JPH10132056A - Transmission for working vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the oil temperature extensively, and accomplish a long service life of a hydraulic pump and a hydraulic motor, by mixing an oil cooled by an oil cooler to the leak oil in an HST case positively. SOLUTION: In the device in which a hydraulic pump P driven by receiving an engine power, and a hydraulic motor M fluid-connected to the hydraulic pump P through a closed circuit are provided in an HST case 10 to store the leak oil from the closed circuit, and at the same time, a transmission device to communicate and connect the hydraulic motor M to the left and the right running device, is housed, and the HST case 10 is connected to a transmission case 1 to store the lubricating oil for the transmission device, an other hydraulic pump P0 to take out the lubricating oil in the transmission case 1 is provided, and the lubricating oil discharged from the hydraulic pump P0, is joined to the leak oil in the HST case 10 passing through an oil cooler 63, and at the same time, when the storing oil amount in the HST case 10 is made at a specific amount or more, the oil is returned into the transmission case 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technology for cooling leak oil from hydraulic pons and a hydraulic motor in an HST case in a transmission for a working vehicle.

[0002]

2. Description of the Related Art Conventionally, a hydraulic pump is driven by an engine, a hydraulic motor is fluidly connected to the hydraulic pump via a closed circuit, and leak oil from the closed circuit is stored in an HST case. It is known that a predetermined amount of fluid is overflowed and returned to a case in which another lubricant is stored. For example, the technique is disclosed in Japanese Utility Model Laid-Open No. 4-62956 of the same applicant.

[0003]

However, in the prior art, the leak oil is stored in an HST case and is directly returned to a case such as a transmission case where lubricating oil is stored. Therefore, cooling was performed by mixing with the lubricating oil in the transmission case.However, as a means for lowering the oil temperature, cooling was performed by cooling fins provided outside the case. Therefore, the cooling cannot be performed sufficiently, and the life of the hydraulic pump and the hydraulic motor has been shortened.

[0004]

The problem to be solved by the present invention is as described above. Next, means for solving the problem will be described. A hydraulic pump driven by receiving engine power and a hydraulic motor fluidly connected to the hydraulic pump via a closed circuit are disposed in an HST case for storing leaked oil from the closed circuit, and It accommodates a transmission that interlocks and connects the motor and the left and right traveling devices, and
In the case where the HST case is connected to a transmission case for storing lubricating oil for the transmission, another hydraulic pump for extracting the lubricating oil in the transmission case is provided, and the lubricating oil discharged from the hydraulic pump is supplied to an oil cooler. After that, the oil is merged with the leak oil in the HST case, and is returned to the transmission case when the amount of stored oil in the HST case becomes equal to or more than a predetermined amount.

Further, the another hydraulic pump is configured as a drive hydraulic source for a hydraulic actuator mounted on a work vehicle, and a return oil circuit from the hydraulic actuator is connected to the HST case via the oil cooler. It was done.

[0006]

Next, an embodiment of the present invention will be described with reference to the drawings. 1 is a skeleton diagram of a traveling power transmission mechanism of a work vehicle, FIG. 2 is a rear cross-sectional view of the transmission, FIG. 3 is also an enlarged expanded cross-sectional view of FIG. 4, FIG. 4 is an upper plan cross-sectional view thereof, and FIG. 6, FIG. 6 is a right side view, FIG. 7 is a sectional view of a filter mounting portion, and FIG. 8 is a hydraulic circuit diagram.

An embodiment in which the hydraulic circuit configuration of the present invention is applied to a combine transmission will be described. 1 to 4, the power transmission configuration will be described. An HST transmission 2 is mounted on a transmission case 1 and
The ST type transmission 2 has a pump shaft 3 serving as an input shaft protruding from the HST case 5 to one side, and an input pulley 4 is fixedly provided, and a driving force from an engine (not shown) is transmitted to the input pulley 4 via a V-belt 9. ing. By rotating the input pulley 4, the variable displacement hydraulic pump P housed in the HST case 5 is driven, and the hydraulic oil from the hydraulic pump P is supplied to the hydraulic motor M via a normal closed circuit (not shown). Refueled. At this time, by manually changing the shift arm of the hydraulic pump P, the volume of the hydraulic pump P is changed, and the discharge amount and the discharge direction are changed. The motor shaft 6 serving as the output shaft of the hydraulic motor M is continuously variable-speed driven by this pressure oil and driven. An output gear 7 is fixed on the motor shaft 6, and the output gear 7 meshes with a gear 12 loosely fitted on an intermediate shaft 11 in side cases 10 and 43 integrally provided on the upper side surface of the transmission case 1. The gear 12 meshes with an input gear 14 fixed on an input shaft 13 to form an HS.
The power shifted by the T-type transmission 2 is transmitted to a transmission mechanism to the axle in the transmission case 1.

