JPH09315337A - Steering device of work vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain an accurate steering of a vehicle corresponding to a purpose of steering the vehicle by obtaining a steering of the vehicle with a reversible non-step transmission device independent of the transmission running drive mechanism of the vehicle and attaining a transmission running drive mechanism voluntarily. SOLUTION: A reversible continuously variable transmission device 27 which is transmission operated with a steering tool is connected with a right and left traveling drive shafts 31L and 31R. An additional rotation transfer mechanism includes at least two systems of a speed reducing transfer tows which is selectively operated. In one embodiment, two systems of speed reducing transfer row is selectively operated with a brake 54 and a clutch 55 which are selectively operated with a large and a small amount of the steering operation amount.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reversible continuously variable transmission such as a hydraulic transmission capable of continuously changing an output rotation speed including a rotation direction in a working vehicle such as a combine or the like. A steering device to be obtained.

[0002]

2. Description of the Related Art Japanese Patent Application Publication No. Sho 54-54 discloses a technique in which a working drive mechanism causes a left and right traveling means (crawlers or wheels) to be positively given a rotational speed difference by a traveling drive mechanism.
It is known from Japanese Patent No. 34972, Japanese Patent Laid-Open No. 6-34332, Japanese Patent Publication No. 7-2468, and the like. The prior arts disclosed in these publications include a reversible continuously variable transmission, that is, a general-purpose hydraulic transmission, or Jikken Sho 49-26037.
JP, JP-A-56-18150, JP-A-59-
Two sets of other reversible continuously variable transmissions such as a friction mechanical type known from Japanese Patent No. 190556 are used to drive the left and right traveling means separately.

According to this conventional technique, it is easy to change the output rotational speeds of the left and right reversible continuously variable transmissions, including the rotational directions, to obtain the turning of the vehicle at an arbitrary turning radius. In addition, since it is driven by traveling using a reversible continuously variable transmission for each of the left and right sides, a complicated control device is required to ensure the straightness of the vehicle. That is, according to the structure in which the left and right traveling means are driven by different continuously variable transmissions,
It is difficult to obtain constant rotation of the left and right traveling means due to the left and right imbalance of the vehicle load, the left and right imbalance of the running resistance in the field scene, and the like. They needed a control unit.

A turning method similar to the above-described technique cannot be applied to a working vehicle in which the vehicle speed is changed stepwise. This is because a transmission having separate stepped transmission mechanisms for each of the right and left is not practical in terms of cost.

[0005]

SUMMARY OF THE INVENTION Accordingly, the present invention provides a reversible continuously variable transmission, such as a hydraulic transmission, which is independent of a transmission mechanism of a traveling drive system. A work vehicle that makes it easy to obtain a turn at an arbitrary turning radius of the vehicle in the same manner as in the prior art described above, even when the change control is performed or when the change control is performed stepwise. To provide a new steering device.

Another main purpose of the present invention is to turn the vehicle each time, for example, to finely correct the traveling direction of the vehicle during work, or to greatly change the traveling direction of the vehicle in a headland of a field. Accordingly, it is an object of the present invention to provide a steering device capable of achieving proper vehicle turning by operating a steering operation tool.

[0007]

SUMMARY OF THE INVENTION A steering device for a work vehicle according to the present invention is a reversible continuously variable transmission 2 which is operated by a steering operation tool 10 for shifting.
7, the reversible continuously variable transmission 27 is provided to the left and right traveling drive shafts 31L and 31R that are rotationally driven in the same direction at the same speed, and the reversible continuously variable transmission 27 is provided to the left and right traveling drive shafts 31L and 31R in opposite directions. The connection is characterized by an additional rotation transmission device 42 for transmitting additional rotation, the additional rotation transmission device 42 including at least two series of reduction transmission trains that can be operated alternatively.

The left and right traveling drive shafts 31L and 31R described above
May be continuously variable-speed driven or stepwise variable-speed driven. In the present invention, the traveling drive system is provided with respect to the left and right traveling drive shafts 31L and 31R that are evenly driven. Since the reversible continuously variable transmission 27, which is independent of the above, provides additional rotation in the opposite left-right direction via the additional rotation transmission device 42, the steering of the vehicle is obtained. The system is separated from the system, and therefore, a complicated control device for detecting and correcting the difference between the left and right rotational speeds in order to ensure the straightness of the vehicle is not required. Since the reversible continuously variable transmission 27 can continuously change the output speed of the vehicle, it is possible to turn the vehicle in any direction and with any turning radius while the vehicle is moving forward or backward. it can.

By configuring the additional rotation transmission device 42 to include at least two series of deceleration transmission trains that can be selectively operated, the operation amount of the steering operation tool 10 and the vehicle turning obtained thereby. The relationship with the mode can be changed by selecting the deceleration transmission train. That is, if a deceleration transmission train with a large reduction ratio is selected, a relatively small vehicle turning can be obtained even if the steering operation tool is operated relatively large, so for example, let's finely correct the traveling direction of the vehicle during work. If so, the correction can be made precisely.
Conversely, if a deceleration transmission train with a small reduction ratio is selected, a relatively large vehicle turn can be obtained even if the operation amount of the steering operation tool is relatively small. Therefore, for example, the vehicle travels on a headland in a field. When the direction is to be largely changed, a large change in the traveling direction can be swiftly performed by operating the steering operation tool.

