Vehicle axle device

Abstract

To supply a lubrication oil to slide portions between shaft parts of a spider and pinion gears to improve durability of the spider and the pinion gears.SOLUTION: Lubrication oil supply devices 42 for supplying a lubrication oil in a differential case 20 to slide portions between four shaft parts 27B of a spider 27 and four pinion gears 28 are provided around the differential case 20. The lubrication oil supply device 42 includes: an oil passage 43 extending from the tip side of each of the four shaft parts 27B of the spider 27 to a peripheral surface of the shaft part 27B; a first intake port 44 which takes the lubrication oil in the differential case 20 into the device 42 to supply the lubrication oil to the oil passage 43 when the differential case 20 rotates in a forward direction (an arrow A direction); and a second intake port 45 which takes the lubrication oil in the differential case 20 into the device 42 to supply the lubrication oil to the oil passage 43 when the differential case 20 rotates in a reverse direction (an opposite direction of the arrow A direction).SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to a vehicle axle device that is suitable for use in wheeled construction machines such as wheel loaders and wheeled hydraulic excavators. [Background technology]

[0002] A typical example of a wheeled construction machine (construction vehicle) is a wheel loader, which includes a vehicle body equipped with axle devices for driving left and right wheels, and a working device attached to the vehicle body.

[0003] A vehicle axle device is mounted on the vehicle body and consists of a hollow differential body and a pair of axle tubes extending from the differential body. It is equipped with an axle case containing lubricating oil, a pair of axle shafts extending through the pair of axle tubes and having wheels attached to their ends, and a differential mechanism (differential mechanism) provided within the differential body that transmits the rotational force of the drive source to the pair of axle shafts.

[0004] The differential mechanism also includes a hollow differential body that rotates in a forward direction (forward direction) or a reverse direction (reverse direction) around an axis extending in the left-right direction by a drive source such as an engine or an electric motor, a spider that is rotatably arranged around the axis within the differential body and has a plurality of shaft portions extending radially, a plurality of pinion gears rotatably attached to the plurality of shaft portions, and a pair of side gears that are rotatably arranged around the axis within the differential body so as to sandwich the plurality of pinion gears, mesh with the plurality of pinion gears, and are connected to a pair of axle shafts.

[0005] Here, wheel loaders are sometimes used in narrow work sites, and in such sites, wheel loaders often move forward and backward with large steering turns, which increases the difference in rotation speed between the left and right wheels. As a result, in the differential mechanism, the pinion gear rotates at high speed around the spider shaft for a long period of time to absorb the difference in rotation speed between the left and right wheels.

[0006] In this way, if the pinion gear rotates at high speed around the spider shaft for a long period of time, there is a risk of wear due to oil film breakdown at the sliding area between the spider shaft and the pinion gear.

[0007] Therefore, some vehicle axle devices are configured so that an oil hole (opening) is provided in the differential body of the differential mechanism, and lubricating oil in the axle case is supplied to the pinion gear and spider through this oil hole (opening).Furthermore, some vehicle axle devices are configured so that when the wheel loader moves forward and the differential body rotates in the forward direction, the lubricating oil in the axle case is scooped up and supplied toward the oil hole (opening) (Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Publication No. 8-270763 [Patent Document 2] Japanese Patent Application Laid-Open No. 2004-286041 Summary of the Invention [Problem to be solved by the invention]

[0009] Incidentally, a wheel loader travels forward, plunges a bucket into soil and sand, lifts it up, then travels backward, and then travels forward again to load the soil onto a dump truck or the like. Therefore, wheel loaders travel backward more frequently than vehicles such as passenger cars.

[0010] For this reason, when a wheel loader is traveling in reverse while also traveling with the steering turned sharply, there is a risk that the lubrication between the spider shaft and the pinion gear will be insufficient, resulting in wear and tear and reducing the durability of the spider and pinion gear.

[0011] The object of one embodiment of the present invention is to provide an axle device for a vehicle that can improve the durability of the spider and pinion gear by supplying lubricating oil to the sliding portion between the spider shaft and the pinion gear, whether the vehicle is traveling forward or backward. [Means for solving the problem]

[0012] One embodiment of the present invention is mounted on a vehicle having a pair of wheels, and includes an axle case comprising a hollow differential body and a pair of axle tubes extending from the differential body and containing lubricating oil therein; a pair of axle shafts extending through the pair of axle tubes and having the wheels attached to their distal ends; and a differential mechanism provided within the differential body for transmitting rotational force of a drive source to the pair of axle shafts, the differential mechanism including a hollow differential case that is rotated in a forward or reverse direction about an axis by the drive source; a spider provided within the differential case rotatably about the axis and having a plurality of shafts extending radially; a plurality of pinion gears rotatably attached to the plurality of shafts; and a differential mechanism for transmitting the rotational force of the plurality of pinion gears to the differential body. and a pair of side gears rotatably disposed within the differential case around the axis so as to sandwich the pinion gears, meshing with the plurality of pinion gears and connected to the pair of axle shafts. A lubricating oil supply device is provided around the differential case to supply lubricating oil within the differential case to the sliding portion between the shaft portion of the spider and the pinion gears, and the lubricating oil supply device has an oil passage extending from the tip side of the shaft portion of the spider to the circumferential surface of the shaft portion, a first intake port that takes in lubricating oil within the differential case and supplies it to the oil passage when the differential case rotates in the forward direction, and a second intake port that takes in lubricating oil within the differential case and supplies it to the oil passage when the differential case rotates in the reverse direction. [Effects of the Invention]

[0013] According to one embodiment of the present invention, the vehicle axle device can supply lubricating oil to the sliding area between the spider shaft and the pinion gear whether the vehicle is traveling forward or backward, thereby improving the durability of the spider and pinion gear. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a left side view showing a wheel loader according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a rear view showing the front axle device in FIG. 1 from the rear. [Figure 3] FIG. 3 is a plan view showing the front axle device of FIG. 2 from above. [Figure 4] 4 is a cross-sectional view showing the internal structure of the front axle device from the direction of arrows IV-IV in FIG. 3. [Figure 5] 5 is a cross-sectional view showing the internal structure of the front axle device as viewed from the direction of arrow VV in FIG. 4. [Figure 6] FIG. 6 is a cross-sectional view showing the lubricant oil supplying device in FIG. 5. [Figure 7] FIG. 5 is a cross-sectional view showing a front axle assembly equipped with a lubricating oil supply device according to a second embodiment of the present invention. [Figure 8] 8 is a cross-sectional view showing the internal structure of the front axle device taken from the direction of arrows VIII-VIII in FIG. 7. [Figure 9] FIG. 8 is a cross-sectional view showing the lubricant oil supplying device in FIG. [Figure 10] 8 is a cross-sectional view showing the internal structure of the front axle device from the direction of arrow XX in FIG. 7. [Figure 11] FIG. 10 is a cross-sectional view showing a front axle assembly equipped with a lubricating oil supply device according to a third embodiment of the present invention. [Figure 12] 12 is a cross-sectional view showing the internal structure of the front axle device from the direction of arrows XII-XII in FIG. 11. [Figure 13] FIG. 12 is a perspective view showing the spider and the lubricant oil supplying device in FIG. [Figure 14] FIG. 14 is a cross-sectional view of the spider and lubricant supply device shown in FIG. 13. [Figure 15] FIG. 10 is a cross-sectional view showing a spider and a lubricant supplying device according to a fourth embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0015] A vehicle axle device according to an embodiment of the present invention will be described in detail below with reference to the accompanying drawings, taking as an example a case where the axle device is mounted on a wheel loader. Note that in the embodiment, the traveling direction of the wheel loader is defined as the front-rear direction, and the direction perpendicular to the traveling direction of the wheel loader is defined as the left-right direction.

[0016] In Figure 1, a wheel loader 1 as a vehicle according to this embodiment constitutes a wheeled construction machine. The wheel loader 1 is comprised of a rear vehicle body 2 as a vehicle body, a front vehicle body 3 as a vehicle body connected to the front side of the rear vehicle body 2 so as to be able to swing in the left-right direction, rear wheels 4 as wheels provided on both left-right sides of the rear vehicle body 2, front wheels 5 as wheels provided on both left-right sides of the front vehicle body 3 (only the left side of each is shown), a working device 6 provided on the front side of the front vehicle body 3 so as to be rotatable (liftable), and a rear axle unit 11 and a front axle unit 12, which will be described later. The working device 6 is provided with a bucket 6A for storing earth and sand, etc.

[0017] The rear vehicle body 2 is equipped with an engine 7, which serves as a drive source, a torque converter 8, a transmission 9, a hydraulic pump (not shown), etc. The transmission 9 is connected to a rear axle device 11 via a propeller shaft 9A extending rearward. The transmission 9 is also connected to a front axle device 12 via a propeller shaft 9B extending forward. A cab 10 in which an operator rides is provided on the upper side of the rear vehicle body 2.

[0018] The rear axle device 11 is provided below the rear vehicle body 2 and extends in the left-right direction. The rear axle device 11 has rear wheels 4 attached to both left and right ends thereof.

