JP2016220580A - Work vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a lifting/lowering speed to be adjusted in a work machine lifting/lowering device of a work vehicle connected with a work machine so as to be lifted/lowered.SOLUTION: In a work vehicle, a work machine 22 is connected to a rear part of a travel vehicle body 1 and a lifting/lowering arm 50 is turned to lift/lower the work machine 22. The work vehicle includes: a damper arm 123 turned in linkage with the lifting/lowering arm 50; and a damper 137 reducing a turning speed of the damper arm 123. In the work machine, a damper position change member 140 changing and fixing a damper fixing position in a radial direction with respect to a turning fulcrum of the damper arm 123 is arranged in the damper arm 123.SELECTED DRAWING: Figure 7

Description

  The present invention relates to a work vehicle such as a tractor in which a work device such as a tillage device is connected to a rear portion.

  When the work implement is connected to the vehicle so that it can be raised and lowered, when the work implement is lowered and brought into contact with the ground, if it is grounded at a high speed, the work implement is burdened and may be damaged in some cases. It was.

  Also, for example, when using a tilling device such as a rotary working machine that plows a farm field by rotating a tilling claw, if the working machine is rotated and suddenly placed on the ground, the working machine The rotational driving force becomes a driving force of the work vehicle, causing a problem that the work vehicle suddenly starts, that is, a so-called dashing phenomenon occurs.

  In order to prevent this, when the working machine raised by the hydraulic cylinder at the rear of the traveling vehicle body descends to a predetermined position, the work vehicle that narrows the diameter of the oil passage with respect to the hydraulic cylinder and slows down the descent speed until the working machine contacts the ground. For example, JP-A-2001-78508 is known (Patent Document 1).

JP 2001-78508 A

  However, in the invention described in the above-mentioned patent document, a sensor and an oil path switching valve for detecting the height position when the work machine is raised and lowered are required to switch the oil path for raising and lowering the work machine, which is expensive.

  Accordingly, an object of the present invention is to provide a work vehicle having a configuration capable of controlling the descending speed of the work implement with an inexpensive configuration.

  In order to solve the above-described problems, the present invention is a work for connecting the work machine (22) to the rear portion of the traveling vehicle body (1) and rotating the lift arm (50) to move the work machine (22) up and down. In the vehicle, in the work vehicle having a damper arm (123) that rotates in conjunction with the lift arm (50) and provided with a damper (137) that reduces the rotation speed of the damper arm (123), the damper arm (123 The first feature is that the damper arm (123) is provided with a damper position changing member (140) that changes and fixes the damper fixing position in the radial direction with respect to the rotation fulcrum.

  Moreover, this invention has the 1st rotation body (106) rotated in connection with the said raising / lowering arm (50) in invention which has a 1st characteristic, A 1st rotation body (106) and a 1st link A second rotating body (108) connected by an arm (107); a third rotating body (111) connected by a second rotating body (108) and a second link arm (109); The rotating body (111) has a contact portion (131) that contacts the damper arm (123) when rotated to a predetermined position, and when the damper arm (123) contacts the contact portion (131), the third time. The second feature is that the damper arm (123) is rotated by the rotation of the moving body (111).

  According to a third aspect of the present invention, in the invention having the second feature, the third rotating body (111) is provided with a female thread portion that is screwed with a bolt, and the contact portion (131) is configured with a bolt. It is characterized by.

  According to the invention having the first feature, the descent speed of the work machine connected to the lifting arm (50) is provided by providing the damper (137) on the damper arm (123) that rotates in conjunction with the lifting arm (50). In a work vehicle that slows down the speed of the vehicle, by changing the connecting position of the damper (137) in the radial direction of the rotation of the damper arm (123), the force to push down the damper can be changed, so that the damper (137) acts. It is possible to adjust the lowering speed of the work machine when the machine is on.

  According to the invention having the second feature, the lift arm (50) and the damper arm (123) are connected to the damper arm (123) from the first rotating body (106) interlocked with the lift arm (50) by a plurality of links. In the configuration in which the third rotating body (111) and the damper arm (123) are interlocked with each other, the working machine is configured such that the third rotating body (111) starts to be interlocked from a position where the third rotating body (111) is rotated to a predetermined position. It is possible to descend quickly at the beginning of the fall of (22), and to lower the descending speed from the point close to the ground.

