A planetary gearbox first gear cylinder structure

Abstract

This utility model relates to a first-gear cylinder structure for a planetary gearbox, comprising a cylinder body integrally formed with the gearbox cover and connected to the gearbox housing by bolts; the outer wall of the cylinder body is provided with radial reinforcing ribs; the cylinder body has an annular piston cavity for installing the first-gear piston; the cavity is provided with an oil inlet hole communicating with the outside of the cylinder body. By integrally forming the cylinder body with the cover, the independent fixing plate design is eliminated, thus eliminating the risk of thin plate deformation and breakage. The reinforcing ribs on the cylinder body enhance the cylinder's resistance to oil pressure deformation, preventing structural failure under high pressure conditions and improving the overall structural strength and reliability. The oil inlet hole is coaxially connected with the oil passage of the housing, optimizing oil transmission efficiency and reducing pressure loss and leakage risk.

Description

Technical Field

[0001] This utility model belongs to the field of mechanical transmission technology, specifically relating to a first-gear cylinder structure of a planetary gearbox. Background Technology

[0002] The statements herein provide only background information related to this invention and do not necessarily constitute prior art.

[0003] A planetary gearbox is a transmission device that uses a planetary gear mechanism. Through a combination of a central sun gear, multiple planetary gears, and an external ring gear, it achieves efficient and smooth speed transmission, and is widely used in automotive automatic transmissions, industrial machinery, and aerospace. Currently, the planetary gearboxes used in domestic loaders have an independently mounted first-gear cylinder. To ensure the isolator does not rotate when transmitting torque, a locating pin fixed to the gearbox body is milled flat and inserted into a groove machined on the isolator. In this case, the first-gear cylinder is connected to the isolator via a fixing plate and will not rotate. When the first-gear clutch engages, the piston presses against the friction plate, allowing the transmission of working torque.

[0004] Both the first-gear cylinder and the isolation frame are equipped with mounting plates. These plates are usually thin plates that are prone to deformation after heat treatment and have poor toughness. Therefore, they are generally not heat treated and have low strength. As a result, axial slotting can reduce the overall structural strength and make the cylinder more prone to cracking. Furthermore, for ease of assembly and maintenance, there is a gap between the mounting plate and the first-gear cylinder and the isolation frame. This gap can cause the mounting plate to be impacted when switching between forward and reverse gears, which can easily lead to deformation or even breakage of the mounting plate, making it impossible to perform the first-gear shifting operation. Utility Model Content

[0005] The purpose of this invention is to provide a first-gear cylinder structure for a planetary gearbox, which can at least solve one of the above-mentioned technical problems.

[0006] To achieve the above objectives, an embodiment of this utility model provides a first-gear cylinder structure for a planetary gearbox, including a cylinder body and a friction plate isolation frame. The cylinder body is integrally formed with the gearbox cover and connected to the gearbox housing by bolts. The outer wall of the cylinder body is provided with radial reinforcing ribs. The cylinder body has an annular piston cavity for mounting the first-gear piston inside. The cavity is provided with an oil inlet hole communicating with the outside of the cylinder body. The oil inlet hole is connected to the first-gear pressure oil passage of the gearbox housing. The end of the cylinder body away from the cover is provided with an annular pressing surface for pressing the friction plate. The friction plate isolation frame has multiple spring mounting holes evenly distributed circumferentially, through which return springs are evenly installed in the circumferential position to bear the pressing force of the piston on the friction plate. Furthermore, the reinforcing ribs are evenly distributed on the circumference of the cylinder body and extend radially along the axial direction of the cylinder body.

[0007] Furthermore, a flange is provided at the connection between the cylinder body and the middle cover.

[0008] Furthermore, the oil inlet is located on the outer end face of the cylinder body near the middle cover and is coaxially connected with the oil passage of the gearbox housing.

[0009] Furthermore, the outer diameter of the annular pressing surface is larger than the outer diameter of the friction plate, and the axial position of the pressing surface is coaxially aligned with the friction plate.

[0010] Furthermore, the friction plate includes a driving plate and a driven plate. The driving plate is connected to a first gear ring via a spline, and the driven plate is connected to the gearbox housing via a pin.

[0011] Furthermore, the bottom of the cylinder body is provided with a piston mounting groove.

[0012] Furthermore, the piston mounting cavity groove is an annular groove with a depth greater than the piston's free height.

[0013] Furthermore, the inner diameter of the cylinder body cavity is clearance-fitted with the outer diameter of the first-stage piston.

[0014] Furthermore, the inner wall of the cylinder body is provided with a wear-resistant coating.