[0019] The front axle device 12 is provided below the front vehicle body 3 and extends in the left-right direction. Similar to the rear axle device 11, the front axle device 12 has front wheels 5 attached to both left and right ends thereof.

[0020] Here, the rear axle device 11 and the front axle device 12 are configured in the same manner except for the connection positions of the propeller shafts 9A, 9B. Therefore, in this embodiment, the configuration of the front axle device 12 will be described in detail, and a description of the configuration of the rear axle device 11 will be omitted.

[0021] The front axle device 12 is connected to the propeller shaft 9B to rotate the left and right front wheels 5. As shown in Figures 2 to 4, the front axle device 12 includes an axle case 13, a differential mechanism 19, an axle shaft 36, and a lubricating oil supply device 42, which will be described later.

[0022] The axle case 13 is mounted to the wheel loader 1, which has a pair of left and right front wheels 5, and extends in the left-right direction. The axle case 13 forms the outer shape of the front axle device 12. The axle case 13 is located in the middle in the left-right direction and is configured as an airtight container comprising a hollow differential body 14 that houses a differential mechanism 19, a lubricating oil supply device 42, etc., a left axle tube 16 that extends outward in the left-right direction from the left end of the differential body 14, and a right axle tube 16 that extends outward in the left-right direction from the right end of the differential body 14. The left and right axle tubes 16 form a pair of axle tubes.

[0023] The differential body 14 is formed in a generally cylindrical shape centered on an axis OO (described later). As shown in Fig. 4, the upper side of the differential body 14 is closed by a cover 15. In addition, annular partition walls 14A are formed on the left and right sides of the differential body 14 by reducing the diameter at positions recessed a predetermined distance from the ends.

[0024] As a result, the inside of the differential body 14 is divided by left and right partition walls 14A into a central differential mechanism chamber 14B that houses the differential mechanism 19 described below, and left and right brake chambers 14C located on the left and right sides of the differential mechanism chamber 14B and that house the brake mechanism 37 described below.

[0025] 5, a protruding cylinder 14D is provided on the rear side of the differential body 14 so as to protrude toward the transmission 9 (rearward). An input shaft 17, which will be described later, is rotatably disposed within the protruding cylinder 14D.

[0026] 2 and 3, of the pair of left and right axle tubes 16, the left axle tube 16 has a short, cylindrical tubular section 16A on the right side, which faces the differential body 14, and which has approximately the same diameter as the differential body 14, and extends from the tubular section 16A with a reduced diameter on the left side. The tubular section 16A is disposed to surround the left planetary gear reduction mechanism 32, which will be described later, and its interior forms a reduction mechanism chamber 16B that houses the planetary gear reduction mechanism 32. The right tubular section 16A, which is the base end of the left axle tube 16, is attached to the left end of the differential body 14 using multiple bolts.

[0027] On the other hand, the right axle tube 16 is formed similarly to the left axle tube 16, sandwiching the differential body 14. The left tubular portion 16A of the right axle tube 16, which is the base end, is attached to the right end of the differential body 14 using multiple bolts.

[0028] As shown in Fig. 5, input shaft 17 is rotatably provided within protruding tube 14D of differential body 14. As shown in Fig. 3, input shaft 17 has a flange-shaped connecting portion 17A protruding outward, which is connected to propeller shaft 9B. An input gear 18 made of a bevel gear is provided on the differential mechanism 19 side of input shaft 17.

[0029] The differential mechanism 19 is provided in a differential mechanism chamber 14B of the differential body 14. The differential mechanism 19 distributes the rotational force of the propeller shaft 9B of the transmission 9 to a pair of axle shafts 36 (left and right front wheels 5) described below. The differential mechanism 19 is configured to include a differential case 20, a spider 27, a pinion gear 28, and a side gear 29, which will be described below.

[0030] The differential case 20 is formed as a hollow case that rotates in a forward direction (the direction of arrow A in FIG. 5) or a reverse direction (the direction opposite to the direction of arrow A) about an axis OO by the engine 7. As shown in FIG. 4, the differential case 20 is divided in two in the left-right direction (the extension direction of the axis OO) into a first case 21 on the left side and a second case 22 on the right side.

[0031] The first case 21 is formed into a stepped cylindrical shape by a large-diameter cylindrical portion 21A on the second case 22 side and a small-diameter cylindrical portion 21B on the left-side partition wall 14A side. The small-diameter cylindrical portion 21B of the first case 21 is rotatably supported by the left-side partition wall 14A via a bearing 23. Half of a gear chamber 25, which will be described later, is formed inside the large-diameter cylindrical portion 21A. A rotary shaft 30 is inserted into the small-diameter cylindrical portion 21B. Half of a shaft hole 26, which will be described later, is formed at the open end of the large-diameter cylindrical portion 21A.

[0032] The second case 22 is formed into a stepped cylindrical shape by a large-diameter cylindrical portion 22A on the first case 21 side and a small-diameter cylindrical portion 22B on the right-side partition wall 14A side. The large-diameter cylindrical portion 22A faces the large-diameter cylindrical portion 21A of the first case 21 in the direction of the axis OO. A flange portion 22C is formed on the outer periphery of the large-diameter cylindrical portion 22A, positioned toward the right. An internal gear 34, which will be described later, is attached to the flange portion 22C. The flange portion 22C and the internal gear 34 may also be configured to be located on opposite sides in the left-right direction.

[0033] The second case 22 has a small-diameter cylindrical portion 22B rotatably supported on the right-side partition wall 14A via a bearing 23. The second case 22 has a large-diameter cylindrical portion 22A integrally attached to the large-diameter cylindrical portion 21A of the first case 21 using a plurality of bolts 24. This allows the second case 22 to rotate together with the first case 21 about an axis OO extending in the left-right direction. The large-diameter cylindrical portion 22A forms half of a gear chamber 25. A rotary shaft 30 is inserted into the small-diameter cylindrical portion 22B. Half of a shaft hole 26 is formed in the open end of the large-diameter cylindrical portion 22A.

[0034] The gear chamber 25 is formed as a cylindrical space inside the large-diameter cylindrical portions 21A, 22A by fixing the large-diameter cylindrical portion 21A of the first case 21 and the large-diameter cylindrical portion 22A of the second case 22 facing each other. The gear chamber 25 accommodates a spider 27, a pinion gear 28, and a side gear 29, which will be described later.

[0035] 5, the shaft holes 26 are provided as circular holes at a plurality of locations (for example, four locations) spaced apart in the circumferential direction (rotational direction) at the boundary between the large-diameter cylindrical portion 21A of the first case 21 and the large-diameter cylindrical portion 22A of the second case 22. Specifically, the four shaft holes 26 are arranged at regular intervals in the circumferential direction along a plane perpendicular to the axis OO, and extend radially from the axis OO to penetrate the large-diameter cylindrical portions 21A, 22A. In other words, the four shaft holes 26 provided in the circumferential direction are arranged in a cross shape with the axis OO as the center. The four shaft holes 26 hold four shafts 27B of the spider 27, which will be described later, inserted therethrough.

[0036] The spider 27 is provided inside the differential case 20, i.e., in the gear chamber 25, so as to be rotatable about an axis OO. The spider 27 rotates together with the differential case 20. The spider 27 is formed in a cross shape by an annular central portion 27A and a plurality of shafts 27B (for example, four shafts 27B) extending radially from the central portion 27A. A lubricating oil supply device 42, which will be described later, is provided on the four shafts 27B.

[0037] 6, the tip side of shaft 27B of spider 27 forms protruding portion 27C that protrudes from differential case 20 (large-diameter cylindrical portion 21A of first case 21 and large-diameter cylindrical portion 22A of second case 22) by the amount of first intake port 44 and second intake port 45 (described later). Protruding portion 27C of shaft 27B constitutes a part of lubricating oil supply device 42.

[0038] Further, a chamfered portion (not shown) is formed on the circumferential surface of shaft portion 27B to form a space for storing lubricating oil between shaft portion 27B and pinion gear 28. An oil passage 43 (described later) provided in shaft portion 27B opens into the chamfered portion.

[0039] The pinion gears 28 are rotatably attached to the four shaft portions 27B of the spider 27. The four pinion gears 28 are arranged in the gear chamber 25 so that adjacent pinion gears 28 do not come into contact with each other. The pinion gears 28 are bevel gears having shaft insertion holes 28A, through which the shaft portions 27B of the spider 27 are inserted.

[0040] Here, because the pinion gear 28 rotates around the shaft portion 27B, the area between the shaft portion 27B and the shaft insertion hole 28A is a sliding area during rotation. In order to prevent wear and seizure at the sliding area between the shaft portion 27B and the shaft insertion hole 28A, the differential mechanism 19 supplies lubricating oil to the sliding area using a lubricating oil supply device 42 (described later) to form an oil film.

