JP2000179656A - Oil circulating structure for working vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively suppress a lowering of sealing performance caused by the degradation of a sealing compound consequent to temperature rise in a transmission case by heightening lubricating oil cooling effect in view of lubricating oil flowing in the transmission case high in heat radiation. SOLUTION: In this oil circulating structure for a working vehicle using lubricating oil in a transmission case 14 as operating oil, an oil filter 48 is mounted on one side wall 14A of the transmission case 14, and an oil lead-in guide 14a is extended from one side wall 14A toward the opposed other side wall 14B. An oil lead-in part 14b to the oil filter 48 is formed on the other side wall 14B side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oil circulation structure for a working vehicle configured to utilize lubricating oil in a transmission case as hydraulic oil.

[0002]

2. Description of the Related Art In an oil circulation structure for a work vehicle as described above, lubricating oil in a transmission case is taken out as hydraulic oil for a hydraulic actuator through an oil filter mounted on the transmission case. FIG.
As shown in (1), since the flow of the lubricating oil to the oil filter 48 in the transmission case 14 is not regulated, the lubricating oil simply flows in a short circuit toward the oil filter 48.

[0003]

That is, according to the above-mentioned prior art, since the lubricating oil simply flows in a short circuit toward the oil filter, the lubricating oil flows in the transmission case having a high heat radiation property. While making
Lubricating oil, whose temperature rises due to friction with the rotating transmission shaft and transmission gears, cannot be cooled efficiently, which makes it easier for the temperature inside the transmission case to rise, and as a result, the seal associated with the temperature rise This has tended to cause a decrease in sealability due to deterioration of the agent.

[0004] An object of the present invention is to pay attention to the lubricating oil flowing in a transmission case with high heat dissipation, and to enhance the cooling effect of the lubricating oil to prevent the deterioration of the sealant due to the temperature rise in the transmission case. An object of the present invention is to make it possible to effectively suppress a decrease in sealing performance caused by the above.

[0005]

In order to achieve the above object, according to the first aspect of the present invention, an oil circulation of a working vehicle configured to utilize lubricating oil in a transmission case as hydraulic oil. In the structure, an oil filter is mounted on one side wall of the transmission case, and an oil introduction guide extends from one side wall toward the other side wall facing the oil filter, and the oil filter is mounted on the other side wall side. The oil introduction part was formed.

According to the first aspect of the present invention, when lubricating oil in the transmission case is taken out as hydraulic oil for the hydraulic actuator via the oil filter mounted on the transmission case, the lubricating oil is removed from the oil. By the action of the guide for introduction, it is prevented from flowing short-circuiting toward the oil filter in the transmission case, and flows toward the oil introduction section formed on the other side wall side, and from the oil introduction section. It will be introduced into the oil filter. That is, the lubricating oil introduced into the oil filter flows along the other side wall in the transmission case, whereby the retained heat of the lubricating oil is reduced.
During the flow, the oil is conducted to the other side wall and is efficiently radiated from the side wall to the outside.Therefore, the lubricating oil whose temperature rises due to friction with the rotating transmission shaft, transmission gear, etc. Cooling can be performed efficiently.

[Effect] Accordingly, the cooling effect of the lubricating oil can be enhanced, and the temperature rise in the transmission case can be suppressed. It has become possible to effectively suppress the decrease and the like.

According to the second aspect of the present invention,
The invention according to claim 1, wherein the lubricating oil in the transmission case is used as hydraulic oil for a multi-plate transmission clutch for selectively transmitting and connecting a plurality of normally meshed gears built in the transmission case. did.

According to the second aspect of the present invention, the lubricating oil in the transmission case is easily used as lubricating oil or hydraulic oil for a multi-plate transmission clutch that easily generates heat, so that the temperature is easily raised. Even, the lubricating oil is
By flowing along the other side wall when it is taken out as hydraulic oil through the oil filter, it is efficiently cooled through the side wall, so that the temperature rise in the transmission case is effectively suppressed. become able to.

[Effects] Therefore, even in a transmission case equipped with a multi-plate type transmission clutch that easily generates heat, it is possible to effectively suppress a decrease in sealing performance due to deterioration of the sealant due to a rise in temperature in the transmission case. Became.

