JP2003291848A - Working vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To heighten the safety of a working vehicle in turning. <P>SOLUTION: This working vehicle is provided with a low speed holding mechanism for turning for holding a fixed low speed from a region of play of a steering wheel to a designated turning operation angle, and a continuously variable transmission for increasing a rotating speed of a power transmission system for turning in proportion to the turning operating angle of a steering wheel when it exceeds a designated turning operation angle. The car body is turned at a fixed low speed until a designated turning operation angle so that no unexpected fright is given to an operator and the safety can be heightened. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a work vehicle.

[0002]

2. Description of the Related Art Conventionally, as one form of a work vehicle, the rotational speeds of a straight power transmission system that can be operated by a gear shift operation lever and a turning power transmission system that can be operated by a steering wheel are combined, Some of them are equipped with a mission unit that individually drives the pair of left and right crawler type traveling units by the combined rotation speed.

In such a work vehicle, a gear shift operation lever can be used to perform a gear shift operation, and the rotation speed of the turning power transmission system is proportional to the turning operation angle of the steering wheel. It is possible to increase infinitely by the device.

In this way, by rotating the steering wheel, the pair of left and right crawler type traveling portions are individually driven, and a relative speed difference is given to these traveling portions, thereby steering the vehicle body. The wheel can be turned in the turning direction.

[0005]

However, in the above-mentioned work vehicle, when the steering wheel is rotated, if the preset play range of the steering wheel is exceeded, the steering wheel is rotated. Since the rotation speed of the turning power transmission system is increased steplessly by the turning continuously variable transmission in proportion to the angle, depending on the turning operation angle of the steering wheel operated by the operator, the vehicle body is more than expected by the operator. May make a sharp turn and give the operator a fear.

[0006]

In view of the above, in the present invention, the rotational speeds of a straight traveling power transmission system that can be operated by a shift operation lever and a turning power transmission system that can be operated by a steering wheel are combined. In a work vehicle equipped with a mission unit that individually drives a pair of left and right crawler type traveling units by this combined rotation speed, a constant low speed is maintained from the play area of the steering wheel to a predetermined rotation operation angle. A low speed holding mechanism for turning and a continuously variable transmission for turning which increases the rotation speed of the turning power transmission system in proportion to the turning operation angle of the steering wheel when a predetermined turning operation angle is exceeded are provided. A work vehicle characterized by the above.

Further, according to the present invention, a rotating operation angle detecting means for detecting a rotating operation angle of a steering wheel, a control means connecting the rotating operation angle detecting means to its input side, and an output of the controlling means. It is also characterized in that it is provided with switching means connected to the side and switching between a non-functioning state and a functioning state of the turning continuously variable transmission device based on the detection result of the turning operation angle detecting means.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below.

That is, the work vehicle according to the present invention has, as a basic structure, the rotational speeds of a straight traveling power transmission system which can be operated by a gear shift operation lever and a turning power transmission system which can be operated by a steering wheel. Combining,
It is equipped with a mission unit that individually drives the pair of left and right crawler type traveling units by this combined rotation speed.

As a characteristic structure, a low speed holding mechanism for turning which keeps a constant low speed from the play area of the steering wheel to a predetermined turning operation angle, and when a predetermined turning operation angle is exceeded, A turning continuously variable transmission that increases the rotational speed of the turning power transmission system in proportion to the turning operation angle of the steering wheel is provided.

That is, the turning operation angle detecting means for detecting the turning operation angle of the steering wheel, the control means connecting the turning operation angle detecting means to the input side thereof, and the output side of the control means are connected. And a switching means for switching the turning continuously variable transmission between a non-functioning state and a functioning state based on the detection result of the turning operation angle detecting means.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1A shows a work vehicle according to the present invention. The work vehicle A is provided with an elevating mechanism C at a rear portion of a traveling body B, and the elevating mechanism C has a tilling device (working device). (Not shown) are connected.

As shown in FIG. 1, the traveling vehicle body B has a vehicle body frame 2 interposed between a pair of left and right crawler type traveling portions 1, 1 on the vehicle body frame 2 at a front portion thereof.
And the drive unit 4 and the mission unit 5 are arranged one above the other at the rear, and the drive unit 1, 1 is attached to the drive unit 4.
Are linked together via the mission unit 5.