[0041] The pair of side gears 29 are arranged to sandwich the four pinion gears 28 from the left and right. The pair of left and right side gears 29 are provided in the gear chamber 25 inside the differential case 20 so as to be rotatable about the axis OO. The pair of side gears 29 are formed as bevel gears, and each is meshed with the four pinion gears 28. The left side gear 29 is connected to the left axle shaft 36 via the left planetary gear reduction mechanism 32. On the other hand, the right side gear 29 is connected to the right axle shaft 36 via the right planetary gear reduction mechanism 32.

[0042] The pair of rotating shafts 30 are provided rotatably about an axis OO. Of the pair of rotating shafts 30, the left rotating shaft 30 has its right end splined to the left side gear 29 and its left side extending toward a left axle shaft 36 (described later). On the other hand, the right rotating shaft 30 has its left end splined to the right side gear 29 and its right side extending toward a right axle shaft 36 (described later).

[0043] The ring gear 31 is attached to the flange portion 22C so as to surround the second case 22 of the differential case 20. The ring gear 31 is formed as a bevel ring gear that meshes with the input gear 18 of the input shaft 17.

[0044] As a result, the differential mechanism 19 transmits the rotational force from the transmission 9 to the differential case 20 via the input shaft 17 (input gear 18) and the ring gear 31, thereby allowing the left and right rotating shafts 30 to rotate appropriately via four pinion gears 28 and a pair of side gears 29.

[0045] Furthermore, when a difference in rotational speed occurs between the left front wheel 5 and the right front wheel due to a right or left turn (cornering), the differential mechanism 19 can absorb the difference in rotational speed between the left front wheel 5 and the right front wheel by rotating the pinion gear 28 around the shaft portion 27B of the spider 27. In this case, the smaller the turning radius during cornering, the higher the rotational speed of the pinion gear 28. Furthermore, lubricating oil stored inside the axle case 13 (differential mechanism chamber 14B) is supplied between the shaft portion 27B of the spider 27 and the shaft insertion hole 28A of the pinion gear 28, forming an oil film.

[0046] The planetary gear reduction mechanisms 32 are respectively provided in the reduction mechanism chambers 16B of the left and right axle tubes 16. The left and right planetary gear reduction mechanisms 32 reduce the rotation of the rotating shaft 30 and transmit it to left and right axle shafts 36, which will be described later. The planetary gear reduction mechanisms 32 are each configured to include a sun gear 33 integrally formed on the outer side of the rotating shaft 30 in the left-right direction, an internal gear 34 fixedly attached to the inner periphery of the axle tube 16, a plurality of planet gears (not shown) meshing with the sun gear 33 and the internal gear 34, and a carrier 35 that rotatably supports the plurality of planet gears.

[0047] The left axle shaft 36 is rotatably mounted within the left axle tube 16. On the other hand, the right axle shaft 36 is rotatably mounted within the right axle tube 16. The base ends of the left and right axle shafts 36 are spline-connected to the carrier 35 of the planetary gear reduction mechanism 32, and the tip ends protrude from the axle tube 16 and are attached to the front wheels 5.

[0048] The left brake mechanism 37 is provided in a left brake chamber 14C of the differential body 14. On the other hand, the right brake mechanism 37 is provided in a right brake chamber 14C of the differential body 14. The left and right brake mechanisms 37 are configured as, for example, wet multi-plate brake mechanisms.

[0049] The brake mechanism 37 is composed of a plurality of rotating discs 39 splined to the outer periphery of the rotating shaft 30 via a hub 38, a non-rotating disc 40 facing the plurality of rotating discs 39 and attached to the differential body 14 so as not to be rotatable, and a piston 41 that presses the non-rotating disc 40 against the rotating disc 39 by means of external hydraulic force.

[0050] When a brake pedal (not shown) inside the cab 10 is depressed, for example, the brake mechanism 37 moves a piston 41 in the axial direction by hydraulic force. As a result, the brake mechanism 37 presses the non-rotating disc 40 against the rotating disc 39 to generate a braking force by friction, thereby applying the brakes to the front wheels 5.

[0051] Next, the configuration of the lubricating oil supply device 42, which is a characteristic feature of this embodiment, will be described. The lubricating oil supply device 42 is provided around the differential case 20, specifically, on the tip side of the four shafts 27B of the spider 27. The four lubricating oil supply devices 42 supply lubricating oil inside the differential case 20 to the sliding portions between the shafts 27B of the spider 27 and the pinion gear 28 (between the outer peripheral surfaces of the shafts 27B and the shaft insertion holes 28A of the pinion gear 28). The lubricating oil supply device 42 is made up of an oil passage 43, a first intake port 44, a second intake port 45, and a switching mechanism 46, which will be described later.

[0052] An oil passage 43 is provided in each of the four shaft portions 27B of the spider 27. The four oil passages 43 are formed in a T-shape by a vertical passage 43A extending vertically along the shaft portion 27B from the tip end protruding from the differential case 20 toward the base end toward the central portion 27A, and a horizontal passage 43B extending horizontally perpendicularly from the base end side of the vertical passage 43A and opening at the circumferential surface of the shaft portion 27B. The tip end side of the vertical passage 43A communicates with an intermediate portion of a common oil passage 47 of a switching mechanism 46 (described later) at the tip end of the shaft portion 27B.

[0053] As a result, oil passage 43 extends from the tip side of shaft portion 27B of spider 27 through vertical passage 43A and horizontal passage 43B to the circumferential surface of shaft portion 27B, and is connected to the sliding portion between shaft portion 27B and pinion gear .

[0054] A first intake port 44 is provided on each of the protruding portions 27C of the four shaft portions 27B of the spider 27. The four first intake ports 44 open radially of the shaft portions 27B so that lubricating oil from within the differential case 20 enters when the spider 27 rotates in the forward direction (direction of arrow A) about the axis OO. The first intake ports 44 are provided within a first valve seat 48 of a switching mechanism 46, which will be described later. This allows the first intake ports 44 to take in lubricating oil from within the differential case 20 and supply it to the oil passage 43 when the wheel loader 1 moves forward and the differential case 20 rotates in the forward direction (direction of arrow A).

[0055] First intake 44 is formed so that the opening side (the circumferential surface side of shaft 27B) widens. Therefore, when differential case 20 rotates in the direction of arrow A, the large opening area allows a large amount of lubricating oil to be taken in by first intake 44, and a large amount of lubricating oil can be supplied toward oil passage 43.

[0056] Similar to the first intakes 44, the second intakes 45 are provided on the protruding portions 27C of the four shafts 27B of the spider 27. However, the four second intakes 45 differ from the first intakes 44 in that they open radially of the shafts 27B so that lubricating oil from inside the differential case 20 can enter when the spider 27 rotates in the reverse direction (opposite the direction of arrow A) about the axis OO.

[0057] The second intake port 45 is provided in a second valve seat 49 of the switching mechanism 46 located on the radially opposite side of the shaft portion 27B from the first intake port 44. As a result, when the wheel loader 1 moves backward and the differential case 20 rotates in the reverse direction (the direction opposite to the direction of arrow A), the second intake port 45 can take in lubricating oil inside the differential case 20 and supply it to the oil passage 43. Also, like the first intake port 44, the second intake port 45 is formed so that its opening side (the side facing the circumferential surface of the shaft portion 27B) widens.

[0058] The switching mechanism 46 is provided between the oil passage 43 and the first and second inlets 44 and 45. Specifically, the switching mechanism 46 is provided on each of the protruding portions 27C of the four shaft portions 27B of the spider 27. The switching mechanism 46 switches the connection destination of the oil passage 43 between the first inlet 44 and the second inlet 45 depending on the rotation direction of the differential case 20. That is, the switching mechanism 46 switches so that the first inlet 44 is connected to the oil passage 43 when the differential case 20 rotates in the forward direction, and switches so that the second inlet 45 is connected to the oil passage 43 when the differential case 20 rotates in the reverse direction. The switching mechanism 46 is composed of a common oil passage 47, a first valve seat 48, a second valve seat 49, and a valve element 50, which will be described later.

[0059] Common oil passage 47 is provided between first intake port 44 and second intake port 45, and is in communication with oil passage 43. More specifically, common oil passage 47 is formed by linearly penetrating protrusions 27C located at the tips of four shaft portions 27B of spider 27 in the rotational direction (direction of arrow A) and radial direction. A longitudinal intermediate portion of common oil passage 47 is connected to vertical passage 43A of oil passage 43.

[0060] First valve seat 48 is provided between oil passage 43 and first intake port 44 by reducing the diameter of common oil passage 47. Specifically, first valve seat 48 forms an annular stepped portion by inserting an annular body (cylinder) having an inner diameter smaller than that of common oil passage 47 into the open end of common oil passage 47 in the direction of arrow A (the end in the counterclockwise direction in FIG. 6). The inner diameter of first valve seat 48 gradually increases toward the opening side. As a result, the inner periphery of first valve seat 48 forms first intake port 44, which is widened on the circumferential surface side of shaft portion 27B.