The transmission case 1 is divided into left and right halves. The transmission case 1 includes an input shaft 13, an auxiliary transmission shaft 15, a steering shaft 16, a counter shaft 17, and a PTO shaft 18.
Are rotatably mounted on the input shaft 13 in the transmission case 1, and gears 20 and 21 are fixedly mounted on the input shaft 13. The gear 20 is composed of a loose fitting gear 22 on the auxiliary transmission shaft 15 and a counter shaft 17. The gear 2 is always meshed with the gear 24 fixed on the
1 meshes with the loosely fitted gear 23 on the auxiliary transmission shaft 15. A gear 25 is further fixed on the counter shaft 17, and the gear 25 meshes with a gear 26 externally fitted on the PTO shaft 18 via a one-way clutch 29. A PTO pulley 27 is fixed outside the transmission case 1 of the PTO shaft 18 so that rotational power synchronized with the HST transmission 2 can be taken out.

A clutch sliding body 30 is spline-fitted between the free-fitting gear 22 and the free-fitting gear 23 on the auxiliary transmission shaft 15 so as to be slidable in the left-right axial direction.
And a tooth portion 22a on the inner surface of each of the loose fit gears 23.
23a is formed so that the clutch sliding body 30 can be engaged with either the tooth portion 22a or the tooth portion 23a by the sliding operation of the clutch sliding body 30, and the clutch sliding body is provided on the input shaft 13. 8 is slidably fitted in the left and right axial direction, and a loose fitting gear 28 is rotatably loosely fitted therein. The loose fitting gear 28 meshes with a wide gear 31 engraved on the auxiliary transmission shaft 15. Clutch sliding body 8.3 by auxiliary speed shifter (not shown)
By simultaneously sliding 0, three sub-speed rotations of high, middle and low can be obtained. In this way, power is transmitted from the input shaft 13 to the auxiliary transmission shaft 15.
A brake drum 32 is fixed on the auxiliary transmission shaft 15 extending outside the transmission case 1, and the parking brake is braked by rotating a brake arm 33 (FIG. 3).

A driving gear 34 is provided at the center of the steering shaft 16.
The drive gear 34 meshes with the gear 31 on the auxiliary transmission shaft 15 to transmit power. Internal teeth 34L and 34R are formed around the rotation axis on both sides of the drive gear 34. ing. On the other hand, hollow cylinders 35L and 35R are rotatably fitted on both sides of the drive gear 34 on the steering shaft 16, and spline-like teeth are formed on the outer peripheral surfaces of the hollow cylinders 35L and 35R. (Drive gear side) A clutch gear 35a is formed on the outer periphery, and the internal teeth 34L of the drive gear 34 are formed.
(Or 34R) so that the side clutch can be engaged with and disengaged from the side clutch.

The central portion of the teeth of the hollow cylindrical bodies 35L and 35R is always meshed with the reduction gears 36L and 36R as side gears, and the reduction gears 36L and 36R of the traveling drive shafts 19L and 19R supported at the lower part of the transmission case 1. The traveling drive shafts 19L and 19R are fixed to the inner end and the transmission case 1 and the axle cases 47L and 47R are connected via bearings.
, And driving sprockets 48L and 48R are fixed to the other outer ends of the traveling drive shafts 19L and 19R to drive the crawler.

