JPH1156008A - Hydraulic lifting and lowering apparatus of tractor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the subject apparatus saved in weight and having good maintenance property by providing a hydraulic housing with a main port and forming an oil passage which communicates with the port as hole structure in the hydraulic housing. SOLUTION: In a tractor loading a hydraulic lifting and lowering apparatus 10 having a lift arm 9 on the upper surface in the rear of a tractor vehicle body, a hydraulic housing constituting a hydraulic lifting and lowering apparatus 10 is provided with a main port 42 and several oil passages 34 and 35 which communicate with the port 42 are formed as a hole structure in the hydraulic housing to provide the objective apparatus. It is preferable that oil passages 34 and 45 formed in the hydraulic housing are each an oil passage 45 for a draft control valve device 43 and a horizontal control valve device 44 and an oil passage 34 for external hydraulic takeout device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic lift device for a tractor, and more particularly, to a hydraulic lift device having a large capacity and reduced weight, which is particularly useful as a tractor for paddy fields.

[0002]

2. Description of the Related Art A tractor in which a hydraulic lifting device for a working machine having a lift arm is mounted on a rear upper surface of a tractor body is known, and a tractor such as a rotary cultivator is connected via a working machine connecting device such as a three-point link. It is used to carry out paddy work by attaching work equipment. This paddy field tractor is required to have a high horsepower and light weight, while a hydraulic lifting device is required to have a large capacity (increase in lifting force).

[0003]

The tractor hydraulic elevating device requires various hydraulic controls such as draft control and horizontal control in addition to position control. Therefore, various valve units (valve units) are mounted. ing. Supply (including discharge) of hydraulic pressure (oil from the pump) to this valve device is often performed exclusively by pipe members such as steel pipes, copper pipes, and hoses. This increases the weight of the pipe members and reduces the weight. However, it is not suitable as a hydraulic lifting device for tractors for paddy fields, which requires the following.

[0004] In addition, since the piping member is employed, it is necessary to separate (separate) the piping member when performing maintenance and inspection of the hydraulic elevating and lowering device, which has a major problem in terms of maintainability. In particular, an auto-draft valve using an electromagnetic pilot valve that integrates a solenoid valve for piloting up and down and a pilot switching valve as a draft control valve device is sensitive to dust and impurities, and moreover, the judgment of a failed part is difficult. Because of the difficulty, it is necessary to remove the entire hydraulic lifting device from the tractor body for maintenance.However, since the number of piping members and the number of joints and separation sites are increased in the past, it is important for maintenance and inspection. Challenges.

The present invention minimizes the number of piping members by forming an oil passage in a hydraulic housing (hydraulic cylinder main body) itself constituting a hydraulic lifting device, thereby reducing the weight and improving maintainability. It is an object of the present invention to provide a simple tractor hydraulic lifting device. Also, the present invention
When the arm shaft is rotatably supported on the hydraulic housing via the bush, the bushing due to micro-vibration etc. is semi-forced lubricated, thereby reducing the weight without increasing the diameter of the arm shaft and durable. Another object is to improve the performance.

[0006]

According to the present invention, there is provided a tractor 2 in which a hydraulic lifting device 10 having a lift arm 9 is mounted on a rear upper surface of a tractor body 5 in order to achieve the above object. Have taken strategic steps. That is, in the present invention, the hydraulic housing 33 constituting the hydraulic elevating device 10 is provided with the main port 42, and a plurality of oil passages 34, 35 communicating with the port 42 are formed in the hydraulic housing 33 as a hole structure. It is a tractor hydraulic elevating device characterized by the fact that by adopting such a configuration, the piping members are minimized and the weight can be reduced,
This is significant when applied to a paddy field tractor, and the maintenance and improvement of the hydraulic elevating device 10 is facilitated by reducing the joining and separation of piping members.

In the present invention, a plurality of oil passages 34, 45 formed in the hydraulic housing 33 are provided for the oil passage 45 for the draft control valve device 43 and the horizontal control valve device 44, and for the external hydraulic take-out device 1. By adopting such a configuration, even if an automatic draft valve is employed as the draft control valve device 43, the maintainability is ensured, and the horizontal control valve is also provided. The device 44 and the external hydraulic take-out device 1 can also be maintained.