[0061] The first valve seat 48 is disposed at a position spaced a predetermined distance from the position where the vertical passage 43A of the oil passage 43 is connected to the common oil passage 47. More specifically, the distance between the first valve seat 48 and the vertical passage 43A is set to a dimension that allows the valve element 50 seated on (in contact with) the first valve seat 48 to be accommodated in a position that does not interfere with the flow of lubricating oil from the common oil passage 47 to the vertical passage 43A. For example, the distance between the first valve seat 48 and the vertical passage 43A is approximately the diameter of the valve element 50.

[0062] Second valve seat 49 is provided between oil passage 43 and second intake port 45 by reducing the diameter of common oil passage 47. Specifically, second valve seat 49 forms an annular stepped portion by inserting an annular body (cylinder) with an inner diameter smaller than that of common oil passage 47 into the open end of common oil passage 47 opposite the direction of arrow A (the end in the clockwise direction in FIG. 6). The inner diameter of second valve seat 49 gradually increases toward the open side. As a result, the inner periphery of second valve seat 49 forms second intake port 45, which is widened on the circumferential surface side of shaft portion 27B.

[0063] The second valve seat 49 is disposed at a position spaced a predetermined distance from the position where the vertical passage 43A of the oil passage 43 is connected to the common oil passage 47. More specifically, the distance between the second valve seat 49 and the vertical passage 43A is set to a dimension that allows the valve element 50 seated on (in contact with) the second valve seat 49 to be accommodated in a position that does not interfere with the flow of lubricating oil from the common oil passage 47 to the vertical passage 43A. For example, the distance between the second valve seat 49 and the vertical passage 43A is approximately the diameter of the valve element 50.

[0064] The valve element 50 is located between the first valve seat 48 and the second valve seat 49 and is movably provided in the common oil passage 47. The valve element 50 is formed as a sphere with a diameter smaller than the inner diameter of the common oil passage 47 and larger than the inner diameters of the first valve seat 48 and the second valve seat 49.

[0065] The valve element 50 is pushed by the lubricating oil flowing through the common oil passage 47 and seats on the first valve seat 48 or the second valve seat 49. Specifically, as shown in Fig. 6, the valve element 50 is pushed in the direction opposite to the direction of arrow A by the lubricating oil that has flowed into the common oil passage 47 from the first intake port 44, and seats on the second valve seat 49. On the other hand, the valve element 50 is pushed in the direction of arrow A by the lubricating oil that has flowed into the common oil passage 47 from the second intake port 45, and seats on the first valve seat 48.

[0066] In the lubricating oil supply device 42 configured in this manner, when the wheel loader 1 moves forward and the differential case 20 rotates in the forward direction (direction of arrow A), the four shafts 27B (protrusions 27C) of the spider 27 move in the direction of arrow A within the lubricating oil. At this time, the first intake ports 44 provided on the protrusions 27C of the shafts 27B move toward the lubricating oil, and the lubricating oil is taken in from these first intake ports 44 into the common oil passage 47 of the switching mechanism 46. The lubricating oil taken in the common oil passage 47 presses the valve element 50 against the second valve seat 49, closing the valve.

[0067] 6, the lubricating oil taken into the common oil passage 47 from the first intake port 44 flows from the common oil passage 47 to the vertical passage 43A of the oil passage 43, and is supplied from the horizontal passage 43B to the sliding portion between the shaft portion 27B and the pinion gear 28. Moreover, by seating the valve body 50 on the second valve seat 49, the entire amount of lubricating oil taken into the common oil passage 47 can be supplied to the sliding portion.

[0068] Furthermore, when the wheel loader 1 moves backward and the differential case 20 rotates in the reverse direction (opposite to the direction of arrow A), the four shafts 27B (protrusions 27C) of the spider 27 move through the lubricating oil in the direction opposite to the direction of arrow A. At this time, the second intake ports 45 provided on the protrusions 27C of the shafts 27B move toward the lubricating oil, and the lubricating oil is taken in from these second intake ports 45 to the common oil passage 47 of the switching mechanism 46. The lubricating oil taken in the common oil passage 47 presses the valve element 50 against the first valve seat 48, closing the valve.

[0069] As a result, the lubricating oil taken into the common oil passage 47 from the second intake port 45 flows from the common oil passage 47 to the vertical passage 43A of the oil passage 43, and is supplied from the horizontal passage 43B to the sliding portion between the shaft portion 27B and the pinion gear 28. Moreover, by seating the valve body 50 on the first valve seat 48, the entire amount of lubricating oil taken into the common oil passage 47 can be supplied to the sliding portion.

[0070] The wheel loader 1 according to this embodiment has the above-described configuration, and its operation will now be described.

[0071] First, an operator in the cab 10 operates the surrounding levers and pedals (none of which are shown) to activate the transmission 9 for traveling. At this time, the rotational force of the output shaft of the transmission 9 is transmitted from the propeller shaft 9B to the input shaft 17 of the front axle unit 12, the differential mechanism 19, and the planetary gear reduction mechanism 32, to the left and right axle shafts 36. This makes it possible to rotate the left and right front wheels 5 connected to the left and right axle shafts 36. Similarly, by transmitting the rotation of the output shaft of the transmission 9 from the propeller shaft 9A to the rear axle unit 11, it is possible to rotate the left and right rear wheels 4.

[0072] In this way, by driving the front wheels 5 and rear wheels 4 to rotate, the wheel loader 1 can be driven towards the work site. When turning left or right while driving, the four pinion gears 28 of the differential mechanism 19 rotate around the four shaft portions 27B of the spider 27, transmitting rotational force to the pair of meshed side gears 29. As a result, when turning left, for example, the rotation speed of the left front wheel 5 and rear wheel 4 (which are the inner wheels) can be reduced below the rotation speed of the right front wheel and rear wheel (which are the outer wheels), and the difference in rotation speed between the inside and outside wheels allows for a smooth turn.

[0073] The wheel loader 1 travels forward, plunges the bucket 6A of the working implement 6 into soil and sand to lift it up, then travels backward, and then travels forward again to load the soil into a dump truck (not shown), repeating this operation. Therefore, the wheel loader 1 travels backward frequently. Also, the wheel loader 1 may travel with the steering wheel turned sharply to change direction in a narrow space. In this case, in the differential mechanism 19, the pinion gear 28 rotates at high speed around the shaft portion 27B of the spider 27 to absorb the difference in rotational speed.

[0074] Therefore, in a configuration such as those described in Patent Documents 1 and 2 above, in which the lubricating oil inside the axle case is scooped up and supplied toward the oil hole (opening) when the wheel loader moves forward and the differential body rotates in the forward direction, if the wheel loader moves in reverse and is traveling with the steering turned significantly at the same time, there is a risk that the lubrication between the spider shaft and pinion gear will be insufficient, resulting in wear.

[0075] However, according to this embodiment, a lubricating oil supply device 42 is provided around the differential case 20 to supply lubricating oil from within the differential case 20 to the sliding portions between the four shaft portions 27B of the spider 27 and the four pinion gears 28, and the lubricating oil supply device 42 is equipped with an oil passage 43 extending from the tip side of the four shaft portions 27B of the spider 27 to the circumferential surface of the shaft portions 27B, a first intake port 44 that takes in lubricating oil from within the differential case 20 and supplies it to the oil passage 43 when the differential case 20 rotates in the forward direction (direction of arrow A), and a second intake port 45 that takes in lubricating oil from within the differential case 20 and supplies it to the oil passage 43 when the differential case 20 rotates in the reverse direction (opposite the direction of arrow A).

[0076] As a result, whether the wheel loader 1 is traveling forward or backward, lubricating oil inside the differential case 20 can be constantly supplied to the sliding portion between the shaft portion 27B of the spider 27 and the pinion gear 28 through the oil passage 43. As a result, the durability of the spider 27 and the pinion gear 28 can be improved.

[0077] Furthermore, lubricating oil supply device 42 is equipped with a switching mechanism 46 that switches the connection destination of oil passage 43 between first intake port 44 and second intake port 45 depending on the rotational direction of differential case 20. Therefore, the entire amount of lubricating oil taken into common oil passage 47 from first intake port 44 or second intake port 45 can be supplied to the sliding portion between shaft portion 27B of spider 27 and pinion gear 28.

[0078] Furthermore, the switching mechanism 46 includes a common oil passage 47 provided between the first intake 44 and the second intake 45 while communicating with the oil passage 43, a first valve seat 48 provided by reducing the diameter of the common oil passage 47 between the oil passage 43 and the first intake 44, a second valve seat 49 provided by reducing the diameter of the common oil passage 47 between the oil passage 43 and the second intake 45, and a valve body 50 located between the first valve seat 48 and the second valve seat 49, movably provided in the common oil passage 47, and pressed by the lubricating oil flowing through the common oil passage 47 to seat on the first valve seat 48 or the second valve seat 49.

[0079] Therefore, when lubricating oil is taken in through first inlet 44, valve element 50 can be seated on second valve seat 49 to close second inlet 45. On the other hand, when lubricating oil is taken in through second inlet 45, valve element 50 can be seated on first valve seat 48 to close first inlet 44. This allows the entire amount of lubricating oil taken into common oil passage 47 from first inlet 44 or second inlet 45 to be supplied to the sliding portion between shaft portion 27B of spider 27 and pinion gear 28.

