JP2667123B2 - Axle drive - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an HST axle drive used as a tractor propulsion device.

[0002]

2. Description of the Related Art Conventionally, there has been known an axle drive device in which a case of an axle drive device is divided into upper and lower parts, an axle is supported by bearings on the divided surface, and the axle is driven by an HST type transmission attached to the case. -ing For example, Japanese Utility Model Publication No. Sho 62-44198 filed by the same applicant.

[0003]

However, in the prior art, the HST type transmission prepared completely separately from the axle drive is exposed and supported on the outside of the case of the axle drive, so that the overall size is increased. The gross weight is large, and in order to drive the axle horizontally arranged from the motor shaft of the hydraulic motor vertically arranged outside, it was necessary to interpose a bevel gear device in both drive systems. . Further, a spare tank for replenishing the reduction of the hydraulic oil in the HST type transmission is required, and in order to use the lubricating oil in the drive case as the hydraulic oil, the drive case and the HST type transmission are required. There was a problem that it was necessary to specially configure the pipes and oil passages that connect the two. In the present invention, in order to solve the above-mentioned conventional problems, an HST-type transmission including a hydraulic pump and a hydraulic motor is disposed inside a transmission case, and a configuration is adopted in which leakage of hydraulic oil from the HST-type transmission is permitted. It was done.

[0004]

Means for Solving the Problems] constitute Limi Tsu Deployment case by the joining of the horizontally divided into upper and lower the half upper case 1 and the half lower case 2, the half split upper case 1 and a half the horizontal joint surface between the divided lower case 2, a bearing supporting the drive output shaft 5 and the left and right axles 13, 13 to a flat line, between the right and left axles 13, 13 to place the differential gear device D, the differential gear device and D of the ring gear 23, a small diameter gear 17 on the drive output shaft 5 work together to transmit power, the drive output shaft 5
The hydraulic motor M is disposed on the
HST type transmission with pressure motor M and hydraulic pump P
The HST type transmission is arranged inside a transmission case composed of the half upper case 1 and the half lower case 2, and the hydraulic motor M has an axis in the horizontal direction. And the drive output shaft 5 is engaged, and the drive input shaft 4 further projects vertically upward from the hydraulic pump P. The drive input shaft 4 penetrates through the upper half case 1 and projects onto the upper surface of the transmission case. A pulley is fixed to a portion where the drive input shaft 4 protrudes from the half upper case 1,
It is configured to input power from the engine E.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The objects and constitutions of the present invention are as described above. Next, the constitution of the embodiment shown in the attached drawings will be explained. FIG. 1 is a side view of a compact tractor provided with an axle drive device of the present invention, FIG. 2 is a front sectional view of the axle drive device of the present invention, and FIG.
Is the same as I in FIG. 2 with the half upper case 1 removed.
FIG. 4 is a sectional view taken along a line V-V in FIG. 2, and FIG.
FIG. 6 is a perspective view showing another configuration of the oil passage plate 3.

FIG. 1 shows a small tractor on which an engine E having a vertical crankshaft is mounted.
A pulley is fixed to the vertical crankshaft of the engine E, and power is transmitted by a belt to the pulley fixed to the drive input shaft 4 of the hydraulic pump P projecting upward from the axle drive device of the present invention. The tractor is provided with rotary mowers R and R 'at the front or abdomen to perform lawn mowing or the like. The present invention relates to the axle 1 of the tractor.
3 for driving the axle.

Referring to FIGS. 2, 3 and 4, the structure of the axle drive will be described in detail. The case of the axle drive device is composed of upper and lower half cases 1 and 2, and both cases are joined together to form a single sealed mission case. The bearings of the axles 13 and 13 and the drive output shaft 5 are held between the joint surfaces of the upper half case 1 and the lower half case 2. Further, a mounting surface is formed on the lower surface of the half upper case 1, and the oil passage plate 3 in a state where the hydraulic pump P and the hydraulic motor M are fixedly supported is mounted on the mounting surface with the bolt 39 from below. is there. With the oil passage plate 3 in which the hydraulic motor M and the hydraulic pump P are fixedly mounted on the lower surface of the half upper case 1,
The lower half case 2 is joined so as to cover it from below, and the upper half case 1 and the lower half case 2 are fastened with bolts. By constructing both the upper half case 1 and the lower half case 2 by aluminum die casting, the machining portion is reduced and the cost is reduced.

The HST type transmission device housed and disposed inside the axle drive device of the present invention comprises a hydraulic pump P, an oil passage plate 3 and a hydraulic motor M, and the pump is formed as a plane orthogonal to the oil passage plate 3. This constitutes the mounting surface 3d and the motor mounting surface 3e. A pair of crescent-shaped oil passages are formed in the mounting surfaces of the pump mounting surface 3d and the motor mounting surface 3e, and the oil passages 3a and 3b are formed directly in the pair of crescent-shaped oil passages of the motor mounting surface 3e. Oil passages 3a 'and 3b' are drilled downward from a pair of half-moon oil passages of the mounting surface 3d,
The oil passages 3a and 3b are connected.

