Vehicle axle device

Abstract

A plurality of rotating disks (38) which engage with the outer peripheral side spline of the right side gear (35) and a plurality of non-rotating disks (39) which are arranged between the plurality of rotating disks (38) are provided in the differential case (23), and a pressure ring (43) is provided between the right retainer (41) and the rotating disks (38). The right retainer (41) is provided with a piston (46) which applies a load to the pressure ring (43) to bring the rotating disks (38) into frictional contact with the non-rotating disks (39). A lever member (53) is provided between the differential case (23), the right side gear (35), and the pressure ring (43). The lever member (53) transmits a reaction force generated by the meshing of the pinion gear (33) and the right side gear (35) to the pressure ring (43), and controls the load applied to the pressure ring (43) from the piston (46).

Description

Technical Field

[0001] This disclosure relates to a vehicle axle assembly suitable for use in wheeled construction machinery such as wheel loaders and wheeled hydraulic excavators. Background Technology

[0002] As a representative example of wheeled construction machinery, a known wheel loader is an example. A wheel loader has a body with an axle assembly that drives the left and right wheels and a working device mounted on the body. The axle assembly of the body is provided with a differential mechanism, which distributes the driving torque from the drive source to the left and right axles according to the load acting on the left and right wheels (drive wheels).

[0003] Typically, wheel loaders are equipped with a limited slip differential mechanism. This limited slip differential restricts the movement of the differential mechanism according to the magnitude of the drive torque, thereby achieving both the driving and slewing performance of the wheel loader (Patent Document 1). Such a torque-proportional limited slip differential restricts the differential when the drive torque increases and releases the differential restriction when the drive torque decreases. Therefore, in a torque-proportional limited slip differential, the differential torque (the torque difference between the left and right axles) is uniquely determined by the magnitude of the drive torque.

[0004] The driving conditions of a wheel loader vary considerably depending on the road conditions and the nature of the work. Therefore, assuming it's traveling on paved roads, if the differential torque is set to a low value beforehand, the drive wheels of the wheel loader are prone to slippage. On the other hand, if the differential torque is set to a high value beforehand, the differential mechanism may not operate properly during turning, leading to increased losses in absorbing the difference between the inner and outer wheel diameters (e.g., wheel wear, increased steering effort, increased fuel consumption).

[0005] Therefore, it is desirable for wheeled construction machinery such as wheel loaders to appropriately adjust the differential torque of the differential limiting device according to road conditions and driving conditions. As a variable differential limiting device capable of variably adjusting the differential torque, a structure in which a friction clutch and an actuator are incorporated into the differential mechanism is known (reference 2). This variable differential limiting device controls the operation of the differential mechanism by having the friction clutch driven by the actuator, thereby adjusting the differential torque. As actuators for the variable differential limiting device, actuators using the driving force of a motor have been proposed (reference 3), actuators using the electromagnetic force of an electromagnet (reference 4), actuators using the pressing force of a piston actuated by pneumatic pressure (reference 5), and actuators using the pressing force of a piston actuated by hydraulic pressure (reference 6), etc. Furthermore, a device has been proposed that predicts the driving torque distributed to the forward and backward axles based on the hydraulic pressure supplied to the boom cylinder and bucket cylinder mounted on the wheel loader, thereby controlling the operation of the differential limiting device (Patent Document 7).

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Application Publication No. 58-149440

[0009] Patent Document 2: US Patent No. 6620072

[0010] Patent Document 3: Japanese Patent Application Publication No. 2003-184993

[0011] Patent Document 4: Japanese Patent Application Publication No. 8-25995

[0012] Patent Document 5: Japanese Utility Model Application Publication No. 61-140242

[0013] Patent Document 6: Japanese Patent Application Publication No. 63-106140

[0014] Patent Document 7: Japanese Patent Application Publication No. 2010-179696 Summary of the Invention

[0015] The purpose of existing differential mechanisms with variable differential limiting devices is to suppress excessive loads and torques on the shafts (output shafts) of differential limiting devices such as axle shafts, which could reduce shaft life. Therefore, in differential limiting devices that include, for example, hydraulically actuated pistons, the driving torque acting on the shaft is predicted (controlled), and the piston controls the clutch operation according to the predicted driving torque, thereby adjusting the differential torque.

[0016] However, predicting the shaft's drive torque requires various sensors, control devices, and hydraulic control circuits to control the piston's movement according to the predicted drive torque. Therefore, the cost of differential mechanisms that include differential limiting devices increases.

[0017] The purpose of this invention is to provide a vehicle axle device capable of mechanically adjusting differential torque according to driving torque.

[0018] The vehicle axle assembly of the present invention comprises left and right axles on which left and right wheels are respectively mounted, a hollow differential body disposed between left and right axle housings housing the left and right axles and having partitions with through holes extending in the left and right directions on both sides, and a differential mechanism disposed between the left and right partitions of the differential body and transmitting the rotational force of a drive source to the left and right axles. The differential mechanism includes: a differential housing rotatably supported by left and right retainers respectively mounted in the through holes of the left and right partitions and rotated by the drive source; a pinion disposed within the differential housing and rotating together with the differential housing; left and right side gears disposed within the differential housing and meshing with the pinion; and left and right drive shafts connected to the left and right side gears and transmitting the rotation of the differential housing to the left and right axles. The feature is that, within the differential housing, there are a plurality of rotating disks that engage with the outer peripheral spline of one of the left and right side gears, and a plurality of non-rotating disks disposed among the plurality of rotating disks and which are non-rotatable relative to the differential housing but movable in the left and right direction. A pressure ring is provided between the retainer on the side of the left and right side gear and the rotating disk, pressing the rotating disk toward the non-rotating disk. An actuator is provided on the side of the retainer, which applies a load to the pressure ring to bring the rotating disk into contact with the non-rotating disk, thereby engaging the left and right drive shafts. A lever member is provided between the differential housing, the side gear, and the pressure ring, which transmits the reaction force generated by the meshing of the pinion with the side gear to the pressure ring, controlling the load applied to the pressure ring by the actuator.

[0019] According to the present invention, the reaction force generated by the meshing of the pinion with one of the side gears increases proportionally to the driving torque, and this meshing reaction force can be transmitted to the pressure ring via a lever member. As a result, the load applied to the pressure ring from the actuator is mechanically reduced, and the differential torque is mechanically reduced in accordance with the increase in driving torque, thereby extending the life of the left and right axle shafts. Attached Figure Description

[0020] Figure 1 This is a left view showing a wheel loader equipped with a vehicle axle device according to an embodiment.

[0021] Figure 2 This is a three-dimensional view of the front axle assembly as seen from the front.

[0022] Figure 3 This is a cross-sectional view showing the internal structure of the front axle assembly.

[0023] Figure 4 It is magnification Figure 3 A cross-sectional view of the differential mechanism in the image.

[0024] Figure 5 It is shown in magnification Figure 4 Enlarged sectional views of the main components, including the third housing, right gear, pressure ring, piston, and lever assembly.

[0025] Figure 6 This is a perspective view of the first housing of the differential housing shown as a single unit.

[0026] Figure 7 This is a perspective view of the second housing of the differential housing shown as a single unit.

[0027] Figure 8 This is a perspective view of the third housing of the differential housing as seen from the cylindrical side.

[0028] Figure 9 This is a three-dimensional view of the third shell as seen from the side of the convex edge.

[0029] Figure 10 It is a three-dimensional view showing the non-rotating disk as a single unit.

[0030] Figure 11 It is a three-dimensional view of the pressing plate shown as a single unit.

[0031] Figure 12 This is a perspective view showing the right retainer as a single unit.

[0032] Figure 13 This is a three-dimensional view showing the pressure ring as a single unit.

[0033] Figure 14 This is a three-dimensional view of the piston viewed from the side of the large-diameter cylindrical section.

[0034] Figure 15 This is a three-dimensional view of the piston as seen from the side of the small-diameter cylindrical section.

[0035] Figure 16 It is a three-dimensional diagram showing the lever component as a single unit.

[0036] Figure 17 It is a cross-sectional view showing the load exerted by the meshing reaction force of the right gear and pinion on the right gear, lever components, pressure ring, etc.

[0037] Figure 18 This is a right-side view showing the right retainer mounted on the right sidewall of the differential body.

[0038] Figure 19 This is a characteristic curve diagram showing the relationship between the differential torque and the total torque of the output shaft under condition 1.

[0039] Figure 20 This is a characteristic curve diagram showing the relationship between the output shaft torque and the total output shaft torque under condition 1.

[0040] Figure 21 This is a characteristic curve diagram showing the relationship between the differential torque and the total torque of the output shaft under condition 2.

[0041] Figure 22 This is a characteristic curve diagram showing the relationship between the output shaft torque and the total output shaft torque under condition 2. Detailed Implementation

[0042] The following example uses a wheel loader as a reference. Figures 1 to 22 The implementation method of the vehicle axle device will be described in detail. Furthermore, in the implementation method, the travel direction of the wheel loader is described as the forward and backward direction, and the direction orthogonal to the travel direction of the wheel loader is described as the left and right direction.

[0043] Figure 1 In this embodiment, the wheel loader 1 comprises a rear body 2, a front body 3, rear wheels 4, front wheels 5, and a working device 6 disposed on the front side of the front body 3. The front body 3 and the front side of the rear body 2 are connected in a manner that allows them to swing in the left and right directions. The rear wheels 4 are disposed on both sides of the rear body 2 in the left and right directions, and the front wheels 5 are disposed on both sides of the front body 3 in the left and right directions.

[0044] The rear body 2 houses an engine 7, a torque converter 8, a transmission 9, and a hydraulic pump (not shown), which serve as the drive source. The transmission 9 is connected to the rear axle assembly 11 via a drive shaft 9A extending in the longitudinal direction, and to the front axle assembly 12 via a drive shaft 9B. A driver's cab 10 is located on the upper side of the rear body 2.