[0080] 7 to 10 show a second embodiment of the present invention. This embodiment is characterized in that a plurality of L-shaped joints that open in the forward rotation direction and a plurality of L-shaped joints that open in the reverse rotation direction are provided around the differential case, and lubricating oil taken in from the L-shaped joints through oil passages is supplied to the sliding portion between the spider shaft and the pinion gear. In the second embodiment, the same components as those in the first embodiment described above are designated by the same reference numerals, and their description will be omitted.

[0081] In Figure 7, the differential mechanism 51 according to the second embodiment is configured to include the pinion gear 28, side gear 29, rotating shaft 30, ring gear 31 described above, as well as a differential case 52, spider 55, and lubricating oil supply device 56 described below.

[0082] The differential case 52 according to the second embodiment is, like the differential case 20 according to the first embodiment, composed of two separate cases, a first case 53 on the left side and a second case 54 on the right side.

[0083] The first case 53 is formed into a stepped cylindrical shape by a large-diameter cylindrical portion 53A and a small-diameter cylindrical portion 53B, and the small-diameter cylindrical portion 53B is rotatably supported on the left-side partition wall 14A via a bearing 23. Furthermore, first passages 57 (described later) are provided in the large-diameter cylindrical portion 53A at predetermined intervals in the circumferential direction (rotational direction), for example, at intervals of 90 degrees, penetrating the large-diameter cylindrical portion 53A in the direction of the axis OO. Furthermore, a first L-shaped joint 60 (described later) is attached to a left end surface 53A1 and an outer peripheral surface 53A2 of the large-diameter cylindrical portion 53A so as to communicate with the first passages 57.

[0084] The second case 54 is formed into a stepped cylindrical shape by a large-diameter cylindrical portion 54A and a small-diameter cylindrical portion 54B, and the small-diameter cylindrical portion 54B is rotatably supported on the right-side partition wall 14A via a bearing 23. A flange portion 54C for attaching the internal gear 34 is formed on the outer periphery of the large-diameter cylindrical portion 54A.

[0085] Furthermore, a second passage 58 (described later) is provided on the first case 53 side (left side) of the large-diameter cylindrical portion 54A, positioned on the same line as the first passage 57. A second L-shaped joint 62 (described later) is attached to the outer circumferential surface 54A1 of the large-diameter cylindrical portion 54A so as to communicate with the second passage 58.

[0086] The interior of the first case 53 and the second case 54 forms a gear chamber 25. Furthermore, at the boundary between the large diameter cylindrical portion 53A of the first case 53 and the large diameter cylindrical portion 54A of the second case 54, four shaft holes 26 are provided radially penetrating therethrough.

[0087] The spider 55 is provided in the gear chamber 25 inside the differential case 52 so as to be rotatable together with the differential case 52 about the axis OO. The spider 55 is formed by an annular central portion 55A and four shaft portions 55B extending radially (in a cross shape) from the central portion 55A.

[0088] The four shafts 55B of the spider 55 have their tip ends inserted into the four shaft holes 26. The four shafts 55B are provided with an oil passage 59 and a switching mechanism 64 of a lubricating oil supply device 56, which will be described later.

[0089] Lubricating oil supplying devices 56 according to the second embodiment are provided around the differential case 52, specifically, on the differential case 52 and the four shafts 55B of the spider 55. The four lubricating oil supplying devices 56 supply lubricating oil inside the differential case 52 to sliding portions between the shafts 55B of the spider 55 and the pinion gear 28. The lubricating oil supplying devices 56 are made up of a first passage 57, a second passage 58, an oil passage 59, a first intake port 61, a second intake port 63, and a switching mechanism 64, which will be described later.

[0090] The first passages 57 are provided so as to penetrate in the direction of the axis OO on the outer circumferential side of the large-diameter cylindrical portion 53A of the first case 53. Four first passages 57 are provided at predetermined intervals in the circumferential direction (rotational direction) of the large-diameter cylindrical portion 53A, for example, at intervals of 90 degrees as shown in FIG. 10 . The four first passages 57 are arranged so as to intersect with the four shaft holes 26.

[0091] The four second passages 58 are located on the outer circumferential side of the large-diameter cylindrical portion 54A of the second case 54, and are provided at intervals in the circumferential direction so as to be coaxial with the four first passages 57. The four second passages 58 are formed as bottomed holes that are open on the shaft hole 26 side.

[0092] An oil passage 59 is provided in each of the four shaft portions 55B of the spider 55. The four oil passages 59 are formed in a T-shape by a vertical passage 59A extending vertically along the shaft portion 55B from the tip end side of the shaft portion 55B toward the base end side, which is the central portion 55A side, and a horizontal passage 59B extending horizontally perpendicularly from the base end of the vertical passage 59A and opening on the circumferential surface of the shaft portion 55B. The tip end side of the vertical passage 59A communicates with an intermediate portion of a common oil passage 65 of a switching mechanism 64, which will be described later, at the tip end side of the shaft portion 55B.

[0093] As a result, the tip end side of the vertical passage 59A of the oil passage 59 is connected to the first passage 57 and the second passage 58 via the common oil passage 65. In addition, the oil passage 59 extends from the tip end side of the shaft portion 55B of the spider 55 through the vertical passage 59A and the horizontal passage 59B to the circumferential surface of the shaft portion 55B, and is connected to the sliding portion between the shaft portion 55B and the pinion gear 28.

[0094] Eight first L-shaped joints 60 are attached to the left end surface 53A1 and outer peripheral surface 53A2 of the large-diameter cylindrical portion 53A of the first case 53. Of the eight, four first L-shaped joints 60 attached to the left end surface 53A1 are connected to the left ends of the four first passages 57. In addition, four first L-shaped joints 60 attached to the outer peripheral surface 53A2 are connected to the four first passages 57 in the radial direction.

[0095] Here, the eight first L-shaped joints 60 have openings in a direction perpendicular to the installation direction, and these openings serve as first intake ports 61 that take in lubricating oil from inside the differential case 52 and supply it to the oil passage 59. Furthermore, the eight first L-shaped joints 60 are oriented when installed so that the first intake ports 61 open in the forward rotation direction (the direction of arrow A).

[0096] As a result, when the wheel loader 1 moves forward and the differential case 52 rotates in the forward direction (direction of arrow A), the first intake 61 can take in lubricating oil from inside the differential case 52 and supply this lubricating oil to the oil passage 59 through the first L-shaped joint 60, the first passage 57, and the switching mechanism 64.

[0097] 10, the first intake port 61 is formed so that its opening side widens. Therefore, when the differential case 52 rotates in the direction of arrow A, the large opening area allows a large amount of lubricating oil to be taken into the first intake port 61, and a large amount of lubricating oil can be supplied toward the oil passage 59.

[0098] Four second L-shaped joints 62 are attached to the outer peripheral surface 54A1 of the large-diameter cylindrical portion 54A of the second case 54. The four second L-shaped joints 62 are connected to the four second passages 58 in the radial direction. Like the first L-shaped joints 60, the four second L-shaped joints 62 have openings in a direction perpendicular to the attachment direction, and these openings serve as second intakes 63 that take in lubricating oil from within the differential case 52 and supply it to the oil passage 59. Furthermore, the four second L-shaped joints 62 are oriented when attached so that the second intakes 63 open in the reverse direction (the opposite direction to the direction of arrow A). Similarly to the first intake 61, the second intakes 63 are formed so that their openings widen.

[0099] As a result, when the wheel loader 1 moves backward and the differential case 52 rotates in the reverse direction (opposite the direction of arrow A), the second intake 63 can take in lubricating oil from inside the differential case 52 and supply this lubricating oil to the oil passage 59 through the second L-shaped joint 62, the second passage 58, and the switching mechanism 64.

[0100] 9, the switching mechanism 64 is provided between the oil passage 59 and the first and second intake ports 61 and 63. Specifically, the switching mechanism 64 is provided at the tip end side of each of the four shaft portions 55B of the spider 55. The switching mechanism 64 switches the connection destination of the oil passage 59 between the first intake port 61 and the second intake port 63 depending on the rotation direction of the differential case 52.

[0101] That is, the switching mechanism 64 switches so that the first intake port 61 (first L-shaped joint 60) is connected to the oil passage 59 when the differential case 52 rotates in the forward direction, and switches so that the second intake port 63 (second L-shaped joint 62) is connected to the oil passage 59 when the differential case 52 rotates in the reverse direction. The switching mechanism 64 is made up of a common oil passage 65, a first valve seat 66, a second valve seat 67, and a valve body 68, which will be described later.

[0102] The common oil passage 65 is provided between the first intake port 61 and the second intake port 63, and is in communication with the oil passage 59. More specifically, the common oil passage 65 is formed at the tip side of the four shaft portions 55B of the spider 55, penetrating radially so as to be in communication with the first passage 57 and the second passage 58. The middle portion of the common oil passage 65 in the longitudinal direction is connected to the vertical passage 59A of the oil passage 59.

