Work vehicles

Abstract

This makes it easier to switch the external hydraulic valve between single-acting and double-acting modes. [Solution] The solution includes a work implement 14 mounted on a vehicle body 10, operating tools 30 and 34 for operating the work implement 14, an external hydraulic valve unit 60 in which a valve spool 70 operates in conjunction with the operation of the operating tools 30 and 34 to operate hydraulic equipment 17 and 18 mounted on the work implement 14, and a single / double switching valve 80 that switches the pressure of the hydraulic fluid flowing through the port 62 by opening and closing when the operating tools 30 and 34 are operated, and a plate 92 provided with a hole 93 through which a pin 91 attached to the single / double switching valve 80 is inserted, and the opening and closing of the single / double switching valve 80 is switched by moving the pin 91 along the hole 93.

Description

Technical Field

[0001] The present invention relates to a work vehicle such as an agricultural tractor.

Background Art

[0002] There is a known work vehicle in which a working machine such as a front loader is attached to a work vehicle such as an agricultural tractor and the working machine is moved by an external hydraulic operation lever or a JOY stick lever (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When an external hydraulic operation lever or a JOY stick lever is operated, it is configured to be operable through an external hydraulic valve. Depending on whether the hydraulic cylinder connected to the external hydraulic valve is a single-acting type or a double-acting type, there is a known work vehicle having a single / double switching lever capable of switching the external hydraulic valve between a single-acting type and a double-acting type (Patent Document 1).

[0005] The conventional single / double switching lever switched between the single-acting type and the double-acting type by rotating it several times and screwing it in, but there was a problem that it was difficult to rotate because there was a body or cover of an external hydraulic valve in the vicinity.

[0006] Therefore, an object of the present invention is to make it easier to perform an operation of switching an external hydraulic valve between a single-acting type and a double-acting type.

Means for Solving the Problems

[0007] Therefore, the work vehicle according to the invention has taken the following technical means to solve the above problems.

[0008] The system includes a work implement (14) mounted on a vehicle body (10), operating tools (30, 34) for operating the work implement (14), an external hydraulic valve unit (60) in which a valve spool (70) operates in conjunction with the operation of the operating tools (30, 34) to operate hydraulic equipment (17, 18) mounted on the work implement (14), and a single / double switching valve (80) that switches the pressure of the hydraulic fluid flowing through a port (62) by opening and closing when the operating tools (30, 34) are operated, and a plate 92 provided with a hole (93) through which a pin (91) attached to the single / double switching valve (80) is inserted, and the opening and closing of the single / double switching valve (80) is switched by moving the pin (91) along the hole (93). [Effects of the Invention]

[0009] According to the present invention, the operation of switching between single-acting and double-acting modes can be made easier. [Brief explanation of the drawing]

[0010] [Figure 1] Left side view of an agricultural tractor according to an embodiment of the present invention [Figure 2] Plan view of the cabin of an agricultural tractor according to an embodiment of the present invention [Figure 3] Enlarged plan view of the right side dashboard portion of an agricultural tractor according to an embodiment of the present invention. [Figure 4] Perspective view of the interior of the cabin of an agricultural tractor according to an embodiment of the present invention, viewed from the front left. [Figure 5] Perspective view of the rear of the cabin of an agricultural tractor according to an embodiment of the present invention. [Figure 6] Perspective view of the cabin of an agricultural tractor according to an embodiment of the present invention, viewed from the front. [Figure 7] (A) Rear view of the external hydraulic valve in the closed state of the single / double switching valve of an agricultural tractor according to an embodiment of the present invention (B) Exploded view of the external hydraulic valve configuration (C) Partial enlargement view of the vicinity of the single / double switching valve [Figure 8](A) Rear view of the external hydraulic valve in the open state of the single / double selector valve of an agricultural tractor according to an embodiment of the present invention (B) Exploded view of the external hydraulic valve configuration (C) Partial enlarged view of the vicinity of the single / double selector valve [Figure 9] Rear view of the plate of an agricultural tractor according to an embodiment of the present invention [Modes for carrying out the invention]

[0011] Embodiments of the present invention will be described below with reference to the drawings. In this specification, the left and right sides in the forward direction of the work vehicle will be referred to as left and right, respectively, and the front and rear will be referred to as front and rear, respectively.According to embodiments of the present invention, an agricultural machine tractor, which is an example of a work vehicle, will be described below as an example.

