JPH0788893B2 - Lubrication structure of mission case in tractor - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention mounts a hydraulic cylinder for operating a working machine on an upper surface of a transmission case, and supplies and discharges pressure oil to and from the hydraulic cylinder to connect to a tractor. The present invention relates to an agricultural tractor for lifting and lowering a working machine, and more particularly to an oil supply structure in a mission case of such a tractor.

2. Description of the Related Art In an agricultural tractor, an engine is mounted on the front part of a vehicle body and a mission case is mounted on the rear part. The output shaft of the engine is connected to the input shaft of the mission case via a propeller shaft. A transmission mechanism is built in the transmission case, and engine power input to the input shaft is transmitted to the output shaft through the transmission mechanism, and the output shaft drives wheels. The transmission case is further provided with a PTO shaft, and the input engine power is also transmitted to the PTO shaft at variable speeds, and the power is transmitted to the working machine connected to the tractor via the PTO shaft.

The speed change mechanism includes various speed change shafts, and around these speed change shafts, a bearing portion for axially supporting the speed change shafts, a needle bearing for rotatably supporting gears on the speed change shafts, or the like. There are many parts that require lubrication. Therefore, an oil pump for supplying lubricating oil to each of these lubricating parts is attached to the mission case. Further, the transmission case is provided with a brake device for braking each of the left and right rear wheels, and in the case where a wet brake is adopted as this brake device, the oil for cooling the brake plate and preventing wear is also the above-mentioned oil. A pump supplies the brake.

The working machine is lifted and lowered by a hydraulic cylinder mounted on the upper surface of the mission case via a lift arm, and a hydraulic pump for operating the hydraulic cylinder is provided separately from the oil pump and connected to the hydraulic cylinder. Has been done.

Problems to be Solved by the Invention By the way, since the hydraulic pump is used only when raising the working machine, the utilization rate is relatively low. Therefore, the present invention is intended to enable the oil discharged from the hydraulic pump to be utilized for lubricating the wheels as described above and for supplying oil to the wet brake.

Therefore, in the present invention, in the tractor in which the hydraulic cylinder for operating the working machine is mounted on the upper surface of the transmission case, the oil from the hydraulic pump is transferred to the hydraulic cylinder or the transmission case. A switching valve device for selectively directing the oil therein, and an oil sump for accumulating the oil flowing from the switching valve device in the upper part of the transmission case, and the oil sump disposed in the transmission case. And the wet type brake attached to the transmission case.

According to the present invention, by guiding the discharge oil of the hydraulic pump to the hydraulic cylinder through the switching valve device, the hydraulic cylinder operates to raise the working machine, but in other cases, the discharge oil of the hydraulic pump is switched. It is returned to the mission case via the valve device. The oil that has flowed into the mission case is stored in an oil reservoir provided in the upper part of the mission case, flows from the oil reservoir to the shaft lubrication section and the wet brake, and is effectively used as lubricating oil or cooling oil. It Therefore, the utilization efficiency of the hydraulic pump for operating the working machine is improved, and the load on the oil pump for lubricating oil is reduced. Further, since the oil sump is provided at a high position in the mission case, even if the wet brake is provided at a relatively high position, it is possible to refuel the brake, and therefore the position of the brake can be adjusted within the mission case. The height can be set relatively freely without being limited by the height of the oil surface.

Example FIG. 1 is a side view of an agricultural tractor to which the present invention is applied,
A front wheel 2 is mounted on the front part of the body frame 1, and a rear wheel 3 is mounted on the rear part. An engine 4 is mounted on an upper front portion of the body frame 1, and an output shaft of the engine 4 is a propeller shaft 5
Is connected to the input shaft S1 of the mission case 6 via. The mission case 6 is composed of a main clutch case 7, a main mission case 8, an intermediate case 9 and a rear case 10, is fixed to the vehicle body frame 1, and has a transmission groove, a rear wheel drive mechanism and the like built therein. The engine power input to the input shaft S1 is appropriately shifted through the speed change mechanism and then output to the rear wheel 11, the PTO shaft S2, and the front wheel drive shaft S3. The PTO shaft S2 transmits power to a working machine such as a rotary cultivator connected to the rear part of the tractor. Front wheel drive shaft S3
Transmits power to the front wheels 2 via the front wheel drive propeller shaft 12.