In one embodiment of the present invention, the steering operation tool 10
The operation of the deceleration transmission train of the additional rotation transmission device 42 is automatically switched so that the deceleration transmission train having a smaller reduction ratio is operated as the operation amount of the steering operation tool is increased. Device. According to this configuration, when the steering operation tool is operated in a small range for fine course correction of the vehicle, the deceleration transmission train having a large reduction ratio is operated, so that it is suitable for the steering operation purpose at that time. A vehicle turn that can be precisely controlled is obtained, and conversely, when the steering operation tool is largely operated to make a large turn of the vehicle, the deceleration transmission train with a small reduction ratio operates to suit the purpose of the steering operation at that time. Therefore, a large vehicle turn can be quickly obtained.

However, if it is possible to obtain a vehicle turn that largely depends on the operation amount of the steering operation tool while the vehicle is traveling on a road at a relatively high speed, a sudden turn of the vehicle may cause a dangerous situation. It may occur. In preparation for such a case, it is preferable to further configure the steering device to maintain the operating state of the deceleration transmission train having a large reduction ratio when the vehicle speed of the vehicle is equal to or higher than the set value. According to this configuration, if the vehicle speed is equal to or higher than the set value, the deceleration transmission train operating state with a large reduction ratio can be obtained without fail, and the risk of suddenly turning the vehicle by the steering operation tool is greatly reduced.

Since the reversible continuously variable transmission is low in cost and reliable in operation, a hydraulic pump including a variable displacement hydraulic pump 25 whose tilt angle of the pump swash plate 25a is controlled by the steering operation tool 10 is changed. The transmission 27 is preferred.

[0013] Other features and advantages of the present invention will be apparent from the following description with reference to the accompanying drawings.

[0014]

FIG. 2 shows a combine equipped with an embodiment of the steering device according to the invention. The illustrated combine is driven and driven by the left and right crawlers 1 as usual, cuts the planted grain culm in the cutting section 2 in front of the machine body, threshes the cut culm in the threshing section 3 on the machine body, and removes the grain. It is stored in the grain tank 4 on the fuselage, and the waste straw is a waste straw processing device at the rear of the fuselage (bundling, bundling, cutter device or a switchable combination thereof).
5 is performed. The engine 6 is installed near the body, and a transmission 7 that receives input power from the engine is arranged at a lower front position of the engine 6. A control unit 9 having a seat 8 is disposed on the upper front side of the engine 6. The steering section 9 is a steering wheel 1 for steering a vehicle, which is shown as an example of a steering operation tool.
0, main speed change lever 11 and auxiliary speed change lever 1 for vehicle speed control
2. Equipped with a parking brake lever 13 and the like. In FIG. 2, 14 is an axle equipped with a crawler drive wheel 15, 16 is a cutting blade, and 17 is a grain lifting device for discharging grains from the grain tank 4.

FIG. 1 shows a transmission mechanism in the transmission 7. As shown in this figure and FIG. 2, the transmission 7 is provided with an input shaft 18, and an input pulley 19 is fitted on the input shaft 18 to Input transmission from the output pulley 6a of 6 to the input shaft 18 is performed by the belt 20.

As shown in FIG. 1, hydraulic pumps 21 and 25 having an input shaft 18 as a pump shaft and a hydraulic motor 2 connected to the pumps 21 and 25 through a pair of oil supply / discharge circuits.
2, 26 are provided. Each of the hydraulic pumps 21 and 25 is configured as a variable displacement type in which the oil discharge amount and the discharge direction can be freely changed by adjusting the inclination angles of the swash plates 21a and 25a. The combination of the first hydraulic transmission 23 and the combination of the hydraulic pump 25 and the hydraulic motor 26 results in the second hydraulic transmission 27.
Are provided respectively. These hydraulic transmissions 2
Reference numerals 3 and 27 denote reversible continuously variable transmissions that can output reversible continuously variable rotations from their output shafts 24 and 28.

A main drive shaft 3 for traveling drive fitted with a gear 29 which is rotationally driven in variable speed by a first hydraulic transmission 23.
0 and the left and right traveling drive shafts 31L and 31R are concentrically arranged, and the left and right traveling drive shafts 31L and 31R are connected to the left and right axles 14 through left and right gears 32 and 33 reduction mechanisms. There is. The main drive shaft 30 and the left and right traveling drive shafts 31L, 31R are connected to the left and right planetary gear speed reducers 34L,
It is connected by 34R. The illustrated planetary gear speed reducers 34L and 34R fix the sun gear 35 to the main drive shaft 30 and connect the planet carrier 36 to the travel drive shafts 31.
A plurality of planetary gears 38 fixed to L and 31R and rotatably supported by a planetary carrier 36 are configured to be meshed with a sun gear 35 and an internal gear 37. Each internal gear 37 is particularly rotatably supported, and each internal gear 37 is provided with a gear 39 that rotates integrally therewith.

In the second hydraulic transmission 27, the pump swash plate 25a is operated by the steering wheel 10 in FIG. 2, and the left and right internal gears 37 are added in opposite directions via the left and right gears 39. It is used to give rotation and to steer the vehicle. For that purpose, a rotary shaft 41 connected to the output shaft 28 by a coupling 40.
And an additional rotation transmission device 42 as shown in the figure, which is arranged between the left and right gears 39. The additional rotation transmission device 42 is
It is arranged in a transmission case 43 (FIGS. 3 and 4) provided in the transmission 7 of FIG. 2 together with a traveling power transmission mechanism between the output shaft 24 of the first hydraulic transmission 23 and the main drive shaft 30. As shown in FIGS. 3 and 4, a housing 45 is attached to a thick plate 44 mounted on the outer surface of the upper end of the mission case 43, and the hydraulic pumps 21 and 25 and the hydraulic motors 22 and 26 are the housing 45 or a similar one. It is arranged in another housing (not shown) attached to the plate body 44 and mounted on the plate body 44.

