JPH05263899A - Hst-type travelling gear shifter - Google Patents

Abstract

PURPOSE:To avoid cavitation by holding an oil hydraulic motor output axis by means of a separating wall body, dividing the internal part of a mission case into a housing for the oil hydraulic motor and housings for a reduction gear device and a differencial device, and making a cleatance between the output axis and the separating wall body liquid-tight. CONSTITUTION:A mission case 1 comprises divided mission cases 1a and 1b at right and left respectively, and a separating wall body 31 is arranged and fixed at the mating face thereof. A bearing and an oil seal S are interposed on the periphery of an output axis 3 penetrating the separating wall body 31, and a chamber I constructed by the right mission case 1a is rendered a hydraulic oil tank including an oil hydraulic motor arranged therein and a chamber N constructed the left mission case 1b is rendered a lubricating oil tank including a reduction gear device and a differential gear device arranged therein. And then gear damaged scraps of the reduction gear device and the differential gear device and air are not sucked by an oil hydraulic pump and the oil hydraulic motor for preventing an HST gear shifter from generating damage and/or defects.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of an HST type traveling transmission device for driving a drive axle of a tractor.

[0002]

2. Description of the Related Art Conventionally, the same applicant has filed an application for an HST type traveling transmission. For example, it is as in Japanese Utility Model Application No. 61-73481. Further, as other conventional techniques, techniques such as those described in JP-A-61-27366 and JP-A-61-263834 are known.

[0003]

However, in the prior art, the hydraulic oil of the HST transmission attached to the mission case is used as it is as the lubricating oil in the mission case. Especially in the case of a small mission case, the amount of lubricating oil accumulated inside is small,
The bubbles in the lubricating oil that are generated as the gears rotate
The ST transmission device sucks, and the hydraulic pump pressure is no longer generated, and the hydraulic motor does not rotate. The present invention solves the above-mentioned conventional problems. In the past, the lubricating oil used for the gear reduction device and the differential gear device was also used as the operating oil used for the HST transmission device. By providing the separation wall body in the transmission case again, the operating oil tank is obtained. It is separated into a first chamber I and a second chamber N which is a lubricating oil tank.

[0004]

The problems to be solved by the present invention are as described above, and the means for solving the problems will be described below. That is, a mission case is composed of a separation wall body and two divided mission cases arranged and joined to both sides of the separation wall body, and the separation wall body supports the output shaft of the hydraulic motor, and the separation wall body The inside of the mission case is divided into a first chamber for accommodating the hydraulic motor and a second chamber for accommodating the reduction gear device and the differential device, and an oil seal is provided between the output shaft of the hydraulic motor and the separation wall body. It is sealed in a liquid tight state.

[0005]

[Operation] Next, the operation will be described. That is, the first chamber I that houses the hydraulic pump and the hydraulic motor to form the hydraulic oil tank and the second chamber N that houses the reduction gear device and the differential gear device and forms the lubricating oil tank are separated by the separation wall 31. Therefore, the gear damage debris of the reduction gear device or the differential gear device is not sucked into the hydraulic pump or the hydraulic motor,
This prevents damage and failure of the HST transmission.

[0006]

EXAMPLES Next, examples will be described. FIG. 1 shows the HS of the present invention.
A side view of a mower tractor equipped with a T-type traveling transmission,
2 is a perspective view of the HST type traveling transmission of the present invention, FIG. 3 is a plan sectional view of the same, FIG. 4 is a side sectional view of a hydraulic pump portion of the HST transmission, and FIG. 5 is a sectional plan view of a separating wall 31.
FIG. 6 is a perspective view of the divided mission cases 1a and 1b on the hydraulic motor mounting side.

The structure of the mower tractor will be described with reference to FIGS. The engine E is placed in the front hood, and the pulley 2 is attached to the crankshaft of the engine E.
4 is attached. Also, the hydraulic pump P of the HST transmission
A pulley 22 is provided so as to be attached to the pump shaft, and a V belt 23 is interposed between the pulley 24 and the pulley 22. The pump shaft 14 of the hydraulic pump P is extended downward to P
The TO pulley 25 is fixed. The PTO pulley 2
5, the input pulley 27 of the mower device R is driven via the V belt 26. A drive axle 2 projects left and right from the transmission case 1, and a rear wheel is fixed to the tip.

Next, FIGS. 3, 4 and 5 will be described.
The mission case 1 is composed of left and right divided mission cases, and is composed of a right mission case 1a and a left mission case 1b. The separation wall 31 is arranged and fixed on the mating surface of the right mission case 1a and the left mission case 1b.
Therefore, a bearing and an oil seal S are provided on the outer periphery of the output shaft 3 penetrating the part of the separation wall 31, and a hydraulic motor is arranged inside the first chamber I formed by the right transmission case 1a. An oil seal S separates the hydraulic oil tank and the lubricating oil tank in which the reduction gear device and the differential gear device are arranged in the second chamber N formed by the left transmission case 1b.

A hydraulic pump P is attached to the side surface of a hydraulic motor M housed in the right transmission case 1a shown in FIG. 3, and the hydraulic pump P is composed of the right transmission case 1a and a separating wall 31. The hydraulic oil in the hydraulic oil tank for the HST transmission is sucked.

