-type continuously variable transmission 51, the coolant may be circulated using the fan 88.

[0032]

As described above, the present invention has the following advantages. That is, the drive air shaft supported by the belt cover is formed in the belt-type continuously variable transmission to form a hollow inflow path, so that the cooling air flows to the inside of the belt cover. Cooling air can be blown to the CVT belt that can be blown and easily rises in temperature, and the CVT belt rises in temperature and does not continue to be driven in a high temperature state.
The durability of the T-belt can be improved.

According to a second aspect of the present invention, the inflow hole of the drive shaft is formed up to the position where the split pulley is supported, and the discharge hole for discharging the cooling air is opened in the groove of the split pulley. The cooling air can be directly blown into the groove of the split pulley on the input side where friction of the CVT belt is likely to occur, thereby preventing the temperature of the CVT belt from being extremely increased. The driving of the CVT belt does not continue, and the durability of the CVT belt can be improved.

[Brief description of the drawings]

FIG. 1 is an overall side view of a rice transplanter having a seedling table folding mechanism.

FIG. 2 is a plan view of the same.

FIG. 3 is a side sectional view of a belt cover that supports the hollow drive shaft of the present invention.

FIG. 4 is a partial side view and a partial cross-sectional view of another embodiment for sending cooling air to a hollow drive shaft.

FIG. 5 is a partial side view sectional view of a hollow drive shaft.

FIG. 6 is a front view showing a support structure of the belt cover.

FIG. 7 is a side view and a partial cross-sectional view of the same.

FIG. 8 is a partial front sectional view showing a support structure of a belt cover.

FIG. 9 is a partial cross-sectional view of the split pulley on the input side.

FIG. 10 is a partial sectional view of the split pulley.

FIG. 11 is a diagram showing an operation configuration of the belt-type continuously variable transmission.

FIG. 12 is a partial cross-sectional view showing a support structure of a traveling speed change lever.

[Explanation of symbols]

 Reference Signs List 1 traveling vehicle 51 belt-type continuously variable transmission 52 drive shaft 52a inlet hole 52b discharge hole

Claims (2)

[Claims] 1. A traveling vehicle having a belt-type continuously variable transmission for continuously changing power, wherein a drive shaft on the input shaft side is formed in a hollow shape, and cooling air is introduced from an end of the drive shaft. A belt-type continuously variable transmission for a traveling vehicle, wherein holes are formed and cooling air is blown into a belt case. 2. The drive shaft according to claim 1, wherein the inflow hole is formed up to a position where the split pulley is pivotally supported, and a discharge hole for discharging cooling air is radially opened in a groove of the split pulley. Belt-type continuously variable transmission for traveling vehicles.