JP2000108700A - Hst hydraulic circuit of working vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify the structure of a hydraulic circuit of a working vehicle provided with an HST and a wet multiple disc-type hydraulic clutch. SOLUTION: An HST is connected to an end part of a transmission case 1 through a base plate 3, and a wet multiple disc-type hydraulic clutch 2 of approximately same height as the HST is pivoted in the transmission case 1. A tank port T1 of the HST is connected to an oil passage 5 formed in the shaft 4 for pivoting the base plate 31 and the clutch 3, and a downstream circuit side of the oil passage 5 is opened for feeding the oil to the disc 2 part of the hydraulic clutch 3 to cool and lubricate the discs.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an HST hydraulic circuit for an agricultural work vehicle such as a tractor, a combine or a rice transplanter, or a construction or transport work vehicle.

[0002]

2. Description of the Related Art Conventionally, in a transmission mechanism of a working vehicle such as an agricultural tractor,
In a mode in which a clutch in the form of a wet disk for transmitting a traveling portion or a working portion is provided in the transmission case, it is necessary to supply a lubricating oil in order to smoothly perform friction of the disk.

The main transmission of the tractor is H
In the configuration in which the ST is connected to the transmission case for transmission, the tank port of the HST is directly opened to the oil tank or the transmission case.

[0004]

SUMMARY OF THE INVENTION The present invention provides a work vehicle with an H
The purpose of the present invention is to simplify the hydraulic circuit when the ST is provided, and the hydraulic circuit of the HST is configured as follows. That is, an HST is connected to an end of the transmission case 1 via a base plate 31, and a hydraulic clutch 3 in the form of a wet multi-disc is mounted in the transmission case 1 at substantially the same height as or below the HST. Along with
An oil passage 5 communicating the tank port T1 of the HST with a shaft 4 on which the base plate 31 and the clutch 3 are mounted.
, And opens the lower side of the circuit of the oil passage 5 to supply the disk 2 of the hydraulic clutch 3 to the HS of the working vehicle.
A T hydraulic circuit was used.

[0005]

The power continuously variable by the HST is as follows.
The power is transmitted to a traveling unit or a working unit via a transmission mechanism in the transmission case 1. Also, a hydraulic clutch 3 provided in the transmission case 1,
Is cooled and lubricated by supplying oil discharged from the tank port T1 of the HST through an oil passage 5 communicating with the base plate 31 and the shaft 4 provided with the clutch 3.

Accordingly, the hydraulic circuit can be simplified as compared with a configuration in which the tank port of the HST and the oil passage for lubricating the clutch are separately provided. Also,
Since the position of the clutch 3 is set at substantially the same height as or lower than the HST, the oil is released from the oil passage opening portion over a wide range, and the clutch can be cooled and lubricated as uniformly as possible. .

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below for an agricultural tractor. The tractor 6 is integrally formed by connecting an HST case body, a transmission case 1 (a front transmission case 9, a rear transmission case 10) and the like from the front engine 7 to the rear side.

A front axle bracket 11 is provided at the front of the engine 7, and a center pivot 12 is provided at the lower side.
A front axle housing 13 is supported so as to freely roll around the vehicle, and a steering case 15 is provided at both left and right ends of the front axle for transmitting the front wheel 14 by a shaft. Has become. 17
Is a dashboard and 18 is a hood.

On the upper side of the transmission case 1 at the rear of the vehicle body 6, a seat floor 20 connecting the left and right fenders 19 is provided.
And has a cockpit 21 on the seat floor 20. 22 is a safety frame. On the upper side of the rear transmission case 10, there are provided a hydraulic case 24 with a hydraulic cylinder 23 inside, a lift arm 25 pivoted up and down by the hydraulic cylinder 23, and a rear axle housing 26 on both left and right sides. 27 is mounted and driven.

Reference numeral 28 denotes a front wheel transmission shaft, reference numeral 29 denotes a rear PTO shaft projecting rearward of the rear transmission case 10, and reference numeral 30 denotes a mid PTO shaft projecting forward below the rear PTO shaft. HST
The pump unit 32 and the motor unit 33 are integrally formed, and are attached to an HST unit base 31 serving as a base plate described later. Then, the rotational power of the input shaft 34 is input to the pump unit 32, and the angle of the internal swash plate is changed by the forward and backward rotation operation of the trunnion shaft 35, and the output shaft 36 of the motor 33
The rotation is continuously variable from the neutral position to the forward rotation or the reverse rotation position.