The traveling unit 1 has front driven wheels 11 at the front end of a traveling frame 10 extending in the front-rear direction and idler forks 12.
On the other hand, the rear driven wheel 13 is attached to the rear end of the front and rear driven wheels 11 and 13, and
A drive wheel 15 interlockingly connected to the mission unit 5 is arranged above the traveling frame 10, and a crawler belt 16 is wound around these driving wheels 11, 13 and 15. Four 1st, 2nd, 3rd, 4th rolling wheels 17 spaced apart in the direction
Attached a, 17b, 17c, 17d. 11a is a front driven wheel support shaft, 13a is a rear driven wheel support shaft, and 15a is a drive shaft.

The front and rear portions of the pair of left and right traveling frames 10, 10 are respectively provided with front and rear support frames 18, 18,
19 and 19 are formed so as to rise upward and extend in the left-right direction between the front support frames 18, 18 facing each other in the left-right direction and between the rear support frames 19, 19 facing each other in the left-right direction. Before forming part of the body frame 2
The rear connecting frames 20, 21 are laid horizontally, and a pair of left and right front and rear supporting frames 18, 18, 19, are connected to both connecting frames 20, 21.
19 are connected so that the slide position can be adjusted in the left-right direction, and the space between the pair of left and right running parts 1, 1 in the left-right direction can be increased or decreased.

The vehicle body frame 2 is formed of the above-mentioned front / rear connecting frames 20 and 21, and the guard frame 22 which is provided across the connecting frames 20 and 21 via front and rear guard frame stays 28 and 29. ing. 35 is a safety frame.

In the operation unit 3, a floor 23 is stretched on the front half of the guard frame 22, an operation column 24 is erected on the front of the floor 23, and a steering wheel is provided on the upper end of the operation column 24.
25 is mounted via the wheel support shaft 26, the forward / reverse switching lever 36 is mounted on the left side wall of the operation column 24, the seat 27 is arranged at the rear position of the steering wheel 25, and the left side position of the seat 27 is arranged. A gear shift operation lever 37 is arranged on the other hand, and an elevating operation lever 38 is arranged on the right side position.

As shown in FIGS. 1 and 2, the prime mover section 4 has an engine E disposed behind the seat 27,
The output shaft 30 of the engine E is interlockingly connected to the mission unit 5 via a first transmission mechanism 31 and a second transmission mechanism 32, and
A PTO shaft 33 is linked to the output shaft 30 via a third transmission mechanism 34.

As shown in FIG. 2, a hydrostatic stepless speed change gear HST40, which is a hydrostatic stepless transmission, is interlockingly connected to the mission section 5 so that the vehicle speed can be continuously changed. 5, the transmission input shaft 41 interlockingly connected to the second transmission mechanism 32 is provided with a forward switching clutch 42, while the counter shaft 43 arranged near the transmission input shaft 41 is provided with a reverse switching clutch 44.

In this way, when the forward / reverse switching lever 36 is rotated forward, the forward switching clutch 42 is brought into the connected state and the reverse switching clutch 44 is brought into the disengaged state, while the forward / backward switching lever 36 is moved backward. When the rotary switch is turned to, the forward changeover clutch 42 is disengaged and the reverse changeover clutch 44 is in the connected state. When the forward / reverse changeover lever 36 is rotated to the neutral position, both the forward / reverse changeover clutch 4 are engaged.
2,44 is set to the disconnected state.

Further, the mission section 5 is provided with an intermediate output shaft 47 interlockingly connected to the mission input shaft 41 and the counter shaft 43, and the intermediate output shaft 47 and the turning power transmission mechanism 48 are provided.
As shown in FIG. 3, between the turning input shaft 60 and the turning input shaft 60, a constant low speed is maintained from the play area (play angle) θ1 of the steering wheel 25 to a predetermined turning operation angle θ2. A low speed holding mechanism 61 for turning which holds the turning speed and a HST 40 for turning which increases the turning speed of the turning power transmission system in proportion to the turning operation angle of the steering wheel 25 when a predetermined turning operation angle θ2 is exceeded. On the other hand, the intermediate input shaft 50 forms the input shaft of the linear power transmission mechanism 49 on the intermediate output shaft 47.
Are linked together.