The structure of the additional rotation transmission device 42 will be described with reference to FIGS. 1 and 3-5. The rotation shaft 41 and the left and right gears 3 will be described.
Two intermediate shafts 46 and 47 are arranged between the nine shafts. Of these, the intermediate shaft 47 is, as shown in FIGS. 1 and 3, one of the two gears 48, 49 of equal diameter fixed to it.
Is directly meshed with the gear 39 on one side, and the gear 4
9, the idler gear 50 has a shaft 50a supported by the transmission case 43 as shown in FIG.
The left and right gears 39 are connected to the left and right gears 39 so as to rotate in the opposite directions at a constant speed.

As shown in FIGS. 1 and 4, on the rotary shaft 41,
Two gears 51 and 52 are arranged. Gear 5
Reference numeral 1 designates a deceleration drive by the rotary shaft 41 via a planetary gear mechanism 53 provided on the rotary shaft 41.
In order to obtain the rotation, the brake 54 is attached to the planetary gear mechanism 53. Further, the gear 52 is connected to the rotary shaft 41 by the operation of a clutch 55 provided on the rotary shaft 41, and is rotationally driven at a constant speed with the rotary shaft 41. As shown in FIG. 1, the rotary shaft 4 is provided on the intermediate shaft 46.
1 is engaged with the gears 51, 52 on the gear 1,
Gears 56 and 57, which are driven by deceleration rotation by 52, respectively.
Is fixedly installed. The intermediate shaft 46 is connected to the driven intermediate shaft 47 by reduction gears 58 and 59.

As shown in FIG. 4, in the planetary gear mechanism 53 on the rotary shaft 41, the sun gear 61 is fixed to the rotary shaft 41, and the planet carrier 62 and the internal gear 63 are arranged on the rotary shaft 41.
It is supported so that it can rotate relative to it, and pin 6 is attached to the planet carrier 62.
A plurality of planetary gears 64, which are rotatably supported by 2a, are configured to mesh with the sun gear 61 and the internal gear 63. The illustrated planet carrier 62 includes a spline cylinder 62b loosely fitted on the rotating shaft 41.
The carrier body is spline-fitted to 2b and is held in position by a pair of circlip 62c so that it can be slightly displaced in the axial direction and the radial direction, thereby achieving smooth meshing rotation of the planetary gear 64. There is. Then, the gear 51 is spline-fitted to the spline cylinder 62b,
It is supposed to rotate integrally with the planet carrier 62.

Similarly, as shown in FIG. 4, the brake 54 is
The boss portion 63a of the internal gear 63 and the inwardly facing tubular portion 65 integrally formed on one side wall of the transmission case 43 support a plurality of friction elements slidably and at the same time, a piston facing the friction element group. 54a is slidably fitted to the tubular portion 65, and a spring 54b having a base end received by a cover 66 closing the end of the tubular portion 65 is engaged with the piston 54a between the friction elements via the piston 54a. It is configured as a spring actuated multi-disc brake that is actuated to obtain. Cylindrical portion 65 and piston 5
4a is formed in a stepped manner as shown in the drawing, and an annular oil chamber 54c for releasing the braking by the brake 54 by moving the piston 54a against the force of the spring 54b is formed in the cylindrical portion 65. , Formed. Clutch 55
Fixes the clutch / cylinder 55a to the rotary shaft 41, and allows the friction elements for a plurality of sheets to be slidably supported by the cylinder 55a and the boss portion of the gear 52, and the return spring 55b is provided in the cylinder 55a. By providing a piston 55c that is urged to move and exerting a hydraulic pressure on an annular oil chamber 55d formed in the cylinder 55a, the movement of the piston 55c against the force of the spring 55b is obtained, and the friction elements are engaged. It is configured as a hydraulically actuated multi-plate clutch.

From the above, in the operating state of the brake 54, the internal gear 63 of the planetary gear mechanism 53 is restrained from rotating,
As a result, the rotation of the sun gear 61 rotating together with the rotating shaft 41 is significantly reduced and transmitted to the planet carrier 62, and the rotation thereof is further slightly reduced by the gears 51 and 56 and transmitted to the intermediate shaft 46. On the other hand, when the brake 54 is disengaged and the clutch 55 is engaged, the planetary gear mechanism 53 can no longer transmit power because the internal gear 63 of the planetary gear mechanism 53 can rotate freely. And the gears 52, 5 are rotated at a constant speed.
The speed is slightly reduced by 7 and transmitted to the intermediate shaft 46. The rotation of the intermediate shaft 46 is further decelerated and transmitted to the left and right gears 39 in opposite directions.