[0012] Figure 1 is a left side view of the agricultural tractor according to this embodiment. Figure 2 shows a plan view of the cabin of the agricultural tractor according to this embodiment, and Figure 3 shows an enlarged plan view of the right side dashboard. Figure 4 is a perspective view of the interior of the cabin of the agricultural tractor according to this embodiment, viewed from the front left, Figure 5 is a perspective view of the cabin, viewed from the rear, and Figure 6 is a perspective view of the cabin, viewed from the front.

[0013] As shown in Figure 1, the tractor 10 of this embodiment is configured with a pair of drive rear wheels 12 mounted on the rear of the vehicle body and left and right front wheels 11, which are steered by a steering wheel 20, mounted on the front. The tractor 10 has a cabin that surrounds the driver's seat 21 equipped with a steering wheel 20, and the front side of the cabin is covered with a bonnet 13. Inside the bonnet, the engine and its auxiliary components, namely the radiator, oil cooler, air conditioning condenser, intercooler, air cleaner, battery, etc., are installed.

[0014] As shown in Figure 1, the tractor 10 is equipped with a front loader 14 on the front of the vehicle body.

[0015] The front loader 14 includes a pair of left and right side frames 19 attached to both sides of the body of the tractor 10, a main frame 16 pivotally connected to the upper part of the side frame 19 and supported so as to be vertically swingable, and a bucket 15 pivotally connected to the tip side of the main frame 16 and supported so as to be vertically swingable. Further, a main frame swing cylinder 18 that can be telescopically operated is connected between the base of the side frame 19 and the central part of the main frame 16, and a bucket swing cylinder 17 that controls the swing of the bucket 15 is connected to the upper front part of the main frame 16.

[0016] Note that the tractor 10 is an example of the work vehicle of the present invention, and the front loader 14 is an example of the working machine of the present invention.

[0017] Further, the tractor 10 of the present embodiment can be attached to a three-point link mechanism configured with a working machine (not shown) such as a rotary tiller at the rear of the machine body so as to be able to be raised and lowered, and can perform ground work.

[0018] Next, the arrangement of each operating tool in the cab of the tractor 10 of the present embodiment will be described.

[0019] The driver's seat 21 arranged at the center of the cab has an armrest 26 on the left side. On both sides of the driver's seat 21, a right-side dashboard 22 and a left-side dashboard 23 are erected.

[0020] A step is provided at the upper part of the right-side dashboard 22, and it has two substantially horizontal surfaces, an upper surface 24 and a lower surface 25. As shown in FIG. 4, the upper surface 24 is formed at the rear outer side of the upper part of the right-side dashboard 22, and the lower surface 25 is formed at the front inner side of the upper part of the right-side dashboard 22.

[0021] Operating tools for operating the working machine are concentratedly arranged on these upper surface 24 and lower surface 25.

[0022] A triple external hydraulic lever 34 is arranged on the upper surface 24.

[0023] A position lever 31 is located at the front end of the lower surface 25, and a PTO selector switch 32 and a tilling depth adjustment dial 33 are located near the rear end of the position lever 31. Further behind the PTO selector switch 32 and tilling depth adjustment dial 33, a PTO on / off switch 35 is located. The PTO selector switch 32 is a switch that switches between an automatic mode in which the PTO is turned on and off in conjunction with the vehicle status, and a manual mode in which the PTO is turned on and off only by the PTO on / off switch 35.

[0024] As shown in Figure 3, a lower position adjustment dial 37 is provided at the front end of the base of the position lever 31, and an upper position adjustment dial 38 is provided at the rear end of the base of the position lever 31.