Here, the turning power transmission mechanism 48 constitutes a turning power transmission system in which gear shifting can be performed by the steering wheel 25, and the straight-ahead power transmission mechanism 49 can be gear shifting operated by the gear shifting operation lever 37. A straight-line power transmission system is configured.

As shown in FIG. 2, the turning low speed holding mechanism 61 has a first electromagnetic clutch 62a interposed between the intermediate output shaft 47 and the input shaft 40a of the turning HST 40, and the first electromagnetic clutch The output sprocket 63 for turning is attached to the intermediate output shaft 47 located on the upstream side of 62a, while one end of the input shaft 60 for turning is interlockingly connected to the output shaft 40b of the HST 40 for turning via the second electromagnetic clutch 62b. Then, the boss portion 64 is rotatably fitted to the turning input shaft 60, and the turning input sprocket 65 is attached to the outer peripheral surface of the boss portion 64 via the third electromagnetic clutch 62c. The turning transmission chain 66 is wound around the boss portion 64, and the low speed holding output gear 68 is attached to the outer peripheral surface of the boss portion 64, and the low speed holding output gear 68 forms a part of the turning power transmission mechanism 48. Configured by meshing with the low speed input gear 70 attached to the turning first shaft 69 To have.

A proportional speed increasing output gear 71 is attached to the turning input shaft 60, and the proportional speed increasing output gear 71 is meshed with the proportional speed increasing input gear 72 attached to the turning first shaft 69. ing.

Further, the turning power transmission mechanism 48 interlocks the above-described first turning shaft 69 with a pair of left and right planetary gear mechanisms 51, 51 described later through the second and third turning shafts 76, 77. And
Ring gear 51a forming part of the left planetary gear mechanism 51
The left side of the turning third shaft 77 is engaged with the turning third shaft left output gear 77a, while the right side planetary gear mechanism 5 is engaged.
A ring gear 51a forming a part of 1 is engaged with a turning third shaft right output gear 77b attached to the right side of the turning third shaft 77 via a counter gear 78. 69a is the first for turning
A shaft output gear, 76a is a second shaft input gear for turning that meshes with a first shaft output gear 69a for turning, 76b is a second shaft output gear for turning, and
Reference numeral 7c denotes a turning third shaft input gear that meshes with the turning second shaft output gear 76b.

Here, as shown in FIG. 2, the turning operation angle of the steering wheel 25 is detected by a turning operation angle detecting means 73 such as a potentiometer. The first, second, and third electromagnetic clutches 62a, 62b, and 62c are connected to the input side of the control means 74, and the output side of the control means 74 is connected to the first, second, and third electromagnetic clutches. The clutches 62a, 62b, 62c constitute the switching means 75.

In this way, the steering wheel 25
When the rotation operation angle detection means 73 detects that the rotation operation angle of the is within the range from the play range θ1 to the predetermined rotation operation angle θ2, the detection result is input to the control means 74 and the same control is performed. means
74 outputs to the switching means 75, and the switching means 75 causes the turning HST 40 not to function, that is, the first and second electromagnetic clutches 62a and 62b are in the power disengaged state, and the third electromagnetic clutch 62c is powered. In the connected state, the power is transmitted to the turning power transmission mechanism 48 through the turning low speed holding mechanism 61 so that the vehicle body is turned at a constant low speed S1 regardless of the turning operation of the steering wheel 25. Can be maintained.

At this time, the vehicle body turns at a constant low speed S1, so that good safety can be ensured.

When the turning operation angle detecting means 73 detects that the turning operation angle of the steering wheel 25 exceeds a predetermined turning operation angle θ2, the detection result is detected by the control means.
74, and the control means 74 outputs it to the switching means 75 so that the turning continuously variable transmission functions by the switching means, that is, the first and second electromagnetic clutches 62a, 62b are brought into a power connection state. At the same time, the third electromagnetic clutch 62c is put into the power disengaged state, and the power transmission mechanism for turning is transmitted via the HST40 for turning.
By transmitting power to the steering wheel 48, the rotational speed of the turning power transmission mechanism 48 can be increased in proportion to the turning operation angle of the steering wheel 25. In FIG. 3, S2 is a proportional increase speed of the vehicle body that increases in proportion to the turning operation angle of the steering wheel 25.

