JPH11278074A - Front axle case of working vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To supply lubricating oil along both sides of a differential mechanism without a hindrance only by providing a lubricating oil supply port on the one side of the differential mechanism without causing weight increase and diametral increase of the front axle case. SOLUTION: Grooves 22 for distribution of air and lubricating oil are respectively provided on upper and lower positions of an inner peripheral surface of a front axle case 20 at points of places corresponding to a differential bearing to support a differential mechanism. These grooves 22 for distribution are to form a channel to allow distribution of air and lubricating oil and are constituted of recessed grooves formed by case wall bulged line parts 23 bulged outward in the diametrical direction in a rib shape along the longitudinal direction of the front axle case 20.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a lubricating oil supply structure in a front axle case of a working vehicle used in a front wheel drive mode such as a tractor, a riding lawn mower, and the like.

[0002]

2. Description of the Related Art In a work vehicle as described above, a front axle case is provided with a differential mechanism and a transmission shaft for driving a front wheel. In the front axle case, since the differential mechanism is located at an intermediate portion of the front axle case, lubrication in the front axle cases on both sides of the interior of the differential mechanism is limited to the differential mechanism. The lubricating oil flow tends to be impaired by the differential bearing portion supporting the lubrication oil. For this reason, conventionally, it has been known that the technique described in the following [1] or [2] is employed to lubricate the left and right sides of the front axle case. [1] A lubricating oil injection structure is provided on both sides of the intermediate part of the front axle case in which the differential mechanism is installed. [2] The space in the middle of the front axle case
It is formed much larger than the size capable of accommodating the differential mechanism, and extends as a bearing portion for supporting the differential bearing, a wall portion protruding inward from the inner peripheral surface of the front axle case,
By forming a lubricating oil flow hole in the wall, the lubricating oil can flow to the left and right sides of the axle case bypassing the outside of the differential mechanism (for example, see Japanese Utility Model Application Laid-Open No. 57-57).
128522).

[0003]

As in the prior art described in the above [1], when lubricating oil injection structures are provided on both sides of an intermediate portion of a front axle case in which a differential mechanism is installed. In this case, it is necessary to perform a lubricating oil supply operation on both the left and right sides of the front axle case, and the operation is complicated. In addition, [
2], the space in the case at the intermediate portion of the front axle case is large enough to form a wall for bearing outside the differential mechanism and a hole for lubricating oil. Then, there is a problem that the front axle case in this portion has a large diameter, and the minimum ground clearance of the working vehicle is too low. Therefore, for example, on the inner surface of the front axle case that supports the differential bearing of the differential mechanism, it is inconceivable to cut a part of the thickness of the front axle case wall to form an oil passage for the lubricating oil. However, in this case, it is difficult to obtain a sufficiently large opening for distribution unless the front axle case is very thick, and if the front axle case is thick, the weight of the entire vehicle body increases. There is a new problem of inviting. SUMMARY OF THE INVENTION An object of the present invention is to provide a lubricating oil supply port on one side of a differential mechanism without any increase in the weight and diameter of the front axle case, and to supply lubricating oil to both sides of the differential mechanism without any support. The point is to do so.

[0004]

Means for Solving the Problems The technical means of the present invention taken to achieve the above-mentioned object is to provide a front axle case of a working vehicle, wherein a portion corresponding to a differential bearing for supporting a differential mechanism is provided in the front axle case. That is, air and lubricating oil circulation grooves are provided at upper and lower positions on the peripheral surface, respectively. Further, the lubricating oil distribution groove is formed on the front axle case wall in a range extending on both sides of the differential bearing existing position, in a rib shape along the longitudinal direction of the front axle case, and in the radial direction. It is good to adopt what was constituted by the indentation groove formed by the case wall bulging streak part which bulges outside in the above.
As described in claim 3, the upper and lower distribution grooves may be integrally formed by cutting or casting. 5. A transmission bevel gear for transmitting power from the front axle case to deceleration drive cases provided at left and right ends of the front axle case, and a support bearing for supporting the transmission bevel gear. May be provided, and distribution grooves may be provided on the upper and lower surfaces of the inner peripheral surface of the front axle case corresponding to the support bearings. As described in claim 5, it is preferable that the distribution grooves provided at the differential bearing existing position and the transmission bevel gear existing position are provided so as to have substantially the same phase in the circumferential direction of the front axle case. As described in claim 6, a plurality of lubricating oil circulation grooves provided at the lower portion on the inner peripheral surface of the front axle case may be formed at intervals in the circumferential direction of the front axle case.