[0025] The position lever 31 is a lever that controls the raising and lowering of the work implement. The rear position controls "raising," and the front position controls "lowering," allowing the work implement to be raised or lowered during machine rotation, etc. The lowering position adjustment dial 37 and the raising position adjustment dial 38 adjust the forward and backward range of motion of the position lever 31, thereby regulating the height range in which the work implement moves up and down.

[0026] Furthermore, the PTO on / off switch 35 is a dial type, so it will not malfunction even if part of the operator's body touches it. Also, because it is positioned closest to the operator's seat 21 behind the tillage depth adjustment dial 33, the operator can operate it immediately, making it effective in terms of safety.

[0027] By placing frequently used controls on the lower surface 25, which is close to the driver's seat 21, the operator can operate the controls smoothly.

[0028] Furthermore, the JOY stick lever 30 is positioned in front of the right-side dashboard 22, in a location that is easily operated with the right hand by an operator seated in the driver's seat 21.

[0029] On the other hand, the controls for the driving system are concentrated between the driver's seat 21 and the right-side dashboard 22.

[0030] The main shift lever 40 is positioned between the driver's seat 21 and the right-side dashboard 22, in a location easily accessible with the right hand. Behind the main shift lever 40, the sub-shift lever 41 and the creep speed lever 42 are positioned in order. The sub-shift lever 41 can be fixed in any position, and the travel speed of the tractor 10 can be maintained at a constant level depending on the position of the lever.

[0031] The PTO selector switch 32 is located on the lower surface 25 of the right-side dashboard 22, in a position close to the main shift lever 40.

[0032] In this way, by concentrating the operating tools for the work equipment on the right-side dashboard 22 and concentrating the operating tools for the drive system between the driver's seat 21 and the right-side dashboard 22, the operator can easily understand the location of the operating tools and operate them smoothly.

[0033] The JOY stick lever 30 is an example of the loader lever of the present invention, and the main change lever 40 is an example of the main gear shift lever of the present invention. Also, the right-side dashboard 22 is an example of the side dashboard of the present invention.

[0034] As shown in Figure 4, the JOY stick lever 30 is positioned so that its tip is higher than the seat surface of the driver's seat 21, and the main change lever 40 is also positioned so that its tip is higher than the seat surface of the driver's seat 21.

[0035] Furthermore, although both the JOY Stick Lever 30 and the Main Change Lever 40 are levers that are operated in the forward and backward directions, they are positioned such that when an operator grips the tip of either lever at the closest position between the JOY Stick Lever 30 and the Main Change Lever 40, there is a gap between the hand gripping that lever and the other lever. Therefore, when an operator operates the JOY Stick Lever 30 or the Main Change Lever 40, their body will not accidentally come into contact with the other lever, resulting in incorrect operation.

[0036] Furthermore, instead of arranging the JOY stick lever 30 and the main change lever 40 side by side in the front-to-back direction of the aircraft, they are positioned offset from each other in the left-to-right direction of the aircraft, as shown in Figure 2. This improves operability when frequently operating these levers.

[0037] The accelerator pedal 49 is located on the floor to the right and front of the driver's seat 21.

[0038] Additionally, a 4WD lever 43 is located below and to the right of the driver's seat 21, and a PTO shift lever 36 is located below and to the left of the driver's seat 21. Furthermore, a differential lock pedal 44 is located below and to the right of the driver's seat 21.

[0039] A hazard switch 50 is located to the left front of the steering wheel 20.

[0040] As shown in Figure 5, a center horn 51 is provided in the center of the steering wheel 20. From the perspective of an operator seated in the driver's seat 21, the forward / reverse lever 45 is located to the left rear of the steering wheel 20, and the turn signal lever 52 is located to the right rear of the steering wheel 20. The throttle lever 46 is located to the right front of the steering wheel 20, and the key switch 53 and parking lever 54 are located to the lower right of the steering wheel 20.