The structure of the traveling power transmission mechanism between the output shaft 24 of the first hydraulic transmission 23 and the main drive shaft 30 will be described with reference to FIGS.
8, an intermediate shaft 69 and an auxiliary transmission shaft 70 are provided. The output shaft 24 and the clutch shaft 68 are connected by reduction gears 71 and 72. A pedal 73a is provided on the clutch shaft 68.
(FIG. 2) A clutch 73 to be operated and a gear 74 which is always connected to the shaft 68 by the clutch 73 are provided.
The gear 74 meshes with a larger diameter gear 75 fixedly installed on the intermediate shaft 69. A mechanical three-stage auxiliary transmission device 76 is arranged between the intermediate shaft 69 and the auxiliary transmission shaft 70. This sub-transmission device 76 has two gears 77 and 79 loosely fitted on the intermediate shaft 69, and a single shift gear 78 is slidably provided on the intermediate shaft 69.
The gears 80 and 82 meshed with the gears 7 and 79 and the gear 81 capable of meshing the shift gear 78 are fixedly installed. The shift gear 78 is to be shifted by the auxiliary shift lever 12 of FIG. 2, and clutch means is interposed between the shift gear 78 and the gears 77 and 79. As described above, the auxiliary transmission device 76 has a high speed shift stage (road traveling shift stage) depending on the gears 77 and 80, a medium speed shift stage (dried field shift stage) depending on the gears 78 and 81, and a gear shift 79 depending on the gears 79 and 82 sequence. Rotation of the low speed shift stage (shift stage during wetland work) is obtained by the auxiliary shift shaft 70. Then, the gear 82 having the maximum diameter on the auxiliary transmission shaft 70 meshes with the gear 29 on the main drive shaft 30. A parking brake 83, which is operated by the parking brake lever 13 shown in FIG. 2, is arranged on the auxiliary transmission shaft 70.

As shown in FIG. 3, the left and right planetary carrier 36 in the left and right planetary gear speed reducers 34L and 34R.
Is the left and right traveling drive shafts 31L, 3 due to the spline fitting.
It is fixed to 1R and has the number of pins 36a corresponding to the number of planetary gears 38. The gears 39 are supported on the traveling drive shafts 31L and 31R via the boss portion of the carrier 36 and a pair of ball bearings 84, and the internal gear 37 is supported by the gears 39 so as not to rotate relative to each other.

FIG. 6 shows a hydraulic circuit and a control mechanism. As with the hydraulic pumps 21 and 25, an oil pump 85 that is driven by the engine 6 is provided, and the oil pump 85 supplies oil to the brake 54 and the clutch 55. It is said that. This oil supply control is performed by the electromagnetic directional control valve 8
6, the switching valve 86 drains oil from the oil chambers 54c and 55d described above with reference to FIG. 4 to activate the brake 54 and disengage the clutch 55, and the oil chamber. The oil is supplied to 54c and 55d to deactivate the brake 54 and the clutch 55.
Has a second position II, where The direction switching valve 86 is moved from the first position I to the second position by exciting the solenoid 86a.
Displace to position II.

There is provided a rotation control plate 87 which is rotated by the steering wheel 10 and changes and controls the inclination angle of the pump swash plate 25a of the second hydraulic transmission device 27. The control plate 87 has an operation angle detection switch. 88 is provided opposite. The detection switch 88 is provided with an actuator that abuts a cam surface formed on the control plate 87, and is maintained in an off state while the operation angle from the neutral position of the control plate 87 by the operation of the steering wheel 10 is smaller than the illustrated angle θ _1. It is configured to turn on when the operation angle is θ ₁ or more. As another sensor, as shown in FIG. 1, a rotation speed detection switch 89 for detecting the rotation speed of the auxiliary transmission shaft 70 is provided. The rotation speed of the auxiliary transmission shaft 70 is proportional to the vehicle speed, but the rotation speed detection switch 89 moves the auxiliary transmission shaft 70 to a rotation speed corresponding to the standard minimum vehicle speed when the illustrated combine is run on the road. When the rotation speed is increased,
It is configured to turn on. As shown in FIG. 6, both detection switches 88 and 89 are connected to a controller 90 for controlling the demagnetization of the solenoid 86a.

FIG. 7 shows a control routine of the electromagnetic directional control valve 86 by the controller 90 of FIG. 6, and the first directional control valve 86 is provided as long as the rotation speed detection switch 89 for detecting the vehicle speed is on. It is supposed to be held at the position I. If the detection switch 89 is not turned on, that is, if the vehicle speed is within the combine vehicle speed range in the field, the operation angle detection switch 88 that detects the operation amount of the steering wheel 10 is turned on, that is, the steering wheel. If the operation amount of the wheel 10 is equal to or larger than the planned value, the electromagnetic directional control valve 86 is displaced to the second position II, and conversely, the operation amount of the steering wheel 10 is smaller than the planned value and the switch 88 is turned on. Otherwise, the electromagnetic directional control valve 86 is placed in the first position I.

In FIG. 6, reference numeral 91 is a charge pump for supplying hydraulic oil to the first and second hydraulic power transmission devices 23, 27, 92 is a relief valve for setting the hydraulic pressure of the supplied hydraulic oil, and 93 is It is a relief valve that sets the oil pressure of the oil supplied to the brake 54 and the clutch 55 by the oil pump 91.

In the combine shown in FIG. 2, depending on the traveling conditions, the auxiliary transmission lever 12 causes the auxiliary transmission 76 shown in FIGS. 1 and 3 to provide a high speed during road traveling, a first low speed during dry field work, and a lower first during wet field work. The low speed gear position of 2 is selected and set, and the main speed lever 11 operates the pump swash plate 21a of the first hydraulic transmission 23 shown in FIGS. 1 and 6 to continuously change the vehicle speed including the control of the traveling direction. It is controlled and driven. Steering wheel 10 when the vehicle goes straight
The pump swash plate 25a of the second hydraulic transmission 27 shown in FIGS. 1 and 6 is not operated, and the hydraulic transmission 27 is maintained in the neutral state. In this state, when the internal gears 37 of the left and right planetary gear speed reducers 34L and 34R try to rotationally displace in the same direction at the same speed, the rotational displacements are reversed from the left and right gears 39 to the intermediate shaft 47 in opposite directions. Since the intermediate shaft 47 cannot be rotated in any direction because it is transmitted at a constant speed, the intermediate shaft 47 is locked so as not to rotate. A brake for positively locking the left and right internal gears 37 while the vehicle is traveling straight,
It may be provided in the additional rotation transmission device 42.