[Operation] With the above configuration, air and lubricating oil circulation grooves are provided at upper and lower positions on the inner peripheral surface of the front axle case at locations corresponding to the differential bearings.
While lubricating the left and right sides of the differential mechanism can be performed by lubricating one side of the differential mechanism, for example, a wall that protrudes inward from the inner peripheral surface of the front axle case as a bearing that supports a differential bearing As compared with the conventional structure in which a portion is extended and a lubricating oil flow hole is formed in the wall thereof, an increase in the space in the case at the intermediate portion of the front axle case can be avoided.
Further, as a groove for lubricating oil distribution, in the front axle case wall extending over both sides of the differential bearing existing position, as a lubricating oil distribution groove, in a rib shape along the longitudinal direction of the front axle case, and in a radial direction. By adopting a recess formed by a bulging strip portion of the case wall bulging outwardly of the case, the bearing wall for the bearing and the flow hole are provided in the case described above. In addition to avoiding an extremely large diameter of the front axle case, it is also possible to avoid a decrease in the case wall thickness as in the case of forming a concave groove in the thickness of the front axle case. In addition, the reinforcing rib-like effect of the rib-shaped case wall bulging portion forming the distribution groove can improve the strength of the front axle case without making the front axle case thick. A support bearing for supporting a transmission bevel gear in a deceleration drive case provided at each of the left and right ends of the front axle case is provided, and upper and lower surfaces of an inner peripheral surface of the front axle case corresponding to the support bearing are provided. However, by providing the flow grooves, the transmission bevel gear can be efficiently lubricated using the lubricating oil supply structure to the differential mechanism. As described in claim 5, when the distribution grooves provided at the differential bearing existing position and the bevel gear existing position are provided so as to have substantially the same phase in the circumferential direction of the front axle case, the distribution grooves are formed. The flow of the lubricating oil flowing along is hardly hindered, and it is possible to supply a good lubricating oil to each of the differential bearing existing position and the bevel gear existing position. As described in claim 6, when a plurality of lubricating oil circulation grooves provided at a lower portion on the inner peripheral surface of the front axle case are formed at intervals in the circumferential direction of the front axle case, the lubricating oil circulation grooves are formed. By further increasing the flow passage area, the lubricating oil flow in the front axle case can be performed more smoothly.

[0006]

Next, a preferred embodiment of the present invention will be described. [Overall Structure] FIG. 1 shows an agricultural tractor which is an example of a working vehicle according to the present invention. This agricultural tractor transmits the power of an engine 1 mounted on the front of the fuselage to a transmission installed in a transmission case 2 at the rear of the fuselage, drives the rear wheels 3 with the output from the transmission, and transmits the transmission case 2 The front wheels 4 are driven via a front wheel drive shaft 5 projecting toward the front of the vehicle from the vehicle. In the figure, reference numeral 6 denotes a control handle, 7 denotes a control seat, 8 denotes a hydraulically driven lift arm, and 9 denotes a rear part P output from the transmission.
The TO shaft 10 and the front PTO shaft 10 are capable of intermittently transmitting power separately from the rear PTO shaft 9.

[Structure of Front Wheel Drive System] FIG. 2 is an exploded view of the structure of the front wheel drive system for convenience, and shows a transmission structure in a plan view on the right side from a boundary line L in the figure. On the left side of the boundary line L, a diagram viewed from the front-back direction of the aircraft is shown. The power of the front wheel drive shaft 5 is transmitted to a differential mechanism 30 housed in a front axle case 20 as shown in FIG.
It is input from the differential mechanism 30 to the left and right deceleration drive cases 40 via the output shafts 33 to the left and right sides. The vertical transmission shaft 41 and the wheel shaft 42 in the deceleration drive case 40
, The front wheel 4 is decelerated and rotationally driven.