  According to the invention having the third feature, the contact position of the contact portion (131) can be adjusted by configuring the contact portion (131) provided on the third rotating body (111) with a bolt. Therefore, it is possible to adjust the position of the work machine in which the descending speed starts to slow down.

Side view of the entire tractor Top view of the entire tractor Rear view of the entire tractor Configuration diagram inside the lifting cylinder case Internal link configuration diagram when lowering arm Internal link configuration diagram when raising and lowering arm Side view of link mechanism Perspective view of third rotating body and damper arm

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

  FIG. 1 is an overall side view of a tractor shown as an example of a work vehicle according to the present invention, FIG. 2 is a plan view of the tractor, and FIG. 3 is a rear view of the tractor not equipped with a work machine. The tractor includes front wheels 2, 2 and rear wheels 3, 3 at the front and rear portions of the fuselage 1, and the rotational power of the engine E mounted on the front of the fuselage 1 is appropriately decelerated by a transmission in the transmission case 4, It is configured to transmit to the front wheels 2 and 2 and the rear wheels 3 and 3.

  A steering handle 6 is supported on a handle post 5 disposed in the center of the airframe 1, and a driver's seat 7 is provided behind the steering handle 6. Below the steering handle 6, a throttle lever 8 for adjusting the rotational speed of the engine E is provided. Further, a clutch pedal 9 for adjusting the clutch is provided at a corner portion of the step floor 12 on the opposite side of the throttle lever 8 with the handle post 5 interposed therebetween, and right and left rear wheels 3, 3, left and right brake pedals 10L and 10R for operating the brake are provided.

  The main speed change lever 14 is in the left front part of the driver's seat 7, and the sub speed change lever 16 that can select any of the low speed, medium speed, high speed and neutral positions is in the rear thereof, and further on the right side of the driver's seat 7. Is provided with a tilling depth adjusting lever 17 for setting the depth of tilling. Further, a position lever 18 for setting the height of the work implement 22 (rotary or the like) by operating the lifting arm 50 is disposed on the right side. A safety frame 19 is supported by a rear frame 44 at the rear of the vehicle and is erected after the driver's seat 7.

  The work machine 22 is supported by a left and right 2P hitch 45 fixed to the lower part of the rear frame 44, a lifting arm 50 and a lift rod 52 so as to be movable up and down, and from a PTO shaft 51 provided on the rear surface of the transmission case 4, The driving force transmitted from the engine E is taken out and the tilling work is performed by rotating the tilling claw 22a.

  Further, a link mechanism 100 described later is provided in front of the rotation shaft 50a of the lifting arm 50. The link mechanism 100 is connected to the lifting arm 50 in the cylinder case 55, and the rotation speed of the link mechanism 100 that is interlocked with the rotation of the lifting arm 50 is limited by the damper 137, so that the lowering speed of the work machine 22 is reduced. It becomes the structure which becomes late.

  FIG. 4 is a configuration diagram showing the inside of the cylinder case 55 in a side view. When the valve spool 56a of the elevating valve 56 is moved back and forth, the elevating cylinder 57 installed obliquely in the vertical direction inside the cylinder case 55 is operated, and the cylinder connecting portion 50b of the elevating arm 50 connected to the elevating cylinder arm 57a is operated. By pushing and pulling, the lifting arm 50 pivots up and down with the lifting arm pivot shaft 50a as a pivot point.

  FIG. 5 is a configuration diagram showing the inside of the cylinder case 55 in a state where the lifting arm 50 is lowered. FIG. 6 is a configuration diagram showing the inside of the cylinder case 55 in a state where the lifting arm 50 is raised. The case where the lifting arm 50 is raised from the lowered position will be described below. When the position lever 18 is operated from the lowered position where it is tilted forward to the raised position pulled backward, the position lever end 18a pushes down the lever abutting portion 106a of the first rotating body 106 (see FIG. 1). The moving body 106 rotates counterclockwise. An internal arm 106 b is provided inside the first rotating body 106 and rotates integrally with the first rotating body 106.

