JP2887146B2 - Agricultural tractor oil cooling system - Google Patents

Description

The present invention relates to a cooling device for lubricating oil and hydraulic oil in an agricultural tractor.

(B) Conventional technology Conventionally, as a fluid cooling device for lubricating oil of an agricultural tractor, the technology described in Japanese Utility Model Laid-Open No. Sho 57-6988 has been known.

(C) Problems to be Solved by the Invention However, in the conventional technique, it is necessary to provide a recirculation vane for recirculating high-temperature working lubricating oil, and a pipe connecting between the rear axle cases hangs down. The pipe was in the way.

 The present invention has solved these problems.

(D) Means for Solving the Problems The object of the present invention is as described above, and a configuration for achieving the object will be described below.

A power transmission device and an HST conversion device are arranged in a transmission case 3, and the lubricating oil of the power transmission device and the hydraulic oil of the HST transmission are shared and stored in the transmission case 3. A rear axle case 5 is additionally provided on both sides of the rear axle case, and a drain recirculation port 8 is formed on the upper surface of the rear axle case 5 at an end remote from the transmission case 3 to discharge from the HST drain port 7 of the HST transmission. The high-temperature drain oil is guided to the drain return port 8 through a drain return pipe 6, and then the drain oil is introduced from the rear axle case 5 into the transmission case 3, and is used as hydraulic oil for the HST transmission. , The strainer S for sucking hydraulic oil into the charge pump CP
It is arranged in the transmission case 3 in front of a position away from the rear axle case 5.

(E) Embodiment The purpose and configuration of the present invention are as described above. Next, the configuration of the embodiment shown in the attached drawings will be described.

1 is a side sectional view showing an agricultural tractor oil cooling device according to the present invention, FIG. 2 is a side view showing an oil pipe, FIG. 3 is a plan view of the same, FIG. 4 is a hydraulic motor M and a strainer S
FIG. 5 is a plan sectional view of the rear axle case 5, FIG. 6 is a front view of the hydraulic pump P, FIG. 7 is a plan view thereof, FIG. 8 is a side view thereof, and FIG. Is a rear view of the safety frame F, FIG. 10 is a side view thereof, FIG. 11 is a plan view of the strainer S, and FIG. 12 is a hydraulic circuit diagram of the agricultural tractor oil cooling device of the present invention.

1 and 4, the power transmission mechanism of the agricultural tractor will be briefly described.

A transmission device is constituted by connecting the clutch case 1, the oil passage plate 2, and the transmission case 3 in series.

The crankshaft of the engine protrudes into the clutch case 1, and the clutch shaft inputs power to the pump shaft 10a of the HST transmission via the main clutch.

The charge pump CP and the hydraulic pump P are driven by the pump shaft 10a.

The oil passage plate 2 is disposed between the hydraulic pump P and the hydraulic motor M, and also serves as a support fixed plate of the HST transmission and an oil passage interposition plate.

A PTO transmission shaft 12 is coupled to a portion where the rear end of the pump shaft 10a protrudes from the oil passage plate 2, and transmits power to the PTO shaft 13.

The motor shaft 15 of the hydraulic motor M outputs the rotation after shifting,
Power is transmitted to the pinion shaft 14 via a gear sliding type auxiliary transmission. The pinion shaft 14 drives the differential gear device D.

In addition, the rotation after shifting by the auxiliary transmission is transmitted to the front wheel drive shaft.
The tractor's front wheels are also driven for 15.

A strainer S is disposed below the pinion shaft 14 via the baffle plate 4 in the left-right direction.

The baffle plate 4 is closed at the front and the upper side and opened only at the rear side, so that the high-temperature hydraulic oil from the upper HST transmission is not immediately sucked into the strainer S.

Next, the configuration of the hydraulic pump P will be described with reference to FIGS. 6, 7, and 8. FIG.

A charge pump CP is disposed on all of the hydraulic pumps P, and the hydraulic oil sucked from the strainer S is sucked by the suction pipe 20 toward the charge pump CP.

The tip of the suction pipe 20 is sucked into the charge pump CP from the pipe joint 20a on the side of the charge pump CP.

Further, by pushing and pulling the link 21 from the outside of the clutch case 1, the turning arm 22 on the pivot shaft 23 is turned, and the link 24 further causes the arm 25 of the swash plate turning shaft 26 to move.
Is operated to change the pressure oil discharge direction and discharge pressure of the hydraulic pump P.

 Next, a description will be given with reference to FIGS.

From the side of the oil passage plate 2 for filtering hydraulic oil in a closed circuit connecting the hydraulic pump P and the hydraulic motor M,
A take-out pipe 19 to the line filter 9 and a return pipe 18
Is plumbed.

The discharge pipe 19 is pushed out by the discharge force by the charge pump CP, passes through the line filter 9, and returns to the joint pipe 18 a of the oil passage plate 2 by the return pipe 18.

The essential part of the present invention is that the high-temperature hydraulic oil discharged from the HST drain port 7 opened to the hydraulic motor M does not directly return to the inside of the transmission case 3,
L and 5R are returned via drain return pipes 6L and 6R to drain return ports 8L and 8R provided at ends remote from the transmission case 3.