Further, in the present invention, the hydraulic lifting device 1
The arm shaft 38 having the lift arm 9 is rotatably supported by a hydraulic housing 33 constituting a bush 70 via a bush 70, and means 71 for semi-forced lubrication of the bush 70,
72, and by adopting such a configuration, seizure of the bush 70 can be reliably prevented, and the arm shaft 38 is used to withstand minute vibration.
Without increasing the diameter (thereby eliminating the increase in the diameter of the boss 39 formed in the hydraulic housing 33), and the hydraulic housing 33 can be reduced in weight.

The semi-forced lubricating means 71, 72
A piping member 71 connected to the tank ports of the valve devices 43 and 44 provided on the left and right side walls of the hydraulic housing 33 separately.
72, and by adopting such a configuration, the baking of the bush 70 can be prevented by forming (creating) a reliable oil film.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows the entire configuration of a two-shaft, four-wheel tractor 2 equipped with a hydraulic lifting device 10 according to the present invention. In FIG. 1, the tractor 2 includes left and right front wheels 3 and left and right rear wheels 4, and the front wheels 3 are steerable wheels and can be driven. Here, the tractor 2 is a four-wheel drive tractor. The front wheels 3 can also be connected to and disconnected from each other to perform two-wheel drive (rear-wheel drive).

The tractor body 5 is constructed by connecting a transmission case 7 to a rear portion of a mounted engine 6 via a crack housing. The engine 6 and an engine auxiliary device such as a radiator provided in front of the transmission case 7 have a top plate. It is covered with a hood 8 that can be freely opened and closed. A hydraulic lifting device 10 having left and right lift arms 9 is mounted on the rear upper surface of the tractor body 5. In the figure, a rotary work machine 12 is detachably mounted so as to be liftable and controllable by a three-point link 11.

The left and right rear wheels 4 are covered by rear wheel fenders 13 erected on the inside thereof, and a driver's seat 14 is disposed between the left and right rear wheel fenders 13. A driving control device 16 is constituted by a control handle 15 provided in front of the vehicle.
Reference numeral 6 denotes an independently mounted cabin 17 (removably mounted on the vehicle body 5) including left and right rear wheel fenders 13.
Surrounded by

The cabin 17 comprises a pair of left and right front supports 18,
A pair of left and right rear struts 19, an intermediate strut 20 rising from a rear wheel fender 13 between the front and rear struts 18, 19 and approaching the rear strut 19, and an air conditioner (cooling, heating, cooling / heating) And a ceiling 21 having ventilation, etc.), the bottom plate (floor seat) 22 of the cabin 17 is such that the mounting portion 22A of the driver's seat 14 is one step higher than the front portion 22B.

Further, the cabin 17 has a door 23 which can be opened and closed by using a pivot fitting 20A provided on the intermediate support 20 as a fulcrum. The tractor is mounted on the tractor body 5 by anti-vibration support means such as anti-vibration rubber provided on the left and right bottoms. Further, the rear support 19 of the cabin 17 is formed in an inverted shape via an intermediate bending connection 19A, and the bending connection 19A is located near a vertical plane crossing the rotation fulcrum (arm axis) of the lift arm 9. , So that the entire cabin 17 is forward (approximately 5
cm) and the center of gravity of the entire tractor 2 is shifted forward, so that even when the rotary working machine 12 is mounted to be able to move up and down, the front and rear weight balance is good, and as a result, As a whole, the tractor is made lighter and adaptable to paddy field work.

Referring to FIG. 2, the left and right rear supports 19 in the cabin 17 are mounted on a hat-shaped support base 26 bolted to a rear axle case 25 on a tractor vehicle body 5 by brackets 27 and anti-vibration support means 28. Left and right lower bodies 29 fixed to the lower end of the rear support 19.
Are extended forward and are connected to the left and right front supports 18.