On the other side (outside) teeth of the hollow cylindrical bodies 35L and 35R, rotating friction plates 37 for a multi-plate type side brake are locked so as not to rotate relatively. Are arranged between the friction plates 37, and the bearing cases 42 for supporting both outer ends of the steering shaft 16 are mounted. From the portion of the transmission case 1, the friction plates 38, 38 are provided on the inner periphery of a hollow cylindrical portion 1 a that is recessed and formed inward of the case.
Are locked so that they cannot rotate, and the friction plates 37 and 38
.. Constitute a side (steering) brake. The other ends (outer ends) of the hollow cylindrical bodies 35L and 35R
, A piston member 41 is disposed in a bearing case 42 so as to face the friction plates 37, 38,..., And is provided with a steering lever provided on a work vehicle (not shown). By turning a steering switching valve 50 described later by rotating operation, oil pressure is supplied to a cylinder chamber formed in the bearing case 42, and the piston member 41 is advanced into the transmission case, so that the side clutch and the side The brakes are sequentially activated to turn the aircraft.

When the working vehicle is a combine, a mowing device is mounted as a working machine in front of the machine body, and the mowing device is moved up and down by controlling the expansion and contraction of a hydraulic cylinder 54. The piston member 41 for operating the side clutch / side brake is controlled by a hydraulic circuit shown in FIG. That is, the input shaft of the hydraulic pump P0 is fixedly mounted on the output shaft of the engine E in addition to the drive pulley 55 for driving the input pulley 4;
The hydraulic pump P0 is being driven. By driving the hydraulic pump P0, the lubricating oil in the transmission case 1 is sucked through the strainer 67. As shown in FIG. 5, FIG. 6, and FIG. 7, the strainer 67 is suspended in a compartment formed in the oil sump of the transmission case 1, and the outlet side of the strainer 67 is branched into two, one of which is branched. The other is connected to the suction port of the hydraulic pump P0 via a pipe 69, and the other is further filtered by a filter 70 mounted on the upper surface of the transmission case 1 and connected to the suction port of a charge pump CP via a pipe 71. The oil discharged from the pump CP charges a closed circuit that fluidly connects the hydraulic pump P and the hydraulic motor M.

The oil discharged from the hydraulic pump P0 is:
As shown in FIG. 8, oil is sent to a flow divider 57 via a filter 56, and one of the divided oil flows is sent to the steering switching valve 50 by the flow divider 57, and the steering switching valve 50 By the switching operation of 50, the piston member 41 is supplied to one of the cylinder chambers. A drain hole is provided in the cylinder chamber at a stroke position corresponding to a side clutch disengagement position, and each drain hole communicates with the inside of the transmission case 1 via a side brake relief valve 58. When the side clutch is activated, the relief valve 58 for the side brake is opened, and when the brake is activated, the relief set pressure of the relief valve 58 for the side brake is increased in proportion to the operation amount of the steering lever. .

The other oil flow divided by the flow divider 57 is supplied to the lift valve 5 of the hydraulic lift controller 39.
9, connected to the hydraulic cylinder 54 via a check valve 60 and the like, and operated by a lift lever (not shown)
Are artificially switched so that the hydraulic cylinder 54 can be controlled to expand and contract. Reference numeral 61 denotes a relief valve for setting the operating pressure of the hydraulic cylinder 54. These directional control valves 5
9, the load check valve 60, the relief valve 61, the flow divider 57, and the side brake relief valve 38 are housed in a valve case 74. The return oil from the elevating valve 59 is sent to the oil cooler 63 via the pipe 62, and the return oil is cooled. The oil cooler 63 is arranged near the radiator 65 of the engine E, and the oil flowing through the oil cooler 63 is forcibly cooled by the cooling fan 66 of the engine E. The cooled oil that has flowed out of the oil cooler 63 is returned into the HST case 5 through a pipe 64 as shown in FIG.

The HST case 5 contains a hydraulic pump P and a hydraulic motor M, and stores lubricating oil. Oil leaking from the rotary sliding portions of the hydraulic pump P and the hydraulic motor M is also used in the HST case 5. Is stored within. 2 and 6, the HST case 5 is closed by a lid 72, and the lid 72 is fixed to the upper side surface of the side case 43 fixed to the side surface of the transmission case 1. ing. The cover 72 has an overflow hole 72a for setting the stored amount of leaked oil in the HST case 5 inside and outside the case. In the side case 43, an oil hole 43a for receiving oil from the overflow hole 72a is opened inside and outside of the case, and both the overflow hole 72a and the oil hole 43a are aligned with each other so that the lid 72 and the oil hole 43a coincide with each other. When the side cases 43 are interconnected, the lubricating oil that has flowed into the HST case 5 enters the side cases 10 and 43 from the overflow holes 72a through the oil holes 43a when exceeding a predetermined amount.