The construction of the hydraulic pump P is shown in FIG. The pump shaft 14 is fixed to the pulley 22 driven by the V-belt 23, and the rotation of the pump shaft 14 causes the piston holder 12 to rotate. Plural pistons 8 are fitted in the cylinder holes of the piston holder 12, and the rotation of the swash plate 9 changes the stroke of the piston 8 to change the discharge amount. Reference numeral 21 is a thrust bearing. The pressure oil discharged by the piston 8 opens from the oil passage of the pump case 30 to the mounting surface of the hydraulic pump P of the right transmission case 1a as shown in FIG.
5a and 35b, the gas flows between the piston 7 and the cylinder of the piston holder 11. Therefore, although the hydraulic pump P is arranged outside the mission case, the hydraulic oil in the first chamber I formed in the right transmission case 1a is sucked.

The hydraulic oil in the right transmission case 1a is sucked into the hydraulic pump P via the oil passage 35c shown in FIG. Depending on the amount of pressure oil flowing into the cylinder, the piston holding member 11 is moved along the inclined thrust bearing 10.
A rotational force is generated in the output shaft 3, and the output shaft 3 rotates. The output shaft 3 is supported via a bearing, an oil seal S is fitted on the inside of the output shaft 3, passes through the separating wall 31, and is supported by the bearing inside the left transmission case 1b. The gear 4 on the output shaft 3 drives the gear 5 on the intermediate shaft 6. The output shaft 3 is further extended, and the brake drum 13 is fixed to the portion protruding from the left-side mission case 1b to form a brake device B.

A hydraulic motor M is arranged inside the right mission case 1a, and a hydraulic pump P is attached to the right side surface of the right mission case 1a. Further, the output shaft 3 of the hydraulic motor M projects inside the left transmission case 1b, and the gear 4 is fixed to the output shaft 3. Also, the output shaft 3 of the left mission case 1b
The intermediate shaft 6 is supported by bearings between the drive shaft 2 and the drive axle 2, and the intermediate shaft 6 is provided with the engraved gear 6a. The engraved gear 6a meshes with the gear 4. Further, the engraved gear 6a is arranged so as to mesh with the ring gear 15 of the differential gear device arranged on the drive axle 2.

The intermediate shaft 6 is bearing-supported between the separating wall 31 and the left transmission case 1b. The engraved gear 6a on the intermediate shaft 6 meshes with the ring gear 15 of the differential gear device to rotate the differential gear device. In the diff gear device, the ring gear 15 also serves as a diff gear case, and the diff pinion shaft 16 is fixed in the opening inside the ring gear 15. The differential pinion 1 is attached to the differential pinion shaft 16.
7 and 17 are loosely fitted, and the diff pinions 17 and 17 mesh with the side gears 19 and 19 which are spline-engaged on the drive axle 2.

The side gears 19, 19 are fixedly mounted on the left and right drive axles 2, and the left and right retainers are held by bearings 2a, 2a of the drive axle 2. The bearings 2a, 2a support the drive axle. A lubricating oil tank for containing the lubricating oil for the reduction gear device and the differential device is formed between the left-side mission case 1b and the separating wall 31. The separation wall body 31 which is the main part of the present invention is constructed as shown in FIG.

Bearing holes 31c and 31d for inserting the bearing of the output shaft 3 and the bearing of the intermediate shaft 6 are opened on the left surface of the separating wall 31, and an inclined hole 31a for inserting the inclined thrust bearing 10 is formed. It is provided. Reference numeral 31b is an opening into which the support cylinder of the drive axle 2 is fitted, the outer circumference of the support cylinder is also formed in the hydraulic oil tank, and an oil seal S is interposed in this portion to form a complete oil-tight structure. ing.

Next, referring to FIG. 4, a portion where the PTO pulley 25 is fixedly provided on the extension portion of the pump shaft 14 will be described. Since the PTO pulley 25 is not always necessary, the portion of the PTO shaft 28 can be inserted and fixed to the pump shaft 14.

[0017]

Since the present invention is configured as described above, it has the following effects. That is, the HST of the present invention
In the traveling travel transmission, a housing containing a hydraulic pump device, a hydraulic motor device, a gear reduction device, and a differential gear device is divided into a first chamber I and a second chamber N by a partition wall that supports an output shaft 3 of the hydraulic motor. Since the output shaft of the hydraulic motor and the separating wall are hermetically sealed by the oil seal S, the air mixed with the lubricating oil by the gears is mixed inside the hydraulic pump and the hydraulic motor. Cavitation phenomenon that occurs when the air is compressed and contracted by the high pressure portion, and adversely affects the gear ratio of the HST transmission,
It is possible to avoid fluctuations when neutral.

[Brief description of drawings]

FIG. 1 is a side view of a mower tractor equipped with an HST type traveling transmission according to the present invention.

FIG. 2 is a perspective view of an HST type traveling transmission according to the present invention.

FIG. 3 is a plan sectional view of the same.

FIG. 4 is a side sectional view of a hydraulic pump portion of the HST transmission.

FIG. 5 is a plan sectional view of the separation wall body 31.

FIG. 6 is a perspective view of a half transmission case 1a, 1b on a hydraulic motor mounting side.

[Explanation of symbols]

 I 1st chamber N 2nd chamber 1 Mission case 1a Right side mission case 1b Left side mission case 2 Drive axle 31 Separation wall M Hydraulic motor P Hydraulic pump S Oil seal

Claims (1)

[Claims] 1. A transmission case is composed of a separation wall body and two division mission cases arranged and joined to both sides of the separation wall body, and the separation wall body supports an output shaft of a hydraulic motor and the separation case. A wall body divides the interior of the mission case into a first chamber for accommodating the hydraulic motor and a second chamber for accommodating the reduction gear device and the differential device, and between the output shaft of the hydraulic motor and the separation wall member. An HST type traveling transmission device characterized in that the oil is sealed in a liquid-tight state by an oil seal.