[0045] The rear axle assembly 11 is located on the lower side of the rear vehicle body 2. The rear axle assembly 11 extends in the left-right direction, and rear wheels 4 are respectively installed at both ends of the rear axle assembly 11 in the left-right direction.

[0046] The front axle assembly 12 is located on the lower side of the front vehicle body 3. The front axle assembly 12 extends in the left-right direction in the same way as the rear axle assembly 11, and front wheels 5 are respectively installed at both ends of the front axle assembly 12 in the left-right direction.

[0047] The rear axle assembly 11 and the front axle assembly 12 are identical in construction, except for the connection positions of the drive shafts 9A and 9B. Therefore, in this embodiment, the structure of the front axle assembly 12 will be described in detail, while the description of the structure of the rear axle assembly 11 will be omitted.

[0048] The front axle assembly 12 is connected to the drive shaft 9B to rotate and drive the left and right front wheels 5. For example... Figure 2 , Figure 3 As shown, the front axle assembly 12 is configured to include the following components: housing 13, left axle 19L, right axle 19R, differential mechanism 20, left planetary gear reduction mechanism 54L, right planetary gear reduction mechanism 54R, left brake mechanism 58L, and right brake mechanism 58R.

[0049] The housing 13 constitutes the housing of the front axle assembly 12. The housing 13 includes a hollow differential body 14 located in the middle of the left-right direction, a left axle housing 15L located to the left of the differential body 14, and a right axle housing 15R located to the right of the differential body 14. The differential mechanism 20 and left and right braking mechanisms 58L and 58R are housed inside the differential body 14. A left axle 19L is rotatably supported within the left axle housing 15L, and a right axle 19R is rotatably supported within the right axle housing 15R. Front wheels 5 are mounted on the front ends of the left and right axles 19L and 19R, respectively.

[0050] like Figures 2 to 4 As shown, the differential body 14 is constructed of a cylindrical body centered on an axis XX extending in the left-right direction (axial direction). The differential body 14 has a single-piece structure comprising a left partition wall 14B and a right partition wall 14C integrally formed therein. The left and right ends of the differential body 14 are respectively open ends 14A. The left partition wall 14B is integrally provided on the left side of the differential body 14, and the right partition wall 14C is integrally provided on the right side of the differential body 14. The left and right partition walls 14B and 14C extend radially inward from their inner circumferential surfaces, which are located further inward than the open ends 14A. The left and right partition walls 14B and 14C each have through holes 14D, which are smaller in diameter than the open ends 14A, formed through them in the left-right direction (axial direction).

[0051] The interior of the differential body 14 is divided into a gear chamber 14E located between left and right partitions 14B and 14C, a left brake chamber 14F located on the left side of the gear chamber 14E, and a right brake chamber 14G located on the right side of the gear chamber 14E. The differential mechanism 20 is housed in the gear chamber 14E, the brake mechanism 58L is housed in the left brake chamber 14F, and the brake mechanism 58R is housed in the right brake chamber 14G. Furthermore, a protruding cylinder 14H protruding towards the transmission 9 is provided on the rear side of the differential body 14 (rear axle assembly 11 side). The protruding cylinder 14H opens into the gear chamber 14E, and the input shaft 17 described below is rotatably supported within the protruding cylinder 14H.

[0052] The base ends of the left axle housing 15L and the right axle housing 15R are each formed into a short cylindrical portion 15A. The aforementioned left and right cylindrical portions 15A have an outer diameter equal to the two ends of the differential body 14 in the left-right direction. The interiors of the left and right cylindrical portions 15A respectively form reduction chambers 15B, with a planetary gear reduction mechanism 54L housed in the left reduction chamber 15B and a planetary gear reduction mechanism 54R housed in the right reduction chamber 15B. The front ends of the left and right axle housings 15L and 15R are respectively rectangular and extend outwards in the left-right direction from the cylindrical portions 15A. The cylindrical portions 15A of the left and right axle housings 15L and 15R are mounted to the open ends 14A of the differential body 14 using multiple bolts 16. The left and right axle housings 15L and 15R extend from the differential body 14 while simultaneously narrowing in diameter in the left-right direction.

[0053] Rectangular mounting portions 15C are respectively provided on the upper surface of the left and right axle housings 15L and 15R, adjacent to the cylindrical portion 15A. These left and right mounting portions 15C are mounted on the front body 3 of the wheel loader 1. That is, the front axle assembly 12 is an in-machine type axle assembly with a differential mechanism 20, left and right planetary gear reduction mechanisms 54L and 54R, and left and right braking mechanisms 58L and 58R provided between the mounting portions 15C of the left and right axle housings 15L and 15R. Furthermore, the rear axle assembly 11 is mounted on the rear body 2 (see reference 11A) via the axle support 11A. Figure 1 ).

[0054] The input shaft 17 is rotatably mounted within the protruding sleeve 14H of the differential body 14 via two bearings 18A and 18B. One end of the input shaft 17 protrudes outward from the protruding sleeve 14H, and a connecting flange 17A is provided at this end. The connecting flange 17A is connected to the drive shaft 9B. The other end of the input shaft 17 protrudes into the gear chamber 14E of the differential body 14, and a drive pinion 17B composed of bevel gears is formed at this other end. The drive pinion 17B meshes with the gear ring 30 described below.

[0055] The left axle 19L extends axially and is disposed within the left axle housing 15L. The right axle 19R extends axially and is disposed within the right axle housing 15R. The aforementioned left and right axles 19L and 19R are arranged on axis XX. The base end of the left axle 19L is splinedly engaged with the planetary gear carrier 57 of the planetary gear reduction mechanism 54L. The front end of the left axle 19L protrudes from the left axle housing 15L, and the left front wheel 5 is mounted on its front end. The base end of the right axle 19R is splinedly engaged with the planetary gear carrier 57 of the planetary gear reduction mechanism 54R. The front end of the right axle 19R protrudes from the right axle housing 15R, and the right front wheel 5 is mounted on its front end.

[0056] Next, the differential mechanism 20 of this embodiment will be described.

[0057] The differential mechanism 20 is housed within the gear chamber 14E of the differential body 14. The differential mechanism 20 distributes and transmits the driving force (rotational force) of the engine 7, which becomes the drive source, to the left and right front wheels 5 via the left and right axle shafts 19L and 19R. Here, the differential mechanism 20 is a differential mechanism (limited-slip differential mechanism) that is temporarily locked (differential lock-up state) depending on the situation. This differential mechanism 20 is configured to include the following components: differential housing 23, ring gear 30, multiple pinions 33, left gear 34, right gear 35, left drive shaft 36, right drive shaft 37, multiple rotating discs 38, multiple non-rotating discs 39, piston 46, and multiple lever components 53.

[0058] A cylindrical left retainer 21 with a protruding edge 21A is installed in the through hole 14D of the left partition 14B constituting the differential body 14. The protruding edge 21A of the left retainer 21 is fixed to the left partition 14B using bolts 22. A right retainer 41 is installed in the through hole 14D of the right partition 14C constituting the differential body 14. The right retainer 41 is fixed to the right partition 14C using bolts 22.

[0059] The differential housing 23 is disposed within the gear chamber 14E of the differential body 14. The differential housing 23 is supported by the left retainer 21 and the right retainer 41 via bearings 24A and 24B in a manner that allows it to rotatably along the axis XX. The differential housing 23 forms the outer shell of the differential mechanism 20 and is composed of a first housing 25, a second housing 26, and a third housing 27.

[0060] like Figure 4 and Figure 6As shown, the first housing 25 is formed as a stepped cylindrical body having a small-diameter cylindrical portion 25A and a large-diameter cylindrical portion 25B. A through-hole 25C extending in the left-right direction is formed at the center of the first housing 25. A large-diameter circular plate-shaped protrusion 25D is provided between the small-diameter cylindrical portion 25A and the large-diameter cylindrical portion 25B. The small-diameter cylindrical portion 25A is supported by the left retainer 21 via a bearing 24A. A plurality of bolt through holes 25E are formed throughout the circumference of the protrusion 25D. A plurality of threaded holes (internal threaded holes) 25G are formed throughout the circumference of the axial end face 25F of the large-diameter cylindrical portion 25B. Furthermore, four semi-circular recesses 25H are formed at 90° intervals on the axial end face 25F of the large-diameter cylindrical portion 25B.

[0061] like Figure 4 and Figure 7 As shown, the second housing 26 is formed as a hollow, stepped cylinder having a small-diameter cylindrical portion 26A and a large-diameter cylindrical portion 26B. The small-diameter cylindrical portion 26A has the same outer diameter and wall thickness as the large-diameter cylindrical portion 25B of the first housing 25. Multiple bolt insertion holes 26C extending in the left-right direction are formed throughout the circumference of the small-diameter cylindrical portion 26A. These multiple bolt insertion holes 26C correspond to the threaded holes 25G of the first housing 25. Four semi-circular recesses 26E are formed at 90° intervals on the axial end face 26D of the small-diameter cylindrical portion 26A. These multiple recesses 26E correspond to the recesses 25H of the first housing 25. Multiple threaded holes 26G are formed throughout the circumference of the axial end face 26F of the large-diameter cylindrical portion 26B. Furthermore, four shallow, rectangular engaging recesses 26H are formed at 90° intervals on the axial end face 26F. Furthermore, a plurality of (e.g., four) axially extending grooves 26L with semi-circular cross-sections are formed at equal angular intervals on the inner circumferential surface 26K of the large-diameter cylindrical portion 26B. The protrusion 39A of the non-rotating disk 39 described below engages with the plurality of grooves 26L.