Further, an overflow hole 43b for setting the amount of lubricating oil stored in the side case 43 is opened in and out of the case so that oil can flow between the side cases 10 and 43 and the inside of the transmission case 1. doing. An oil hole 1b for receiving oil from the overflow hole 43b is opened in and out of the case on the side wall of the transmission case 1 so that the positions of the overflow hole 43b and the oil hole 1b coincide with each other. By communicating the transmission case 43 and the transmission case 1 with each other, when a predetermined amount or more of lubricating oil is accumulated in the side cases 10 and 43, the lubricating oil is returned from the overflow hole 43b to the transmission case 1 through the oil hole 1b.

In such a configuration, the lubricating oil in the transmission case 1 is sucked up as hydraulic oil by the hydraulic pump P0, and is sent to the elevation control device 39 so that the hydraulic cylinder 54 for driving the working machine can be driven. ,
The return oil from the elevation control device 39 is sent to an oil cooler 63 via a pipe 62, where the return oil is cooled and further sent into the HST case 5 via a pipe 64,
It mixes with the leak oil of the hydraulic pump P and the hydraulic motor M in the HST case 5 to lower the oil temperature and cool the hydraulic pump P, the hydraulic motor M, and the like. Then, the oil that has overflowed the predetermined oil amount in the HST case 5 flows from the overflow hole 72a to the side case 1 through the oil hole 43a of the side case 43.
0.43 Side case 10 that is inside 0.43 and is in contact with the outside air
· Cooled down again while flowing down 43, the side case 10
The oil overflowing the predetermined oil amount of 43 is returned from the overflow hole 43b into the transmission case 1 through the oil hole 1b of the transmission case 1, and the oil is cooled while passing through the HST case through the oil cooler 63 as described above. 5 and the transmission case 1.

[0019]

As described above, the present invention has the following advantages. That is, since the oil cooler is positively mixed with the leak oil in the HST case by the oil cooler, the oil temperature can be greatly reduced, and the height of the hydraulic pump and the hydraulic motor can be reduced. Life extension can be achieved.

According to the second aspect of the present invention,
There is no need to provide a dedicated hydraulic unit for driving the hydraulic actuator, which also serves as a hydraulic pump for cooling the leak oil in the HST case and a hydraulic drive source for the hydraulic actuator, thereby simplifying the configuration and reducing costs. Can be achieved. Also, return oil from the heated hydraulic actuator is
Instead of returning the oil directly to the transmission case, the oil is cooled by an oil cooler, and then returned to the transmission case via the HST case, so that the oil can be efficiently cooled as a whole.

[Brief description of the drawings]

FIG. 1 is a skeleton diagram of a traveling power transmission mechanism of a work vehicle.

FIG. 2 is a rear cross-sectional view of the transmission.

FIG. 3 is an enlarged expanded sectional view of the upper part.

FIG. 4 is an upper plan sectional view of the same.

FIG. 5 is a left side view of the transmission.

FIG. 6 is a right side view of the same.

FIG. 7 is a sectional view of a filter mounting portion.

FIG. 8 is a hydraulic circuit diagram.

[Explanation of symbols]

 P Hydraulic pump P0 Hydraulic pump M Hydraulic motor 1 Transmission case 5 HST case 63 Oil cooler

Claims (2)

[Claims] A hydraulic pump driven by receiving engine power and a hydraulic motor fluidly connected to the hydraulic pump via a closed circuit are configured to store leakage oil from the closed circuit.
In the case where the HST case is connected to a transmission case which is disposed in an ST case and accommodates a transmission device for interlockingly connecting the hydraulic motor and the left and right traveling device, and stores lubricating oil for the transmission device. , Provided another hydraulic pump to take out the lubricating oil in the transmission case,
Lubricating oil discharged from this hydraulic pump is combined with leak oil in the HST case through an oil cooler,
A transmission for a working vehicle, wherein the transmission is recirculated into the transmission case when the amount of oil stored in the HST case becomes equal to or more than a predetermined amount. 2. The hydraulic pump according to claim 1, wherein the another hydraulic pump is configured as a driving hydraulic source for a hydraulic actuator mounted on a work vehicle, and a return oil circuit from the hydraulic actuator is connected to the HST case via the oil cooler. The transmission for a work vehicle according to claim 1, wherein the transmission is provided.