[0015] The beneficial effects of the above technical solutions are as follows: This utility model integrates the cylinder body and the middle cover into one piece, eliminating the need for an independent fixing plate design, thus eliminating the risk of deformation and breakage of thin plates. The cylinder body is equipped with reinforcing ribs to enhance the cylinder's resistance to oil pressure deformation, preventing structural failure under high pressure conditions and improving the overall structural strength and reliability.

[0016] The oil inlet is coaxially connected to the oil passage in the housing, optimizing oil transmission efficiency and reducing pressure loss and leakage risk. Attached Figure Description

[0017] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments of this application and their descriptions are used to explain this application and do not constitute a limitation thereof.

[0018] Figure 1 This is a cross-sectional view of the connection between the cylinder body and the middle cover in an embodiment of this utility model; Figure 2 This is a front perspective three-dimensional schematic diagram of the cylinder body in an embodiment of this utility model; Figure 3 This is a rear-view perspective view of the cylinder body in an embodiment of this utility model; Figure 4 This is a three-dimensional schematic diagram of the friction plate isolation frame in an embodiment of this utility model.

[0019] In the diagram, 1 is the cylinder body; 2 is the gearbox cover; 3 is the reinforcing rib; 4 is the oil inlet; 5 is the piston cavity; 6 is the spring mounting hole; and 7 is the friction plate isolation bracket. Detailed Implementation

[0020] like Figures 1 to 4 As shown, this embodiment provides a first gear cylinder structure for a planetary gearbox, including a cylinder body 1.

[0021] like Figure 1 As shown, the cylinder body 1 and the gearbox cover 2 are integrally formed, eliminating the need for a fixing plate for connection. This avoids the problem of the fixing plate breaking due to stress concentration during operation, and improves the reliability and durability of the overall structure.

[0022] like Figure 1 and Figure 2 As shown, a flange is provided at the connection between the cylinder body 1 and the middle cover. The gearbox middle cover 2 is connected to the gearbox housing by bolts passing through the flange, and a sealing gasket is used to ensure the stability and sealing between the two, preventing loosening or leakage during operation, and ensuring the reliability and long service life of the entire system.

[0023] The outer wall of the cylinder body 1 is provided with radial reinforcing ribs 3; the reinforcing ribs 3 are evenly distributed on the circumference of the cylinder body 1 and extend radially along the axial direction of the cylinder body 1 to enhance the overall structural strength of the cylinder body 1, effectively resist the stress generated by the internal oil pressure, and prevent the cylinder from deforming or breaking under high pressure.

[0024] like Figure 1 and Figure 3 As shown, the cylinder body 1 has an annular piston cavity 5 inside for mounting the first-gear piston. The inner diameter of the cavity of the cylinder body 1 is clearance-fitted with the outer diameter of the first-gear piston to facilitate smooth piston sliding and gear shifting. The cavity is provided with an oil inlet hole 4 that connects directly to the outside of the cylinder body 1, facilitating efficient injection of hydraulic oil. The oil inlet hole 4 is connected to the first-gear pressure oil passage inside the gearbox through a sealing ring interface to ensure no oil leakage and smooth pressure transmission. Specifically, the oil inlet 4 is directly connected to the outer surface of the cylinder body 1, serving as the inlet channel for hydraulic oil and ensuring that the oil can flow into the cavity efficiently. The oil inlet 4 is coaxially connected to the first-gear pressure oil passage of the gearbox housing, ensuring smooth transmission of hydraulic oil from the oil passage to the cavity and supporting the oil pressure requirements of first-gear operation.

[0025] The cylinder body 1 has an annular pressing surface at one end away from the middle cover for pressing the friction plate. The outer diameter of the annular pressing surface is similar to the outer diameter of the friction plate, and the axial position of the pressing surface is coaxially aligned with the friction plate to provide uniform axial pressure. The outer diameter of the annular pressing surface is slightly larger than the outer diameter of the friction plate to ensure that the friction surface is completely covered during pressing and to avoid local stress concentration. The axial position of the pressing surface is strictly coaxially aligned with the friction plate to achieve uniform pressure distribution. It is used to press the friction plate assembly during gear shifting, providing reliable clamping force to achieve smooth power transmission and reduce wear and operating noise.

[0026] The friction plates consist of a driving plate and a driven plate. The driving plate is securely connected to the first gear ring via a spline structure, and the spline design ensures reliable power transmission and efficient drive. The driven plate is fixedly connected to the gearbox housing via a pin, which provides positioning and stable support, thereby enabling the friction plates to effectively perform the clutch function during gear shifting, ensuring smooth and reliable power transmission.