The front axle case 20 has a mounting boss 2 extending in the front and rear directions at a middle portion in the left-right direction.
1 and is attached to the lower part of the body by a pair of front and rear mounting brackets 11. In this mounted state, the center line in the front-rear direction located at the center in the left-right direction of the body is set as a rolling center P so as to freely roll left and right, and the rolling center P is the differential mechanism 3.
Bevel gear portion 31 meshing with zero input bevel gear 32
a coincides with the axis of an input shaft 31 provided at the shaft end, and the front end of the front wheel drive shaft 5 is connected to the input shaft 31 on the rolling center P line.

The differential mechanism 30 disposed inside the front axle case 20 is located at a position deviated to one side from the rolling center P, and both ends thereof are supported by differential bearings 50. The output shafts 33 extending from the differential mechanism 30 to the left and right sides are respectively connected to connection holes 43a of a transmission bevel gear 43 supported via support bearings 51 near the entrances of the left and right deceleration drive cases 40. The transmission bevel gear 4 is configured to be freely inserted and removed, and inserted into the connection hole 43a.
In order to transmit the rotational power to the motor 3, it has an integral rotation mechanism such as a spline or a serration and is configured to be integrally rotatable.

[Configuration of Lubrication Portion] The front axle case 20
In the case wall, a flow groove 22 is formed in a range extending on both sides of the differential bearing 50 existing position. The flow grooves 22 form flow paths that allow the flow of air and lubricating oil at upper and lower positions on the inner peripheral surface of the front axle case 20 at locations corresponding to the differential bearings 50, respectively.
As shown in FIG. 6, the front axle case 20 is formed by a recessed groove formed by a rib-like shape extending along the longitudinal direction and a case wall bulging strip portion 23 bulging outward in the radial direction. I have. Of the flow grooves 22, the upper flow groove 22 bulges from a position near the rolling center P in a plan view to a position slightly outside the differential bearing 50 farther from the rolling center of the differential mechanism 30. It is constituted by the formed case wall bulging strip portion 23, and mainly serves to smoothly flow the air inside. As shown in FIG. 6, the lower distribution groove 22 of the distribution grooves 22 is not located immediately below the upper distribution groove 22 but at a position slightly closer to the front and at a position from the rear. It is provided at a plurality of locations, and is formed from a position substantially the same as the outermost end of the upper circulation groove 22 so as to extend over a substantially equal left and right length range across the rolling center P. That is, each of the upper and lower distribution grooves 22 is formed in a range extending on both sides of the location where the differential bearing 50 exists at the left and right ends of the differential mechanism 30.

The front axle case 20 is integrally cast from a casting, and the mounting portion 24 of the differential bearing 50 of the differential mechanism 30, the case wall bulging strip portion 23, and the oil supply port 25 are integrally formed. I have. Reference numeral 26 shown in FIGS. 4 and 5 is a contact portion for determining a rolling operation limit when the front axle case 20 performs rolling differential, and is in contact with a limit regulating portion (not shown) at the lower part of the body. For the time being constitutes.

In the deceleration drive case 40, a part of a mounting seat portion 44 of a support bearing 51 for supporting the transmission bevel gear 43 is partially provided in the vertical and horizontal positions as shown in FIGS. The groove 22 for circulation of air and lubricating oil is formed.

[Another Example of Embodiment] [1] The flow grooves 22 are not limited to those having one groove formed on the upper side and two grooves formed on the lower side as shown in the above embodiment. For example, for each of the upper side and the lower side, a pair is provided vertically opposed to each other, or a pair of upper and lower, but configured such that the lower groove is wide, or Both of them can be arbitrarily set such that the air and the lubricating oil can flow favorably, for example, by using a plurality of appropriate grooves. Further, not only the number of grooves but also the length of the grooves can be freely set. For example, the lengths of the upper and lower circulation grooves 22 are set to be the same, or set to a long range including immediately below the oil supply port 25. Or, it can be set appropriately. [2] Only the distribution groove 22 in the front axle case 20 has the configuration described in the above-described embodiment, or
Not only the configuration described in [1], but also the same configuration may be employed on the deceleration drive case side. In this case, the flow groove on the front axle case side and the deceleration drive case side Can be formed in such a manner that the phase in the circumferential direction with the flow groove 22 is matched.