8 (L) and 8 (R) schematically show the left and right planetary gear speed reducers 34L and 34R. In the state where the hydraulic motor 22 of the first hydraulic transmission device 23 is normally rotating, the sun gear 35 rotates in the direction of arrow A, whereby each planetary gear 38 rotates in the direction of arrow B while rotating in the direction of arrow C. At 8, the planet carrier 36 (not shown) is revolved while rotating. In this case, the planet carrier and each traveling drive shaft 31
The number of revolutions R given to L and 31R is such that the number of revolutions of the sun gear 35 is ₁ , the number of teeth of the sun gear 35 is N ₁ , and the internal gear 37.
If the number of teeth of N is N ₂ , it is given by R = N ₁ / (N ₁ + N ₂ ), so by setting the number of teeth N ₂ appropriately, a significant deceleration can be obtained. When the hydraulic motor 22 rotates in the reverse direction, only the rotation direction is reversed, and the situation is the same as described above.

While the vehicle is moving forward, the steering wheel 10
To rotate the second hydraulic transmission device 27 shown in FIGS.
When the pump swash plate 25a is tilted and the hydraulic motor 25 is rotated in the forward direction, the additional rotation transmission device 42 causes the internal gear 37 of the left planetary gear reduction device 34L to indicate the arrow D ₁
Rotation in the direction of arrow D ₂ is applied to the internal gear 37 of the right planetary gear reducer 34R. Depending on the rotation speed of the left internal gear 37 in the direction of the arrow D ₁ , the rotation speed of the planetary gear 38 in the direction of the arrow C, that is, the rotation speed of the left planet carrier 36 and the traveling drive shaft 31L is reduced, Conversely, the right internal gear 3
By rotating 7 in the direction of arrow D ₂ , the number of rotations of the planetary gear 38 in the direction of arrow C, that is, the number of rotations of the planet carrier 36 and the traveling drive shaft 31R on the right side is increased by the rotation speed. Therefore, the vehicle is turned to the left, and its turning radius can be freely selected by adjusting the operation amount of the steering wheel 10 and controlling the rotational speed of the hydraulic motor 25. A right turn while the vehicle is moving forward and a left or right turn while moving backward can be obtained in a similar manner.

FIG. 9 shows the operation angle in the left-right direction from the neutral position N of the steering wheel 10 as the operation angle θ of the rotation control plate 87 in FIG. 7 is a graph schematically showing the relationship between θ and AR with the vertical axis representing the absolute value AR of the additional rotational speed given to the drive shafts 31L and 31R. Operating angle range D in FIG.
Corresponds to the range of play of the steering wheel 10.

Under the condition that the combine is traveling at a relatively low speed and the rotation speed detection switch 89 (FIGS. 1 and 6) is kept in the OFF state, the operating angle θ is the operating angle θ shown in FIG. _{In the} range smaller than ₁ , operating angle detection switch 8
8 (FIG. 6) is in the OFF state, and the electromagnetic directional control valve 8 of FIG.
6 has the first position I. Therefore, as described above, the brake 54 is operated, the internal gear 63 in the planetary gear mechanism 53 of FIGS. 1 and 4 is restrained from rotating, and the clutch 55 is disengaged. Therefore, as described above, the rotation of the hydraulic motor 26 of the second hydraulic transmission 27 causes the planetary gear mechanism 5 to rotate.
3 is greatly decelerated and transmitted to the gear 51 on the rotating shaft 41, and the rotation of the gear 51 is further decelerated so that the left and right internal gears 37 and the traveling drive shafts 31L, 31R are rotated.
Therefore, the additional rotation speed (absolute value) AR increases along the relatively gentle relationship line C ₁ as the operation angle θ increases. For this reason, the traveling direction of the vehicle can be finely adjusted by adjusting the operation amount of the steering wheel 10 within the range up to the operation angle θ ₁ , and for example, the traveling direction of the combine is correctly aligned with the planted culm row in the field. It is possible to precisely adjust the course such as making it move.

When the steering wheel 10 is largely operated to largely change the traveling direction of the vehicle and the operation angle θ becomes θ ₁ or more, the operation angle detection switch 88 is turned on and the electromagnetic directional control valve 86 is set to the second position in FIG. Take II. Therefore, as described above, in FIGS. 1 and 4, the brake 54 is deactivated, the clutch 55 is engaged, and the gear 52
Are coupled to the rotating shaft 41. Therefore, as described above, the reduction ratio in the additional rotation transmission device 42 is reduced, and the additional rotation speed (absolute value) AR given to the left and right internal gears 37 and the traveling drive shafts 31L and 31R is as shown in FIG. Increases along a relatively steep relationship line C ₂ . For this reason, the steering wheel 1 is operated in the range of the operation angle θ ₁ or more.
By increasing or decreasing the operation amount of 0, the traveling direction of the vehicle can be made large and can be rapidly changed at an arbitrary turning radius. For example, the combine traveling direction in a headland of a field can be drastically changed.

When the vehicle speed is set to a relatively high value such as when traveling on the road, under the condition that the rotation speed detection switch 89 shown in FIGS. The electromagnetic directional control valve 86 is kept at the first position I regardless of the operation amount of the wheel 10. Therefore, since the brake 54 is activated and the clutch 55 is disengaged, the additional rotation transmission device 42 operates at a large reduction ratio. Therefore, when the vehicle speed is relatively high, the vehicle always turns relatively gently even if the steering wheel 10 is operated to a large extent, and there is a risk associated with a sudden turn of the vehicle at a high vehicle speed. Prevented in advance.