[0103] The first valve seat 66 is provided between the oil passage 59 and the first intake port 61 by reducing the diameter of the common oil passage 65. Specifically, the first valve seat 66 forms an annular stepped portion by inserting an annular body (cylinder) having an inner diameter smaller than the inner diameter of the common oil passage 65 into the open end of the common oil passage 65 on the first passage 57 side.

[0104] The first valve seat 66 is disposed at a position spaced a predetermined distance from the position where the vertical passage 59A of the oil passage 59 is connected to the common oil passage 65. More specifically, the distance between the first valve seat 66 and the vertical passage 59A is set to a dimension that allows the valve element 68 seated on (in contact with) the first valve seat 66 to be accommodated in a position that does not interfere with the flow of lubricating oil from the common oil passage 65 to the vertical passage 59A. For example, the distance between the first valve seat 66 and the vertical passage 59A is approximately the diameter of the valve element 68.

[0105] The second valve seat 67 is provided between the oil passage 59 and the second intake port 63 by reducing the diameter of the common oil passage 65. Specifically, the second valve seat 67 forms an annular stepped portion by inserting an annular body (cylinder) having an inner diameter smaller than the inner diameter of the common oil passage 65 into the open end of the common oil passage 65 on the second passage 58 side.

[0106] The second valve seat 67 is disposed at a position spaced a predetermined distance from the position where the vertical passage 59A of the oil passage 59 is connected to the common oil passage 65. More specifically, the distance between the second valve seat 67 and the vertical passage 59A is set to a dimension that allows the valve element 68 seated on (in contact with) the second valve seat 67 to be accommodated in a position that does not interfere with the flow of lubricating oil from the common oil passage 65 to the vertical passage 59A. For example, the distance between the second valve seat 67 and the vertical passage 59A is approximately the diameter of the valve element 68.

[0107] The valve element 68 is located between the first valve seat 66 and the second valve seat 67 and is provided movably in the common oil passage 65. The valve element 68 is formed as a sphere with a diameter smaller than the inner diameter of the common oil passage 65 and larger than the inner diameters of the first valve seat 66 and the second valve seat 67.

[0108] The valve element 68 is pressed by the lubricating oil flowing through the common oil passage 65 and seats on the first valve seat 66 or the second valve seat 67. Specifically, as shown in Fig. 9, the valve element 68 is pressed by the lubricating oil that has flowed into the common oil passage 65 from the first intake port 61 through the first passage 57 and seats on the second valve seat 67. On the other hand, the valve element 68 is pressed by the lubricating oil that has flowed into the common oil passage 65 from the second intake port 63 through the second passage 58 and seats on the first valve seat 66.

[0109] In the lubricating oil supply device 56 according to the second embodiment configured in this manner, when the wheel loader 1 moves forward and the differential case 52 rotates in the forward direction (the direction of arrow A), the eight first L-shaped joints 60 and four second L-shaped joints 62 move in the direction of arrow A within the lubricating oil. At this time, the eight first inlets 61 that open in the direction of arrow A move toward the lubricating oil, and the lubricating oil is taken from these first inlets 61 through the first passage 57 into the common oil passage 65 of the switching mechanism 64. The lubricating oil taken into the common oil passage 65 presses the valve element 68 against the second valve seat 67, closing the valve.

[0110] 9, the lubricating oil taken into the common oil passage 65 from the first intake port 61 flows from the common oil passage 65 to the vertical passage 59A of the oil passage 59, and is supplied from the horizontal passage 59B to the sliding portion between the shaft portion 55B and the pinion gear 28. Moreover, by seating the valve body 68 on the second valve seat 67, the entire amount of lubricating oil taken into the common oil passage 65 can be supplied to the sliding portion.

[0111] Furthermore, when the wheel loader 1 moves backward and the differential case 52 rotates in the reverse direction (opposite to the direction of arrow A), the eight first L-shaped joints 60 and four second L-shaped joints 62 of the lubricating oil supply device 56 move in the direction opposite to the direction of arrow A within the lubricating oil. At this time, the four second intake ports 63 that open in the direction of arrow A move toward the lubricating oil, and lubricating oil is taken from these second intake ports 63 through the second passage 58 into a common oil passage 65 of the switching mechanism 64. The lubricating oil taken into the common oil passage 65 presses the valve body 68 against the first valve seat 66, closing the valve.

[0112] As a result, the lubricating oil taken into the common oil passage 65 from the second intake port 63 flows from the common oil passage 65 to the vertical passage 59A of the oil passage 59, and is supplied from the horizontal passage 59B to the sliding portion between the shaft portion 55B and the pinion gear 28. Moreover, by seating the valve body 68 on the first valve seat 66, the entire amount of lubricating oil taken into the common oil passage 65 can be supplied to the sliding portion.

[0113] Thus, the second embodiment configured as described above can also achieve the same functions and effects as the first embodiment. In particular, in the second embodiment, the first L-shaped joint 60 having the first intake port 61 and the second L-shaped joint 62 having the second intake port 63 can be formed as the same member with the orientation changed when attached. This makes it possible to suppress increases in costs.

[0114] 11 to 14 show a third embodiment of the present invention. This embodiment is characterized in that an intake attachment equipped with a first intake port, a second intake port, and a switching mechanism is attached to the tip of the spider shaft. In the third embodiment, the same components as those in the first embodiment are designated by the same reference numerals, and their description will be omitted.

[0115] 11 and 12, a differential mechanism 71 according to the third embodiment is provided in a differential mechanism chamber 14B of a differential body 14, similar to the differential mechanism 19 according to the first embodiment. The differential mechanism 71 includes the differential case 20, pinion gear 28, side gear 29, and a spider 72, which will be described later.

[0116] Similar to the spider 27 according to the first embodiment, the spider 72 according to the third embodiment is rotatably mounted in the gear chamber 25 in the differential case 20 around the axis OO. As shown in Figures 13 and 14, the spider 72 is formed in a cross shape by a central portion 72A and four shaft portions 72B. However, the spider 72 according to the third embodiment differs from the spider 27 according to the first embodiment in that the positions of the tips of the four shaft portions 72B are aligned with the outer peripheral surface of the differential case 20.

[0117] Lubricating oil supply devices 73 according to the third embodiment are provided around the differential case 20, specifically, on the four shafts 72B of the spider 72 and on four intake attachments 75, which will be described later. The four lubricating oil supply devices 73 supply lubricating oil inside the differential case 20 to the sliding portions between the shafts 72B of the spider 72 and the pinion gears 28. The lubricating oil supply devices 73 are composed of an oil passage 74, a first intake port 76, a second intake port 77, and a switching mechanism 78, which will be described later.

[0118] An oil passage 74 is provided in each of the four shaft portions 72B of the spider 72. The four oil passages 74 are formed in a T-shape by a vertical passage 74A extending vertically along the shaft portion 72B from the tip end, which is the outer peripheral surface side of the differential case 20, to the base end, which is the central portion 72A side, and a horizontal passage 74B extending horizontally perpendicularly from the base end side of the vertical passage 74A and opening on the peripheral surface of the shaft portion 72B. A mounting portion 75B of an intake attachment 75, which will be described later, is attached to the tip of the vertical passage 74A.

[0119] As a result, oil passage 74 extends from the tip side of shaft portion 72B of spider 72 through vertical passage 74A and horizontal passage 74B to the circumferential surface of shaft portion 72B, and is connected to the sliding portion between shaft portion 72B and pinion gear .

[0120] The intake attachments 75 are attached to the tips of the four shafts 72B of the spider 72. Each of the four intake attachments 75 includes a cylindrical portion 75A extending in the rotational direction of the differential case 20 and an attachment portion 75B protruding radially from a longitudinal intermediate portion of the cylindrical portion 75A. Inside the attachment portion 75B is a connecting passage 75C that connects a vertical passage 74A of the oil passage 74 with an intermediate portion of a common oil passage 79 (described later).

[0121] The first intake ports 76 are provided in the cylindrical portions 75A of the four intake attachments 75, respectively. The four first intake ports 76 open at the ends of the cylindrical portions 75A in the direction of arrow A so that lubricating oil from inside the differential case 20 can enter when the spider 72 rotates in the forward direction (the direction of arrow A) about the axis OO.

[0122] This allows the first intake port 76 to take in lubricating oil from the differential case 20 and supply it to the oil passage 74 when the wheel loader 1 moves forward and the differential case 20 rotates in the forward direction (direction of arrow A).

[0123] The first intake 76 is formed so that its opening side widens. Therefore, when the differential case 20 rotates in the direction of arrow A, the large opening area allows a large amount of lubricating oil to be taken into the first intake 76, and a large amount of lubricating oil can be supplied toward the oil passage 74.

[0124] Like the first inlets 76, the second inlets 77 are provided in the cylindrical portions 75A of the four inlet attachments 75. However, the four second inlets 77 differ from the first inlets 76 in that they open at the end of the cylindrical portions 75A opposite to the direction of arrow A so that lubricating oil from inside the differential case 20 can enter when the spider 72 rotates in the reverse direction (opposite the direction of arrow A) about the axis OO. Like the first inlets 76, the second inlets 77 are formed so that the opening side (the side facing the circumferential surface of the shaft portion 72B) widens.