[0027] In addition, a first-position piston is installed at the bottom of the cavity of the cylinder body 1, and a set of piston return springs and spring pins are evenly arranged along the outer ring of the piston; the return spring passes through the friction plate isolation frame 7, and the other end acts on the reverse piston; the friction plate isolation frame 7 is provided with a spring mounting hole 6 through which the spring passes; the inner wall of the cavity of the cylinder body 1 is provided with a wear-resistant coating.

[0028] Specifically, such as Figure 4 As shown, the bottom of the cylinder body 1 has an annular groove for mounting the piston. The groove is located in the center of the bottom of the cavity to ensure stable installation and precise alignment of the piston. The groove depth is greater than the piston thickness to ensure the piston's engagement and disengagement stroke. Furthermore, the inner wall of the cylinder body 1 is coated with a wear-resistant coating made of existing wear-resistant materials, which effectively reduces frictional loss during piston reciprocating motion, extending the cylinder's service life and maintenance cycle. The return spring is installed in the isolator hole and connected to the first-gear piston end face via a spring pin. The other end is connected to the reverse-gear piston end face. The spring pin guides the spring during extension and retraction, ensuring reliable piston return. The length of the spring pin is less than the distance between the reverse-gear piston and the first-gear piston to ensure sufficient piston stroke.

[0029] The working principle of this utility model: The cylinder body 1 and the gearbox cover 2 are integrally cast and rigidly connected to the gearbox housing with bolts, forming a stable support structure. When the gearbox needs to shift into first gear, the hydraulic system injects high-pressure oil into the oil inlet 4 of the cylinder body 1 through the first-gear pressure oil passage in the gearbox housing. After the oil enters the annular piston cavity 5, it pushes the first-gear piston to move axially. The piston overcomes the resistance of the return spring and drives the annular pressing surface at the far end of the cylinder body 1 to press against the friction plate assembly. At this time, power is transmitted to the planetary gear mechanism through the friction plate to achieve torque output. When the shift ends, the hydraulic pressure is released, the return spring pushes the piston to return to its original position, the friction plate separates, and the power is interrupted.

[0030] Although the specific embodiments of the present utility model have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present utility model. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solution of the present utility model are still within the scope of protection of the present utility model.

Claims

1. A planetary gearbox first-gear cylinder structure, characterized by, The system includes a cylinder body and a friction plate isolation frame. The cylinder body is integrally formed with the gearbox cover and connected to the gearbox housing by bolts. The outer wall of the cylinder body is provided with radial reinforcing ribs. The cylinder body has an annular piston cavity for mounting a first-gear piston. The cavity has an oil inlet hole that connects to the outside of the cylinder body. The oil inlet hole is connected to the first-gear pressure oil passage of the gearbox housing. The end of the cylinder body away from the cover has an annular pressing surface for pressing the friction plate. The friction plate isolation frame has multiple spring mounting holes evenly distributed circumferentially. Return springs are evenly installed in the circumferential position through the spring mounting holes to bear the pressing force of the piston on the friction plate.

2. The one-gear cylinder structure of the planetary gearbox according to claim 1, characterized in that, The reinforcing ribs are evenly distributed on the circumference of the cylinder body and extend radially along the axial direction of the cylinder body.

3. The one-gear cylinder structure of the planetary gearbox according to claim 1, characterized in that, A flange is provided at the connection between the cylinder body and the middle cover.

4. The one-gear cylinder structure of the planetary gearbox according to claim 1, characterized in that, The oil inlet is located on the outer end face of the cylinder body near the middle cover and is coaxially connected with the oil passage of the gearbox housing.

5. The one-gear cylinder structure of the planetary gearbox according to claim 1, characterized in that, The outer diameter of the annular pressing surface is larger than the outer diameter of the friction plate, and the axial position of the pressing surface is coaxially aligned with the friction plate.

6. The one-gear cylinder structure of a planetary gearbox according to claim 1, characterized in that, The friction plate includes a driving plate and a driven plate. The driving plate is connected to a first gear ring via a spline, and the driven plate is connected to the gearbox housing via a pin.

7. The first gear cylinder structure of a planetary gearbox according to claim 1, characterized in that, The bottom of the cylinder body is provided with a piston mounting groove.

8. The one-gear cylinder structure of the planetary gearbox according to claim 7, characterized in that, The piston mounting cavity groove is an annular groove with a depth greater than the piston's free height.

9. The one-gear cylinder structure of a planetary gearbox according to claim 1, characterized in that, The inner diameter of the cylinder body cavity is clearance-fitted with the outer diameter of the first-stage piston.

10. The one-gear cylinder structure of a planetary gearbox according to claim 1, characterized in that, The inner wall of the cylinder body is provided with a wear-resistant coating.

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