[0062] The third housing 27 is located on the opposite side of the first housing 25 in the left-right direction and is mounted on the second housing 26. For example... Figure 4 , Figure 8 as well as Figure 9As shown, the third housing 27 has a cylindrical portion 27A and a large-diameter, plate-shaped protruding edge portion 27B. The protruding edge portion 27B has an outer diameter slightly larger than that of the large-diameter cylindrical portion 26B of the second housing 26, and its outer periphery engages with the large-diameter cylindrical portion 26B of the second housing 26 from the outer periphery. A through-hole 27C extending axially is formed at the center of the third housing 27. The cylindrical portion 27A is supported by a right retainer 41 via a bearing 24B. A plurality of bolt through-holes 27D are formed throughout the circumference of the protruding edge portion 27B. These bolt through-holes 27D correspond to the threaded holes 26G of the second housing 26. Furthermore, four threaded holes 27E, smaller in diameter than the bolt through-holes 27D, are formed at 90° intervals on the protruding edge portion 27B. These four threaded holes 27E correspond to the pin through-holes 43B of the pressure ring 43 described below. In the protruding edge 27B, a plurality of (e.g., eight) rectangular holes 27F are formed on the radially inner side compared to the bolt insertion hole 27D, extending axially. A rectangular protrusion 43D of a pressure ring 43 is movably inserted into these rectangular holes 27F. Four rectangular holes 27F arranged at 90° intervals in the rectangular holes 27F are connected to form a lever component receiving groove 27G extending toward the center of the cylindrical portion 27A. The lever component 53 is received within the lever component receiving groove 27G.

[0063] A bolt 28 is inserted into the bolt insertion hole 26C of the second housing 26. The bolt 28 is threaded into the threaded hole 25G of the first housing 25. Thus, the second housing 26 is fixed relative to the first housing 25. At this time, the axial end face 25F of the first housing 25 abuts against the axial end face 26D of the second housing 26 (small diameter cylindrical portion 26A). The shaft 32A of the cross shaft 32 described below is locked between the recess 25H of the first housing 25 and the recess 26E of the second housing 26. Furthermore, bolts 29 are inserted into the bolt insertion holes 27D of the third housing 27. The bolts 29 are threaded into the threaded hole 26G of the second housing 26. Thus, the third housing 27 is fixed relative to the second housing 26. In this way, the differential housing 23, which is composed of the first housing 25, the second housing 26, and the third housing 27, is assembled. Inside the differential housing 23, the cross shaft 32, a plurality of pinions 33, and left and right side gears 34 and 35 are arranged.

[0064] The gear ring 30 is mounted on the differential housing 23 within the gear chamber 14E of the differential body 14. The gear ring 30 is composed of annular bevel gears. The gear ring 30 is fixed to the protruding edge 25D of the first housing 25 by a plurality of bolts 31 inserted into bolt holes 25E in the first housing 25. The gear ring 30 meshes with the drive pinion 17B of the input shaft 17. Therefore, the rotation of the engine 7 is transmitted to the input shaft 17 via the transmission 9, driving the pinion 17B to mesh with the gear ring 30, thereby rotating the differential housing 23.

[0065] A cross shaft 32 is disposed within the differential housing 23. The cross shaft 32 has four shafts 32A arranged in a cross shape at 90° intervals. The front ends of the four shafts 32A are clamped between the recesses 25H of the first housing 25 and the second housing 26 that constitute the differential housing 23. Therefore, the cross shaft 32 rotates integrally with the differential housing 23.

[0066] Multiple (four) pinions 33 are rotatably supported by four shafts 32A of the cross shaft 32. Each of the four pinions 33 is composed of a bevel gear and is formed as a single unit by the cross shaft 32. The pinions 33 mesh with the left gear 34 and the right gear 35 within the differential housing 23.

[0067] The left gear 34 and the right gear 35 are respectively disposed within the differential housing 23. The left and right side gears 34 and 35 are paired in the left-right direction, separated by the cross shaft 32. In this embodiment, the right gear 35 constitutes one of the left and right side gears 34 and 35. The left and right side gears 34 and 35 are each composed of bevel gears and mesh with the four pinions 33 supported by the cross shaft 32. A thrust plate 34A is provided between the left gear 34 and the first housing 25 to reduce wear on the first housing 25. A thrust plate 35A is provided between the right gear 35 and the third housing 27 to reduce wear on the third housing 27. Furthermore, a shaft spline portion 35B is formed on the outer peripheral surface of the right gear 35, and a hole spline portion 35C is formed on the inner peripheral surface of the right gear 35.

[0068] The left drive shaft 36 is connected to the left gear 34. The right drive shaft 37 is connected to the right gear 35. The left drive shaft 36 and the right drive shaft 37 are arranged in pairs on axis XX. The left drive shaft 36 transmits the rotation of the differential housing 23 to the left axle shaft 19L via the planetary gear reduction mechanism 54L, and the right drive shaft 37 transmits the rotation of the differential housing 23 to the right axle shaft 19R via the planetary gear reduction mechanism 54R.

[0069] The base end of the left drive shaft 36 is splinedly engaged with the inner circumferential side of the left gear 34. The left drive shaft 36 extends through the left partition 14B of the differential body 14 into the left axle housing 15L. A sun gear 36A constituting the planetary gear reduction mechanism 54L is integrally formed at the front end of the left drive shaft 36. On the other hand, a shaft spline portion 37A is provided at the base end of the right drive shaft 37, and the shaft spline portion 37A is splinedly engaged with the hole spline portion 35C of the right gear 35. The right drive shaft 37 extends through the right partition 14C of the differential body 14 into the right axle housing 15R, and a sun gear 37B constituting the planetary gear reduction mechanism 54R is integrally formed at the front end of the right drive shaft 37.

[0070] A plurality of rotating disks 38 and a plurality of non-rotating disks 39 are provided between the inner circumferential surface 26K of the second housing 26 constituting the differential housing 23 and the shaft spline portion 35B of the right gear 35. The plurality of rotating disks 38 and the plurality of non-rotating disks 39 are each composed of annular plates and are arranged alternately overlapping in the axial direction.

[0071] The inner circumferential side of the rotating disk 38 is splinedly engaged with the splined portion 35B of the right gear 35. Therefore, the rotating disk 38 can rotate relative to the differential housing 23 together with the right gear 35 in a state where it can move axially along the right gear 35. Figure 10 As shown, four semi-circular protrusions 39A protruding radially outward are formed at 90° intervals on the outer periphery of the non-rotating disc 39. These protrusions 39A engage with grooves 26L formed on the inner peripheral surface 26K of the second housing 26. Therefore, the non-rotating disc 39 is held in a non-rotatable state relative to the differential housing 23, while being able to move axially in the differential housing 23.

[0072] The pressure plate 40 is located inside the differential housing 23 and is positioned between the third housing 27 and the non-rotating disc 39. For example... Figure 11 As shown, the pressing plate 40 is composed of an annular plate body, and four semi-circular protrusions 40A protruding radially outward are provided at 90° intervals on the outer periphery of the pressing plate 40. These four semi-circular protrusions 40A engage with the grooves 26L of the second housing 26. Therefore, the pressing plate 40 rotates integrally with the differential housing 23 in a state where it can move axially along the grooves 26L. Furthermore, on the outer periphery of the pressing plate 40, and at a position different from the semi-circular protrusions 40A, four rectangular protrusions 40B protruding radially outward are provided at 90° intervals. These four rectangular protrusions 40B engage (abut) with the engaging recesses 26H of the second housing 26, thereby limiting the amount of movement of the pressing plate 40 towards the rotating disk 38.

[0073] The right retainer 41 is mounted in the through hole 14D of the right partition 14C that constitutes the differential body 14. The right retainer 41 constitutes a retainer located on the side of the right-side gear 35. (As...) Figure 5 and Figure 12 As shown, the right retainer 41 has a stepped cylindrical portion 41A that engages with the through hole 14D, and a convex edge portion 41B that is larger in diameter than the cylindrical portion 41A. Multiple bolt insertion holes 41C are formed around the entire circumference of the convex edge portion 41B of the right retainer 41. Bolts 22 are inserted into the bolt insertion holes 41C, and the bolts 22 are threaded into threaded holes 14J provided in the right partition wall 14C of the differential body 14 (see reference). Figure 18 Thus, the right retainer 41 is installed on the right partition wall 14C in such a state that the cylindrical portion 41A is engaged with the through hole 14D.

[0074] A piston receiving portion 41D with two stepped sections is formed on the outer peripheral surface of the cylindrical portion 41A constituting the right retainer 41. The piston receiving portion 41D is composed of a large-diameter stepped portion 41E and a small-diameter stepped portion 41F that are adjacent in the axial direction, and the piston 46 described above is mounted thereon. An annular groove 41G is provided on the outer peripheral surface of the large-diameter stepped portion 41E, and an annular groove 41H is provided on the outer peripheral surface of the small-diameter stepped portion 41F. O-rings 42 are respectively installed in the annular grooves 41G and 41H to liquidally seal the piston 46 and the right retainer 41 (piston receiving portion 41D). A circumferential groove 41K is formed on the end face 41J of the piston receiving portion 41D located at the boundary between the large-diameter stepped portion 41E and the small-diameter stepped portion 41F. A hydraulic chamber 47 is formed between the circumferential groove 41K and the piston 46, and the retainer-side oil passage 51B described above opens at the bottom of the circumferential groove 41K. Furthermore, a plurality of (e.g., four) pin holes 41L are provided at the bottom of the circumferential groove 41K. The aforementioned pin holes 41L are arranged at 90° intervals and fit one end of the pin 48 described below. In addition, a nut 41M is threadedly engaged on the inner circumferential side of the right retainer 41. The nut 41M applies axial pressure to the bearing 24B between itself and the cylindrical portion 27A of the third housing 27.

[0075] A pressure ring 43 is disposed between the pressing plate 40 and the piston 46. The pressure ring 43 is pressed by the piston 46 and moves axially upwards, pressing the rotating disk 38 towards the non-rotating disk 39 via the pressing plate 40. Figure 4 and Figure 13 As shown, the pressure ring 43 is formed as an annular body with an outer diameter smaller than that of the protruding edge 27B of the third housing 27. Four protrusions 43A are provided at 90° intervals on the outer periphery of the pressure ring 43, protruding radially outward. Each of the four protrusions 43A has a pin insertion hole 43B, which corresponds to a threaded hole 27E formed in the protruding edge 27B of the third housing 27.