At this time, the vehicle body can be efficiently turned to a desired turning angle.

As shown in FIG. 2, the rectilinear power transmission mechanism 49 has a sun gear support shaft 54 interlockingly connected to a rectilinear input shaft 50 via rectilinear first and second shafts 52 and 53. Input shaft 50
A main speed change mechanism 55 is formed between the first straight movement shaft 52 and the first straight movement shaft 52, and a sub transmission mechanism 56 is formed between the first straight movement shaft 52 and the second straight movement shaft 53.

The main speed change mechanism 55 is provided for the straight-moving input shaft 50.
The first, second, and third main transmission output gears 50a, 50b, 50c are rotatably and coaxially attached to these second main transmission output gears.
Between the 50b and the third main transmission output gear 50c, the straight-moving input shaft 50
Main slider slider 50d is splined to
A second main transmission gear 50b is connected to the main transmission slider 50d,
The main shift slider 50d can be engaged / disengaged with the first main shift output gear 50a or the third main shift output gear 50c, while the first, second, and third main shifts for the straight-moving first shaft 52 are performed. The first, second, and third main transmission input gears 52a, 52b, 52c that mesh with the output gears 50a, 50b, 50c are coaxially attached and formed.

Moreover, the gear shift operating lever 37 is interlockingly connected to the main gear shift slider 50d described above,
The 37 allows the power transmission mechanism 49 for rectilinear movement to perform main shifting in three stages.

The subtransmission mechanism 56 coaxially mounts the first and second subtransmission output gears 52d and 52e on the first shaft 52 for straight movement, while the first and second subshafts 52a and 52e are attached to the second shaft 53 for straight movement. Variable speed input gear 53
The a and 53b are rotatably coaxially mounted, and the auxiliary shift slider 53c is spline-fitted to the straight-moving second shaft 53 between the first and second auxiliary shift input gears 53a and 53b. The second auxiliary shift input gear 53b is connected to the slider 53c for engagement, and the auxiliary shift slider 53c is engaged with the first auxiliary shift input gear 53a.
It is said to be detachable.

Moreover, an auxiliary shift operating lever (not shown) is interlockingly connected to the above-described auxiliary shift slider 53c, so that the linear power transmission mechanism 49 can be shifted in two steps by the auxiliary shift operating lever. I am able to do it. 57 is a parking brake.

The sun gear support shaft 54 also forms a part of a pair of left and right planetary gear mechanisms 51, 51 which will be described later.
1b, the sun gear support shaft 54 is fitted with a straight-travel input sprocket 54a, while the above-mentioned straight-travel second sprocket 54a is mounted.
A straight advancing output sprocket 53d is attached to the shaft 53, and a straight advancing transmission chain 58 is wound between both sprockets 53d and 54a.

As shown in FIG. 2, each planetary gear mechanism 51, 51 has a primary gear 51c, 51c interposed between each ring gear 51a, 51a and each sun gear 51b, 51b, and each primary gear 51c, 51c. The drive wheels 15 and 15 are attached to the cages 51d and 51d that support the shafts via the drive shafts 15a and 15a. Reference numeral 59 is a power take-off shaft for driving a charge pump, and P is a charge pump.

In this way, the power is transmitted from the turning power transmission mechanism 48 to the ring gears 51a, 51a forming a part of the left and right planetary gear mechanisms 51, 51, and at the same time, the left and right power is transmitted from the straight drive power transmission mechanism 49. The power is transmitted to the sun gears 51b, 51b forming a part of the planetary gear mechanism 51, 51, and these powers are combined by the primary gears 51c, 51c, and the combined power is transmitted via the cages 51d, 51d. The power is transmitted to the drive shafts 15a, 15a, and output from the drive shafts 15a, 15a to the drive wheels 15, 15.