FIGS. 10-12 show a second embodiment. As shown in FIG. 10, the left and right planetary gear reduction devices 34 are provided between the main drive shaft 30 and the left and right traveling drive shafts 31L and 31R.
Although L and 34R are provided, the planetary gear speed reducers 34L and 34R of FIG. 10 fix the internal gear 37 to the main drive shaft 30 and the planet carrier 36 to the traveling drive shafts 31L and 31R, respectively. The sun gear 35 is loosely fitted and supported on each of the traveling drive shafts 31L and 31R, and a plurality of planet gears 38 that are rotatably supported by the planet carrier 36 are meshed with the sun gear 35 and the internal gear 37. Configured to one. The left and right sun gears 35 correspond to the left and right gears 3 corresponding to the gear 39.
9, an additional rotation transmission device 42 for transmitting additional rotations in opposite directions from the steering hydraulic transmission 27 to the left and right sun gears 35 via the left and right gears 39.
Are provided.

The additional rotation transmission device 42 is the intermediate shaft 4
7 In the same way, the one side gear 39 is composed of gears 48 and 39,
Further, the other side gear 39 is provided with an intermediate shaft 47 which is respectively connected by a train of gears 49, 50 and 39, and a rotary shaft 100 which is connected to an output shaft 28 of a steering hydraulic power transmission 27 and is parallel to the rotary shaft 100. The control operating shaft 101 and the intermediate shaft 102 concentric with the intermediate shaft 47 are provided.

A planetary gear mechanism 103 is provided between the intermediate shaft 102 and the intermediate shaft 47. The planetary gear mechanism 103 fixes the sun gear 104 to the intermediate shaft 102 and the planet carrier 105 to the intermediate shaft 47, respectively. The internal gear 106
The planetary carrier 105 by loosely fitting and supporting the intermediate shaft 102.
A plurality of planetary gears 107 that are rotatably supported by the sun gear 104 and the internal gear 106,
It is configured. A gear 108 is integrally formed with the internal gear 106.

Two gears 109, 1 are mounted on the rotary shaft 100.
10 is fixedly installed, and one of these gears 109 is in mesh with the larger diameter gear 108. On the control operating shaft 91, a gear 111 meshed with the gear 110 is loosely fitted and a multi-plate clutch 112 for connecting the gear 111 to the operating shaft 101 is provided.
In addition, a multi-plate brake 113 for braking the control operating shaft 101 is also provided, and the control operating shaft 101 is a gear 11
It is connected to the intermediate shaft 102 by a 4,115 deceleration train.

Of the multi-plate type clutch 112 and brake 113 described above, the clutch 112 is of the spring load type which is engaged by the action of the spring 112a shown in FIGS.
It is supposed to be cut by the action of hydraulic pressure against 12a. The brake 113 is configured to be hydraulically operated, and when the hydraulic pressure is not applied, the spring 11 shown in FIG.
The braking operation is released by the action of 3a.

As shown in FIG. 11, an oil pump 85 for supplying oil to the clutch 112 and the brake 113,
And a directional control valve 120 for controlling the oil supply. The directional control valve 120 has a first position I for removing oil from the clutch 112 and the brake 113, and a second position I for supplying oil to the clutch 112 and the brake 113.
Position II of. This directional control valve 120 is of a hydraulic pilot type that is moved from a first position I to a second position II when a hydraulic pressure above a predetermined value is applied from the opposite side of the valve spring 120a. Pilot circuit 1 for applying pilot hydraulic pressure to 120
A shuttle valve 122 is provided at the base end of 21. The shuttle valve 122 includes a pair of hydraulic pressure take-out circuits 123A and 123B.
Is connected to a pair of oil supply / drain circuits 27A and 27B that connect between the pump 25 and the motor 26 in the hydraulic transmission 27, and the high-pressure oil that is determined by the tilting direction from the neutral position of the pump swash plate 25a. Supply / discharge circuit 27A or 27B
This hydraulic pressure is selected by the shuttle valve 122 and applied to the direction switching valve 120 as pilot hydraulic pressure.

In the combine according to the second embodiment, no hydraulic transmission device corresponding to the first hydraulic transmission device 23 (FIGS. 1 and 6) for continuously variable vehicle speed is provided. That is, FIG.
As shown in FIG. 5, in order to change the speed of the main drive shaft 30 by the mission input shaft 18 which receives the input transmission from the engine, the mechanical sub-speed transmission 131 and the third forward speed and the first reverse speed are used. A hydraulic clutch type main transmission device 132 having four shift speeds is used. Sub transmission 131
Is arranged between the input shaft 18 and a sub-transmission shaft 136 parallel to the input shaft 18, and a shift gear 137 is slidably installed on the input shaft 18, and the shift of the shift gear 137 causes the input shaft 18 to shift. Two gears 138 and 139 that are clutch-engaged with 18 are loosely fitted and installed. Sub speed change shaft 1
36, a gear 140 capable of meshing with a shift gear 137,
Gears 141 and 142 meshed with the gears 138 and 139 are fixedly installed. Therefore, the sub transmission 131 is shifted by the shift operation of the shift gear 137.
It is configured to obtain a gear shift.