[0076] Furthermore, a plurality of (e.g., eight) rectangular protrusions 43D are provided on the end face 43C of the pressure ring 43 that faces the third housing 27 axially and at a position corresponding to the rectangular hole 27F of the third housing 27. These rectangular protrusions 43D are inserted into the rectangular hole 27F of the third housing 27, with their front ends abutting against the pressing plate 40. On the inner circumferential side of the rectangular protrusions 43D, a stepped lever component receiving recess 43E is formed by cutting the inner circumferential surface of each protrusion from its front end toward the end face 43C. The lever component receiving recess 43E receives the lever component 53 (see reference 53). Figure 5 ).

[0077] Four pins 44 are provided on the protruding edge 27B of the third housing 27. Each pin 44 has a threaded portion 44A, which is threaded into a threaded hole 27E in the protruding edge 27B. The pins 44 protrude axially from the protruding edge 27B toward the right retainer 41 and are inserted into a pin insertion hole 43B in the protrusion 43A of the pressure ring 43. Furthermore, a retaining ring 45 is installed on the outer periphery of each pin 44. Therefore, the pressure ring 43 is guided axially by the pins 44 while being prevented from disengaging axially by the retaining ring 45.

[0078] The piston 46, acting as an actuator, is disposed in the piston receiving portion 41D of the right retainer 41. For example... Figure 14 and Figure 15 As shown, the piston 46 is formed as a stepped cylinder having a large-diameter cylindrical portion 46A and a small-diameter cylindrical portion 46B. An annular inner diameter protrusion 46C extending radially inward is provided on the inner circumferential side of the boundary between the large-diameter cylindrical portion 46A and the small-diameter cylindrical portion 46B. The outer diameter of the large-diameter cylindrical portion 46A is set to be equal to the outer diameter of the cylindrical portion 41A of the right retainer 41, and the inner circumferential surface 46D of the large-diameter cylindrical portion 46A can slidably engage with the outer circumferential surface of the large-diameter stepped portion 41E of the right retainer 41. The inner circumferential surface 46E of the inner diameter protrusion 46C can slidably engage with the outer circumferential surface of the small-diameter stepped portion 41F of the right retainer 41.

[0079] Thus, the right retainer 41 is provided with a piston housing portion 41D consisting of a large-diameter stepped portion 41E and a small-diameter stepped portion 41F, both with an outer diameter smaller than that of the cylindrical portion 41A. The piston 46 is assembled into the piston housing portion 41D of the right retainer 41. Therefore, the outer diameter of the large-diameter cylindrical portion 46A of the piston 46 is equal to that of the cylindrical portion 41A of the right retainer 41. Thus, with the piston 46 assembled into the piston housing portion 41D of the right retainer 41, the piston 46 can be inserted into the through hole 14D formed in the right partition wall 14C of the differential body 14. Furthermore, by fixing the right retainer 41 to the right partition wall 14C, the piston 46 can abut against the pressure ring 43 via the thrust bearing 49 described below.

[0080] The end face of the piston 46 on the side of the small-diameter cylindrical portion 46B in the inner diameter protrusion 46C forms an annular pressing surface 46F. The pressing surface 46F presses against the end face of the pressure ring 43 to apply a load. The end face 46G on the side opposite to the pressing surface 46F (the side of the large-diameter cylindrical portion 46A) in the inner diameter protrusion 46C abuts against the end face 41J of the right retainer 41. As a result, an annular hydraulic chamber 47 is formed circumferentially between the end face 46G of the piston 46 and the circumferential groove 41K formed on the end face 41J of the right retainer 41 (piston housing portion 41D). Therefore, by supplying pressurized oil to the hydraulic chamber 47, the piston 46 moves axially and applies a load to the pressure ring 43.

[0081] Four pin holes 46H are formed at 90° intervals on the end face 46G of the piston 46. These pin holes 46H correspond to the pin holes 41L formed in the circumferential groove 41K of the right retainer 41. One end of a pin 48 is fitted into the pin hole 41L of the right retainer 41, and the other end of the pin 48 is fitted into the pin hole 46H of the piston 46. Thus, the piston 46 can move axially in a state where it is prevented from rotating relative to the piston housing portion 41D of the right retainer 41. On the other hand, four pin holes 46J are formed at 90° intervals on the pressing surface 46F of the piston 46.

[0082] An annular thrust bearing 49 is provided between the pressing surface 46F of the piston 46 and the pressure ring 43. Four pins 50 are inserted through the thrust bearing 49, and the pins 50 engage with the pin holes 46J of the piston 46. Thus, the thrust bearing 49 is radially positioned relative to the piston 46 and prevents rotation relative to the piston 46. Therefore, the piston 46 presses against the pressure ring 43 via the thrust bearing 49 to suppress friction between the piston and the pressure ring 43.

[0083] Oil passage 51 is provided in the right partition 14C and right retainer 41 of the differential body 14, supplying discharge pressure oil (hydraulic pressure) to the hydraulic chamber 47. Oil passage 51 consists of a partition-side oil passage 51A formed in the right partition 14C and a retainer-side oil passage 51B formed in the right retainer 41. The inlet of oil passage 51 (partition-side oil passage 51A) opens on the outer peripheral surface of the differential body 14, and the outlet of oil passage 51 (retainer-side oil passage 51B) opens in the circumferential groove 41K of the end face 41J of the piston receiving portion 41D formed in the right retainer 41. A hydraulic source (not shown) is connected to the inlet of partition-side oil passage 51A, and pressure oil ejected from this hydraulic source is supplied to the hydraulic chamber 47 through partition-side oil passage 51A and retainer-side oil passage 51B.

[0084] An annular sealing groove 41N is formed on the end face of the protruding edge 41B of the right retainer 41 that abuts against the right partition wall 14C of the differential body 14, surrounding the oil passage 51B on the retainer side (see reference). Figure 12 An O-ring 51C is installed in the sealing mounting groove 41N in such a way that it surrounds the connection between the partition-side oil passage 51A and the retainer-side oil passage 51B. The O-ring 51C liquid-tightly seals the connection between the partition-side oil passage 51A and the retainer-side oil passage 51B.

[0085] Exhaust passage 52 is located between the right partition 14C and the right retainer 41 of the differential body 14. Exhaust passage 52 is a passage for venting air from the hydraulic chamber 47 to the outside when the piston 46 is assembled in the piston housing 41D of the right retainer 41. Figure 18As shown, the exhaust passage 52 is composed of a partition-side passage 52A formed in the right partition 14C and a retainer-side passage 52B formed in the right retainer 41. One end of the exhaust passage 52 (retainer-side passage 52B) opens at the bottom of the circumferential groove 41K formed in the piston housing portion 41D of the right retainer 41. The other end of the exhaust passage 52 (partition-side passage 52A) opens on the outer peripheral surface of the differential body 14. Thus, when the piston 46 is assembled in the piston housing portion 41D of the right retainer 41, air in the hydraulic chamber 47 is discharged to the outside through the retainer-side passage 52B and the partition-side passage 52A, thereby enabling smooth assembly of the piston 46.

[0086] An annular sealing groove 41P is formed on the end face of the protruding edge 41B of the right retainer 41 that abuts against the right partition wall 14C of the differential body 14, surrounding the retainer-side passage 52B. An O-ring (not shown) is installed in the sealing groove 41P in such a way that it surrounds the connection between the partition wall-side passage 52A and the retainer-side passage 52B, and the O-ring provides an airtight seal to the connection between the partition wall-side passage 52A and the retainer-side passage 52B. Furthermore, after the piston 46 is assembled, the other end of the partition wall-side passage 52A is sealed by a sealing plug (not shown).

[0087] Next, the lever component 53 used in this embodiment will be described.

[0088] Multiple (e.g., four) lever components 53 are provided between the third housing 27 of the differential housing 23, the right-side gear 35, and the pressure ring 43. Figure 16 As shown, the lever member 53 is formed as a trapezoidal plate with a narrower width at one end 53A and a wider width at the other end 53B in the longitudinal direction. The middle portion of the lever member 53 in the longitudinal direction is bent into a mountain shape, and this middle portion 53C in the longitudinal direction becomes a convex portion corresponding to the bent shape. For example... Figure 5 and Figure 17 As shown, the four lever components 53 are housed in the lever component receiving groove 27G and the lever component receiving recess 43E of the pressure ring 43 in the rectangular hole 27F of the third housing 27, with the rectangular protrusion 43D of the pressure ring 43 combined in the rectangular hole 27F of the third housing 27.

[0089] In this state, one end 53A of the lever member 53 abuts (contacts) with the lever member receiving groove 27G, and the other end 53B of the lever member 53 abuts (contacts) with the lever member receiving recess 43E. Furthermore, the middle portion 53C of the lever member 53 abuts (contacts) with the thrust plate 35A of the right-side gear 35. Figure 17As shown, the portion of one end 53A of the lever member 53 that abuts against the lever member receiving groove 27G becomes the first abutting part F, which constitutes the fulcrum of the lever member 53. The portion of the middle part 53C of the lever member 53 that abuts against the thrust plate 35A becomes the second abutting part E, which constitutes the force point of the lever member 53. The portion of the other end 53B of the lever member 53 that abuts against the lever member receiving recess 43E becomes the third abutting part A, which constitutes the point of action of the lever member 53. Here, the distance between the first abutting part F and the second abutting part E in the direction orthogonal to the axis XX is Le. On the other hand, the distance between the first abutting part F and the third abutting part A in the direction orthogonal to the axis XX is La, and the distance La is greater than the distance Le (La > Le). The second abutting part E and the third abutting part A of the lever member 53 can move in the direction of the axis XX with the first abutting part F as the fulcrum.