[0041] The left and right brake pedals 48 are positioned near the floor, slightly to the right and forward of the driver's seat 21, while the clutch pedal 47 is positioned near the floor, slightly to the left and forward of the driver's seat 21. Additionally, the tilt pedal 55 is positioned near the floor, slightly to the left and below the steering wheel 20.

[0042] In the above description, the 4WD lever 43 and the PTO shift lever 36 are positioned on a surface that rises vertically from the floor below the driver's seat 21 and have a lever shape that extends forward. However, they may also be positioned closer to the side of the driver's seat 21 and have a lever shape that extends upward.

[0043] As shown in Figures 7, 8, and 9, the external hydraulic valve unit 60 adjusts the supply of hydraulic fluid to the main frame swinging cylinder 18, bucket swinging cylinder 17, and other hydraulic equipment of the work machine of the front loader 14 by using a spool 70 that slides in conjunction with the JOY stick lever 30 and the external hydraulic lever 34. This allows the front loader 14 and other work machines such as the reversible plow to be freely operated by operating the JOY stick lever 30 and the external hydraulic lever 34.

[0044] Hydraulic fluid flows into the external hydraulic valve unit 60 by pushing the first poppet valve 71 from the first port 61. For example, when the JOY stick lever 30 is pushed forward, the valve spool 70 moves in conjunction with it, being pulled out of the body 69. As a result, the hydraulic fluid that flows in by pushing the first poppet valve 71 from the first port 61 flows to the second port 62, the main frame oscillating cylinder 18 retracts, and the hydraulic fluid that exits the main frame oscillating cylinder 18 enters from the third port 63 and is discharged to the tank port 64.

[0045] A single-acting and double-acting switching valve 80 is provided between the second port 62 and the tank port 64. As shown in Figure 7, when the single-acting and double-acting switching valve 80 is closed, when the JOY stick lever 30 is pushed forward, pressure is applied to the oil passage of the second port 62, forcibly retracting the main frame oscillating cylinder 18 and forcibly lowering the front loader 14.

[0046] The single / double switching valve 80 is provided with an oil passage 81 and a pressure receiving section 82. The oil passage 81 connects the second port 62 to the oil chamber 83, which is formed on the opposite side of the second port 62, with the pressure receiving section 82 in between. When the single / double switching valve 80 is closed, pressure is applied to the second port 62, causing the end 84 of the single / double switching valve 80 on the second port 62 side to experience pressure in a direction that pushes the single / double switching valve 80 open. On the other hand, the pressure receiving section 82 receives pressure from the hydraulic fluid ejected to the oil chamber 83 side through the oil passage 81 in a direction that closes the single / double switching valve 80. Since the pressure receiving area of ​​the pressure receiving section 82 is larger than the pressure receiving area of ​​the end 84, the single / double switching valve 80 can remain closed.

[0047] Furthermore, the end 84 and the opposite end 85 of the single / double switching valve 80 protrude outward from the body 69 of the external hydraulic valve unit 60, and a pin 91 is attached in a direction intersecting the axial direction of the single / double switching valve 80. The pin 91 is inserted through a Z-shaped hole 93 provided in a plate 92 fixed to the body 69. As shown in Figure 9, the Z-shaped hole 93 consists of a first end 93a through which the pin 91 slides when the single / double switching valve 80 is rotated around its axis in a closed state, a second end 93b through which the pin 91 slides when the single / double switching valve 80 is rotated around its axis in an open state, and an intermediate end 93c that connects the first end 93a and the second end 93b, through which the pin 91 slides when the single / double switching valve 80 is slid in the axial direction. As a result, even if the single / double switching valve 80 tries to move in the direction of pushing it open while it is closed, the pin 91 will come into contact with the first end edge 93a of the hole 93, restricting the sliding of the single / double switching valve 80.

[0048] As shown in Figure 8, when the single / double switching valve 80 is open, when the JOY stick lever 30 is pushed forward, the oil passage of the second port 62 is open to the tank port 64, so the pressure does not rise significantly. As a result, the main frame oscillating cylinder 18 is not forcibly retracted, and the front loader 14 descends by its own weight.