That is, while the rear bottom surface 29A of the left and right lower bodies 29 is conventionally mounted on the hat-shaped support base 26 via the vibration isolating support means 28, in the embodiment of the present invention,
A bracket 2 fixed to the column 19 with the lower part of the rear column 19 positioned vertically in front of the rear axle case 25.
The cabin 17 is mounted on the tractor vehicle body 5 via the anti-vibration support means 28 and the anti-vibration support means 28. The cabin 17 is located about 5 cm ahead of the conventional one, and the cabin 17 When the hydraulic lifting device 10 is detachably mounted and fixed on the upper surface of the tractor vehicle body 5 because the living space is secured even if it is located at the front position than before and the cabin 17 is mounted at the front position as compared with the conventional case. The lifting space 30 is secured.

The head portion 10A of the hydraulic lifting device 10 is covered from above by a mounting portion 22A of the floor seat 22, and the driver's seat 14 is mounted on the mounting portion 22A via a seat support 31. The driver's seat 14 can be freely attached to and detached from the mounting portion 22A together with the seat support 31.
Hydraulic lifting device 1 from above through an opening window formed in 2A
0 is fixed to the vehicle body 6 in an up-down direction, and the hydraulic lifting device 10 is lifted up from the vehicle body 6 in the space 30 and pulled out rearward. Maintenance is possible.

A hydraulic pump device 32 driven by the engine 6 is provided on the transmission case 7 in front of the hydraulic lifting device 10. The hydraulic pump device 32 is covered by a mounting portion 22A. Part 2
Maintenance can be performed together with the head unit 10A through the opening window formed in the 2A. Hydraulic pump device 32
Is driven via a PTO propulsion shaft directly connected to the output shaft of the engine 6 via a gear or the like (not shown), and the hydraulic pump device 32 is normally (conventionally) provided on a side surface of the engine 6. Since the transmission case is provided on the upper surface of the transmission case 7, the transmission case 7 itself also serves as a hydraulic oil tank, so that the piping member can be omitted or shortened. The limitation of the diagonal angle has been eliminated.

Also, the floor sheet 22 is
A is constituted by a thin plate, and the front portion 22B is constituted by a thick plate, whereby the center of gravity of the vehicle is also shifted forward. The strength is ensured by the stay for the sheet support 31 fixed to the peripheral edge of. FIG.
5 to FIG. 5, there is shown an embodiment in which a hydraulic lifting device 10 having left and right lift arms 9 according to the present invention is mounted, and an external hydraulic pressure is applied to a hydraulic housing (hydraulic cylinder body) 33 constituting the hydraulic lifting device 10. Oil passage 34 for removal
Is formed, and a valve 35 for the external hydraulic pressure take-out device 1 connected (communicated) to the oil passage 34 is provided between the left and right lift arms 9 at the upper part of the hydraulic housing 33.

More specifically, the hydraulic housing 33
Is made of a casting, and a mounting hole 36A for the transmission case 7 is formed in the pedestal portion 36, and the arm shaft 38 for the lift arm 9 is turned around the rear left and right walls of the main body portion 37 formed in the pedestal portion 36. Left and right bosses 39 are movably supported, and a cylinder tube 40 is provided in the front inside of the main body 37 so as to be inclined upward and forward. A piston is slidably fitted to the cylinder tube 40. The opening end of the tube 40 is closed by the head lid 41, and the pedestal portion 36 in a state where the hydraulic housing 33 covers the upper opening of the transmission case 7 is mounted detachably with vertical bolts. I have.

An inlet (main) port 42 for hydraulic oil from the hydraulic pump device 32 is formed on a side wall (right side wall in the figure) of the hydraulic housing 33.
Reference numeral 2 denotes a substantially threaded tube configuration, and a steel pipe can be detachably connected to the port 42 from the lateral direction in the left-right direction. A draft control valve device 43 and a horizontal control valve device 44 are mounted on the hydraulic housing 33 so as to be distributed to the left and right, and an oil passage 4 for these valve devices 43 and 44 is provided.
5, a priority valve 46, a relief valve 47 and the like are mounted, and when a front loader is mounted on the tractor 2, a hydraulic take-out port 48, a neutral port 49, a drain port 50, and the like for the loader are provided.