A cylinder block 10 of the hydraulic pump P is rotatably mounted on the pump mounting surface 3d, and a piston 12 is fitted into a plurality of piston holes of the cylinder block 10 so as to be slidable up and down. . When the drive input shaft 4 supported by the bearing of the half upper case 1 and the spherical bush of the pump mounting surface 3d is rotated, the cylinder block 10 and the piston 12 rotate, and the thrust bearing 15 in contact with the upper end of the piston 12 Is changed by the swash plate 9 to change the discharge amount and the discharge direction of the hydraulic pump P, and the discharge pressure oil is supplied to the oil passages 3a ′, 3a of the oil passage plate 3.
The oil is supplied to the hydraulic motor M from b ′ via 3a and 3b. The angle of the swash plate 9 can be changed in conjunction with the rotation of the shift lever shaft 6, and the detent device 20 is configured at a neutral position of the shift lever shaft 6.

As shown in FIGS. 2 and 3, a short-circuit valve 25 for short-circuiting between the two oil passages 3a and 3b on the discharge side and the return side is provided. The hydraulic motor M side is driven so as to avoid a situation in which hydraulic oil is sent to the hydraulic pump P side. Reference numeral 7 denotes an operation unit for operating the short-circuit valve 25. The short-circuit valve 25 and the operation unit 7 are of a push operation type in which the engagement state is eliminated so that the operation can be performed in the contact state. With this configuration, assembly becomes possible.

A check valve 26, 27 is interposed between the oil passages 3a, 3b of the oil passage plate 3 to form a replenishing oil passage 30, and a hydraulic oil suction extending downward between the check valves 26, 27. The hole 3c is formed. Then, a sponge-shaped oil filter 8 is fitted to the lower end of the hydraulic oil suction port 3c, and the lower part of the oil filter 8 is prevented from coming off by abutting the half lower case 2. Since the oil filter 8, the hydraulic oil suction hole 3 c, and the check valves 26, 27 are provided as such components and communicate with the oil passages 3 a, 3 b via the check valves 26, 27, the hydraulic motor M and the hydraulic pump P operate. When the amount of hydraulic oil is reduced inside, negative pressure is generated in the oil passages 3a and 3b, and the lubricating oil in the case is sucked as hydraulic oil. O indicates the oil level of the lubricating oil filled in the transmission case.

The pump mounting surface 3d of the oil passage plate 3 is a surface on which the hydraulic pump P is mounted, and the same plane is formed slightly wider. It is configured on the surface to be attached. Oilway board 3
Cylinder block 1 on the motor mounting surface 3e
1 is rotatably mounted, presses the piston 14 with the pressure oil from the oil passages 3a and 3b, and the piston 14 comes into contact with the thrust bearing 16, so that the cylinder block 11 and the drive output shaft 5 rotate. Is what you do.

A spherical bush is used for a shaft support portion of the drive output shaft 5 on the oil passage plate 3 side, and a spherical bush is also used for the other end side, and is held between upper and lower half cases 1 and 2.
A small-diameter gear 17 is engraved on the drive output shaft 5, and the small-diameter gear 17 meshes with a gear 21 on a counter shaft 24. The small-diameter gear 22 on the counter shaft 24 meshes with the ring gear 23 of the differential gear device D, and the differential gear device D is provided with differential rotation to drive the axles 13, 13. A brake drum 18 is fixedly mounted at the tip of the drive output shaft 5.
In contrast, the brake shoe is opened and expanded by the brake lever 19 to make contact and perform braking.

FIG. 4 shows a portion of the motor mounting surface 3e with which the cylinder block 11 of the hydraulic motor M contacts. 5 and 6 show another configuration of the oil passage plate 3. In the case of the oil passage plate 3 ′, the pump mounting surface 3 ′ d and the motor mounting surface 3 ′ e are configured to be parallel to the left and right, and the drive input shaft 4 projects in a direction parallel to the axles 13. It is used in the case of.
In the case of the oil passage plate 3 ", the pump mounting surface 3" d is projected in the front-rear direction, and the motor mounting surface 3 "e is connected to the axles 13,1.
3 shows a configuration protruding in parallel with FIG. In this case, when the engine of the horizontal crankshaft is disposed above the axles 13, 13, belt driving is facilitated. By changing the configuration of the oil passage plate 3 as described above, the projecting direction of the drive input shaft 4 can be changed.

FIG. 7 is a rear sectional view of another embodiment in which the arrangement of the check valves 26 and 27 is changed, FIG. 8 is a plan view of the same, and FIG. 9 is a sectional view of the oil passage plate 3 in FIG. , FIG. 10 is FIG.
It is sectional drawing in the XX arrow of No ..