[0049] In this case, since the pressure-receiving area of ​​the pressure-receiving portion 82 is larger than the pressure-receiving area of ​​the end portion 84, the hydraulic fluid ejected to the oil chamber 83 side through the oil passage 81 exerts pressure in the direction of closing the single / double switching valve 80. However, since this force is generated by pressure loss, it is very small. Furthermore, if the pin 91 is located at the end of the second end side 93b of the Z-shaped hole portion 93, even if pressure is applied in the direction of closing the single / double switching valve 80, the pin 91 will come into contact with the second end side 93b, limiting the sliding of the single / double switching valve 80.

[0050] The single / double switching valve 80 is inserted into the first sleeve 87 and the second sleeve 88 located inside the body 69, and is sealed by an O-ring 86 between the inner diameter and cylindrical surface of the first sleeve 87 and the second sleeve 88. This suppresses leakage, and the valve switches between open and closed by sliding within the range of the step formed by the first sleeve 87 and the second sleeve 88.

[0051] With the above configuration, the single / double switching valve 80 can be easily switched between single-acting and double-acting modes by sliding the pin 91 along the Z-shaped hole 93. Since there is no need to rotate the single / double switching valve 80 multiple times to screw it in, the single / double switching can be easily performed without interference with the body 69 of the external hydraulic valve unit 60 or the cover of the valve spool 70.

[0052] In the above embodiment, a front loader 14 operated by a JOY stick lever 30 was shown as the work implement to be attached, but it is not limited to this, and other work implements may be a reversible plow with a reversing mechanism, a harrow with a folding mechanism used for puddling work, a rake for collecting hay, or a tedda for spreading hay, which are equipped with hydraulic equipment such as hydraulic cylinders and operated by an external hydraulic lever 34 and an external hydraulic valve unit 60. [Explanation of symbols]

[0053] 10. Tractor (vehicle body) 14. Front loader (work equipment) 17. Bucket swinging cylinder (hydraulic equipment) 18. Cylinder for main frame oscillation (hydraulic equipment) 30 Joy Stick Lever (Control Device) 34. External hydraulic lever (operating device) 60 External Hydraulic Valve Unit 62 Second port (port) 70 Valve Spool 80 Single / Double Switching Valve 81 Oil road 83 Oil room 91 pins 93 Hole 93a First shaped part (first edge) 93b Second shaped part (second edge) 93c Third shape section (intermediate side)

Claims

1. A work implement (14) attached to the vehicle body (10), Operating tools (30, 34) for operating the aforementioned work machine (14), An external hydraulic valve unit (60) operates in conjunction with the operation of the aforementioned operating tools (30, 34) to activate the valve spool (70) and the hydraulic equipment (17, 18) mounted on the work machine (14), The system includes a single / double switching valve (80) that switches the pressure of the hydraulic fluid flowing through the port (62) by opening and closing when the aforementioned operating tools (30, 34) are operated, The plate 92 is provided with a hole (93) through which a pin (91) attached to the single / double switching valve (80) is inserted. A work vehicle that switches the opening and closing of the single / double switching valve (80) by moving the pin (91) along the hole (93).

2. In a configuration where closing the single / double switching valve (80) increases the pressure of the hydraulic fluid flowing through the port (62) when the operating tools (30, 34) are operated, The work vehicle according to claim 1, wherein the single / double switching valve (80) is provided with an oil passage (81) that connects the port (62) and the oil chamber (83), and the pressure from the hydraulic fluid flowing through the oil passage (81) into the oil chamber (83) presses the single / double switching valve (80) in a closing direction.

3. The work vehicle according to claim 1 or 2, wherein the hole (93) has a first shaped portion (93a) that contacts the pin (91) and suppresses sliding in the opening direction when the single / double switching valve (80) is closed, a second shaped portion (93b) that contacts the pin (91) and suppresses sliding in the closing direction when the single / double switching valve (80) is open, and a third shaped portion (93c) on which the pin (91) slides when switching the opening and closing of the single / double switching valve (80).

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