As shown in FIGS. 3 and 4, the rear axle cases 5L and 5R are constructed by mounting the same parts on the left and right, so that the drain recirculation ports 8L and 8R are located above and below the rear axle cases 5L and 5R. Therefore, the positions of the drain reflux ports 8L and 8R are upside down on the left and right.

As shown in FIG. 4, the HST drain port 7 protrudes from the hydraulic motor M, penetrates the transmission case 3, and
It protrudes from the upper surface.

Also, as shown in FIGS. 9 and 10, since the lower portion of the safety frame F is fixed around the rear axle cases 5L and 5R, even when the temperatures of the rear axle cases 5L and 5R themselves increase. In addition, the safety frame F can function as a cooling fin to lower the temperature.

The temperature of the drain shaft discharged from the HST drain port 7 of the HST transmission is about 100 ° C., the temperature of the lubricating oil inside the transmission case 3 is 60 to 70 ° C., and the temperature difference between the high and low temperature parts is about 30
There is also a ° C.

If the hydraulic oil of the HST transmission is not lower than about 80 ° C., it will not operate efficiently. Therefore, the hydraulic oil of the HST drain port 7 at about 100 ° C. immediately after being mixed with the lubricating oil in the transmission case 3 Efficiency drops when oil is sucked.

In the present invention, 100
℃ drain oil by the drain return pipe 6L, 6R, the drain return port 8L of the rear axle case 5L, 5R furthest to the strainer S
In the portion of 8R, by mixing with the lubricating oil, before returning to the transmission case 3 from inside the rear axle case 5L, 5R,
Since the lubricating oil is cooled by the safety frame F or the like, the overall temperature of the lubricating oil can be reduced by about 10 ° C.

In FIG. 12, in addition to the HST transmission of the present invention,
A configuration in which a hydraulic circuit for a panner steering mechanism 30, a hydraulic elevating mechanism 31, and an external hydraulic take-out device 32 is provided in parallel is disclosed.

The hydraulic oil discharged from the hydraulic pump 34 is supplied to the hydraulic elevating mechanism 31 and the external hydraulic take-out device 32, and the hydraulic oil discharged from the hydraulic pump 33 is supplied to the power steering mechanism 30.

These hydraulic devices suck lubricating oil from the strainer S previously fitted in the transmission case 3 and use it as hydraulic oil.

(F) Effects of the Invention The present invention is configured as described above, and has the following effects.

First, in an agricultural tractor in which the transmission device lubricant oil and the hydraulic device hydraulic oil are shared and stored in the transmission case 3,
A drain recirculation port 8 is formed on the upper surface of the rear axle case 5 at an end remote from the transmission case 3 to guide the high-temperature drain oil from the hydraulic device to the rear axle case 5. In this case, suction is not performed by the charge pump CP of the pump P.

Second, the oil temperatures of the lubricating oil and the working oil can be made uniform.

Third, by using the rear axle cases 5L and 5R as cooling devices, it is not necessary to separately provide a dedicated hydraulic oil cooling device, or the cooling capacity can be reduced.

Fourth, if there is an axle or a safety frame F attached to the rear axle cases 5L, 5R, these can also be used as cooling and heat radiating parts.

Fifth, by reducing the temperature of the suction hydraulic oil of the HST transmission, the reliability and life of the equipment of the HST transmission can be improved.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing an agricultural tractor oil cooling device of the present invention, FIG. 2 is a side view showing an oil pipe, FIG. 3 is a plan view of the same, and FIG. 4 shows a hydraulic motor M and a strainer S. FIG. 5 is a plan sectional view of the rear axle case 5, FIG. 6 is a front view of the hydraulic pump P, FIG. 7 is a plan view thereof, FIG. 8 is a side view thereof, and FIG. FIG. 10 is a side view, FIG. 11 is a plan view of the strainer S, and FIG. 12 is a hydraulic circuit diagram of the agricultural tractor oil cooling device of the present invention. P ... Hydraulic pump M ... Hydraulic motor S ... Strainer 1 ... Clutch case 2 ... Transmission case 4 ... Baffle plate 5L, 5R ... Rear axle case 6L, 6R ... Drain return pipe 7 ... HST drain Mouth 8L, 8R …… Drain reflux port

Claims (1)

(57) [Claims] An agricultural tractor in which a power transmission and an HST transmission are arranged in a transmission case 3 and lubricating oil for the power transmission and hydraulic oil for the HST transmission are shared and stored in the transmission case 3. A rear axle case 5 is additionally provided on both sides of the transmission case 3, and a drain recirculation port 8 is drilled at an end of the upper surface of the rear axle case 5 away from the transmission case 3, and an HST of the HST transmission device is provided. The high-temperature drain oil discharged from the drain port 7 is guided to the drain return port 8 via a drain return pipe 6, and then the drain oil is introduced from the rear axle case 5 to the transmission case 3, and the HST transmission An agricultural tractor oil cooling device characterized in that a strainer S for sucking hydraulic oil into the charge pump CP as hydraulic oil for the device is disposed in the transmission case 3 in front of a position away from the rear axle case 5.