The draft control valve device 43 is an electromagnetic pilot valve in which an ascending and descending solenoid valve and a pilot switching valve are integrated, and receives signals from a draft sensor 51 and a lift arm sensor 52 as shown in FIG. The draft control is automatically enabled by a control signal from the control box 53.

The horizontal control valve device 44 transmits a signal of a rolling sensor 54 provided in the tractor body 5 shown in FIG. 6 to the control box 53, and transmits a lift cylinder (lift rod) 55 of the three-point link 11 to a stroke sensor 56. This is controlled by a signal from the controller.
In FIG. 6, the control box 53 can be set and switched freely from a switch box 57 such as draft / horizontal control switching, draft control and position control. Of course, the draft / position control can also be operated manually as described later. For this reason, a mounting hole for manual operation is opened on the right side of the hydraulic cylinder main body 33, and this opening is covered with a removable cover when automatic control is performed.

The lift arm 9 has a mounting hole 9A for a telescopic hydraulic cylinder (assist cylinder) for lifting force (assisting hydraulic pressure enhancement), and a hydraulic outlet 58 for the assist cylinder is provided in the cylinder head. The head 41 has a drop adjusting valve 59
Is incorporated. The valve 35 for taking out the external hydraulic pressure is provided with a switching spool 62 in a valve case 61, and the spool 62 can be switched by the operating force of a push-pull cable 64 via a swing arm 63. The take-out section (including the hydraulic take-out and return) 35A is constituted by a quick coupler that allows the hydraulic take-out hose to be substantially detachable.

The valve 35 (including a valve case and a spool, the same applies hereinafter) for taking out the external hydraulic pressure can be directly mounted on the upper surface of the hydraulic housing 33 in communication with the oil passage 34. Connecting oil passage 6 communicating with passage 34
Hydraulic housing 3 with spacer 60 having
3 Removably mounted on the upper part. Also, the valve 35
May be mounted, but in the illustrated example, a plurality of them are vertically stacked via an intermediate spacer 65 and a head spacer 66, and are detachably mounted by bolts 67. At the rear, which makes it easy to attach and detach the hydraulic outlet hose.

Since the oil passage 34 for the valve 35 for taking out the hydraulic pressure is formed in the hydraulic housing 33,
No exposed piping is required, and when stacking the spacer 60 and the intermediate spacer (there is also an oil passage) 65, it is possible to reliably prevent oil leakage by ensuring the positioning and sealing of the overlapped surface. Since the lift arm 9 is provided between the left and right lift arms 9, the lifting operation of the lift arm 9 does not interfere with the hydraulic take-out hose.

The hydraulic housing 33 is equipped with a top link mounting base device 69 having a torsion bar (a load sensing member, serving as a draft sensor) 68 on an upright surface, and also supplies hydraulic oil to the transmission case 7. Since the plug A and the like are provided, as shown in FIGS. 4 and 5, the valve 35 is mounted eccentrically to one side in the left and right direction, in the figure, to the left. 35 less interference,
As a result, the lift angle of the three-point link 11 (lift arm 9) is sufficiently ensured.

Referring to FIG. 7 to FIG.
A illustrates details of the spacer 60 having a seat 60B with respect to the hydraulic housing 33.
Has a plurality of bolt insertion holes 60C, the drain port 50 is formed in the seating portion 60B, and is detachably mounted on the upper surface of the hydraulic housing 33 by vertical bolts inserted into the bolt insertion holes 60C. Therefore, the valve 35 is detachable via the spacer 60 in a state where the hydraulic housing 33 is mounted on the tractor vehicle body 6.

Further, a mounting seat 60D for the valve 35 is formed on the spacer 60 so as to protrude. The valve 35 can be detachably mounted on the mounting seat 60D by a bolt 67 via an intermediate spacer 65 and a head spacer 66. From that
With the spacer 60 mounted on the hydraulic housing 33, the valve (valve unit) 35 is detachable, thereby making maintenance easier.