[0011]

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

FIG. 1 shows an overall side view of a combine, which is an example of a working vehicle. The combine is composed of a traveling body 1 having a pair of left and right crawler-type traveling devices 1A, and a hydraulic cylinder 2 at a front portion thereof. It comprises a cutting unit 3 connected so that it can be driven up and down by operation, a threshing device 4 mounted on the traveling machine body 1, a grain tank 5, an engine 6, an operating unit 7, and the like.

As shown in FIGS. 2 to 4, the power from the engine 6 is transmitted to a transmission 8, and the transmission 8 has an input shaft 9 to which the power from the engine 6 is belt-transmitted. A sub-transmission mechanism 10 capable of shifting the power input to the input shaft 9 between high and low gears, and a main transmission mechanism 1 capable of shifting the power from the sub-transmission mechanism 10 to six forward gears and two reverse gears.
1. A reaping transmission unit 12 for transmitting the post-shift power from the main transmission mechanism 11 to the reaping unit 3, and a left and right crawler traveling device 1A.
Is constituted by a hydraulic straight / swing switching mechanism 13 capable of switching between a straight running state and a turning state, and a transmission case 14 surrounding them.

A first transmission gear 9a is formed integrally with the input shaft 9, and the cylindrical shaft 15 is fitted around the input shaft 9 so as to be relatively rotatable without relative sliding. In the first transmission gear 9a,
A second transmission gear 16a integrally formed with the first rotating shaft 16 is always meshed. The cylindrical shaft 15 has a large-diameter low-speed driven gear 15a, a small-diameter high-speed driven gear 15b, and a transmission gear 15c.
Are integrally formed. The first rotating shaft 16 has a shift member 17 integrally formed with a low-speed driving gear 17a meshable with the low-speed driven gear 15a and a high-speed driving gear 17b meshable with the high-speed driven gear 15b. They are spline-fitted so as to rotate integrally with each other so as to be relatively slidable. The shift member 17 is linked to a sub-transmission lever (not shown) provided in the operation unit 7, and operates the sub-transmission lever to operate a low-speed transmission state in which the low-speed drive gear 17a meshes with the low-speed driven gear 15a. High speed drive gear 1
7b is selectively switched to a high-speed transmission state in which it meshes with the high-speed driven gear 15b. That is, the cylinder shaft 15 and the shift member 17 constitute the gear shift type auxiliary transmission mechanism 10.

The low-speed driven gear 15a of the cylindrical shaft 15 has a second
A small-diameter high-speed gear 19 which is fitted to the rotary shaft 18 so as to be relatively rotatable relative to the rotary shaft 18 is always meshed. The transmission gear 15c of the cylindrical shaft 15 is always meshed with a large-diameter low-speed gear 20 that is fitted to the second rotating shaft 18 so as to be relatively rotatable relative to the second rotating shaft 18. A multi-plate hydraulic high-speed clutch 2 that can transmit high-speed power via the high-speed gear 19 to the second rotary shaft 18 between the second rotary shaft 18 and the high-speed gear 19.
1 is interposed. Between the second rotating shaft 18 and the low-speed gear 20, a multi-plate hydraulic low-speed clutch 22 capable of transmitting low-speed power via the low-speed gear 20 to the second rotating shaft 18 is interposed. A third transmission gear 18 is provided on the second rotation shaft 18.
a and the fourth transmission gear 18b are integrally formed. Third
The transmission gear 18a is always meshed with a first forward gear 24 externally fitted to the third rotation shaft 23 so as to be relatively rotatable in a state where the third rotation shaft 23 cannot slide relatively. The fourth transmission gear 18b is relatively non-slidable on the fourth rotation shaft 25 and is relatively rotatably fitted on the second forward gear 26, and is relatively non-slidable on the third rotation shaft 23. The third forward gear 27 rotatably fitted to the outside is always meshed. The first forward gear 24 is always meshed with a reverse gear 28 which is fitted to the fourth rotating shaft 25 so as to be relatively rotatable in a state in which it cannot slide relatively. Third rotating shaft 2
A multi-plate hydraulic first forward clutch 29 capable of transmitting forward power via the first forward gear 24 to the third rotating shaft 23 is interposed between the third forward gear 24 and the first forward gear 24. . 4th
A multi-plate hydraulic second forward clutch 30 capable of transmitting forward power via the second forward gear 26 to the fourth rotary shaft 25 is interposed between the rotary shaft 25 and the second forward gear 26. ing. Between the third rotating shaft 23 and the third forward gear 27, forward power via the third forward gear 27 is applied to the third rotating shaft 23.
A third forward clutch 31 of a multi-plate hydraulic type that can be transmitted to the vehicle is interposed. Between the fourth rotation shaft 25 and the reverse gear 28, the reverse power via the reverse gear 28 is supplied to the fourth rotation shaft 2.
5 is provided with a multi-plate hydraulic type reverse clutch 32 that can transmit power to the clutch. A fifth transmission gear 23a is provided on the third rotation shaft 23,
A sixth transmission gear 25a is formed integrally with the fourth rotating shaft 25, and the fifth transmission gear 23a and the sixth transmission gear 25a are formed integrally with each other.
The transmission gear 25a is always meshed with a center gear 34 which is spline-fitted so as to rotate integrally with the fifth rotation shaft 33 in a state where the transmission gear 25a cannot relatively slide.