[0090] By supplying pressurized oil to the hydraulic chamber 47, the piston 46 presses the pressure ring 43 against the press plate 40 with a load Fp corresponding to the pressure of the pressurized oil. On the other hand, the reaction force (meshing reaction force) generated by the meshing of the right gear 35 and the pinion 33 applies a load Fm to the right gear 35 toward the piston 46. As a result, a load Fe is applied to the second abutment portion E of the lever member 53 toward the piston 46. When the right gear 35 moves axially along the right drive shaft 37, a frictional force Fs1 or Fs2 is generated between the hole spline portion 35C and the shaft spline portion 37A of the right drive shaft 37. Therefore, the load Fe acting on the second abutment portion E of the lever member 53 varies according to the direction of the frictional force, i.e., whether the frictional force is Fs1 or Fs2.

[0091] The load Fe acting on the second abutment portion E of the lever member 53 generates a load Fa towards the piston 46 at the third abutment portion A of the lever member 53 (the other end 53B). This load Fa is a load converted from the load Fe at a ratio corresponding to the distance Le between the first abutment portion F and the second abutment portion E of the lever member 53 and the distance La between the first abutment portion F and the third abutment portion A. Moreover, the load Fa acts in the opposite direction to the load Fp acting on the pressure ring 43 from the piston 46. Therefore, the load Fen of the pressure ring 43 (rectangular protrusion 43D) pressing the rotating disk 38 via the pressing plate 40 reduces the amount of load Fa acting on the third abutment portion A of the lever member 53 relative to the load Fp acting on the pressure ring 43 from the piston 46. That is, the lever member 53 controls the load applied to the pressure ring 43 from the piston 46 by transmitting the meshing reaction force of the right gear 35 and the pinion 33 to the pressure ring 43.

[0092] Here, when the load Fp acting on the pressure ring 43 from the piston 46 is greater than the load Fa acting on the third abutment portion A of the lever member 53, the pressure ring 43 displaces towards the pressing plate 40. At this time, the third abutment portion A of the lever member 53 displaces towards the pressing plate 40 by a displacement Da, and the second abutment portion E of the lever member 53 also displaces towards the pressing plate 40 by a displacement De. This displacement De is a displacement amount converted from the displacement amount Da by a ratio corresponding to the distance Le between the first abutment portion F and the second abutment portion E of the lever member 53 and the distance La between the first abutment portion F and the third abutment portion A. As a result, the right gear 35 is pressed by the second abutment portion E of the lever member 53 and displaces towards the pinion 33 by a displacement De.

[0093] On the other hand, if the supply of pressurized oil to the hydraulic chamber 47 is stopped, the load Fm acting on the right gear 35 presses the second abutment portion E of the lever member 53 towards the piston 46. As a result, the second abutment portion E of the lever member 53 displaces towards the piston 46 by a displacement De, and the right gear 35 also displaces towards the piston 46 by a displacement De. Consequently, the third abutment portion A of the lever member 53 displaces towards the piston 46 by a displacement Da, accompanying the displacement of the second abutment portion E of the lever member 53. Thus, the right gear 35 repeatedly undergoes axial displacement according to the meshing reaction force with the pinion 33 and the load applied from the piston 46.

[0094] When pressurized oil is supplied to the hydraulic chamber 47 and a load Fp is applied to the pressure ring 43 from the piston 46, a load Fen is applied to the press plate 40 from the pressure ring 43 (rectangular protrusion 43D). As a result, the rotating disk 38 and the non-rotating disk 39 are pressed by the press plate 40, creating frictional contact between the second housing 26 and the piston 46. Therefore, when the torque difference between the left axle shaft 19L and the right axle shaft 19R is less than the torque capacity that can be transmitted through the frictional contact between the rotating disk 38 and the non-rotating disk 39, the differential mechanism 20 is locked. Consequently, the left gear 34 and the right gear 35 rotate integrally with the differential housing 23, transmitting torque to the left axle shaft 19L and the right axle shaft 19R, respectively.

[0095] On the other hand, when the supply of pressurized oil to the hydraulic chamber 47 is stopped, the load Fp acting on the pressure ring 43 from the piston 46 is 0. In this state, when a driving torque is applied to the input shaft 17, a load Fm is applied to the right gear 35 by the reaction force generated by the meshing with the pinion 33. The load Fm is designed to be greater than the frictional force Fs1 or Fs2 between the right drive shaft 37 and the right gear 35. Therefore, a load Fe is applied to the piston 46 side from the second abutment portion E of the lever member 53 from the thrust plate 35A, and a load Fa is applied to the pressure ring 43 to the piston 46 side from the third abutment portion A of the lever member 53. As a result, the piston 46 moves away from the pressure plate 40, releasing the frictional contact between the rotating disk 38 and the non-rotating disk 39. Therefore, the right gear 35 can rotate relative to the differential housing 23, and the difference in friction between the left and right front wheels 5 and the road surface is distributed to the left front wheel 5 and the right front wheel 5 by the difference in the rotational force of the engine 7.

[0096] Here, the lever ratio iL of the lever member 53 is determined by the following formula 1, based on the distance La from the first abutment part F to the third abutment part A and the distance Le from the first abutment part F to the second abutment part E of the lever member 53. This lever ratio iL is uniquely determined by the shape of the lever member 53, and the load and displacement of the second abutment part E and the third abutment part A can be varied according to this lever ratio iL.

[0097] Formula 1

[0098]

[0099] One end 53A of the lever component 53 abuts against the third housing 27 at the first abutment portion F. The other end 53B of the lever component 53 abuts against the pressure ring 43 at the third abutment portion A. The middle portion 53C of the lever component 53 abuts against the thrust plate 35A of the right gear 35 at the second abutment portion E. Therefore, the load Fe acting on the second abutment portion E of the lever component 53 is calculated as the resultant force of the load Fm and the frictional force Fs1 or Fs2.

[0100] When pressurized oil is supplied to the hydraulic chamber 47 with the driving torque of the input shaft 17 being 0 (zero), the frictional force becomes the frictional force Fs1 in the opposite direction to the load Fm when the driving torque is generated (hereinafter referred to as condition 1). Therefore, the load Fe is calculated by the following equation 2.

[0101] Formula 2

[0102] Fe=Fm-Fs1

[0103] On the other hand, when the driving torque of the input shaft 17 is generated, pressurized oil is supplied to the hydraulic chamber 47. When the driving torque increases (hereinafter referred to as condition 2), the frictional force becomes the frictional force Fs2 in the same direction as the load Fm. Therefore, the load Fe is calculated by the following equation 3.

[0104] Formula 3

[0105] Fe=Fm+Fs2

[0106] At this time, the load Fa acting on the pressure ring 43 from the third abutment part A of the lever component 53 is calculated according to the lever ratio iL of the lever component 53 and the load Fe by the following formula 4.

[0107] Formula 4

[0108]

[0109] The load Fen of the pressure ring 43 pressing the rotating disk 38 via the pressing plate 40 is calculated based on the load Fp acting on the pressure ring 43 from the piston 46 and the load Fa acting on the pressure ring 43 from the third abutment part A of the lever member 53, and is given by the following formula 5.

[0110] Formula 5

[0111] Fen = Fp - Fa

[0112] When a load Fen is applied to the pressing plate 40 from the pressure ring 43, the displacement De of the second abutment part E of the lever member 53 in the axial direction is calculated based on the displacement Da of the third abutment part A of the lever member 53 and the lever ratio iL of the lever member 53 by the following formula 6.

[0113] Formula 6

[0114]

[0115] The planetary gear reduction mechanism 54L on the left side is located in the reducer chamber 15B of the left axle housing 15L (see reference). Figure 3 The planetary gear reduction mechanism 54L consists of a sun gear 36A, a ring gear 55, multiple planetary gears 56, and a planetary gear carrier 57, all integrally formed on the front end side of the left drive shaft 36. The ring gear 55 is located on the inner circumference of the left axle housing 15L (cylindrical portion 15A). The multiple planetary gears 56 are rotatably supported by the planetary gear carrier 57 and mesh with the sun gear 36A and the ring gear 55. The planetary gear carrier 57 is splined into the left axle shaft 19L. Therefore, the rotation of the left drive shaft 36 is transmitted to the left axle shaft 19L in a state reduced by the planetary gear reduction mechanism 54L.

[0116] The planetary gear reduction mechanism 54R on the right side is located within the reducer chamber 15B of the right axle housing 15R. Similar to the planetary gear reduction mechanism 54L on the left side, the planetary gear reduction mechanism 54R consists of a sun gear 37B integrally formed on the front end side of the right drive shaft 37, a ring gear 55, multiple planetary gears 56, and a planetary gear carrier 57. The planetary gear carrier 57 is splined into the right axle shaft 19R. Therefore, the rotation of the right drive shaft 37 is transmitted to the right axle shaft 19R in a state reduced by the planetary gear reduction mechanism 54R.

[0117] The left-side braking mechanism 58L is located within the left brake chamber 14F of the differential body 14. The braking mechanism 58L may be configured as, for example, a wet multi-plate type braking mechanism. Figure 4 As shown, the braking mechanism 58L consists of multiple brake discs 60, brake pads 61, and brake pistons 62 splined together on the outer periphery of the left drive shaft 36 via a hub 59. The brake discs 60 rotate integrally with the left drive shaft 36. The brake pads 61 are arranged facing the brake discs 60 and remain in a non-rotating state relative to the differential body 14. Furthermore, the brake pistons 62 apply braking force to the left drive shaft 36 by pressing the brake pads 61 against the brake discs 60 using external hydraulic pressure.