Two clutch shafts 144, 145 and an output shaft 146 are provided in parallel with the shafts 18, 136, and two gears 148, 149 on the clutch shaft 144 and the gears are selected for the clutch shaft 144. 2 hydraulic clutches CF ₁ and CF ₂ for electrically connecting the clutch shaft 1
Two gears 150, 151 and two hydraulic clutches CF ₃ , CR for selectively connecting the gears to the clutch shaft 145 are installed on the 45. The gear 148 meshes with the gear 152 fitted to the sub-transmission shaft 136 to rotate in the forward direction, and the gears 149 and 150 mesh with the gear 153 fitted to the sub-transmission shaft 136 to rotate in the forward direction. Gear 1
The gear 51 meshes with the gear 148 on the clutch shaft 144 and rotates in the reverse direction. The gears 155 and 156 fitted to the clutch shafts 144 and 145 are meshed with the gear 157 fitted to the output shaft 146, so that the output shaft 146 can be shifted and rotated by the hydraulic clutch type main transmission 132. . The output shaft 146 has hydraulic clutches CF ₁ , C.
The first speed, the second speed, and the third speed are obtained by operating each of F ₂ and CF _{3, and} the first reverse speed is obtained by operating the hydraulic clutch CR.

The output shaft 146 has a gear 158 fitted thereto.
Is engaged with the gear 29 on the main drive shaft 30 similar to that described above, and the main drive shaft 30 is decelerated. It should be noted that the output shaft 146 is provided with an internally expanding traveling brake 16
0 is set.

In the second embodiment of FIGS. 10-12,
When the steering wheel 10 is operated in one direction or the other direction from the neutral position and the pump swash plate 25a is tilted in one direction or the other direction from the neutral position, the larger the swash plate inclination angle is, the higher the oil supply / discharge circuit becomes at that time. While the hydraulic pressure of 27A or 27B is increased, the directional control valve 120 moves from the first position I to the second position when the hydraulic pressure reaches a predetermined value.
Moved to II.

When the directional control valve 120 is in the first position I, the clutch 112 shown in FIGS. 10 and 11 is engaged, the gear 111 is connected to the control operating shaft 101, and the brake 113 is inactive. Control operating axis 1
01 is rotatable. Therefore, the control operating shaft 101 is rotated by the rotating shaft 100 via the gears 110 and 111, and the rotation thereof is performed via the gears 114 and 115.
It is transmitted to 02. The direction switching valve 120 is in the second position II.
10 and 11, the clutch 112 in FIGS. 10 and 11 is disengaged, the gear 111 is disengaged from the control operating shaft 101, and the brake 113 is activated to restrain the control operating shaft 101 from rotating, whereby the gears 114 and 115 are rotated. The intermediate shaft 102 is non-rotatably restrained via the. The internal gear 106 of the planetary gear mechanism 103 is provided at any position of the directional control valve 120.
Is rotated by the rotating shaft 100 via gears 109 and 108.

In the planetary gear mechanism 103, the sun gear 10
4 is fixed, the rotational speed R _C obtained on the planet carrier 105 and the intermediate shaft 47 fixing the planet carrier 105 is 1, the rotational speed of the internal gear 106 is 1, the sun gear 104 and the internal gear 10
When the number of teeth of 6 is Z ₁ and Z ₂ , respectively, it is given by R _C = Z ₂ / (Z ₁ + Z ₂ ). On the other hand, at the first position I of the directional control valve 120, the rotation of the rotary shaft 100 is also transmitted to the intermediate shaft 102 via the control operation shaft 101 as described above, and thus the sun gear 104 fixed to the intermediate shaft 102. Is the internal gear 1
It rotates in the opposite direction to 06. Reverse rotation of the sun gear 104 has the same effect on the reduction ratio obtained by the planetary gear mechanism 103 as if the number of teeth of the sun gear 104 were increased from the actual number of teeth Z ₁ , and so is increased. If the apparent number of teeth is Z ₁ ′ (Z ₁ <Z ₁ ′), the rotational speed R _C ′ of the planet carrier 105 and the intermediate shaft 47 thus obtained is R _C ′ = Z ₂ / (Z ₁ '+ Z ₂₎ would be given by _{(R C> R C')} .

That is, the first position I of the directional control valve 120.
Then, the decelerated rotation according to the latter formula above is applied to the planet carrier 10.
5 and intermediate shaft 47. On the other hand, the directional control valve 1
In the second position II of 20, the intermediate shaft 102 is non-rotatably restrained by the brake 113 via the control operation shaft 101 as described above, and the sun gear 104 on the intermediate shaft 102 is fixed. The decelerated rotations obtained on the planet carrier 105 and the intermediate shaft 47 are in accordance with the former formula. The above R _C and R _C ′ can be made significantly different by appropriately setting the relationship between the gear ratios of the gears 109 and 108 and the gear ratios of the gears 110 and 111 and the gears 114 and 115.

In FIG. 12, the horizontal axis represents the hydraulic pressure P obtained in the oil supply / discharge circuits 27A and 27B on the high pressure side by tilting in one direction and the other direction from the neutral position of the pump swash plate 25a.
The absolute value AR of the additional rotational speed given to the left and right traveling drive shafts 31L and 31R in FIG.
And V ₁ corresponds to the displacement pilot hydraulic pressure from the position I to the position II of the directional control valve 120. The hydraulic pressure P on the horizontal axis may be regarded as the operating angle of the steering wheel 10. Similar to the case of the first embodiment, the gentle turning of the vehicle can be finely adjusted, and a large change in the traveling direction of the vehicle can be quickly performed. It will be.

[Brief description of drawings]

FIG. 1 is a mechanism diagram showing a transmission mechanism provided in a combine equipped with a first embodiment.

FIG. 2 is a schematic side view of the combine.