That is, the high-speed clutch 21, the low-speed clutch 22, the first forward clutch 29, the second forward clutch 30,
The third forward clutch 31 and the reverse clutch 32 include a third transmission gear 18 a and a fourth transmission gear, which are a plurality of stages of normally meshing gears G disposed from the second rotation shaft 18 to the fourth rotation shaft 25. 18b, fifth transmission gear 23a, sixth transmission gear 25
a, high speed gear 19, low speed gear 20, first forward gear 24,
A multi-plate type transmission clutch C for selectively transmitting and connecting the second forward gear 26, the third forward gear 27, and the reverse gear 28, and a hydraulic type clutch using a plurality of stages of the normal mesh gear G and the multiple disk type shift clutch C. Of the main speed change mechanism 11 of FIG.

A third transmission gear 18a of the second rotary shaft 18 is always meshed with a seventh transmission gear 36 that rotates integrally with an output shaft 35 for taking out power to the reaper 3 in addition to the first forward gear 24. . That is, the high-speed gear 1 of the main transmission mechanism 11
The transmission gear 12 is constituted by an output shaft 35 to which the shifting power is transmitted via the low speed gear 9 or the low speed gear 20 and the seventh transmission gear 36, whereby the sub transmission mechanism 10 performs a high / low transmission and further a main transmission. Since the shifting power after the high and low speed shifting by the mechanism 11 is transmitted to the reaping unit 3, it is possible to suppress an increase in the difference between the traveling speed and the reaping speed due to the shifting operation, and thereby, It is possible to effectively suppress the occurrence of inconveniences such as poor harvesting conveyance due to a large speed difference.

Side clutches and brakes 37 are mounted on the left and right sides of the fifth rotating shaft 33, respectively, and the corresponding input gears 1a of the left and right crawler type traveling devices 1A are linked via the respective side clutches and brakes 37. ing. The left and right side clutches and brakes 37 are rotatably and relatively slidably attached to the rotating body 38 spline-fitted so as to rotate integrally with the shaft end side of the fifth rotating shaft 33 and the fifth rotating shaft 33. A cylindrical gear 3 which is fitted and always meshes with an input gear 1a of a corresponding crawler type traveling device 1A.
9, the meshing claw 38a formed on the rotating body 38 and the cylindrical gear 3
9, an urging spring 40 for pressing and urging the cylindrical gear 39 so as to mesh with the meshing claw 39a, and a cylindrical gear with supply of hydraulic oil to an oil chamber 41 formed in the transmission case 14. A ring-shaped piston 42 that slides toward the center gear 34 against the urging of the urging spring 40, and the cylindrical gear 39 and the piston 42 are adapted to allow relative rotation of the cylindrical gear 39 with respect to the piston 42. , A multi-plate brake 44 interposed between the transmission case 14 and the cylindrical gear 39, and a multi-plate brake 44 interposed between the needle bearing 43 and the multi-plate brake 44. The power from the fifth rotating shaft 33 is transmitted to the input gear 1a via the cylindrical gear 39 by adjusting the supply amount of the working oil to the oil chamber 41 by the pressure plate 45 or the like. A driving state, a non-transmission state in which the power from the fifth rotating shaft 33 is not transmitted to the input gear 1a, and a braking state in which the braking force from the multiple disc brake 44 is transmitted to the input gear 1a via the cylindrical gear 39. It is configured to be switchable.