A hydraulic cylinder 13 is placed on the upper surface of the rear case 10, and a lift arm 14 that swings up and down in conjunction with an internal piston.
Extends rearward from the hydraulic cylinder 13. The rear end of the lift arm 14 is connected to the working machine via a link device, and the swinging of the lift arm 14 causes the working machine to move up and down. A hydraulic pump 15 for supplying hydraulic pressure to the hydraulic cylinder 13 is provided on the upper part of the intermediate case 9 and the hydraulic cylinder 13
It is attached to the back of. 16 is a seat and 17 is a steering wheel.

FIG. 2 is a schematic cross-sectional view of the inside of the rear case 10 as viewed from the rear, but shows the auxiliary transmission portion in front of the rear case 10 except for the rear wheel drive mechanism. There is. The auxiliary transmission device is composed of a final shaft S4, an auxiliary transmission counter shaft S5 and an auxiliary transmission idle shaft S6. Third
As shown in the figure, the final shaft S4 is arranged coaxially with a main transmission counter shaft S7 extending rearward from the main transmission in the main transmission case 8. A gear G ₇₁ rotatably supported on the bearing wall 18 of the transmission case via a bearing 19 is spline-fitted to the rear end of the main transmission counter shaft S7.
The front end of the final shaft S4 is rotatably supported by ₇₁ via a needle bearing 20.

The rear end of the final shaft S4 is pivotally supported by the rear bearing wall 21, and the bevel gear 22 fixed to the rear end meshes with the input bevel gear of the differential device. Gear G ₄₂ which is slidably mounted, secured to the gear G ₄₅ to rotate loosely been gears G ₄₃ and integrally through the needle shaft is provided back and forth through the spline to the final shaft S4 ing. Similarly, the sub-transmission counter shaft S5 and the sub-transmission idle shaft S6 are also supported by the bearing wall 18 and the bearing wall 21, and the sub-transmission counter shaft S5 always has a gear G ₅₁ and a gear G _{42 which} mesh with the gear G _71. A gear G ₅₂ capable of meshing with the gear G _53, a loosely fitted gear G _53, and a gear G ₅₄ integral therewith are provided.

Vice The speed change idle shaft S6 always with the gear G ₅₂ meshing tooth decay wheel G
₆₂ is loosely fitted, and a gear G ₆₄ integral therewith meshes with the gear G ₅₄ . Since the sub transmission is configured in this way, when the gear G ₄₂ is slid to the front position,
Last shaft main transmission counter shaft S7, the gear G _71, via a gear G ₄₂
Directly connected to S4. When the gear G ₄₂ is slid to an intermediate position where it meshes with the gear G ₅₂ , the rotation of the main transmission counter shaft S7 is
The reduced speed is transmitted to the final shaft S4 via the G ₇₁ , the gear G ₅₁ , the auxiliary transmission force counter shaft S5, the gear G ₅₂ and the gear G ₄₂ . Further, when the gear G ₄₂ is slid to the rear position, the rotation of the main gear shift counter shaft S7 is changed to the gear G ₇₁ , the gear G ₅₁ , and the sub gear shift counter shaft.
S5, gear G ₅₂ , gear G ₆₂ , gear G ₆₄ , gear G ₅₄ , gear G _53, and gear G ₄₃ are transmitted to the final shaft S4 after being greatly reduced.

The auxiliary shift counter shaft S5 and the auxiliary shift idle shaft S6 are provided with axial lubricating oil passages 24 and 25, respectively, and these lubricating oil passages 24 and 25 have radial communication ports 24a and 25a, respectively. Through the needle bearings of the gears G ₅₄ , G ₅₃ ,
The gear bearings G ₆₂ and G ₆₄ communicate with the needle bearing portions, and these bearing portions are lubricated by the lubricating oil supplied to the lubricating oil passages 24 and 25.