[0118] The right-side braking mechanism 58R is located within the right brake chamber 14G of the differential body 14. Similar to the left-side braking mechanism 58L, the braking mechanism 58R consists of multiple brake discs 60, brake pads 61, and a brake piston 62 splined together via bushings 59 on the outer periphery of the right drive shaft 37. Furthermore, the brake piston 62 applies braking force to the right drive shaft 37 by pressing the brake pads 61 against the brake discs 60 using external hydraulic pressure.

[0119] The front axle assembly 12 of this embodiment has the structure described above. Hereinafter, the operation of the front axle assembly 12 when the wheel loader 1 is in motion will be explained.

[0120] If the driver in the cab 10 operates the engine 7, the rotational force of the engine 7 is transmitted to the input shaft 17 via the drive shaft 9B of the transmission 9. The rotation of the input shaft 17 is transmitted from the drive pinion 17B to the gear ring 30 of the differential mechanism 20, thereby rotating the differential housing 23 on which the gear ring 30 is mounted.

[0121] Four shafts 32A of the cross shaft 32 are held between the recess 25H of the first housing 25 and the recess 26E of the second housing 26 that constitute the differential housing 23. Therefore, the cross shaft 32 rotates together with the differential housing 23 while the four pinions 33 are supported by the four shafts 32A.

[0122] With the supply of pressurized oil to the hydraulic chamber 47 stopped, the load Fp applied from the piston 46 to the pressure ring 43 is 0. In this state, when a driving torque is applied to the input shaft 17, the meshing reaction force of the pinion 33 and the right gear 35 applies a load Fm towards the piston 46 to the right gear 35. The load Fm is designed to be greater than the frictional force Fs1 or Fs2 between the right drive shaft 37 and the right gear 35. Therefore, a load Fe is applied towards the piston 46 from the second abutment portion E of the lever member 53 from the thrust plate 35A. Simultaneously, a load Fa is applied towards the piston 46 from the third abutment portion A of the lever member 53 to the pressure ring 43. As a result, the piston 46 moves away from the pressing plate 40, and the rotating disk 38 and the non-rotating disk 39 remain in a non-contact state.

[0123] Therefore, the differential housing 23 rotates together with the pinion 33, and the left gear 34 and right gear 35, which mesh with the pinion 33, also rotate. The rotation of the left drive shaft 36, which is splinedly engaged with the left gear 34, is transmitted to the left axle 19L in a state reduced by the planetary gear reduction mechanism 54L. Similarly, the rotation of the right drive shaft 37, which is splinedly engaged with the right gear 35, is transmitted to the right axle 19R in a state reduced by the planetary gear reduction mechanism 54R. As a result, the left and right front wheels 5 are simultaneously driven by rotation.

[0124] When the wheel loader 1 is traveling straight, with the friction between the left front wheel 5 and the road surface equal to that between the right front wheel 5 and the road surface, the left gear 34 and the right gear 35 rotate integrally with the differential housing 23. As a result, the rotational force of the engine 7 is evenly transmitted to the left and right front wheels 5, enabling the wheel loader 1 to travel straight. On the other hand, when the wheel loader 1 is turning, with the friction between the left front wheel 5 and the road surface different from that between the right front wheel 5 and the road surface, the left gear 34 and the right gear 35 rotate at different speeds. Thus, the rotational force of the engine 7 is distributed to the left and right front wheels 5 according to the difference in friction between the left and right front wheels 5 and the road surface, enabling the wheel loader 1 to turn.

[0125] Here, when the wheel loader 1 is traveling, and the road surface conditions contacted by the left and right front wheels 5 are different, the differential mechanism 20 is needed to prevent one of the left and right front wheels 5 from spinning freely.

[0126] In this case, differential limiting of the differential mechanism 20 is achieved, for example, by operating the foot pedals, manual switches, etc. (not shown) located in the cab 10, or by a calculation device that measures or predicts the freewheeling of the left and right front wheels 5. That is, pressurized oil from the hydraulic source is supplied to the hydraulic chamber 47 through the partition side oil passage 51A and the retainer side oil passage 51B.

[0127] In this embodiment, the differential limiting characteristics differ when pressure oil is supplied to the hydraulic chamber 47 after the driving torque of the input shaft 17 is 0 (zero) (stop state) (condition 1) and when pressure oil is supplied to the hydraulic chamber 47 after the driving torque of the input shaft 17 is generated (driving state) and the driving torque increases (condition 2).

[0128] Under condition 1, the load Fm acting on the right gear 35 is 0, and the frictional force Fs1 between the right gear 35 and the right drive shaft 37 is 0. In this state, using the pressurized oil supplied to the hydraulic chamber 47, the piston 46 applies a load Fp to the pressure ring 43. According to equations 2, 4, and 5 above, the load Fen acting on the pressing plate 40 from the pressure ring 43 is greater than 0 (Fen > 0). Therefore, the pressure ring 43 uses the thrust of the piston 46 to press the pressing plate 40. As a result, the rotating disk 38 and the non-rotating disk 39 come into frictional contact, generating a clutch transmission torque corresponding to the load Fen between the rotating disk 38 and the non-rotating disk 39.

[0129] At this time, the third abutting part A of the lever component 53, which abuts against the pressure ring 43, and the second abutting part E, which abuts against the thrust plate 35A of the right gear 35, are displaced towards the pinion 33. The aforementioned Equation 6 holds true between the displacement amount of the third abutting part A of the lever component 53 (i.e., the displacement amount of the pressure ring 43) Da and the displacement amount of the second abutting part E of the lever component 53 (i.e., the displacement amount of the right gear 35). Thus, when pressurized oil is supplied to the hydraulic chamber 47 with a driving torque of 0, the right gear 35 is displaced towards the pinion 33 by the displacement amount De.

[0130] Next, with the right gear 35 displaced towards the pinion 33, and the driving torque generated by the input shaft 17 (when the wheel loader 1 is in motion), a load Fm, generated by the meshing reaction force with the pinion 33, acts on the right gear 35. This load Fm is directly proportional to the driving torque. Furthermore, since the right gear 35 intends to displace towards the piston 46 due to the load Fm, a frictional force Fs1, acting in the opposite direction to the load Fm, acts between the right gear 35 and the right drive shaft 37. Therefore, the load Fe acting on the second contact portion E of the lever member 53 is calculated using Equation 2 above.

[0131] Here, the load Fm is designed to be larger than the frictional force Fs1 (Fm > Fs1) and is proportional to the driving torque. Furthermore, the load Fp acting from the piston 46 on the pressure ring 43 is always a constant value. Therefore, the load Fe acting from the right gear 35 (thrust plate 35A) on the second abutment portion E of the lever member 53 is directly proportional to the driving torque, while the load Fen acting from the pressure ring 43 on the pressing plate 40 is inversely proportional to the driving torque. The clutch transmission torque generated between the rotating disk 38 and the non-rotating disk 39 is generated accordingly with the load Fen. Therefore, the torque capacity (the value obtained by multiplying the clutch transmission torque by the reduction ratio of the left and right planetary gear reduction mechanisms 54L and 54R) decreases as the driving torque increases.

[0132] On the other hand, under condition 2, with the right gear 35 positioned on the piston 46 side due to the load Fm generated by the meshing reaction force between it and the pinion 33, a load Fp from the piston 46 acts on the pressure ring 43. Consequently, the right gear 35 is pressed by the pressure ring 43 and attempts to displace towards the pinion 33. At this time, a frictional force Fs2 acts between the right gear 35 and the right drive shaft 37 in the same direction as the load Fm. Therefore, the load Fe acting from the right gear 35 on the second contact portion E of the lever member 53 is calculated using Equation 3 above.

[0133] Here, the load Fm is designed to be larger than the friction force Fs2 (Fm > Fs2) and is proportional to the driving torque. Therefore, the load Fe is directly proportional to the driving torque, and the load Fen is inversely proportional to the driving torque. Since the clutch transmission torque generated by the rotating disk 38 and the non-rotating disk 39 is generated accordingly with the load Fen, the torque capacity decreases as the driving torque increases.

[0134] Thus, under condition 1, the direction of the load Fm is opposite to the direction of the frictional force Fs1. As a result, the clutch-transmitted torque decreases slowly (sluggishly) relative to the increase in drive torque. On the other hand, under condition 2, the direction of the load Fm is the same as the direction of the frictional force Fs2. As a result, the clutch-transmitted torque decreases rapidly (sensitively) relative to the increase in drive torque.

[0135] Figure 19 This shows the relationship between the differential torque and the total output shaft torque under condition 1. The differential torque is the torque difference between the left axle shaft 19L and the right axle shaft 19R. The total output shaft torque is the sum of the torques of the left axle shaft 19L and the right axle shaft 19R. Figure 19In the diagram, the short dashed characteristic line represents the differential torque TA1 generated by load Fp, and the single-dotted characteristic line represents the differential torque TB1 generated by load Fm. Furthermore, the double-dotted characteristic line represents the differential torque TC1 generated by frictional force Fs1, and the solid characteristic line represents the differential torque TD1. Figure 19 Point C in the diagram indicates the point where the maximum torque capacity transmitted by the rotating disk 38 and the non-rotating disk 39 is equal to the total torque of the output shaft. Under condition 1, the load Fm becomes a load in the opposite direction relative to the load Fp, and the frictional force Fs1 becomes a load in the same direction. Therefore, the torque capacity TV1 obtained by the rotating disk 38 and the non-rotating disk 39 is calculated by the following equation 7 and is represented by the characteristic line with a long dashed line.

[0136] Formula 7

[0137] TV1 = TA1 - TB1 + TC1

[0138] Because the hydraulic pressure supplied to the hydraulic chamber 47 is constant, the differential torque TA1 generated by the load Fp remains constant throughout the entire region. Since the load Fm is proportional to the total output shaft torque, the differential torque TB1 generated by the load Fm increases as the total output shaft torque increases. The differential torque TC1 generated by the frictional force Fs1 increases rapidly up to point C, resulting in a large inclination; beyond point C, the inclination decreases accordingly as the differential torque decreases. On the other hand, since the differential torque TD1 in the region below point C is (torque capacity) > (total output shaft torque), the relationship TD1 = (total output shaft torque) is maintained. In the region above point C, (torque capacity) < (total output shaft torque), and the rotating disk 38 and non-rotating disk 39 slide out. Therefore, the differential torque TD1 = (torque capacity). That is, after point C, the load Fm increases with the increase of the total output shaft torque, therefore the torque capacity TV1 decreases, and the differential torque TD1 also decreases.