The left and right side clutches
By switching the brake 37 to the transmission state, a straight-ahead state in which the left and right crawler-type traveling devices 1A are driven at a constant speed can appear, and one side clutch / brake 37 is maintained in the transmission state, and By switching the other side clutch / brake 37 to the non-transmission state, only the one crawler-type traveling device 1A is driven, and a driven turning state in which the other crawler-type traveling device 1A is driven can be exhibited. , One side clutch
By maintaining the brake 37 in the transmission state and switching the other side clutch / brake 37 to the braking state, only one crawler traveling device 1A is driven,
A braking turning state in which the other crawler traveling device 1A is braked can appear. That is, the right / left side clutch / brake 37 constitutes the straight / turning switching mechanism 13.

As shown in FIGS. 4 and 5, a pressure plate 45 of the left side clutch / brake 37 is provided.
The engagement piece 46a of the operation shaft 46, which is rotatably supported on the transmission case 14 around the horizontal axis P, is engaged with the groove 45a, and is interlocked with the rotation of the operation shaft 46. Thus, it rotates about the fifth rotation shaft 33 as a fulcrum. The opposing surfaces of the pressure plate 45 and the transmission case 14 face each other with the rotation of the pressure plate 45.
A climbing type cam 47 for sliding operation of the cam 5 along the fifth rotation shaft 33 is formed. The operation shaft 46 has an operation arm 46b integrally provided at an outer end thereof linked to a brake pedal (not shown). In this configuration, in a straight running state in which both the left and right side clutches and brakes 37 are switched to the transmission state, the operation of the operation shaft 46 by the depression operation of the brake pedal is performed, whereby the cam 4 is rotated.
7, the pressure plate 45 on the left side can be slid toward the center gear 34 side, whereby the multi-plate type brake 44 on the left side can be switched to the braking state. The applied braking force can be transmitted to the input shaft 1a of the left and right crawler type traveling device 1A via the fifth rotating shaft 33, the left and right rotating bodies 38, and the left and right cylindrical gears 39. That is, the left side clutch / brake 3
Numeral 7 is configured to function as a traveling brake that brakes the left and right crawler traveling devices 1A in accordance with the depression operation of the brake pedal. Further, the brake pedal can be fixed at the depressed operation position by a lock mechanism (not shown), whereby the left side clutch / brake 37 can also function as a parking brake.

As shown in FIG. 6, the transmission case 14
The oil filter 48, the first hydraulic pump 49, which is connected through a high-pressure transmission oil passage ra, which is a hydraulic oil supply path to each multi-plate transmission clutch C of the main transmission mechanism 11,
Rotary valve 50, pressure reducing valve 5 for setting clutch pressure
1. The accumulator 52 for accumulating pressure, the brake cylinder 53, and the high-pressure steering oil passage rb, which is a hydraulic oil supply passage for the side clutch / brake 37 branched from the shift oil passage ra. The transmission case 1 includes a sequence valve 54, a steering valve 55, a variable relief valve 56, and the like.
The lubricating oil in 4 is used as hydraulic oil for shifting operation and steering operation.

The rotary valve 50 is supplied to the neutral position N where hydraulic oil from the first hydraulic pump 49 is not supplied to the main transmission mechanism 11, and hydraulic oil from the first hydraulic pump 49 is supplied to the main transmission mechanism 1.
The first forward speed position F1 to be supplied to the first low speed clutch 22 and the first forward clutch 29, and the forward travel to supply the hydraulic oil from the first hydraulic pump 49 to the low speed clutch 22 and the second forward clutch 30 of the main transmission mechanism 11. In the second speed position F2, the hydraulic oil from the first hydraulic pump 49 is supplied to the low speed clutch 2 of the main transmission mechanism 11.
Third forward speed position F to be supplied to the second and third forward clutch 31
3. Hydraulic oil from the first hydraulic pump 49 is supplied to the main transmission mechanism 11
Forward fourth speed position F4 to be supplied to the high speed clutch 21 and the first forward clutch 29, and forward 5 to supply the hydraulic oil from the first hydraulic pump 49 to the high speed clutch 21 and the second forward clutch 30 of the main transmission mechanism 11. In the speed position F5, the hydraulic oil from the first hydraulic pump 49 is supplied to the high speed clutch 21 of the main transmission mechanism 11.
Forward sixth speed position F to be supplied to the third forward clutch 31
6. The hydraulic oil from the first hydraulic pump 49 is supplied to the main transmission mechanism 11
1st reverse speed position RL to be supplied to the low speed clutch 22 and the reverse clutch 32, and 2nd reverse speed position to supply the hydraulic oil from the first hydraulic pump 49 to the high speed clutch 21 and the reverse clutch 32 of the main transmission mechanism 11. An RH is provided, and a main shift lever 57 provided in the driving unit 7 is linked. That is, the main speed change mechanism 11 is
The shift operation can be performed by rotating the rotary valve 50 by the above operation.