The hydraulic cylinder 13 is mounted on the upper surface of the rear case 10 as described above, and the hydraulic cylinder 13 is provided with a control box 26 as shown in FIG. The discharge oil of the hydraulic pump 15 is supplied to the internal switching valve 27 through the supply pipe 28. When raising the working machine, the switching valve 27 is operated to connect the oil supply pipe 28 to the oil supply passage 29, and guide the oil into the hydraulic cylinder 13. Hydraulic cylinder
As shown in FIG. 4, a piston 30 is slidably fitted in the piston 13, and a swing shaft 32 is mounted on the piston 30 via an arm 31.
The lift arm 14 is attached to the swing shaft 32, and the piston 30 slides backward by the hydraulic pressure introduced into the hydraulic cylinder 13 as described above, whereby the lift arm 14 is moved. Through the work machine rises. When the work implement is not moved upward, the oil supply pipe 28 is a switching valve.
It communicates with the oil drain passage 33 through 27, and the oil drain passage 33 is a rear case.
It penetrates through the top wall of 10 and leads to the inside of the rear case 10.
Therefore, the oil discharged from the hydraulic pump 15 is discharged into the rear case 10 via the oil supply pipe 28, the switching valve 27 and the oil discharge passage 33. Further, when the working machine is lowered from the raised position, the oil in the hydraulic cylinder 13 is also discharged into the rear case 10 via the oil discharge path 33.

An oil sump 35 is formed in the rear case 10 by a partition wall 34 that partitions the upper part thereof in a substantially horizontal direction, and the oil discharged into the rear case 10 through the oil discharge passage 33 is accumulated in the oil sump 35. To be

An oil-filling hole 36 extending downward in a well shape is opened at a substantially central portion in the width direction of the partition wall 34, and a bottom portion of the oil-filling hole 36 faces the rear end surface of the auxiliary shift counter shaft S5.

Since the lubricating oil passage 24 is opened at the rear end surface of the sub-transmission counter shaft S5, the oil discharged from the drain oil passage 33 flows into the lubricating oil passage 24 through the oil sump 35 and the oil supply hole 36, and It reaches the needle bearing portions of the gears G ₅₄ , G ₅₃ through the communication port 24a and lubricates the bearing portions.

The partition wall 34 also has a similar oil supply hole 37 slightly rearward and leftward from the oil supply hole 36 (FIGS. 2 and 5).
This lubrication hole 37 is divided into an upper lubrication hole 37a and a lower lubrication hole 37b by a partition wall 38 provided in the middle.
The a and 37b communicate with each other through a communication port 39 provided in the partition wall 38. A brake oil supply passage 40 branches from the oil supply hole 37a, extends leftward in the rear case 10, and communicates with a wet brake device 41 attached to the left side of the rear case 10.
The lower oil supply hole 37b is directed forward, and the rear end of the front wheel drive shaft S3 is rotatably supported via a bearing 42 at the front end opening thereof. Front-wheel drive shaft S3 is driven by said final shaft S4 through the gears G ₄₅ meshes caries wheel G _35. The front wheel drive shaft S3 also has an axial lubricating oil passage 43 similar to the lubricating oil passages 24 and 25.
The oil flowing from the oil sump 35 into the oil supply hole 37a through the oil supply hole 37a and the communication port 39 into the lubricating oil passage 4
3 is supplied to the lubrication portion around the front wheel drive shaft S3 via the lubricating oil passage 43.

A similar lubrication hole 44 is provided on the right side of the rear case 10 almost symmetrically with the lubrication hole 37 (Fig. 2), and the upper lubrication hole is provided.
44a communicates with the wet brake device 46 on the right side through the brake oil supply passage 45, and the lower oil supply hole 44b forms the auxiliary shift idle shaft S.
It communicates with the lubricating oil passage 25 of 6. As described above, the lubricating oil passage 25 communicates with the needle bearing portions of the gear G ₆₂ and the gear G ₆₄ via the communication port 25a.

FIG. 6 is a plan sectional view showing a rear wheel drive mechanism provided in the rear portion of the rear case 10, in which the bevel gear 22 of the final shaft S4 meshes with the input large gear 47 of the differential device 23. The differential shaft 48, which is the output shaft of the differential device 23, penetrates the rear case 10 through the partition plate 50 that is fastened together with the brake housing 49, and the outer end thereof is connected to the brake housing 49.
In the brake chamber 51 which is pivotally supported by and is surrounded by the brake housing 49 and the partition plate 50, a brake device 41 including a plurality of brake plates 52 and an operation member 53 for pressing the brake press plates 52 against each other is built-in. The differential shaft 48 is braked by the braking device 41. Since the differential shaft 48 is connected to the rear axle 11 via the reduction gear device 54, the rear wheel 3 is braked by braking the differential shaft 48. The brake device 41 is a wet type brake device, and oil is supplied into the brake chamber 51 through a communication port 55 provided in the partition plate 50, and the brake oil supply passage 40 is connected to this communication port 55. Therefore, the oil discharged from the hydraulic cylinder 13 to the oil sump 35 in the rear case 10 is supplied to the brake device 41 through the oil supply hole 37 and the brake oil supply passage 40. Although the left-side brake device 41 has been described above, the right-side brake device 46 has the same structure, and oil in the oil sump 35 is similarly supplied through the oil supply hole 44 and the brake oil supply passage 45.