[0125] This allows the second intake port 77 to take in lubricating oil from the differential case 20 and supply it to the oil passage 74 when the wheel loader 1 moves backward and the differential case 20 rotates in the reverse direction (opposite the direction of arrow A).

[0126] The switching mechanism 78 is provided between the oil passage 74 (connection passage 75C) and the first and second intake ports 76 and 77. Specifically, the switching mechanism 78 is provided in each of the four intake attachments 75. The switching mechanism 78 switches the destination of the oil passage 74 between the first intake port 76 and the second intake port 77 depending on the rotation direction of the differential case 20. That is, the switching mechanism 78 switches so that the first intake port 76 is connected to the oil passage 74 when the differential case 20 rotates in the forward direction, and switches so that the second intake port 77 is connected to the oil passage 74 when the differential case 20 rotates in the reverse direction. The switching mechanism 78 is composed of a common oil passage 79, a first valve seat 80, a second valve seat 81, and a valve body 82, which will be described later.

[0127] Common oil passage 79 is provided between first intake port 76 and second intake port 77, in communication with oil passage 74. More specifically, common oil passage 79 is formed inside cylindrical portion 75A of intake attachment 75. A longitudinal intermediate portion of common oil passage 79 is connected to vertical passage 74A of oil passage 74 via connection passage 75C.

[0128] First valve seat 80 is provided between oil passage 74 and first intake port 76 by reducing the diameter of common oil passage 79. Specifically, first valve seat 80 forms an annular stepped portion by inserting an annular body (cylindrical body) with an inner diameter smaller than the inner diameter of common oil passage 79 into a position extending from the open end side in the direction of arrow A of common oil passage 79 (cylindrical portion 75A of intake attachment 75) (the end side in the counterclockwise direction in FIG. 12).

[0129] The first valve seat 80 is disposed at a position spaced a predetermined distance from the position where the connecting passage 75C (the vertical passage 74A of the oil passage 74) is connected to the common oil passage 79. More specifically, the distance between the first valve seat 80 and the connecting passage 75C is set to a dimension that allows the valve element 82 seated on (in contact with) the first valve seat 80 to be accommodated in a position that does not interfere with the flow of lubricating oil from the common oil passage 79 to the connecting passage 75C. For example, the distance between the first valve seat 80 and the connecting passage 75C is approximately the diameter of the valve element 82.

[0130] Second valve seat 81 is provided between oil passage 74 and second intake port 77 by reducing the diameter of common oil passage 79. Specifically, second valve seat 81 forms an annular stepped portion by inserting an annular body (cylinder) with an inner diameter smaller than that of common oil passage 79 into the open end of common oil passage 79 opposite the direction of arrow A (the end side in the clockwise direction in FIG. 12 ).

[0131] The second valve seat 81 is disposed at a position spaced a predetermined distance from the position where the connecting passage 75C (the vertical passage 74A of the oil passage 74) is connected to the common oil passage 79. Specifically, the distance between the second valve seat 81 and the connecting passage 75C is set to a dimension that allows the valve element 82 seated on (in contact with) the second valve seat 81 to be accommodated in a position that does not interfere with the flow of lubricating oil from the common oil passage 79 to the connecting passage 75C. For example, the distance between the second valve seat 81 and the connecting passage 75C is approximately the diameter of the valve element 82.

[0132] The valve element 82 is located between the first valve seat 80 and the second valve seat 81 and is provided movably in the common oil passage 79. The valve element 82 is formed as a sphere with a diameter smaller than the inner diameter of the common oil passage 79 and larger than the inner diameters of the first valve seat 80 and the second valve seat 81.

[0133] The valve element 82 is pushed by the lubricating oil flowing through the common oil passage 79 and seats on the first valve seat 80 or the second valve seat 81. Specifically, as shown in Fig. 14, the valve element 82 is pushed in the direction opposite to the direction of arrow A by the lubricating oil that has flowed into the common oil passage 79 from the first intake port 76, and seats on the second valve seat 81. On the other hand, the valve element 82 is pushed in the direction of arrow A by the lubricating oil that has flowed into the common oil passage 79 from the second intake port 77, and seats on the first valve seat 80.

[0134] In the lubricating oil supply device 73 configured in this manner, when the wheel loader 1 moves forward and the differential case 20 rotates in the forward direction (direction of arrow A), the four shafts 72B of the spider 72 move in the direction of arrow A within the lubricating oil together with the four intake attachments 75. At this time, the first intake port 76 provided in the cylindrical portion 75A of the intake attachment 75 moves toward the lubricating oil, and the lubricating oil is taken in from this first intake port 76 into the common oil passage 79 of the switching mechanism 78. The lubricating oil taken in the common oil passage 79 presses the valve element 82 against the second valve seat 81, closing the valve.

[0135] 14, the lubricating oil taken into the common oil passage 79 from the first intake port 76 flows from the common oil passage 79 through the connecting passage 75C to the vertical passage 74A of the oil passage 74, and is supplied from the horizontal passage 74B to the sliding portion between the shaft portion 72B and the pinion gear 28. Moreover, by seating the valve body 82 on the second valve seat 81, the entire amount of lubricating oil taken into the common oil passage 79 can be supplied to the sliding portion.

[0136] Furthermore, when the wheel loader 1 moves backward and the differential case 20 rotates in the reverse direction (opposite to the direction of arrow A), the four shafts 72B of the spider 72 move together with the four intake attachments 75 in the direction opposite to the direction of arrow A within the lubricating oil supply device 73. At this time, the second intake port 77 provided in the cylindrical portion 75A of the intake attachment 75 moves toward the lubricating oil, and the lubricating oil is taken in from this second intake port 77 into the common oil passage 79 of the switching mechanism 78. The lubricating oil taken in the common oil passage 79 presses the valve element 82 against the first valve seat 80, closing the valve.

[0137] As a result, the lubricating oil taken into the common oil passage 79 from the second intake port 77 flows from the common oil passage 79 through the connecting passage 75C to the vertical passage 74A of the oil passage 74, and is supplied from the horizontal passage 74B to the sliding portion between the shaft portion 72B and the pinion gear 28. Moreover, by seating the valve body 82 on the first valve seat 80, the entire amount of lubricating oil taken into the common oil passage 79 can be supplied to the sliding portion.

[0138] Thus, the third embodiment configured as described above can also achieve the same effects and advantages as the first embodiment. In particular, in the third embodiment, an oil passage 74 is formed in the shaft portion 72B of the spider 72, and an intake attachment 75 having a first intake port 76, a second intake port 77, and a switching mechanism 78 is attached so as to communicate with the oil passage 74, thereby configuring the lubricating oil supply device 73. As a result, by simply drilling holes in the existing spider 72 and attaching the intake attachment 75, which is a separate member, it is possible to supply lubricating oil to the sliding portion between the shaft portion 72B and the pinion gear 28.

[0139] Next, Fig. 15 shows a fourth embodiment of the present invention. A feature of this embodiment is that when the differential case rotates in the forward direction, lubricating oil is supplied to the sliding portion between the spider shaft and the pinion gear through the first intake and the first oil passage, and when the differential case rotates in the reverse direction, lubricating oil is supplied to the sliding portion between the spider shaft and the pinion gear through the second intake and the second oil passage. In the fourth embodiment, the same components as those in the first embodiment described above are designated by the same reference numerals, and their description will be omitted.

[0140] 15, a spider 91 according to the fourth embodiment is rotatably mounted about an axis OO in a gear chamber 25 in a differential case 20, similar to the spider 27 according to the first embodiment. The spider 91 is formed in a cross shape by a central portion 91A and four shaft portions 91B. However, the spider 91 according to the fourth embodiment differs from the spider 27 according to the first embodiment in that the positions of the tips of the four shaft portions 91B are aligned with the outer peripheral surface of the differential case 20.

[0141] Lubricating oil supplying devices 92 according to the fourth embodiment are provided around the differential case 20, specifically, on four shafts 91B of the spider 91 and four intake attachments 95, which will be described later. The four lubricating oil supplying devices 92 supply lubricating oil inside the differential case 20 to sliding portions between the shafts 91B of the spider 91 and the pinion gears 28. The lubricating oil supplying devices 92 are configured to include a first oil passage 93, a second oil passage 94, a first intake port 96, and a second intake port 97, which will be described later.

[0142] First oil passages 93 and second oil passages 94 are provided in the four shaft portions 91B of the spider 91, respectively. The first oil passages 93 and second oil passages 94 are arranged, for example, side by side in the rotational direction of the spider 91. The four first oil passages 93 are formed in a T-shape by a vertical passage 93A extending vertically along the shaft portion 91B and a horizontal passage 93B extending horizontally perpendicularly from the base end side of the vertical passage 93A and opening on the circumferential surface of the shaft portion 91B. Similarly, the four second oil passages 94 are formed in a T-shape by a vertical passage 94A and a horizontal passage 94B.