The rotary valve 50 is connected to the main transmission mechanism 1.
1, a first forward clutch 29 and a second forward clutch 29 which are disposed on the transmission lower side of the high speed clutch 21 and the low speed clutch 22.
The operating oil to be supplied to the forward clutch 30, the third forward clutch 31, and the reverse clutch 32 is configured to pass through the accumulator 52 once. High-speed clutch 21 or low-speed clutch 22 and first forward clutch 2
9. When any one of the second forward clutch 30, the third forward clutch 31, and the reverse clutch 32 is switched to the transmission state, the transmission coupling operation of the high-speed clutch 21 or the low-speed clutch 22 on the transmission upper side is performed. The transmission coupling operation of the first forward clutch 29, the second forward clutch 30, the third forward clutch 31, or the reverse clutch 32 on the lower side of the transmission can be slowed down.
Gear shifting operation can be performed smoothly without shock.

The brake cylinder 53 is mounted inside the operation arm 46b of the left side clutch / brake 37 in a state in which the operation arm 46b of the left side clutch / brake 37 has flexibility to allow swinging displacement of the operation arm 46b accompanying the depression operation of the brake pedal. The operation arm 46b is operated in the braking operation direction by the action of the biasing spring 53a, and the operating oil is supplied to the oil chamber 53b, and the braking operation direction of the operation arm 46b is opposed to the action of the biasing spring 53a. It is linked to release the operation to. The hydraulic oil is not supplied to the oil chamber 53b of the brake cylinder 53 only when the rotary valve 50 is operated to the neutral position N. That is, the brake cylinder 53 is connected to the main transmission mechanism 11.
When the neutral state appears, the left side clutch / brake 37 is automatically switched to the braking state.

The steering valve 55 and the variable relief valve 5
6 is linked to a steering lever 58 provided in the driving unit 7. When the steering lever 58 is operated to the neutral position N, the steering valves 55 are connected to the oil chambers 41 of the left and right side clutches / brake 37. When the steering lever 58 is switched to the first left operating position L1 to the left of the neutral position N when the steering position is switched to the straight traveling position S in which the hydraulic oil is not supplied, the steering valve 55 is turned to the oil chamber of the left side clutch / brake 37. When the steering lever 58 is switched to the first right operating position R1 to the right of the neutral position N, the steering valve 55 is turned to the right side clutch / brake 37. Can be switched to the right turning position TR for supplying the working oil to the oil chamber 41 of the first embodiment. In these operating positions, the variable relief valve 56 is not affected by the operation of the steering lever 58, and its operating pressure is maintained at zero or a very low pressure close thereto. . Then, the steering lever 58 is moved to the first left operating position L.
When the swing operation is performed from 1 to an operation region extending from the first left operation position L2 to the left, the steering valve 55 is moved to the steering lever 58.
Is maintained at the left turning position TL irrespective of the operating position of, and the operating pressure of the variable relief valve 56 is increased as the steering lever 58 approaches the second left operating position L2. The supply oil pressure to the oil chamber 41 increases. Conversely, when the steering lever 58 is swung to the operation region extending from the first right operation position R1 to the second right operation position R2 to the right thereof, the steering valve 55 is moved regardless of the operation position of the steering lever 58. At the right turning position TR, and as the steering lever 58 approaches the second right operating position R2, the variable relief valve 56
Is increased, and the hydraulic pressure supplied to the oil chamber 41 of the right side clutch / brake 37 increases.

That is, when the steering lever 58 is operated to the neutral position N, the operating oil is not supplied to the oil chambers 41 of the left and right side clutches and brakes 37, so that the cylindrical gears of the left and right side clutches and brakes 37 are not supplied. Since the urging spring 40 meshes with the rotating body 38, the straight traveling state in which the left and right crawler traveling devices 1A are driven at a constant speed can be realized.

