A differential device for tractors with a hydraulically controlled differential lock

Abstract

This utility model discloses a differential device for a tractor with a hydraulically controlled differential lock, including a left bearing housing, a right bearing housing, and a differential housing. Three planetary gears are evenly distributed circumferentially within the differential housing, meshing with the left and right half-shaft bevel gears respectively. The planetary gear shafts are fitted onto the left differential housing and fixed to a central ring. A wear-reducing pad with a positioning flange is provided between the left differential housing and the planetary gears, the positioning flange engaging an annular groove on the inner surface of the left differential housing. It also includes a differential lock piston, a clutch release plate, and friction plates. The outer teeth of the release plate engage with a groove in the left differential housing, and the internal splines of the friction plates engage with the external splines of the right half-shaft gear. A hydraulic circuit is located inside the right bearing housing and the right half-shaft gear and connects to the piston cylinder chamber. This utility model improves the bearing capacity and assembly convenience of the planetary gears, eliminates housing wear, achieves electro-hydraulic control, facilitates operation, avoids gear breakage, and enhances the tractor's traction and passability.

Description

Technical Field

[0001] This utility model relates to the field of tractor technology, specifically to a differential device for tractors with a hydraulically controlled differential lock. Background Technology

[0002] In the tractor industry, the differential is a key component of the transmission system, used to enable differential driving of the left and right drive wheels at different speeds. Current tractor differentials generally employ a cross-type planetary gear shaft or a bushing-type planetary gear shaft, and are equipped with four planetary bevel gears.

[0003] However, this type of planetary gear shaft intersection has relatively weak strength and a complex structure, posing safety hazards under high-power, heavy-load conditions. Furthermore, traditional differential locks mostly employ mechanically operated splined, pin-type, or jaw-type structures, requiring the driver to stop the vehicle during engagement, and gear grinding is prone to occur during this process, resulting in low efficiency. In recent years, hydraulically controlled differential lock structures have emerged, but existing hydraulic differential locks still suffer from insufficient load-bearing capacity of the planetary gear shaft system, easy wear of the planetary gear thrust washers due to planetary gear rotation, and an inefficient hydraulic circuit layout.

[0004] Therefore, it is necessary to provide a hydraulically controlled differential lock structure that is compact, has a high load-bearing capacity, is reliable in operation, and is easy to operate. Utility Model Content

[0005] To address the problems in the prior art, this utility model provides a tractor differential device with a hydraulically controlled differential lock that is compact in structure and reliable in use.

[0006] The technical solution adopted by this utility model to solve its technical problem is a differential device for a tractor with a hydraulically controlled differential lock, including a left bearing housing, a right bearing housing and a differential housing, wherein the differential housing is composed of a left differential housing, a right differential housing and a central drive bevel gear combined into one unit.

[0007] The differential housing contains three planetary gears evenly distributed around its circumference, which mesh with the left and right half-shaft bevel gears of the differential, respectively. It also includes a planetary gear bushing, which is fitted onto the left differential housing and fixed to a central ring. A friction-reducing pad is provided between the left differential housing and the planetary gears, and the friction-reducing pad has a positioning flange. An annular groove is provided on the inner surface of the left differential housing, and the positioning flange engages with the annular groove. The differential housing also includes a differential lock piston, a clutch release plate, and a clutch friction plate. The outer teeth of the clutch release plate engage with the grooves in the left differential housing, and the internal splines of the clutch friction plate engage with the external splines of the right half-shaft gear. A hydraulic circuit is located inside the right bearing housing and the right half-shaft gear, and connects to the cylinder chamber of the differential lock piston.

[0008] Furthermore, the differential housing is supported on the left bearing seat and the right bearing seat by bearings respectively.

[0009] Furthermore, a needle roller bearing is installed between the planetary gear and the planetary gear bushing.

[0010] Furthermore, a gasket is provided between the needle roller bearing and the anti-friction pad.

[0011] Furthermore, the hydraulic circuit includes an oil passage and an annular groove formed in the right bearing housing, and an oil hole formed on the right half-shaft gear. The annular groove is connected to the oil hole, and sealing rings are installed on both sides of the annular groove.

[0012] Furthermore, both the clutch release plate and the clutch friction plate are multiple and arranged in an alternating manner.

[0013] Furthermore, it also includes a rear axle housing, wherein the left bearing housing and the right bearing housing are respectively fixedly installed on the rear axle housing by bolts.