  A first internal link 150 is provided inside the internal arm 106b. The first internal link 150 receives the rotation of the internal arm 106b and rotates counterclockwise about the first internal link rotation fulcrum 150a fixed to the cylinder case 55 as a fulcrum shaft. The first internal link 150 is connected to the internal arm 106b at the upper part and is connected to the second internal link 151 at the lower part by an internal link pin 150b. When the first internal link 150 rotates counterclockwise, the second internal link 151 is pulled forward, so that the valve spool 155a of the lift valve 155 connected near the lower portion of the internal link pin 150b is pushed in.

  When the valve spool 155a is pushed into the elevating valve 155, pressure oil is supplied from the oil passage 57a and the elevating piston 57b in the elevating cylinder 57 is pushed out, thereby raising the elevating arm 50. At this time, if the elevating arm 50 is raised too much with respect to the position of the internal link pin 150b determined by the angle of the first rotating body 106, the internal connection portion 151a between the elevating arm 50 and the second internal link 151 becomes the internal link. By moving forward from the pin 150b, the spool connecting portion 151b moves rearward and the supply of pressure oil to the elevating cylinder 57 is stopped. As described above, the operation position of the position lever 18 and the rotation angles of the elevating arm 50 and the first rotating body 106 are always linked.

  The case where the lifting arm 50 is lowered from the raised position will be described below. When the position lever 18 is operated from the raised position pulled backward to the lowered position tilted forward, the position lever end 18a is separated from the lever abutting portion 106a of the first rotating body 106. The first rotating body 106 rotates clockwise (see FIG. 1). Then, since the internal arm 106b also rotates clockwise, the first internal link 150 receives the rotation of the internal arm 106b and rotates clockwise around the first internal link rotation fulcrum 150a as a fulcrum shaft. When the first internal link 150 rotates clockwise, the second internal link 151 is pulled rearward, so that the valve spool 155a of the elevating valve 155 connected in the vicinity below the internal link pin 150b is pulled out.

  When the valve spool 155a is pulled out from the elevating valve 155, the pressure inside the elevating cylinder 57 is reduced, and the elevating arm 50 is lowered while pushing the elevating piston 57b into the elevating cylinder 57 by its own weight. At this time, if the elevating arm 50 is lowered too much with respect to the position of the internal link pin 150b determined by the angle of the first rotating body 106, the internal connecting portion 151a moves rearward from the internal link pin 150b. The spool connecting portion 151 b moves forward and pressure oil is supplied to the elevating cylinder 57. As described above, the operation position of the position lever 18 and the rotation angles of the lifting arm 50 and the first rotating body 106 are always interlocked even when the lifting arm 50 is lowered.

  FIG. 7 is a side view of the link mechanism 100 attached to the rear portion of the vehicle. FIG. 8 is a perspective view of the third rotating body 111 and the damper arm 123. The external arm 106c of the first rotating body 106 that rotates in conjunction with the lifting arm 50 and the lower arm 108a of the second rotating body 108 are connected by the first link arm 107, and when the lifting arm 50 moves down, When one rotating body 106 rotates counterclockwise, the second rotating body 108 also rotates counterclockwise. The upper arm 108b of the second rotating body 108 is connected by the link connecting arm 111b and the second link arm 109 of the third rotating body 111. When the second rotating body 108 rotates clockwise, the third rotating body 111 is rotated. Also rotate clockwise.

  In the third rotating body 111, a link connecting arm 111b, a return plate 111d, and a bolt mounting plate 111c are welded to a third cylinder 111a serving as a rotation shaft, and rotate together. A hole is formed in the bolt mounting plate 111c, and a nut 111e is welded thereto, and a bolt 131 as an example of a contact portion in the present invention is inserted in an adjustable manner. The return plate 111d is welded to the third cylinder 111a so as to face the bolt mounting plate 111c with a space therebetween. Although the nut 111e is welded to the bolt mounting plate 111c as a female thread portion, the bolt 131 may be inserted by tapping the bolt mounting plate 111c instead of the nut 111e.