Referring to FIG. 14, the arm shaft 38 is inserted through a cylindrical boss which penetrates the hydraulic housing 33 in the left-right direction, and rotates through left and right cylindrical bushes 70 interposed between the cylindrical boss. It is movably supported. The cylindrical bush 70 is required to be lubricated without increasing the diameter of the arm 38 (without increasing the size of the hydraulic housing 33) due to severe seizure due to minute vibration. In this embodiment, the draft control valve is used. Since the device 43 and the horizontal control valve device 44 are disposed on the left and right side walls of the hydraulic housing 33 so as to be distributed left and right, the pipe member 71 is loosely connected to the return oil port (tank port) of the draft control valve device 43. A part of the return oil is supplied to the right bush 70 via the piping member 71 to lubricate the bush 70 semi-forcedly.
The pipe member 72 is loosely connected to the return oil port (tank port) of the horizontal control valve device 44, and a part of the return oil is sent to the left bush 70 via the pipe member 72, and the bush 70 is semi-forced. Lubrication prevents seizure of the bush 70. As shown in FIG. 14, an O-ring 73 and a collar 74 are provided outside the bush 70 to prevent the return oil from leaking outside. The remaining oil that has formed an oil film on the right and left bushings 70 is returned to the transmission case.

When a draft control valve that is mechanically operated (manually operated) is provided on the right side of the piping member 71 instead of the draft control valve device (auto draft) on the right side, this draft control valve is used. Is loosely connected to the tank port. Here, since the piping members 71 and 72 are loosely connected to the tank port, a part of the return oil returns into the transmission case via the loose insertion connection portion, and the remaining return oil passes through the piping members 71 and 72. The left and right bushings 70 are semi-forced lubricated through the above. As described above, a draft control valve (including an automatic or mechanical) and a horizontal control valve are provided on the left and right sides of the hydraulic housing, respectively. By interposing the piping members 71 and 72 in the ports, seizure of the bush 70 is prevented, and the piping members 71 and 72 are also connected to the hydraulic housing 3.
It is sufficient to dispose them in the front-rear direction in the form covered by step 3, and the piping of the piping members 71 and 72 is also facilitated.

The piping members 71 and 72 may be formed in the hydraulic housing 33 in a hole shape. The hydraulic housing 33 includes an oil passage 34 for taking out an external hydraulic pressure and oil passages for the valve devices 43 and 44. By forming the hydraulic housing 33 and the like, the hydraulic housing 33 has a large capacity, but is lightened, and the hydraulic lifting device 10 in the tractor for paddy fields is used.
Is significant.

FIGS. 15 to 18 show a case where the hydraulic lifting device 10 according to the present invention is applied to the tractor 2 having a canopy (shade) 75 and the draft control valve device is mechanical (manual). Thus, portions common to the above-described configuration are denoted by common reference numerals, and different configurations will be described below. In FIGS. 15 and 16,
The canopy 75 is a lower support 75 </ b> A standing upright from the left and right rear axle housing 25 to the vicinity of the upper surface of the fender 13.
And an upper support 75B which is inserted into the upper part of the lower support 75A in a nestable manner so as to be freely inserted and removed, and is attached by a bolt fastener 75C.

The valve 35 for taking out the external hydraulic pressure stacked on the hydraulic housing 33 is connected to the Bowden cable 6.
The remote control lever 76 is provided on the floor seat 22 on the right side of the driver's seat 14 on the lateral pivot shaft 7.
7, a window is formed in a step portion (rise surface) 22 </ b> C of the floor sheet 22, and a lever 76 projects from the window.

A bracket 78 is bolted to the step 22C so as to reinforce the left and right sides of the window of the step 22C. The bracket 78 is provided with a pivot shaft 77, and the cylindrical portion at the root of the lever 76 is pivoted. The cable 63 is rotatably fitted on the support shaft 77, and the cable 63 is connected to the arm formed on the cylindrical portion via a metal fitting 79.
Extends from the right side to the left above the hydraulic housing 33, bypassing the back of the driver's seat 14 (the operation lever 7).
6 and the like are also adopted in the embodiments of FIGS. 1 to 14).