[0014] Furthermore, it also includes a left half-shaft sun gear shaft and a right half-shaft sun gear shaft, wherein the left half-shaft sun gear shaft is connected to the left half-shaft gear via a spline, and the right half-shaft sun gear shaft is connected to the right half-shaft gear via a spline.

[0015] Furthermore, the planetary gear bushing is threaded onto the central ring.

[0016] Furthermore, the differential lock piston is disposed on the right differential housing, and the clutch release plate and clutch friction plate are disposed on the left side of the differential lock piston.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] First, by adopting three planetary gears evenly distributed along the circumference and using a structure in which the planetary gear bushing is fitted onto the left differential housing and fixed to the central ring, the traditional cross shaft or bushing shaft form is replaced. This significantly simplifies the assembly process of the planetary gear shaft, improves the strength and load-bearing capacity of the planetary gear shaft system, and enables it to meet the requirements of heavy-load transmission of high-power tractors.

[0019] Secondly, a wear-reducing pad with a positioning flange is installed between the left differential housing and the planetary gear, and the positioning flange is inserted into the annular groove on the inner surface of the left differential housing. This effectively restricts the wear-reducing pad from rotating circumferentially with the planetary gear, fundamentally eliminating the relative wear between the wear-reducing pad and the inner surface of the differential housing, and greatly improving the reliability and service life of the differential device.

[0020] Furthermore, the hydraulic circuit is located inside the right bearing housing and the right half-shaft gear, and is connected to the cylinder chamber of the differential lock piston. In conjunction with the wet clutch structure of the clutch release plate and the groove of the left differential housing, and the clutch friction plate and the external spline of the right half-shaft gear, the electro-hydraulic control of the differential lock is realized. The driver only needs to press a button to complete the engagement and disengagement of the differential lock, which is convenient and labor-saving.

[0021] Finally, this invention can not only ensure the normal differential function of the differential, but also quickly lock the differential in harsh road conditions, thereby improving the tractor's traction performance and passability. Attached Figure Description

[0022] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0023] Figure 1 This is a cross-sectional view of the differential lock structure of this utility model;

[0024] Figure 2 This is a partial enlarged view of the hydraulic circuit of this practical application;

[0025] Figure 3 for Figure 1 FF section view;

[0026] Figure 4 This is a perspective view of the left differential housing in this utility model;

[0027] Figure 5 This is a perspective view of the friction-reducing pad in this utility model; Figure 6 This is a three-dimensional assembly view of the planetary gear in this utility model.

[0028] In the diagram: 1. Rear axle housing; 2. First bolt; 3. Left bearing housing; 4. Left half-shaft sun gear shaft; 5. First cone bearing; 6. Left differential housing; 7. Left half-shaft bevel gear; 8. Center ring; 9. Central drive bevel gear; 10. Second bolt; 11. Right differential housing; 12. Right half-shaft bevel gear; 13. Second cone bearing; 14. Right bearing housing; 15. Right half-shaft sun gear shaft; 16. Sealing ring; 17. Planetary gear bushing; 18. Needle roller bearing; 19. Differential lock piston; 20. Clutch release plate; 21. Clutch friction plate; 22. Third bolt; 23. Gasket; 24. Anti-friction pad; 25. Planetary gear. Detailed Implementation

[0029] To make the technical means, creative features, objectives and effects of this utility model easier to understand, the present utility model will be further described below in conjunction with specific embodiments.

[0030] like Figures 1 to 6 As shown, the present invention provides a differential device for a tractor with a hydraulically controlled differential lock, comprising a differential housing, a left bearing housing 3, a right bearing housing 14, and a rear axle housing 1.

[0031] The left bearing housing 3 and the right bearing housing 14 are respectively fixedly mounted on the rear axle housing 1 by the first bolt. The differential housing is composed of a left differential housing 6, a right differential housing 11, and a central drive bevel gear 9. Specifically, the central drive bevel gear 9 is threadedly connected to the left differential housing 6 and the right differential housing 11 by the second bolt 10 to form an integral structure. The differential housing is supported on the left bearing housing 3 and the right bearing housing 14 by the first tapered bearing 5 and the second tapered bearing 13, respectively. Specifically, the left differential housing 6 is mounted on the left bearing housing 3 by the first tapered bearing 5, and the right differential housing 11 is mounted on the right bearing housing 14 by the second tapered bearing 13.