As described above, according to the present invention, in the tractor in which the hydraulic shilling for operating the working machine is mounted on the upper surface of the transmission case, the oil from the hydraulic pump is selectively inserted into the hydraulic cylinder or the transmission case. A switching valve device for directing the oil is provided, and an oil sump for accumulating the oil flowing from the switching valve device is provided in an upper portion of the transmission case, and the oil sump is provided with a lubricating portion of a shaft arranged in the transmission case and the mission. Since it is connected to the wet brake attached to the case, the oil discharged from the hydraulic pump for operating the work machine can be effectively used as lubricating oil for the shaft and cooling oil for the wet brake, and therefore the hydraulic pump for operating the work machine can be used. As the efficiency increases, the load on the oil pump for lubrication provided separately from the hydraulic pump is reduced. Be done.

Further, since the oil sump is provided at a high position in the mission case, even if the wet brake is provided at a relatively high position, it is possible to refuel the brake.
Therefore, the position of the brake can be set relatively freely without being restricted by the height of the oil level in the mission case.

[Brief description of drawings]

1 is a side view of an agricultural tractor to which the present invention is applied, FIG. 2 is a schematic cross-sectional view of the inside of a mission case seen from the rear, and FIG. 3 is a cross-sectional view taken along line III-III of FIG. 4 is a sectional view taken along the line VI-VI, FIG. 5 is a sectional view taken along the line VV, and FIG. 6 is a partial plan sectional view of the rear wheel drive mechanism. 1 ... Body frame, 2 ... Front wheel, 3 ... Rear wheel, 4 ... Engine, 5 ... Propeller shaft, 6 ... Mission case, 7
... Main clutch case, 8 ... Main mission case, 9 ... Middle case, 10 ... Rear case, 11 ... Rear axle, 12 ... Front wheel drive propeller shaft, 13 ... Hydraulic cylinder, 14 ... Little arm, 15 ... Hydraulic pump, 16 ... Seat, 17 ... Handle, 18 ... Bearing wall, 19 ... Bearing, 20 ... Needle bearing, 21 ... Bearing wall, 22 ...
Bevel gear, 23 ... Differential device, 24 ... Lubricating oil supply passage, 25 ... Lubricating oil passage, 26 ... Control box. 27 ... Switching valve,
28 ... Oil supply pipe, 29 ... Oil supply passage, 30 ... Piston, 31 ... Arm,
32 ... Oscillation shaft, 33 ... Oil discharge passage, 34 ... Partition wall, 35 ... Oil sump, 36 ... Oil supply hole, 37 ... Oil supply hole, 38 ... Partition wall, 39 ... Communication port,
40 ... Brake oil supply passage, 41 ... Brake device, 42 ... Bearing, 43
… Lubricant passage, 44… Lubrication hole, 45… Brake lubrication passage, 46…
Brake device, 47 ... Input gear, 48 ... Differential shaft, 49 ... Brake housing, 50 ... Partition plate, 51 ... Brake chamber, 52 ... Braking plate, 53 ... Operating member, 54 ... Reduction gear device,
55 ... oil port.

Claims (1)

[Claims] 1. A tractor in which a hydraulic cylinder for operating a working machine is mounted on an upper surface of a transmission case, and a switching valve device for selectively directing oil from a hydraulic pump into the hydraulic cylinder or the transmission case is provided. An oil sump for accumulating oil that has flowed in from the switching valve device is provided in an upper part of the mission case, and the oil sump has a lubricating portion of a shaft arranged in the mission case and a wet brake attached to the mission case. The oil supply structure of the mission case is characterized by communicating with the.