[0139] Figure 20 The relationship between the output shaft torque and the total output shaft torque is shown under condition 1. Figure 20 In the diagram, solid characteristic line 63 shows the output shaft torque on the high torque side of the differential mechanism 20 in this embodiment, and dashed characteristic line 64 shows the output shaft torque on the low torque side. Furthermore, single-dotted characteristic line 65 shows the output shaft torque on the high torque side of the differential mechanism (hereinafter referred to as the comparative example) equipped with a general torque proportional differential limiting device, and double-dotted characteristic line 66 shows the output shaft torque on the low torque side.

[0140] In this embodiment, the differential mechanism 20 is locked up (differential lock-up state) until the total output shaft torque reaches point C (the point where the maximum torque capacity equals the total output shaft torque). Therefore, from point C to point C, the output shaft torque (high torque side) shown by characteristic line 63 is equal to the total output shaft torque, and the output shaft torque (low torque side) shown by characteristic line 64 is 0. On the other hand, if the total output shaft torque exceeds point C, the rotating disk 38 and the non-rotating disk 39 slide out, so the slope of the output shaft torque (high torque side) shown by characteristic line 63 becomes smaller. Since the differential torque gradually decreases if it exceeds point C, the slope of the output shaft torque (high torque side) becomes smaller and rises while maintaining this small slope.

[0141] Next, Figure 21 The relationship between the differential torque and the total torque of the output shaft is shown under condition 2. Figure 21 In the diagram, the short dashed characteristic line represents the differential torque TA2 generated by load Fp, and the single-dotted characteristic line represents the differential torque TB2 generated by load Fm. Furthermore, the double-dotted characteristic line represents the differential torque TC2 generated by frictional force Fs2, and the solid characteristic line represents the differential torque TD2. Figure 21 Point C in the diagram indicates the point where the maximum torque capacity transmitted by the rotating disk 38 and the non-rotating disk 39 is equal to the total torque of the output shaft. Under condition 2, the load Fm and the frictional force Fs2 become loads in opposite directions relative to the load Fp. Therefore, the torque capacity TV2 formed by the rotating disk 38 and the non-rotating disk 39 is calculated by the following equation 8 and is represented by the characteristic line with a long dashed line.

[0142] Formula 8

[0143] TV2 = TA2-TB2-TC2

[0144] Under condition 2, the frictional force Fs2 acts in the opposite direction to the load Fp, thus reducing the differential torque. Therefore, compared to condition 1, under condition 2, the maximum differential torque is smaller, and point C, where the maximum torque capacity equals the total output shaft torque, is also smaller than under condition 1. In the region where the total output shaft torque exceeds point C, the rotating disk 38 and the non-rotating disk 39 slide out. After point C, since the load Fm increases with the increase of the total output shaft torque, the torque capacity TV2 decreases, and the differential torque TD2 also decreases. Moreover, regarding the load Fen, if it exceeds point D, Fen < 0, and even if hydraulic pressure is supplied to the hydraulic chamber 47, the piston 46 remains stationary, thus the differential torque TD2 remains 0.

[0145] Figure 22 The relationship between the output shaft torque and the total output shaft torque is shown under condition 2. Figure 22In the diagram, solid characteristic line 67 shows the output shaft torque on the high torque side of the differential mechanism 20 in this embodiment, and dashed characteristic line 68 shows the output shaft torque on the low torque side. Furthermore, single-dotted characteristic line 69 shows the output shaft torque on the high torque side of the differential mechanism (hereinafter referred to as the comparative example) equipped with a general torque proportional differential limiting device, and double-dotted characteristic line 70 shows the output shaft torque on the low torque side.

[0146] In this embodiment, the differential mechanism 20 is locked (differential locked state) from the point where the total output shaft torque is 0 to point C. Therefore, from point C to point C, the output shaft torque (high torque side) shown by characteristic line 67 is equal to the total output shaft torque, and the output shaft torque (low torque side) shown by characteristic line 68 is 0. On the other hand, if the total output shaft torque exceeds point C, the rotating disk 38 and the non-rotating disk 39 slide out, so the slope of the output shaft torque (high torque side) shown by characteristic line 67 becomes smaller. Since the differential torque gradually decreases if it exceeds point C, the slope of the output shaft torque (high torque side) becomes smaller, and it rises to point D while maintaining this small slope. Then, if it exceeds point D, the differential torque becomes 0.

[0147] Here, in Figure 20 and Figure 22 In the gray-marked areas, the differential mechanism 20 of this embodiment exhibits a larger differential torque compared to the differential mechanism of the comparative example. Therefore, in regions with lower driving torque, i.e., regions where there is less impact on the lifespan of the left and right axle shafts 19L and 19R, the differential mechanism 20 can better ensure the differential torque. Thus, in Figure 20 and Figure 22 In the gray area marked in the figure, even if the vehicle equipped with the differential mechanism of the comparative example slips, the wheel loader 1 of this embodiment can suppress slippage and generate appropriate traction.

[0148] On the other hand, Figure 20 and Figure 22 In the area marked with shaded lines, the differential mechanism 20 exhibits a smaller differential torque compared to the differential mechanism in the comparative example. Therefore, in areas with high drive torque, i.e., areas that significantly impact the lifespan of the left and right axle shafts 19L and 19R, the differential mechanism 20 can suppress the differential torque to a smaller value. Here, in Figure 20 and Figure 22In the area marked with shaded lines, the wheel loader 1 experiences slippage under a smaller output shaft torque compared to a vehicle equipped with the differential mechanism of the comparative example. However, the area marked with shaded lines generates a larger output shaft torque, providing sufficient traction for normal operation. Therefore, suppressing the differential torque to a small level in this area is not a major problem for the wheel loader 1 during operation. Furthermore, the differential mechanism 20 reduces the frequency of excessive output shaft torque compared to the differential mechanism of the comparative example. As a result, the lifespan of the left and right axle shafts 19L and 19R can be extended.

[0149] Thus, in areas where the lifespan of the left and right axles 19L and 19R is less significantly affected (areas with lower driving torque), the differential mechanism 20 of this embodiment can maximize the differential torque. This suppresses slippage, for example, when the wheel loader 1 is climbing hills or traveling on snow tracks with low friction coefficients, thereby improving its driving performance. Furthermore, it improves operational performance, for example, when using the working device 6 of the wheel loader 1 for digging operations, i.e., when inserting the working device 6 at low speed into piles of sand. Moreover, the differential mechanism 20 mechanically reduces the differential torque in response to an increase in driving torque, thereby reducing the frequency at which excessive torque acts on the left and right axles 19L and 19R. As a result, the lifespan of the left and right axles 19L and 19R can be extended.

[0150] Furthermore, in this embodiment, the differential mechanism 20 utilizes the fact that the meshing reaction force between the pinion 33 and the right-side gear 35 increases proportionally to the driving torque, and transmits this meshing reaction force to the piston 46 via the lever member 53. This mechanically reduces the load Fen exerted on the pressure plate 40 by the piston 46 from the pressure ring 43 inversely proportional to the driving torque. In other words, the differential mechanism 20 mechanically reduces the differential torque in response to the increase in driving torque, thereby extending the lifespan of the left and right axle shafts 19L and 19R. Thus, the differential mechanism 20 does not require various sensors for predicting driving torque, control devices, or hydraulic control circuits that adjust the piston thrust accordingly to the predicted driving torque, thereby suppressing cost increases.

[0151] Furthermore, the differential mechanism 20 includes a lever member 53 between the right gear 35 and the piston 46. The lever member 53 determines the lever ratio iL based on the distance La between the first abutment part F and the third abutment part A, and the distance Le between the first abutment part F and the second abutment part E. Therefore, relative to the stroke of the piston 46 (the displacement of the third abutment part A), the movement of the right gear 35 (the displacement of the second abutment part E) can be reduced according to the lever ratio iL of the lever member 53. This ensures proper stroke of the piston 46 and reduces the axial movement of the right gear 35. Therefore, even if the right gear 35 moves axially in response to the supply and discharge of pressurized oil to the hydraulic chamber 47, the change in backlash between the pinion 33 and the right gear 35 can be suppressed. As a result, noise and vibration during meshing of the pinion 33 and the right gear 35 can be suppressed, as can the reduction in transmission efficiency and lifespan between the pinion 33 and the right gear 35.

[0152] Furthermore, four rectangular protrusions 40B are provided on the outer periphery of the pressing plate 40, which engage with four engaging recesses 26H provided on the axial end face 26F of the second housing 26. Therefore, even if the rotating disk 38 and the non-rotating disk 39 wear, the rectangular protrusions 40B prevent the pressing plate 40 from moving further toward the rotating disk 38 than necessary. As a result, the approach of the right gear 35 to the pinion 33 can be suppressed, and an appropriate backlash can be maintained between the right gear 35 and the pinion 33. Consequently, the reduction in transmission efficiency between the pinion 33 and the right gear 35, and the reduction in the lifespan of the pinion 33 and the right gear 35, can be suppressed.