[0143] As a result, the first oil passage 93 and the second oil passage 94 extend from the tip side of the shaft portion 91B of the spider 91 to the circumferential surface of the shaft portion 91B, and are connected to the sliding portion between the shaft portion 91B and the pinion gear .

[0144] The intake attachments 95 are attached to the tips of the four shafts 91B of the spider 91. Each of the four intake attachments 95 includes a cylindrical portion 95A extending in the rotational direction of the differential case 20 and a mounting portion 95B protruding radially from a longitudinally intermediate portion of the cylindrical portion 95A. The mounting portion 95B of each intake attachment 95 is attached to the tip of the shaft 91B.

[0145] The cylindrical portion 95A is provided with a first passage 95C that opens in the direction of arrow A and extends to the middle of the length, and a second passage 95D that opens on the opposite side of the direction of arrow A and extends to the middle of the length. The first passage 95C and the second passage 95D are separated at the middle of the length of the cylindrical portion 95A. The mounting portion 95B is provided with a first connecting passage 95E that connects the deepest portion of the first passage 95C to the vertical passage 93A of the first oil passage 93, and a second connecting passage 95F that connects the deepest portion of the second passage 95D to the vertical passage 94A of the second oil passage 94.

[0146] The first intake ports 96 are provided in the cylindrical portions 95A of the four intake attachments 95, respectively. The four first intake ports 96 are provided on the opening side of the first passage 95C so that the lubricating oil in the differential case 20 enters when the spider 91 rotates in the forward direction (the direction of arrow A) about the axis OO.

[0147] Therefore, when the wheel loader 1 moves forward and the differential case 20 rotates in the forward direction (the direction of arrow A), the first intake port 96 can take in lubricating oil inside the differential case 20 and supply it to the first oil passage 93. This allows the lubricating oil taken in by the first intake port 96 to be supplied to the sliding portion between the shaft portion 91B of the spider 91 and the pinion gear 28.

[0148] The first intake port 96 is formed so that its opening side widens. Therefore, when the differential case 20 rotates in the direction of arrow A, the large opening area allows a large amount of lubricating oil to be taken into the first intake port 96, and a large amount of lubricating oil can be supplied toward the first oil passage 93.

[0149] Similar to the first intakes 96, the second intakes 97 are provided in the cylindrical portions 95A of the four intake attachments 95. However, the four second intakes 97 differ from the first intakes 96 in that they are provided on the opening side of the second passage 95D so that lubricating oil from inside the differential case 20 can enter when the spider 91 rotates in the reverse direction (opposite the direction of arrow A) about the axis OO. Similar to the first intakes 96, the second intakes 97 are formed so that their openings widen.

[0150] Therefore, when the wheel loader 1 moves backward and the differential case 20 rotates in the reverse direction (the opposite direction to the direction of arrow A), the second intake port 97 can take in lubricating oil inside the differential case 20 and supply it to the second oil passage 94. As a result, the lubricating oil taken in by the second intake port 97 can be supplied to the sliding portion between the shaft portion 91B of the spider 91 and the pinion gear 28.

[0151] In the lubricating oil supply device 92 configured in this manner, when the wheel loader 1 moves forward and the differential case 20 rotates in the forward direction (the direction of arrow A), the four shafts 91B of the spider 91 move together with the four intake attachments 95 in the direction of arrow A within the lubricating oil. At this time, the first intake port 96 provided in the cylindrical portion 95A of the intake attachment 95 moves toward the lubricating oil, and the lubricating oil is taken in from this first intake port 96 into the first passage 95C.

[0152] As a result, the lubricating oil taken in from the first intake port 96 to the first passage 95C flows from the first passage 95C through the first connecting passage 95E to the vertical passage 93A of the first oil passage 93, and is supplied from the horizontal passage 93B to the sliding portion between the shaft portion 91B and the pinion gear 28. Moreover, the passage from the first intake port 96 to the sliding portion between the shaft portion 91B and the pinion gear 28 is a dedicated passage, so that the entire amount of lubricating oil taken in can be supplied to the sliding portion.

[0153] Furthermore, when the wheel loader 1 moves backward and the differential case 20 rotates in the reverse direction (opposite to the direction of arrow A), the four shafts 91B of the spider 91 move together with the four intake attachments 95 in the direction opposite to the direction of arrow A within the lubricating oil supply device 92. At this time, the second intake port 97 provided in the cylindrical portion 95A of the intake attachment 95 moves toward the lubricating oil, and lubricating oil is taken in from this second intake port 97 into the second passage 95D.

[0154] As a result, the lubricating oil taken in from the second intake port 97 to the second passage 95D flows from the second passage 95D through the second connecting passage 95F to the vertical passage 94A of the second oil passage 94, and is supplied from the horizontal passage 94B to the sliding portion between the shaft portion 91B and the pinion gear 28. Moreover, the passage from the second intake port 97 to the sliding portion between the shaft portion 91B and the pinion gear 28 is a dedicated passage, just like the passage from the first intake port 96 to the sliding portion, so that the entire amount of lubricating oil taken in can be supplied to the sliding portion.

[0155] Thus, the fourth embodiment configured as described above can also achieve the same effects and advantages as the first embodiment. In particular, the fourth embodiment is configured to provide a dedicated passage for supplying lubricating oil from the first intake port 96 to the sliding portion between the shaft portion 91B and the pinion gear 28 during forward travel, and a dedicated passage for supplying lubricating oil from the second intake port 97 to the sliding portion between the shaft portion 91B and the pinion gear 28 during reverse travel. As a result, in the fourth embodiment, the entire amount of lubricating oil taken in can be supplied to the sliding portion without using a switching mechanism, thereby simplifying the configuration.

[0156] In the first embodiment, the vehicle axle device has been described using the rear axle device 11 and the front axle device 12 provided on the wheel loader 1 as an example. However, the present invention is not limited to this and can be widely applied to axle devices provided on other vehicles, such as wheeled hydraulic excavators. This configuration can be similarly applied to the other embodiments. [Explanation of symbols]

[0157] 1 Wheel loader (vehicle) 4 Rear wheel (wheel) 5 Front wheels 11 Rear axle device (vehicle axle device) 12 Front axle device (vehicle axle device) 13 Axle case 14 Differential body 16 Axle tube 19,51,71 Differential mechanism 20,52 Differential case 27,55,72,91 Spider 27B,55B,72B,91B Shaft 28 Pinion gear 29 Side gear 36 axle shaft 42,56,73,92 Lubricating oil supply device 43,59,74 Oil road 44,61,76,96 1st intake 45,63,77,97 2nd intake 46,64,78 switching mechanism 47,65,79 Common oilway 48,66,80 First valve seat 49, 67, 81 Second valve seat 50, 68, 82 Valve body 93 No. 1 oilway (oilway) 94 2nd oilway (oilway) OO axis A Direction of rotation when moving forward (forward direction)

Claims

1. an axle case mounted on a vehicle having a pair of wheels, the axle case comprising a hollow differential body and a pair of axle tubes extending from the differential body, the axle case containing lubricating oil; a pair of axle shafts extending through the pair of axle tubes and having the wheels attached to their distal ends; a differential mechanism provided in the differential body and configured to transmit rotational force of a drive source to the pair of axle shafts; Equipped with The differential mechanism includes: a hollow differential case that rotates in a forward or reverse direction about an axis by the drive source; a spider provided in the differential case to be rotatable about the axis line and having a plurality of shaft portions extending radially; a plurality of pinion gears rotatably attached to the plurality of shaft portions; a pair of side gears rotatably disposed within the differential case around the axis line so as to sandwich the plurality of pinion gears, the side gears meshing with the plurality of pinion gears and connected to the pair of axle shafts; In a vehicle axle device comprising: a lubricating oil supply device is provided around the differential case to supply lubricating oil from within the differential case to a sliding portion between the shaft portion of the spider and the pinion gear; The lubricating oil supply device is an oil passage extending from a tip side of the shaft portion of the spider to a circumferential surface of the shaft portion; a first intake port that takes in lubricating oil in the differential case and supplies it to the oil passage when the differential case rotates in the forward direction; a second intake port that takes in lubricating oil in the differential case and supplies it to the oil passage when the differential case rotates in the reverse direction; An axle device for a vehicle, comprising:

2. 2. The vehicle axle assembly according to claim 1, The lubricating oil supply device is characterized in that it is equipped with a switching mechanism that switches the destination of the oil passage between the first intake and the second intake depending on the rotation direction of the differential case.

3. 3. The vehicle axle device according to claim 2, The switching mechanism includes: a common oil passage provided between the first intake and the second intake in a state of communication with the oil passage; a first valve seat provided between the oil passage and the first intake port by reducing the diameter of the common oil passage; a second valve seat provided between the oil passage and the second intake port by reducing the diameter of the common oil passage; a valve element located between the first valve seat and the second valve seat, movably provided in the common oil passage, and pressed by lubricating oil flowing through the common oil passage to seat on the first valve seat or the second valve seat; An axle device for a vehicle, comprising:

Images