[0032] The differential housing contains three planetary gears 25 evenly distributed along the circumference. Each planetary gear 25 meshes with the left half-shaft bevel gear 7 and the right half-shaft bevel gear 12 of the differential, respectively. The left half-shaft sun gear shaft 4 is connected to the left half-shaft bevel gear 7 via a spline, and the right half-shaft sun gear shaft 15 is connected to the right half-shaft bevel gear 12 via a spline.

[0033] The planetary gear 25 is installed as follows: a planetary gear sleeve 17 is provided, which is fitted onto the left differential housing 6 and fixed to a central ring 8 by a third bolt 22 as a fastener. The planetary gear 25 is fitted onto the planetary gear sleeve 17, and a needle roller bearing 18 is installed between the planetary gear 25 and the planetary gear sleeve 17 to reduce frictional resistance during relative rotation. Preferably, a friction-reducing pad 24 is provided between the left differential housing 6 and the planetary gear 25, and the friction-reducing pad 24 has a positioning flange E; the inner surface of the left differential housing 6 has an annular groove D, and the positioning flange E is engaged in the annular groove D, thereby restricting the friction-reducing pad 24 from circumferentially rotating relative to the left differential housing 6 during operation, effectively avoiding wear between the friction-reducing pad 24 and the inner surface of the left differential housing 6.

[0034] Preferably, a shim 23 is provided between the friction-reducing pad 24 and the needle roller bearing 18 for axial positioning.

[0035] Preferably, the present invention further includes a differential lock actuator, specifically comprising a differential lock piston 19, a clutch release plate 20, and a clutch friction plate 21. The differential lock piston 19 is disposed on the right differential housing 11, and the clutch release plate 20 and clutch friction plate 21 are disposed to the left of the differential lock piston 19, with multiple clutch release plates 20 and clutch friction plates 21 arranged alternately along the axial direction. The outer teeth of the clutch release plate 20 engage with a groove on the left differential housing 6, allowing the clutch release plate 20 to rotate synchronously with the left differential housing 6 and to move axially. The internal splines of the clutch friction plate 21 engage with the external splines of the right half-shaft bevel gear 12, allowing the clutch friction plate 21 to rotate synchronously with the right half-shaft bevel gear 12 and to move axially.

[0036] Preferably, the present invention further includes a hydraulic circuit for controlling the engagement and disengagement of the differential lock. This hydraulic circuit is located inside the right bearing housing 14 and the right half-shaft bevel gear 12, and connects to the cylinder chamber of the differential lock piston 19. Specifically, the hydraulic circuit includes an oil passage A and an annular groove B located within the right bearing housing 14, and an oil hole C located on the right half-shaft bevel gear 12; wherein, the oil passage A communicates with the oil inlet passage within the rear axle housing 1, the annular groove B communicates with the oil passage A, and the position of the oil hole C corresponds to the annular groove B, such that the annular groove B communicates with the oil hole C;

[0037] Preferably, sealing rings 16 are installed on both sides of the annular groove B to ensure the sealing of high-pressure oil when it enters the rotating right half-shaft bevel gear 12 from the right bearing housing 14. The oil hole C is further connected to the cylinder chamber of the differential lock piston 19. When the high-pressure oil enters the cylinder chamber, it pushes the differential lock piston 19 to the left, thereby pressing the clutch release plate 20 and the clutch friction plate 21, so that the left differential housing 6 and the right half-shaft bevel gear 12 rotate synchronously, realizing the engagement of the differential lock. When it is necessary to disengage the differential lock, the hydraulic oil pressure in the cylinder chamber is released. At this time, the pressing force of the differential lock piston 19 on the clutch release plate 20 and the clutch friction plate 21 disappears, so it cannot transmit torque, that is, the functional separation state is realized, the synchronous rotation relationship between the left differential housing 6 and the right half-shaft bevel gear 12 is released, and the differential returns to normal differential function. It should be noted that the differential lock can be restored to the disengaged state simply by releasing the hydraulic oil pressure. The differential lock piston does not need to rely on an external reset element to actively return to its original position. As long as the clamping force on the clutch plate is removed, the differential lock is disengaged.