In the embodiment shown in FIGS. 2 and 3, the oil passages 3a and 3b and the supply oil passage 30 are arranged in the same plane, but the oil passages 3a and 3b When the replenishing oil passages are juxtaposed, the motor mounting surface 3e has to be separated from the pump mounting surface 3d, and the oil passage plate 3 cannot be made compact by that much. In the embodiment of FIGS. 7 to 10, the supply oil passage 30 is arranged within the thickness of the oil passage plate 3 below the oil passages 3a and 3b so as to overlap the oil passages 3a and 3b. . The replenishing oil passage 30 has an upper half portion connected to the oil passage 3
a, 3b are drilled so as to overlap and communicate with the lower half. Thereby, an oil passage for connecting the two is unnecessary, and the thickness of the oil passage plate 3 can be reduced as much as possible. A hydraulic oil suction hole 3c is opened in the center of the supply oil passage 30 toward the lower oil filter 8, and the hydraulic oil suction hole 3c is opened.
The check valves 26 and 27 for opening and closing the communicating portions with the oil passages 3a and 3b are provided on both sides of the replenishing oil passage 30 with the check valve 26 and 27 interposed therebetween. Then, the replenishing oil from the hydraulic oil suction hole 3c flows to the oil passages 3a and 3b in the replenishment oil passage 30 at the position where the replenishment oil has passed the check valves 26 and 27. By arranging the oil passages 3a and 3b, the supply oil passage 30, and the oil filter 8 in the oil passage plate 3 in this manner, the pump mounting surface 3d
, The motor mounting surface 3e can be made to approach, and the oil passage plate 3 can be made compact. The rest of the configuration is the same as the configuration of the embodiment of FIGS.

[0017]

As described above, the present invention has the following advantages. First, the HST type transmission that drives the axle 13 is arranged and fixed inside the case where the upper half case 1 and the lower half case 2 are joined together, so that the HST type transmission as in the related art is mounted on the case. Since the case of the HST type transmission device itself, which is fixed outside, can be eliminated, the overall size and weight of the axle drive device can be reduced.

Second, since the HST type transmission constituted by the hydraulic pump P and the hydraulic motor M is housed in the transmission case of the axle drive unit, when the space for mounting on the vehicle body is small like a small tractor, etc. Also, an axle drive device can be attached.

Third, the drive output shaft 5 of the hydraulic motor M is arranged in parallel with the axle 13 and is supported by a bearing at the joint surface between the upper half case 1 and the lower half case 2. 4 is arranged vertically so that in the case of a small tractor on which the engine E having a vertical crankshaft is mounted, power can be easily transmitted to the pulleys and the belt. In addition, the power transmission from the drive output shaft 5 to the axle can be easily configured with gears, chains, and the like, and there is no need to change the direction of power transmission using a bevel gear device as in the related art.

Fourth, since the HST type transmission constituted by the hydraulic pump P and the hydraulic motor M is housed inside the transmission case, the hydraulic oil leaking from the HST type transmission is returned into the transmission case. The transmission case receives the oil leakage and can be used again as hydraulic oil.

[Brief description of the drawings]

FIG. 1 is a side view of a small tractor provided with an axle drive device of the present invention.

FIG. 2 is a front sectional view of the axle drive device of the present invention.

FIG. 3 is a sectional view taken along the line II of FIG. 2 with the half upper case 1 removed.

FIG. 4 is a view taken in the direction of arrows VV in FIG. 2;

FIG. 5 is a perspective view showing another configuration of the oil passage plate 3;

FIG. 6 is a perspective view showing another configuration of the oil passage plate 3;

FIG. 7 is a rear sectional view of another embodiment in which the arrangement of check valves 26 and 27 is changed.

FIG. 8 is a plan view of the same.

FIG. 9 is a cross-sectional view of the oil passage plate 3 of FIG.

FIG. 10 is a sectional view taken along the line XX of FIG. 7;

[Explanation of symbols]

 Reference Signs List 1 half upper case 2 half lower case 3 oil passage plate 3a, 3b oil passage 3c hydraulic oil suction hole 3d pump mounting surface 3e motor mounting surface 4 drive input shaft 5 drive output shaft 17 small diameter gear 23 ring gear D differential gear device P Hydraulic pump M Hydraulic motor

Claims (1)

(57) [Claims] [Claim 1] constitute Limi Tsu <br/> Deployment case by the joining of the horizontally divided into upper and lower the half upper case 1 and the half lower case 2, the half split upper case 1 When the horizontal joint surface between the half lower case 2, a bearing supporting the drive output shaft 5 and the left and right axles 13, 13 in a flat line, the left and right axles 13, 13
Between, arranged differential gear device D, and the ring gear 23 of the differential gear device D, and a small diameter gear 17 on the drive output shaft 5 work together to transmit power, on of the drive output shaft 5, a hydraulic motor
Motor M, the hydraulic motor M
An HST type transmission is constituted by the hydraulic pump P, and the HS
The T-type transmission device disposed within the transmission case constituted by the half upper case 1 and the half lower case 2, the hydraulic motor M is then provided with a shaft center in the horizontal direction, the hydraulic
The drive output shaft 5 is engaged with the motor M, and further, the drive input shaft 4 projects vertically upward from the hydraulic pump P. The drive input shaft 4 penetrates through the upper half case 1 and projects onto the upper surface of the transmission case. An axle drive device characterized in that a pulley is fixed to a portion where the drive input shaft 4 protrudes from the half upper case 1 to input power from the engine E.