  A damper arm 123 is rotatably provided on the outer side coaxial with the third rotating body 111. The damper arm 123 has a configuration in which a contact plate 123b and a damper connecting portion 123c are welded to a fourth cylinder 123a serving as a rotation shaft, and rotates integrally. Since the contact plate 123b is provided so as to be inserted between the bolt mounting plate 111c and the return plate 111d of the third rotating body 111, when the third rotating body 111 rotates clockwise, it rotates more than a predetermined angle. When the bolt 131 comes into contact with the contact plate 123 d when moved, the rotation of the third rotating body 111 is transmitted to the damper arm 123. Therefore, by adjusting the insertion depth of the bolt 131, it is possible to adjust the timing at which the damper arm 123 connected to the damper starts to rotate, so the position at which the lowering speed of the work implement 22 is reduced is adjusted. can do. When the third rotating body 111 rotates counterclockwise, the return plate 111d contacts and rotates the damper arm 123 counterclockwise.

  A damper position changing member 140 that adjusts the mounting position of the damper is attached to the damper connecting portion 123c. The damper position changing member 140 has a U-shaped shape with an opening at the bottom, and is attached so as to cover the damper connecting portion 123c, and a damper 137 is attached to the lower part by pivoting a damper attachment rod 140a. The damper mounting rod 140a passes through a long hole 123d provided in the radial direction of rotation at the lower part of the damper connecting portion 123c, and the mounting position of the damper 137 can be changed in the radial direction of rotation of the damper arm 123.

  A substantially rectangular hole 140 b and a plate spring 141 for fixing the position of the damper position changing member 140 are provided on the top of the damper position changing member 140. The leaf spring 141 is bent downward and is folded downward through the rear portion 140b. By fitting the folded portion into one of a plurality of grooves formed on the upper surface of the damper connecting portion 123c, the damper position changing member 140 is fixed.

  By making it possible to change the mounting position of the damper 137 in the radial direction of rotation, it is possible to change the distance between the fourth cylindrical body 123a serving as a rotation fulcrum and the damper mounting rod 140a serving as an action point of a force pushing the damper. The closer the distance, the stronger the force to push the damper, and the farther the distance, the weaker the force to push the damper. The lowering speed of the work machine 22 after the damper 137 starts to work is faster as the force for pushing the damper is stronger, and slower as the force for pushing the damper is weaker. Therefore, the lowering speed of the work machine 22 can be adjusted.

DESCRIPTION OF SYMBOLS 1 Traveling vehicle body 22 Work implement 50 Lifting arm 106 1st rotation body 107 1st link arm 108 2nd rotation body 109 2nd link arm 111 3rd rotation body 123 Damper arm 131 Bolt (contact part)
137 Damper 140 Damper Position Change Member

Claims (3)

  In a work vehicle in which a work machine (22) is connected to the rear portion of the traveling vehicle body (1) and the lift arm (50) is rotated to move the work machine (22) up and down, the work vehicle (1) is interlocked with the lift arm (50). In a work vehicle having a damper arm (123) that rotates and a damper (137) that reduces the rotation speed of the damper arm (123), the damper is fixed in a radial direction with respect to the rotation fulcrum of the damper arm (123). A working machine lifting device for a work vehicle, characterized in that a damper position changing member (140) for changing and fixing a position is provided on a damper arm (123).   A first rotating body (106) that rotates in conjunction with the elevating arm (50), and a second rotating body (108) connected by the first rotating body (106) and the first link arm (107). A third rotating body (111) connected by a second rotating body (108) and a second link arm (109), and when the third rotating body (111) rotates to a predetermined position, a damper arm ( 123), and the damper arm (123) is rotated by the rotation of the third rotating body (111) when the damper arm (123) is in contact with the contact portion (131). The working machine lifting device for a work vehicle according to claim 1.   The working machine lifting device for a work vehicle according to claim 2, wherein the third rotating body (111) is provided with a female screw portion to be screwed with a bolt, and the contact portion (131) is constituted by a bolt.

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