Further, the steering lever 58 is moved from the neutral position N to the first position.
When operating to the left operating position L1, the left side clutch
Hydraulic oil is supplied only to the oil chamber 41 of the brake 37, and only the left cylindrical gear 39 separates from the rotating body 38 against the action of the biasing spring 40. Since the valve 56 is opened to prevent the pressure plate 45 of the left side clutch / brake 37 from pressing against the multi-plate type brake 44, only the right side crawler type traveling device 1A is connected to the main transmission mechanism 11A. And a left driven turning state in which the left crawler-type traveling device 1A is driven.

Further, the steering lever 58 is moved to the first left operating position L
1 to the second left operation position L2, the operating pressure of the variable relief valve 56 is increased in accordance with the operation position, and the oil chamber 4 of the left side clutch / brake 37 is increased.
1, the pressure plate 45 of the left side clutch / brake 37 presses the multi-plate type brake 44, and accordingly, the right crawler type traveling device 1A Only the power from the main transmission mechanism 11 drives only the left crawler-type traveling device 1A, and a left-brake turning state can be achieved.

Conversely, when the steering lever 58 is operated from the neutral position N to the first right operation position R1, hydraulic oil is supplied only to the oil chamber 41 of the right side clutch / brake 37,
Only the right cylindrical gear 39 separates from the rotating body 38 against the action of the biasing spring 40, and the pressure rises to the distance, the variable relief valve 56 opens, and the right side clutch / brake 37 Since the pressure plate 45 is prevented from pressing against the multiple disc brake 44, only the left crawler traveling device 1A is driven by the power from the main transmission mechanism 11, and the right crawler traveling device 1A is driven. A right driven turning state in which 1A is driven can appear.

Further, the steering lever 58 is moved to the first right operating position R.
When operating from 1 to the second right operating position R2, the operating pressure of the variable relief valve 56 is increased in accordance with the operating position, and the oil chamber 4 of the right side clutch / brake 37 is increased.
1 is further supplied with hydraulic oil, and the pressure plate 45 of the right side clutch / brake 37 is pressed against the multi-plate type brake 44 accordingly. Only the right braking turning state in which only the right transmission is driven by the power from the main transmission mechanism 11 and the right crawler traveling device 1A is braked.

The transmission case 14 is provided with a raising and lowering valve 59, a fall prevention valve 60, a high-pressure relief valve 61, and the like, which are connected via a lifting oil passage rc, which is a hydraulic circuit for raising and lowering the cutting unit. A valve unit 62 for raising and lowering the unit is mounted. The lifting oil passage rc has a supply oil passage rc1 connected to a second hydraulic pump 63 and a hydraulic cylinder 2 mounted on the engine 6 via a hydraulic hose 64, and a return oil passage rc2 connected to the transmission case 14. Is connected to a low-pressure oil passage rd that is connected to the low-pressure oil passage rd via a low-pressure relief valve 65. Second hydraulic pump 63
Is connected via a hydraulic hose 64 to a high-pressure preliminary supply oil passage re branched from the transmission oil passage ra. That is, the lubricating oil in the transmission case 14 is also used as hydraulic oil for the operation of raising and lowering the mowing unit.

The low pressure oil passage rd is provided with a low pressure relief valve 65.
The lubricating oil supply passage rf is connected to the oil passage portion rd1 on the more upstream side, and the lubricating oil supply passage rf is connected to the valve unit 6.
Hydraulic fluid for raising and lowering the reaping unit from the main transmission mechanism 11
High-speed clutch 21, low-speed clutch 22, first forward clutch 29, second forward clutch 30, third forward clutch 3
1, and the reverse clutch 32 is supplied as lubricating oil.

As shown in FIGS. 6 and 7, the transmission oil passage r
a, steering oil passage rb, low pressure oil passage rd, preliminary supply oil passage r
e and the lubricating oil supply path rf
This is an internal oil passage formed by attaching the piping plate 66 to the right side wall 14A of FIG. Piping plate 66
A transmission oil passage ra, a steering oil passage rb, and a preliminary supply oil passage re, which are high-pressure oil passages, are formed on the center side, and a low-pressure oil passage rd is formed on the periphery of the transmission oil passage rd. ra, the steering oil passage rb, and the preliminary supply oil passage re.