[0153] Thus, the vehicle axle assembly of this embodiment comprises left and right axle shafts 19L and 19R, respectively, on which left and right front wheels 5 are mounted; a hollow differential body 14 disposed between left and right axle housings 15L and 15R, which house the left and right axle shafts 19L and 19R, and having partitions 14B and 14C with through holes 14D extending in the left and right directions on both sides; and a differential mechanism 20 disposed between the left and right partitions 14B and 14C of the differential body 14, which transmits the rotational force of the engine 7 to the left and right axle shafts 19L and 19R. It includes: a differential housing 23, which is rotatably supported by left and right retainers 21 and 41 respectively installed in the through holes 14D of the left and right partitions 14B and 14C, and rotated by the engine 7; a pinion 33, which is disposed in the differential housing 23 and rotates together with the differential housing 23; left and right side gears 34 and 35, which are disposed in the differential housing 23 and mesh with the pinion 33; and left and right drive shafts 36 and 37, which are connected to the left and right side gears 34 and 35 and transmit the rotation of the differential housing 23 to the left and right axle shafts 19L and 19R. The differential housing 23 contains: a plurality of rotating disks 38 that engage with the outer periphery of the right gear 35 of the left and right side gears 34 and 35 via splines; and a plurality of non-rotating disks 39 disposed among the plurality of rotating disks 38 and which are non-rotatable relative to the differential housing 23 but movable in the left and right directions. A pressure ring 43 is provided between the right retainer 41, located on the side of the right gear 35, and the rotating disks 38, pressing the rotating disks 38 toward the non-rotating disks 39. A piston 46 is provided on the right retainer 41 side, which applies a load to the pressure ring 43 to make the rotating disks 38 contact the non-rotating disks 39, thereby engaging the left and right drive shafts 36 and 37. A lever member 53 is provided between the differential housing 23, the right gear 35, and the pressure ring 43, which transmits the reaction force generated by the meshing of the pinion 33 and the right gear 35 to the pressure ring 43, thereby controlling the load applied to the pressure ring 43 by the piston 46.

[0154] According to this structure, taking advantage of the fact that the meshing reaction force between the pinion 33 and the right-side gear 35 increases proportionally to the driving torque, this meshing reaction force can be transmitted to the pressure ring 43 via the lever member 53. This mechanically reduces the load applied to the pressure ring 43 from the piston 46 inversely proportional to the driving torque. Consequently, the differential torque can be mechanically reduced in accordance with the increase in driving torque, thereby extending the life of the left and right axles 19L and 19R located after the differential mechanism 20.

[0155] In this embodiment, the lever member 53 includes: a first abutting portion F, which abuts against the differential housing 23; a second abutting portion E, which abuts against the right gear 35 and receives the reaction force generated by the meshing of the pinion 33 and the right gear 35; and a third abutting portion A, which abuts against the pressure ring 43, transmitting the reaction force generated by the meshing of the pinion 33 and the right gear 35 to the pressure ring 43 with the first abutting portion F as the fulcrum. According to this structure, the reaction force of the meshing of the pinion 33 and the right gear 35 acts on the second abutting portion E, which becomes the force point of the lever member 53, thereby causing the third abutting portion A, which becomes the point of action of the lever member 53, to rotate and displace with the first abutting portion F as the fulcrum. Thus, the lever member 53 transmits the meshing reaction force to the pressure ring 43 according to the lever ratio iL determined by the positions of the first abutting portion F, the second abutting portion E, and the third abutting portion A. Therefore, by changing the leverage ratio iL of the lever component 53, the load Fen acting on the rotating disk 38 from the pressure ring 43 via the pressing plate 40 can be appropriately adjusted.

[0156] In this embodiment, the lever member 53 is composed of a component whose middle portion is bent into a mountain shape along its length. A first abutment portion F is provided at one end 53A along the length, a third abutment portion A is provided at the other end 53B along the length, and a second abutment portion E is provided at the middle portion 53C along the length. According to this structure, by using the mountain-shaped component, a lever member 53 with a first abutment portion F serving as a fulcrum, a second abutment portion E serving as a force point, and a third abutment portion A serving as an application point can be easily formed. Furthermore, by changing the position of the bent portion, the leverage ratio iL of the lever member 53 can be appropriately changed.

[0157] In this embodiment, a pressing plate 40 is provided within the differential housing 23, positioned between the pressure ring 43 and the rotating disk 38, transmitting the pressing force of the pressure ring 43 to the rotating disk 38. The pressing plate 40 has a rectangular protrusion 40B protruding outwards, and the differential housing 23 has a locking recess 26H that engages with the rectangular protrusion 40B to limit the movement of the pressing plate 40. With this structure, even if the rotating disk 38 and the non-rotating disk 39 wear, the engagement of the rectangular protrusion 40B with the locking recess 26H limits the movement of the pressing plate 40 towards the rotating disk 38. Therefore, an increase in the displacement Da of the third abutment portion A of the lever member 53 can be suppressed, thereby preventing the right gear 35 from approaching the pinion 33 beyond the desired distance. As a result, an appropriate backlash can be maintained between the right gear 35 and the pinion 33, thereby extending the lifespan of both the right gear 35 and the pinion 33.

[0158] Furthermore, in this embodiment, an example is shown where a rotating disk 38 is splinedly coupled to the outer periphery of the right gear 35, one of the left and right side gears 34, 35. However, the present invention is not limited to this; for example, the rotating disk may also be splinedly coupled to the outer periphery of the left gear 34. In this case, a pressure ring is provided between the left retainer 21 and the rotating disk 38, a piston is provided in the left retainer 21, and a lever member is provided between the differential housing, the left gear 34, and the pressure ring.

[0159] Furthermore, in one embodiment, an example is shown where a lever member 53 is formed such that the middle portion of a trapezoidal plate is bent into a mountain shape along its length, so that one end 53A becomes the first abutment F, the other end 53B becomes the third abutment A, and the middle portion 53C becomes the second abutment E. However, the present invention is not limited to this, and a lever member may also be formed in which, for example, a protrusion is provided in the middle portion along the length of a flat plate, the two ends along the length become the first and third abutments, and the protrusion becomes the second abutment.

[0160] Furthermore, in the embodiments, a hydraulic piston 46 is shown as an example of an actuator that applies a load to the pressure ring 43. However, the present invention is not limited to this, and for example, pistons driven by water pressure or air pressure, electric motors, actuators utilizing the excitation force of electromagnets, etc., may also be used.

[0161] Furthermore, in this embodiment, a wheeled loader 1 is illustrated as a vehicle equipped with a rear axle assembly 11 and a front axle assembly 12. However, the present invention is not limited thereto and can be widely applied to other wheeled construction machinery, such as wheeled excavators.

[0162] Symbol Explanation

[0163] 4—Rear wheel, 5—Front wheel, 11—Rear axle assembly, 12—Front axle assembly, 14—Differential body, 15L—Left axle housing, 15R—Right axle housing, 19L—Left axle shaft, 19R—Right axle shaft, 20—Differential mechanism, 21—Left retaining element, 23—Differential housing, 26—Second housing, 26H—Activation recess, 33—Pin gear, 34—Left side gear, 35—Right side gear (one side gear) 36—Left drive shaft, 37—Right drive shaft, 38—Rotating disk, 39—Non-rotating disk, 40—Pressing plate, 40B—Rectangular protrusion (protrusion), 41—Right retainer (one retainer), 43—Pressure ring, 46—Piston (actuator), 53—Lever component, 53A—One end, 53B—The other end, 53C—Middle part, F—First abutment part, E—Second abutment part, A—Third abutment part.

Claims

1. A vehicle axle assembly comprising left and right axles on which left and right wheels are respectively mounted, a hollow differential body disposed between left and right axle housings housing the left and right axles and having partitions on both sides having through holes extending in the left and right directions, and a differential mechanism disposed between the left and right partitions of the differential body and transmitting rotational force of a drive source to the left and right axles. The above differential mechanism has: The differential housing is rotatably supported by left and right retainers respectively mounted on the through holes of the left and right partitions, and rotates by the drive source. A pinion is disposed within the differential housing and rotates together with the differential housing. Left and right side gears, which are disposed within the differential housing and mesh with the pinion; and The left and right drive shafts are connected to the left and right side gears mentioned above and transmit the rotation of the differential housing to the left and right axle shafts mentioned above. The aforementioned vehicle axle device is characterized in that, The differential housing contains: a plurality of rotating disks that engage with the outer peripheral splines of one of the left and right side gears; and a plurality of non-rotating disks disposed among the plurality of rotating disks and which are non-rotatable relative to the differential housing but movable in the left and right directions. A pressure ring is provided between the retainer located on the side gear side of one of the aforementioned left and right retainers and the aforementioned rotating disk, pressing the rotating disk toward the non-rotating disk. An actuator is provided on the retaining side of one of the aforementioned components. This actuator applies a load to the pressure ring to bring the rotating disk into contact with the non-rotating disk, thereby engaging the left and right drive shafts. A lever component is provided between the differential housing, the side gear of one of the gears, and the pressure ring. The lever component transmits the reaction force generated by the meshing of the pinion and the side gear of one of the gears to the pressure ring, thereby controlling the load applied to the pressure ring from the actuator.

2. The vehicle axle device according to claim 1, characterized in that, The lever component has: a first abutting portion that abuts against the differential housing; a second abutting portion that abuts against one of the side gears and receives the reaction force generated by the meshing of the pinion and the side gear; and a third abutting portion that abuts against the pressure ring, using the first abutting portion as a fulcrum to transmit the reaction force generated by the meshing of the pinion and the side gear to the pressure ring.

3. The vehicle axle device according to claim 2, characterized in that, The lever component is composed of a component that is bent into a mountain shape in the middle part along the length direction. The first abutment part is provided at one end along the length direction, the third abutment part is provided at the other end along the length direction, and the second abutment part is provided in the middle part along the length direction.

4. The vehicle axle device according to claim 1, characterized in that, A pressing plate is provided inside the differential housing, positioned between the pressure ring and the rotating disk, to transmit the pressing force of the pressure ring to the rotating disk. The aforementioned pressing plate is provided with a protrusion that extends outward to its outer periphery. The differential housing is provided with an engaging recess that engages with the protrusion to limit the movement of the pressing plate.

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