[0038] The working principle of the differential device for tractors with hydraulically controlled differential lock of this invention is as follows:

[0039] During operation, the tractor's travel power is input through the central drive bevel gear 9, which drives the left differential housing 6 and the right differential housing 11 to rotate together. As the planetary gear bushing 17 rotates with the left differential housing 6, the planetary gear 25 also revolves. Simultaneously, the planetary gear 25 meshes with the left half-shaft bevel gear 7 and the right half-shaft bevel gear 12, thereby driving the left half-shaft sun gear shaft 4 and the right half-shaft sun gear shaft 15 to rotate. When the left and right drive wheels need to rotate at different speeds, the planetary gear 25 rotates to achieve the differential function.

[0040] When the differential needs to be locked, high-pressure hydraulic oil enters the cylinder chamber of the differential lock piston 19 through the oil inlet of the rear axle housing 1, the oil passage A and ring groove B of the right bearing seat 14, and the oil hole C of the right half-shaft bevel gear 12. This pushes the differential lock piston 19 to press against the staggered clutch release plate 20 and clutch friction plate 21, forcing the left differential housing 6 and the right half-shaft bevel gear 12 to rotate synchronously, thereby achieving synchronous rotation of the left and right half-shafts and improving the tractor's traction and passability in harsh road conditions.

[0041] When it is necessary to release the differential lock, the oil pressure is released, and the clutch release plate 20 and the clutch friction plate 21 separate under the action of the reset force, and the differential resumes normal differential function.

[0042] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The descriptions of the above embodiments and specifications are merely illustrative of the principles of this utility model. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of protection claimed by this utility model. The scope of protection of this utility model is defined by the appended claims and their equivalents.

Claims

1. A differential device for a tractor with a hydraulically controlled differential lock, comprising a left bearing housing, a right bearing housing, and a differential housing, wherein the differential housing is an integral assembly of the left differential housing, the right differential housing, and the central drive bevel gear, characterized in that: The differential housing contains three planetary gears evenly distributed around the circumference, which mesh with the left half-shaft bevel gear and the right half-shaft bevel gear of the differential, respectively. It also includes a planetary gear bushing, which is fitted onto the left differential housing and fixed to a central ring; A friction-reducing pad is provided between the left differential housing and the planetary gear, and a positioning flange is provided on the friction-reducing pad. An annular groove is provided on the inner surface of the left differential housing, and the positioning flange is inserted into the annular groove. It also includes a differential lock piston, a clutch release plate, and a clutch friction plate. The outer teeth of the clutch release plate engage with the grooves of the left differential housing, and the internal splines of the clutch friction plate engage with the external splines of the right half-shaft gear. The hydraulic circuit is located inside the right bearing housing and the right half-shaft gear, and is connected to the cylinder chamber of the differential lock piston.

2. The differential device for a tractor with a hydraulically controlled differential lock according to claim 1, characterized in that: The differential housing is supported on the left and right bearing seats by bearings respectively.

3. The differential device for a tractor with a hydraulically controlled differential lock according to claim 1, characterized in that: A needle roller bearing is installed between the planetary gear and the planetary gear bushing.

4. The differential device for a tractor with a hydraulically controlled differential lock according to claim 3, characterized in that: A gasket is also provided between the needle roller bearing and the anti-friction pad.

5. The differential device for a tractor with a hydraulically controlled differential lock according to claim 1, characterized in that: The hydraulic circuit includes an oil passage and an annular groove formed in the right bearing housing, and an oil hole formed on the right half-shaft gear. The annular groove is connected to the oil hole, and sealing rings are installed on both sides of the annular groove.

6. The differential device for a tractor with a hydraulically controlled differential lock according to claim 1, characterized in that: The clutch release plate and the clutch friction plate are both multiple and arranged in an alternating manner.

7. The differential device for a tractor with a hydraulically controlled differential lock according to claim 1, characterized in that: It also includes a rear axle housing, wherein the left bearing housing and the right bearing housing are respectively threaded onto the rear axle housing.

8. The differential device for a tractor with a hydraulically controlled differential lock according to claim 1, characterized in that: It also includes a left half-shaft sun gear shaft and a right half-shaft sun gear shaft, wherein the left half-shaft sun gear shaft is connected to the left half-shaft gear via a spline, and the right half-shaft sun gear shaft is connected to the right half-shaft gear via a spline.

9. The differential device for a tractor with a hydraulically controlled differential lock according to claim 1, characterized in that: The planetary gear bushing is fixed to the central ring by bolts.

10. The differential device for a tractor with a hydraulically controlled differential lock according to claim 1, characterized in that: The differential lock piston is mounted on the right differential housing, and the clutch release plate and clutch friction plate are mounted on the left side of the differential lock piston.

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