As shown in FIGS. 7 and 8, the oil filter 48 is provided on the right side wall 14A of the transmission case 14 from the side wall 14A to the opposite left side wall 14B.
It is mounted close to 4C. The transmission case 14 has a left side wall 14 facing the right side wall 14A.
An oil guide 14a is provided extending toward B to cover the oil filter 48, and an oil introduction portion 14b for the oil filter 48 is formed on the left side wall 14B, which is the extension end side. ing.

With this configuration, the lubricating oil in the transmission case 14 is supplied to the hydraulic cylinder 2 and the main transmission mechanism 1 through the oil filter 48 mounted on the transmission case 14.
1, and when taken out as hydraulic oil of the straight / rotation switching mechanism 13, the lubricating oil flows along the left side wall 14B of the transmission case 14 by the action of the oil introduction guide 14a. Due to the flow, the retained heat of the lubricating oil is conducted to the left side wall 14B and is radiated outward from the side wall 14B. In other words, although the lubricating oil in the transmission case 14 is easily raised in temperature by using it as lubricating oil and hydraulic oil for the multi-plate type transmission clutch C, which easily generates heat, the lubricating oil retains heat. Left side wall 14B of mission case 14
The lubricating oil can be effectively cooled since the oil can be efficiently dissipated from the air, so that the temperature of the sealant applied to the joint surface of the transmission case 14 and the piping plate 66 in the transmission case 14 rises. Thus, it is possible to effectively suppress a decrease in the sealing performance due to the deterioration accompanying the above.

[Other Embodiments] Other embodiments of the present invention will be listed below. The work vehicle may be a tractor, a rice transplanter, or the like. As the oil filter 48, the transmission case 1
4 may be an external type that is connected and connected without being inserted into the inside of the device. The oil filter 48 is mounted on the left side wall 14B of the transmission case 14, and the oil introduction guide 14a
From the left side wall 14B of the transmission case 14 to the right side wall 14
A, the oil introduction portion 14b may be formed on the right side wall 14A side, and the oil filter 48 may be mounted on one of the front and rear side walls of the transmission case 14 and the oil introduction guide 14a may be provided. The mission case 14
The oil introduction portion 14b may be formed to extend from one of the front and rear side walls to the other of the front and rear side walls and to face the other front and rear side walls. In the case where the oil filter 48 is mounted on one side wall of the transmission case 14 in a state where it is separated from the bottom wall 14C of the transmission case 14, the oil extending from one side wall toward the other side wall facing the oil case 48 is provided. The guide 14a for introduction may be formed in a cylindrical shape.

[Brief description of the drawings]

FIG. 1 is an overall side view of a combine.

FIG. 2 is a longitudinal sectional front view showing a transmission configuration of the transmission.

FIG. 3 is a longitudinal sectional side view showing a transmission configuration of the transmission.

FIG. 4 is a vertical cross-sectional front view showing a configuration of a straight / turning switching mechanism.

FIG. 5 is a longitudinal sectional side view of a main part showing linkage between an operation shaft and a pressure plate.

FIG. 6 is a hydraulic circuit diagram

FIG. 7 is a longitudinal sectional side view showing an internal oil passage formed in a piping plate.

FIG. 8 is a longitudinal sectional front view showing a shape of an oil filter mounting portion in a transmission case.

FIG. 9 is a longitudinal sectional front view showing a shape of an oil filter mounting portion in a conventional transmission case.

[Explanation of symbols]

 14 Transmission case 14A Side wall (one side) 14B Side wall (other side) 14a Guide (for oil introduction) 14b Oil introduction part 48 Oil filter C Multi-plate type transmission clutch G Normally meshed gear

Claims (2)

[Claims] 1. An oil circulation structure for a working vehicle configured to utilize lubricating oil in a transmission case as hydraulic oil, wherein an oil filter is mounted on one side wall of the transmission case and one side wall thereof. An oil circulation structure for a working vehicle, wherein an oil introduction guide extends toward the other opposite side wall from the other side, and an oil introduction portion for the oil filter is formed on the other side wall side. 2. The system according to claim 1, wherein the lubricating oil in the transmission case is used as hydraulic oil for a multi-plate transmission clutch for selectively transmitting and connecting a plurality of normally meshed gears provided in the transmission case. Item 2. An oil circulation structure for a work vehicle according to Item 1.