FIG. 3 is a partially developed vertical sectional view showing a part of a transmission provided in the combine.

FIG. 4 is a vertical cross-sectional view showing the main parts of the first embodiment.

FIG. 5 is a vertical sectional view showing a part of the first embodiment.

FIG. 6 is a circuit diagram showing a hydraulic circuit according to the first embodiment.

FIG. 7 is a flowchart showing a control mode in the first embodiment.

FIG. 8 is a schematic diagram for explaining the operation of the planetary gear speed reducer provided in the combine.

FIG. 9 is a schematic graph for explaining the operation of the first embodiment.

FIG. 10 is a mechanism diagram showing a transmission mechanism provided in a combine equipped with the second embodiment.

FIG. 11 is a circuit diagram showing a hydraulic circuit according to a second embodiment.

FIG. 12 is a schematic graph for explaining the operation of the second embodiment.

[Explanation of symbols]

 6 engine 10 steering wheel 18 input shaft 25 hydraulic pump 25a pump swash plate 26 hydraulic motor 27 hydraulic transmission 28 output shaft 30 main drive shaft 31L, 31R traveling drive shaft 34L, 34R planetary gear speed reducer 39 gear 41 rotary shaft 42 additional rotation Transmission device 46,47 Intermediate shaft 48,49 Gear 50 Idler gear 51,52 Gear 53 Planet gear mechanism 54 Brake 55 Clutch 56,57 Gear 61 Sun gear 62 Planet carrier 63 Internal gear 64 Planet gear 85 Hydraulic pump 86 Electromagnetic directional control valve 87 Rotation Control Plate 88 Operation Angle Detection Switch 89 Rotation Speed Detection Switch 100 Rotational Axis 101 Control Actuating Axis 102 Intermediate Axis 103 Planetary Gear Mechanism 104 Sun Gear 105 Planetary Carrier 106 Internal Gear 107 Planetary Gear 108 Gear 109, 110 Car 111 gear 112 clutch 113 brakes 114 and 115 gear 120 direction switching valve 122 shuttle valve

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[Procedure amendment]

[Submission date] September 6, 1996

[Procedure amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0002

[Correction method] Change

[Correction contents]

[0002]

2. Description of the Related Art Japanese Patent Application Publication No. Sho 54-54 discloses a technique in which a working drive mechanism causes a left and right traveling means (crawlers or wheels) to be positively given a rotational speed difference by a traveling drive mechanism.
It is known from Japanese Patent No. 34972 , Japanese Patent Laid- Open No. 6-343332 , Japanese Patent Publication No. 7-2468 , and the like. The prior art disclosed in these publications is a reversible continuously variable transmission, that is, a widely used hydraulic transmission or Japanese Utility Model Publication No. 49-2603.
7, JP-A-56-18150, JP-A-59-18150
The left and right traveling means are separately driven by using two sets of other reversible continuously variable transmissions such as a friction mechanical type known from, for example, -190556.

[Procedure amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] 0032

[Correction method] Change

[Correction contents]

While the vehicle is traveling straight, the steering wheel 10
To rotate the second hydraulic transmission device 27 shown in FIGS.
When tilting the pump swash plate 25a and rotating the hydraulic motor 26 in the normal rotation direction, the additional rotation transmission device 42 causes the internal gear 37 of the left planetary gear reduction device 34L to indicate the arrow D _1.
Rotation in the direction of arrow D ₂ is applied to the internal gear 37 of the right planetary gear reducer 34R. Depending on the rotation speed of the left internal gear 37 in the direction of the arrow D ₁ , the rotation speed of the planetary gear 38 in the direction of the arrow C, that is, the rotation speeds of the left planet carrier 36 and the traveling drive shaft 31L are reduced. Conversely, the right internal gear 3
Depending rotation 7 to arrow D ₂ rotating speed in the arrow C direction of the planetary gear 38 by the rotational speed component, thus the rotational speed of the right planet carrier 36 and the traveling drive shaft 31R is increased. Therefore, the vehicle is turned to the left, and its turning radius can be freely selected by adjusting the operation amount of the steering wheel 10 and controlling the rotational speed of the hydraulic motor 26 . A right turn while the vehicle is moving forward and a left or right turn while moving backward can be obtained in a similar manner.

Claims (4)

[Claims] 1. A left and right traveling drive shaft (31L, 3) provided with a reversible continuously variable transmission (27) which is operated to change gears by a steering operation tool (10), and which are rotationally driven in equal directions at equal speeds.
1R), the reversible continuously variable transmission is an additional rotation transmission device for transmitting additional rotations in opposite directions to the left and right traveling drive shafts, and at least two series decelerations that can be selectively operated. A steering device for a work vehicle characterized by being connected by an additional rotation transmission device (42) including a transmission train. 2. The deceleration transmission train of the additional rotation transmission device (42) interlocked with the operation of the steering operation tool (10), the deceleration transmission having a smaller reduction ratio as the operation amount of the steering operation tool increases. A steering system according to claim 1, wherein the rows are automatically switched to be actuated. 3. The steering apparatus according to claim 2, wherein when the vehicle speed of the vehicle is equal to or higher than a set value, the operating state of the deceleration transmission train having a large reduction ratio is maintained. 4. A hydraulic power transmission device comprising the variable displacement hydraulic pump (25), wherein the reversible continuously variable transmission comprises a variable displacement hydraulic pump (25) whose tilt angle of a pump swash plate (25a) is controlled by a steering operation tool (10). 27) The steering apparatus according to any one of claims 1 to 3, which is 27).