Reference numeral 37 denotes a pump shaft which is integral with the input shaft 34 of the HST pump 32, and has a gear 38 as viewed in the front transmission case 9 in which the HST unit base 31 is mounted. The input shaft 34 is connected to the main clutch 3 in the clutch housing 8 from the output shaft of the engine 7.
9 and the transmission shaft 40. At the rear side of the HST unit base 31, an inlet 43 of the charge circuit 42 of the HST circuit 41 is provided, and a tank port T1 is provided.

In the front transmission case 9,
A traveling transmission mechanism for transmitting the front wheel transmission shaft 28 to the front wheels 14, the rear wheel transmission shaft 44 to the rear wheels 27, and the like, and a PTO transmission mechanism for transmitting power to the PTO shaft 29 are provided. The traveling transmission mechanism interlocks a gear 47 of an output shaft 36 of the HST motor 33 with a gear 47 of an intermediate shaft 46, and a counter gear rotatable around a PTO intermediate shaft 49 from a gear 48 at a rear end of the intermediate shaft 46. The gear 50 is interlocked with the sub-transmission gear 51 of the rear wheel transmission shaft 44 through the gear 50.

Further, from the rear wheel transmission shaft 44, a gear 52,
The front wheel input shaft 55 is interlocked with the front wheel input shaft 55 via a clutch gear 53 and a clutch 56, and the 4WD clutch 58 via a 4WD clutch 58 using a hydraulic disc clutch between the clutch shaft 57 and the like. 58 springs 5
By the entry by 9, the front wheel transmission shaft 28 can be transmitted, and the front wheel 14 can be transmitted at substantially the same speed as the rear wheel 27.

Further, a speed increasing gear 6 rotatable around the intermediate shaft 46 is provided on the front side of the 4WD clutch 58 from the gear 56.
0 between the rotatable gear 61 and the clutch shaft 57 through a hydraulic disc clutch 4WD clutch 6
2 is provided. By turning on the speed increasing 4WD clutch 62, the 4WD clutch 58 is disengaged, the clutch shaft 57 is accelerated, and the front wheels 14 are transmitted at a higher speed than the rear wheels 27.

The rear wheel transmission shaft 44 is interlocked with the rear wheel 27 via a rear differential in the rear transmission case 10, and the front wheel transmission shaft 28 is interlocked with the front wheel 14 via a front differential in the front axle housing 13. . The PTO
The transmission mechanism uses the hydraulic clutch 3 in the form of a hydraulic disc clutch on the clutch shaft 4 mounted on the front transmission case 9 as a PTO clutch, and the intermediate shaft 49 and the PTO clutch.
Via the counter shaft 63, the rear PTO shaft 29 and the mid PT
This is a configuration linked to the O-axis 30.

The clutch shaft 4 has a rotatable clutch body 65 having a gear 64 meshed with the gear 38 on the pump shaft 37, and a clutch body 66 and a gear 67 which rotate integrally. Hydraulic disc 2 between bodies 65 and 66
Can be engaged by friction welding.
An oil passage 5 is formed in the clutch shaft 4, and the front end portion
The front end of the front transmission case 9 is connected to the tank port T1 via the HST unit base 31, and the rear end of the front transmission case 9 is opened to the inner peripheral portion of the disk 2.
The HST oil discharged from 1 is supplied between the clutch disks 2 of the hydraulic clutch 3 for cooling and lubrication. The oil that has lubricated between the disks 2 of the hydraulic clutch 3 is lubricated in the front transmission case 9.

Hydraulic oil is fed into a hydraulic push cylinder 68 for pressing the disk 2 from an oil passage 69 at the rear of the clutch shaft 4. The gear 70 at the rear end of the clutch shaft 4 is meshed with the gear 70 of the intermediate shaft 49, and can transmit the PTO shaft 29. 71 is a counter gear on the counter shaft 63, 72
Is a transmission clutch gear on the rear PTO shaft 29,
The O-shaft 29 can be shifted.

Numeral 73 denotes a counter gear, which meshes with one of the counter gears 71, meshes with a clutch gear 74 on the mid PTO shaft 30, and can transmit power to the mid PTO shaft 30. In the case of transmission of the mid PTO shaft 30, the transmission clutch 74 is engaged, and for transmission of the rear PTO shaft 29, the transmission clutch gear 72 is engaged. As shown in FIG. 3, the hydraulic circuit of the tractor communicates the inlet 43 with an oil filter 83, a hydraulic pump P, a diversion valve 75, a full hydraulic steering 76, an oil cooler 77, an oil filter 78, and the like. . 79 is a neutral valve. The hydraulic clutch 3, which is a PTO clutch,
5 through a PTO clutch valve 80, a clutch relief valve 81 and the like. 82 is an external hydraulic pressure take-off valve.