[0014]

According to the first aspect of the present invention, while lubricating the left and right sides of the differential mechanism in the front axle case can be performed by lubricating one side of the differential mechanism,
It is possible to avoid an increase in the space inside the case in the middle part of the front axle case. The lubricating oil flows in a recessed groove formed by a rib-like shape extending along the longitudinal direction of the front axle case and bulging outwardly in the radial direction. By forming the grooves for the front axle case, it is possible to avoid an extremely large diameter of the front axle case as in the case where the bearing wall for the bearing and the flow hole are provided in the case described above, and to reduce the thickness of the front axle case. A good lubrication performance is obtained even though it is a front axle case with a relatively small diameter and no reduction in strength, avoiding a decrease in the wall thickness of the case as in the case where a concave groove is formed in the front axle case. . The lubrication oil supply to the front axle case as well as the front axle case as well as the supply of the lubricating oil to the front axle case as well as to the front axle case by providing the above-mentioned circulation groove not only in the front axle case but also in the deceleration drive case The lubrication oil can be supplied more easily by eliminating the trouble of opening and closing a number of lubrication ports. As described in claim 5, the flow grooves provided in the differential bearing existing position and the transmission bevel gear existing position are provided so as to be substantially in the same phase in the circumferential direction of the front axle case. It can supply a good lubricating oil. In the case where a plurality of lubricating oil circulation grooves provided at the lower portion on the inner peripheral surface of the front axle case are formed, the width of the lower circulation groove is simply increased. Compared to,
The flow path area for distribution is further expanded without any reduction in the strength of the individual bulges of the case wall for forming the distribution grooves, and the lubricating oil flow in the front axle case is further smoothed. I can do it.

[Brief description of the drawings]

FIG. 1 is a side view showing an entire tractor.

FIG. 2 is a development explanatory view of a front wheel drive system.

FIG. 3 is a horizontal sectional view of a front axle case.

FIG. 4 is a sectional view taken along line aa of the front axle case in FIG. 3;

FIG. 5 is a cross-sectional view of the front axle case in FIG. 6 taken along line c-c.

6 is a sectional view of the front axle case taken along line bb in FIG. 3;

FIG. 7 is a sectional view taken along line dd of the deceleration drive case in FIG. 2;

[Explanation of symbols]

 Reference Signs List 20 front axle case 22 flow groove 23 case wall bulging portion 30 differential mechanism 40 reduction drive case 43 transmission bevel gear 50 differential bearing 51 support bearing

Claims (6)

[Claims] 1. A front axle case of a working vehicle in which air and lubrication oil distribution grooves are provided at upper and lower positions on an inner peripheral surface of a front axle case at positions corresponding to a differential bearing for supporting a differential mechanism. 2. A distribution groove formed in a front axle case wall in a range extending to both sides of a differential bearing existing position is formed in a rib shape along a longitudinal direction of the front axle case and bulges outward in a radial direction. 2. The front axle case for a working vehicle according to claim 1, wherein the case wall is formed by a concave groove formed by a bulging portion of the case wall. 3. The front axle case for a working vehicle according to claim 1, wherein the upper and lower communication grooves are integrally formed by cutting or casting. 4. A transmission bevel gear for transmitting power from the front axle case, and a support bearing for supporting the transmission bevel gear are provided in a deceleration drive case provided at each of the left and right ends of the front axle case. The front axle case of a working vehicle according to claim 1 or 2, wherein distribution grooves are provided on the inner peripheral surface of the front axle case corresponding to the support bearings, respectively. 5. The front axle case of a working vehicle according to claim 4, wherein the distribution grooves provided in the differential bearing existing position and the transmission bevel gear existing position have substantially the same phase in the circumferential direction of the front axle case. . 6. A plurality of lubricating oil circulation grooves provided at a lower portion on an inner peripheral surface of the front axle case and formed at intervals in a circumferential direction of the front axle case. The front axle case of the work vehicle described in (1).