[0040]

According to the present invention, the following effects can be obtained.

(1) According to the first aspect of the present invention, a low speed holding mechanism for turning which holds a constant low speed from the play area of the steering wheel to a predetermined turning operation angle, and a predetermined turning operation. A turning continuously variable transmission that increases the rotational speed of the turning power transmission system in proportion to the turning operation angle of the steering wheel is provided.

In this way, from the play area of the steering wheel to a predetermined turning operation angle, a constant low speed is maintained by the turning low speed holding mechanism, and the sensitivity of the turning operation of the steering wheel is set to a predetermined value. Since the rotation operation angle is set to be dull, the vehicle body turns at a constant low speed up to this predetermined rotation operation angle, which does not give an unexpected fear to the operator, and safety is improved. Can be increased.

When the turning operation angle is exceeded, the turning speed of the turning power transmission system can be increased by the turning continuously variable transmission in proportion to the turning operation angle of the steering wheel. It is possible to efficiently turn to a desired turning angle.

(2) In the present invention according to claim 2, there are provided a rotating operation angle detecting means for detecting a rotating operation angle of the steering wheel, and a control means having the rotating operation angle detecting means connected to its input side. And a switching means which is connected to the output side of the control means and which switches the turning continuously variable transmission between a non-functioning state and a functioning state based on the detection result of the turning operation angle detecting means.

In this way, when the turning operation angle detecting means detects that the turning operation angle of the steering wheel is within the range from the play area to the predetermined turning operation angle, the detection result is detected by the control means. The control means outputs it to the switching means so that the continuously variable transmission for turning does not function by the switching means, that is, the vehicle body turns at a constant low speed regardless of the turning operation of the steering wheel. It is possible to retain the state that is set.

At this time, since the vehicle body turns at a constant low speed, good safety can be ensured.

When the turning operation angle detecting means detects that the turning operation angle of the steering wheel exceeds a predetermined turning operation angle, the detection result is input to the control means, and the control means switches. It is possible to increase the rotational speed of the turning power transmission system in proportion to the state in which the continuously variable transmission for turning functions by the switching means, that is, the turning operation angle of the steering wheel.

At this time, the vehicle body can be efficiently turned to a desired turning angle.

[Brief description of drawings]

FIG. 1 is a side view of a work vehicle according to the present invention.

FIG. 2 is a conceptual diagram of power transmission.

FIG. 3 is an explanatory view of a relationship between a steering operation angle of a steering wheel and a vehicle speed.

[Explanation of symbols]

A work vehicle 1 running section 2 body frame 3 driving department 4 prime mover department 5 Mission Department

Continued front page    F-term (reference) 2B043 AA04 AB08 AB19 BA02 BB01                       BB03 DA04 EA02 EB14 EB22                       EC02 EC12 EC14 EC19 ED02                 3D052 AA05 AA11 BB08 DD03 EE01                       FF02 GG03 JJ03 JJ10 JJ11                       JJ21 JJ37

Claims (2)

[Claims] Claim: What is claimed is: 1. A combined rotation speed of a straight driving force transmission system that can be shifted by a shift operation lever (37) and a turning power transmission system that can be shifted by a steering wheel (25). In a work vehicle equipped with a mission unit (5) that individually drives a pair of left and right crawler type traveling units (1, 1) depending on speed, a predetermined rotation operation from the play area (θ1) of the steering wheel (25) The turning low speed holding mechanism (45) that holds a constant low speed (S1) up to the angle (θ2), and the turning operation of the steering wheel (25) when it exceeds a predetermined turning operation angle (θ2). A work vehicle provided with a turning continuously variable transmission (40) for increasing the rotation speed of a turning power transmission system in proportion to an angle. 2. A rotating operation angle detecting means (73) for detecting a rotating operation angle of a steering wheel (25) and a control means (74) having the same rotating operation angle detecting means (73) connected to its input side. ), And a state in which the continuously variable transmission for rotation (40) does not function and a state in which it functions based on the detection result of the rotation operation angle detection means (73) connected to the output side of the control means (74). Switching means to switch to
The working vehicle according to claim 1, further comprising (75).