In the hydraulic circuit of the PTO hydraulic clutch 3,
Oil chamber 116 in the form of piston 115 pushed by spring 117
Is provided to supply replenishment oil pressure against leaks due to a decrease in the rotation of the engine 7 or the like, and keep the oil pressure until the engine 7 stops or the rotation increases, thereby eliminating the slippage of the PTO hydraulic clutch 3. When the oil chamber 116 is not formed, the PTO is kept as it is when the hydraulic clutch 3 is engaged.
When the load is applied and the rotation of the engine 7 decreases to the idling rotation, the flow rate of the hydraulic pump P decreases, the hydraulic pressure of the hydraulic clutch 3 decreases, and the transmission torque decreases, so that the hydraulic clutch 3 slips. When the load decreases, the rotation of the engine 7 increases, and the hydraulic clutch 3 is engaged (connected), causing a hunting phenomenon, and the hydraulic clutch 3 is worn.

However, when the oil chamber 116 is provided, as described above, even if the rotation of the engine 7 is reduced, the oil for replenishing the leak amount is supplied, and it is possible to cope with fluctuations in the engine rotation and the like. The HST circuit structure of the tractor configured as described above includes the tank port T1 of the HST and the hydraulic clutch 3
Compared to the case where each lubrication oil passage is provided separately,
The hydraulic circuit can be simplified.

Further, since the position of the clutch 3 is set at substantially the same height as the HST, the oil is released from the oil passage opening portion over a wide range, and the clutch can be cooled and lubricated as uniformly as possible. By setting the hydraulic clutch 3 further below the case, the pressure of the oil can be increased and the discharge distance can be made wider. 4, the difference from the above example is that the tank port T1 of the HST circuit 41 is
The rear wheel transmission shaft 44 is mounted in the front transmission case 9.
The oil passage 84 communicates with the oil passage 84, and lubricates and cools through a lubrication hole 90 a needle bear link 89 such as a gear 85, 86, 87 rotatable around the rear wheel transmission shaft 44. Further, from the rear end of the oil passage 84, the rear differential gear is lubricated and cooled, and discharged from the rear transmission case 10.

The rear wheel transmission shaft 44 is interlocked with the gear 45 of the HST output shaft 36 via a gear 47, an intermediate shaft 46, a counter gear 50, a gear 85 or 86, and a subtransmission gear 51. Interlocking with the front wheel transmission shaft 28 is performed from the gear 52 at the front end of the rear wheel transmission shaft 44 via the rotatable gear 53 to the front end of the intermediate shaft 49 and the clutch gear 54.

The interlocking of the intermediate shaft 49 interlocking with the rear PTO shaft 29 is performed by the gear 67 at the rear end of the clutch shaft 4 and the gear 8
7, 88 and the gear 91 on the intermediate shaft 49. The intermediate PTO shaft 30 is linked to the intermediate shaft 49 by a rotatable clutch gear 74 and a front wheel clutch 92.
Is performed from the clutch gear 74 via the counter gear 73.

As described above, the auxiliary transmission gear 51 is provided around the rear wheel transmission shaft 44 by the needle bearing 89.
The gears 85 and 86 and the gears 87 and 88 are rotatably mounted on the shaft, and an oil hole 90 is communicated from an oil passage 84 to each needle bearing 89 to be lubricated. Excess lubricating oil is discharged from the throttle hole 93 at the rear end of the oil passage 84.

The mid PTO shaft 30 is provided from the lower part of the front transmission case 9 toward the front. In FIG. 5, the difference from the above example is that a part of the oil flowing out of the tank port T1 of the HST circuit 41 is returned from the front transmission case 9 to the suction pipe 94 connected to the hydraulic pump P. .

Thus, the amount of oil passing through the suction filter 83 is reduced, so that the capacity of the filter 83 can be reduced. The tank port T1 communicates with a low-pressure rubber hose.
6 is different from the above example in that a part of the oil in the tank port T of the HST circuit 41 is returned to the suction side of the hydraulic pump P2 through the oil cooler 77.
The pressure in the tank port T1 of the HST circuit 41 can be reduced by subtracting the pipeline resistance pressure generated in the oil cooler 77 by the negative pressure from the suction.

Further, the oil which has become hot after working in the HST is immediately put into the cooler 77 to enhance the cooling effect. The capacity of the suction filter 83 can be reduced. Note that 95
Is a lift valve for controlling the expansion and contraction of the hydraulic cylinder 23. 96 and 97 are filters. 7 and 8, the difference from the above example is that the rear PTO shaft 29 and the mid P
In a configuration in which one PTO hydraulic clutch 3 is turned on and off with the TO shaft 30, and rotational power is transmitted to the respective PTO shafts 29 and 30, sensors S1 and S2 for detecting the positions of the PTO chain levers 98 and 99 are provided. The PTO hydraulic clutch 3 is turned on and off in accordance with the positions of the PTO change levers 98 and 99.