In place of the automatic draft control device, there is provided a hydraulic control lever device 80 which is manually operated (manually operated). This lever device 80 comprises a position lever 81 and a draft lever 82 and has a hydraulic housing. A support arm 84 that inserts and supports a control shaft 83, which is an inner / outer dual shaft, is projected rightward and outward so as to close an opening formed on the right side of the 33 (slightly behind the auto-draft control valve). Shaft 83 is connected to levers 81 and 8
The valve is rotated by the front-back operation 2 to control a valve housed in the hydraulic housing 33.

In FIGS. 16 and 17, reference numeral 85 denotes a differential lock petal, and front and rear wheels are arranged side by side so that they can be freely depressed. The above-described external hydraulic take-out device 1 according to the present invention can be applied to the tractor 2 that does not include the cabin 17 and the canopy 75, and the valve 35 is not only in the illustrated vertical direction but also in the horizontal direction. It can also be stacked.

Further, with respect to the draft control valve device, in particular, in the case of the automatic draft control valve, since the maintenance opportunities are increased, the application of the present invention is significant. Is also significant.

[0039]

As described above in detail, according to the present invention, it is possible to reduce the weight of the hydraulic elevating device and to improve the maintenance.

[Brief description of the drawings]

FIG. 1 is a side view of a tractor provided with a hydraulic lifting device according to the present invention.

FIG. 2 is an elevational view of a rear part of the tractor.

FIG. 3 is a side view of a hydraulic elevating device having an external hydraulic take-out device according to the present invention.

FIG. 4 is a plan view of FIG. 3;

FIG. 5 is a rear view of a main part of FIG. 3;

FIG. 6 is a configuration diagram of a hydraulic circuit.

FIG. 7 is a plan view of a spacer.

FIG. 8 is a front view of a spacer.

FIG. 9 is a side view of the spacer.

FIG. 10 is a sectional view taken along line AA of FIG. 7;

FIG. 11 is a sectional view taken along line BB of FIG. 7;

FIG. 12 is a sectional view taken along line DD of FIG. 7;

FIG. 13 is a sectional view taken along line EE of FIG. 7;

FIG. 14 is a cross-sectional view of the hydraulic lifting control device.

FIG. 15 is a side view showing another type of tractor to which the present invention is applied.

FIG. 16 is a side view of a main part of FIG.

FIG. 17 is a plan view of a main part in FIG. 15;

18 is a rear (rear) view of a main part of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 External hydraulic take-out device 2 Tractor 9 Lift arm 10 Hydraulic elevating device 33 Hydraulic housing 34 Oil passage 35 Hydraulic take-out valve 42 Main port 43 Draft control valve device 44 Horizontal control valve device 45 Oil passage

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Toshimitsu Yazaki 64 Ishizukitamachi, Sakai-shi, Osaka Inside Kubota Sakai Works

Claims (4)

[Claims] 1. A tractor (2) in which a hydraulic lifting device (10) having a lift arm (9) is mounted on a rear upper surface of a tractor vehicle body (5), wherein a hydraulic housing (10) constituting the hydraulic lifting device (10) is provided. 3
3) having a main port (42);
A hydraulic lift device for a tractor, characterized in that a plurality of oil passages (34) and (35) communicating with the hydraulic housing (33) are formed as a hole structure in the hydraulic housing (33). 2. A plurality of oil passages (34) (45) formed in a hydraulic housing (33) are provided with a draft control valve device (4).
3) and an oil line (4) for the horizontal control valve device (44).
5) and an oil passage (34) for the external hydraulic unloading device (1)
The hydraulic lift device for a tractor according to claim 1, wherein: 3. A tractor (2) in which a hydraulic lifting device (10) having a lift arm (9) is mounted on a rear upper surface of a tractor vehicle body (5), a hydraulic housing (10) constituting the hydraulic lifting device (10). 3
3) an arm shaft (38) having a lift arm (9)
Are rotatably supported via a bush (70), and means (71) (72) for semi-forced lubrication of the bush (70).
A hydraulic lift device for a tractor, comprising: 4. A piping member (71) connected to a tank port of a valve device (43) (44) provided on the left and right side walls of the hydraulic housing (33) by semi-forced lubrication means (71) (72). 4. The method according to claim 3, wherein
A hydraulic lift device for a tractor according to any of the preceding claims.