Rear PTO change lever 98, mid P
Rear PT by forward and backward rotation operation of TO change lever 99
The hydraulic clutch 3 is connected for a short time in a predetermined region from the disengagement position (the sensors S1 and S2 are OFF) of the O-clutch 103 and the mid-PTO clutch gear 74 to the engagement position (the sensors S1 and S2 are ON). Is provided with a clutch control device.

Interlocking with the rear wheel transmission shaft 44 is performed from the gear 45 of the HST motor 33 via the gear 47 and the auxiliary transmission gear 51 on the transmission shaft 100, the counter gear 50 on the rear wheel transmission shaft 44, and the like. Will be Further, the gear 101 which is rotatable around the PTO counter shaft 63 from a part of the counter gear 50 is linked with the clutch gear 54 on the front wheel transmission shaft 28.
This is performed via the gear 53 and the like.

Interlocking with the PTO counter shaft 63 includes the hydraulic clutch 3, the gear 67, the gear 102 rotatable around the rear wheel transmission shaft 44, the clutch gear 70 rotatable around the PTO counter shaft 63, and the clutch gear 70. P that can be mated
This is performed via the rear PTO clutch 103 on the TO counter shaft 63. Interlocking with the mid PTO shaft 30 is performed from the clutch gear 70 via the counter gear 104, the gear 73, the mid PTO clutch gear 74, and the like.

The rear PTO clutch 103 is turned on / off by operating the rear PTO change lever 98,
The mid PTO clutch gear 74 is turned on and off by operating the mid PTO change lever 99. In addition, rear PTO
Chain Lever 98 or Mid PTO Chain Lever 99
Is supported by lever shafts 106 and 107 on a bracket 105 fixed on the front transmission case 9. The rear PTO change lever 98 is connected via a link rod 108 to a shifter 109 for operating the rear PTO clutch 103, and the shifter 109 has a sensor S1 for detecting an operation rotation position.

The mid-PTO change lever 99 is
A sensor S for detecting the rotational position is provided on the lever shaft 107.
2 and the mid P
The TO shaft 30 is connected to the shifter 111 of the clutch gear 74. Reference numeral 112 denotes an auxiliary transmission lever, which is supported on the lever shaft 106 and is linked with a shifter 114 of the auxiliary transmission gear 51 by a link rod 113. The shifter 114 is provided with a sensor S3 for detecting an operation position.

In FIG. 9, the difference from the above example is that the PTO
The clutch shaft 4 of the hydraulic clutch 3 is communicated with the rear end of an oil passage 69 for operating the push cylinder 68 to provide an oil chamber 119 in which a piston 118 is fitted.
Is pressed against the spring 120 by the hydraulic pressure from the oil passage 69. In such a configuration, in the same manner as the configuration of the oil chamber 116, even if the engine 7 suddenly drops and the oil pressure drops, oil is supplied to the push cylinder 68 by pushing back the piston 118 by the spring 120. Thus, slippage of the hydraulic clutch 3 can be prevented.

Reference numeral 121 denotes an oil supply passage communicating with the oil passage 69 of the clutch shaft 4, formed in a bearing metal 122 in the front transmission case 9, and communicating with the PTO clutch velve 80.

[Brief description of the drawings]

FIG. 1 is a diagram showing a transmission mechanism of a tractor.

FIG. 2 is a side view of the tractor.

FIG. 3 is a hydraulic circuit diagram.

FIG. 4 is a transmission mechanism diagram of a tractor showing a partially different form.

FIG. 5 is an HST hydraulic circuit diagram showing a partially different embodiment.

FIG. 6 is an HST hydraulic circuit diagram showing a partially different embodiment.

FIG. 7 is a transmission mechanism diagram showing a partly different embodiment.

FIG. 8 is a rear view and a side view of the arrangement of the transmission lever.

FIG. 9 is an enlarged sectional view of a hydraulic clutch part showing a partly different embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Transmission case 2 Disk 3 Hydraulic clutch 4 Clutch shaft 5 Oil passage T1 Tank port

Claims (1)

[Claims] 1. An HST is connected to an end of a transmission case 1 via a base plate 31, and a hydraulic clutch 3 of a wet multi-plate type is provided in the transmission case 1 at substantially the same height as or below the HST. With the shaft mounted, the H
The tank port T1 of the ST is connected to an oil passage 5 provided in a shaft 4 on which the base plate 31 and the clutch 3 are mounted, and the lower side of the oil passage 5 is opened to open the disk 2 of the hydraulic clutch 3. HST hydraulic circuit of the working vehicle supplied to the section.