Drive axle assembly structure of wet brake system of 5-12T forklift

Abstract

The invention relates to a drive axle assembly structure of a wet brake system of a 5-12T forklift, and relates to the technical field of wet brake drive axles. Comprising an axle housing, a brake and a hub, and the brake adopts a wet brake to brake the hub; a brake gear ring is fixed to the side, close to the wet brake, of the hub and conducts friction braking through a friction pair in the wet brake, and then the hub is braked. And a rotating shaft lip-shaped sealing ring and a box type oil seal are arranged between the brake gear ring and the wet brake for double sealing. The wet brake is adopted, the installation sealing mode of the wet brake is designed, and the defects of a shoe type or caliper disc brake in the prior art in the aspects of sealing performance, stability, heat dissipation effect and anti-pollution capacity are overcome; and the structure and the material process of the transmission gear pair of the main speed reducer are optimized, so that the size and the weight are reduced while the strength is ensured.

Description

Technical Field

[0001] The invention relates to the technical field of wet brake drive axles, and in particular to a 5-12T forklift wet brake system drive axle assembly structure. Background Art

[0002] The braking torque of the traditional forklift drive axle is provided by a shoe-type or caliper-disc brake, and both are dry brakes. The brakes are in an "open" state. When the forklift is used in a relatively harsh environment (such as chemical plants, stone factories with a lot of dust, coal mines and refineries, etc.), if the brakes are not maintained in time, the brake hub, shoe, and brake disc will all be corroded, worn, and other undesirable phenomena will occur. The brake friction pad will be stained with oil, and the brake will fail. The heat energy generated during the braking process of the shoe-type and caliper-disc brakes is cooled by natural ventilation, and the cooling effect is poor. Once the forklift brakes frequently during use, the thermal stability of the brake friction pad is affected, and the braking performance decreases accordingly. Structurally, the size of the shoe-type brake is limited by the axial size and inner diameter of the tire rim, and it is difficult to increase the friction area, so the braking torque is small and the braking performance is poor. * Since the brake friction area is small and the pressure per unit area is relatively high, the caliper brake must use a high-performance friction pad, which is costly and difficult to assemble.

[0003] However, wet brakes have good sealing, strong anti-pollution, and the cooling system is cooled by oil. The cooling effect is stronger than the shoe type and caliper type, the braking torque is large, and the braking stability is high. Therefore, we will design a wet forklift drive axle to replace the traditional shoe type and caliper type forklift drive axle, and the wet drive axle is also the key transformation and development direction of the forklift industry in the future. To this end, we provide a 5-12T forklift wet brake system drive axle assembly structure. Summary of the invention

[0004] The purpose of the present invention is to provide a drive axle assembly structure of a 5-12T forklift wet brake system.

[0005] The present invention can be implemented by the following technical scheme: a 5-12T forklift wet brake system drive axle assembly structure, including a bridge housing and brakes and wheel hubs symmetrically arranged on both sides thereof, a main reducer and a differential are arranged in the bridge housing, half shafts are installed on both sides of the differential, and the output end of the half shaft drives the corresponding wheel hub to rotate; the brake adopts a wet brake to brake the wheel hub;

[0006] A brake gear ring is fixed on the side of the wheel hub close to the wet brake. The brake gear ring is frictionally braked by the friction pair in the wet brake, thereby braking the wheel hub. A rotating shaft lip seal ring and a cartridge oil seal are arranged between the brake gear ring and the wet brake for double sealing.

[0007] A further technical improvement of the present invention is that a closed friction pair installation chamber is provided in the wet brake, and multiple groups of friction pairs are arranged in parallel in the installation chamber, each group of friction pairs includes a static friction plate and a dynamic friction plate, and the gap between the two friction plates in each group of friction pairs is consistent.

[0008] A further technical improvement of the present invention is that three horizontally movable piston rods are evenly distributed at equal angles around the half-shaft axis on one side of the installation chamber, and a clutch plate parallel to the friction pair is fixedly installed on the output ends of the three piston rods, the clutch plate is fixedly connected to multiple static friction plates, and multiple dynamic friction plates are fixedly connected to the brake gear ring.

[0009] A further technical improvement of the present invention is that an oil inlet is provided at the housing position of the wet brake relative to the three piston rods, and the oil inlet is connected to the hydraulic pump system through an oil pipeline, and the hydraulic oil enters from the oil inlet and acts on the piston rod.

[0010] A further technical improvement of the present invention is that a star ring is installed in the slide groove where each piston rod is located to ensure the stability and sealing of the oil pressure of the piston rod during movement.

[0011] A further technical improvement of the present invention is that O-rings are installed at the mounting surface of the wheel hub and the brake gear ring, and at the mounting surface of the wet brake and the bridge body, and are coated with sealant at the same time.

[0012] The further technical improvement of the present invention is that the reduction gear pair of the main reducer adopts a uniform gear structure design and uses 20MnCr5 material, and adopts nitriding quenching and tempering heat treatment processes.

[0013] Compared with the prior art, the present invention has the following beneficial effects:

[0014] 1. The traditional shoe-type or caliper-disc brake has a small friction area and generates a small braking torque, which is not easy to meet the braking force requirements of customers' vehicles; the wet brake used in the present invention is a multi-disc full-disc brake, which is easy to increase the friction area, so the generated braking torque is large and the braking effect is obvious. The pressure on each friction plate is reduced, the unit specific pressure of the friction plate is small, and the braking torque can be adjusted by changing the number of friction pairs.

[0015] 2. The traditional shoe-type or caliper-disc brake is in an open environment. The brake shoe and disc friction plate are easily corroded when in contact with the air, and the temperature drops slowly, the maintenance cycle is short, and the service life is short. The wet brake multi-plate friction plate of the present invention works in a sealed oil bath. The porous fiber surface on both sides of the dynamic friction can ensure that there is an oil film to separate the dynamic friction plate from the static friction plate, and reduce the friction force to a minimum. Due to the immersion in the oil bath, the heat dissipation is strong, and the heat transfer coefficient is increased by 2-4 times. The thermal stability is good, the brake failure is effectively prevented, and the service life is long.

[0016] 3. The conventional wet brake uses a floating oil seal, which is costly and difficult to assemble. The wet brake designed in the present invention uses a rotating shaft lip seal and a cartridge oil seal, which is simple to assemble and of moderate cost while ensuring high sealing performance. It has strong anti-pollution ability, long-term stable braking performance, is not limited to the use environment, and has a long maintenance cycle.

[0017] 4. Traditional shoe-type or caliper-disc brakes rely on friction braking, which results in large losses and unstable braking force. In the wet brake of the present invention, when hydraulic oil enters, the force exerted on the piston is uniform, and the force pushing the piston is also evenly distributed. The hydraulic pressure and the braking force formed are in a linear relationship, so braking is rapid and smooth, with higher safety. At the same time, since the wet brake uses oil-immersed braking, the braking noise is much smaller than that of traditional shoe-type or caliper-disc brakes, and is suitable for more occasions.

[0018] 5. The wet brake of the present invention adopts oil-immersed braking, and the braking noise is much smaller than that of traditional shoe-type or caliper-disc brakes, and is suitable for more occasions.

[0019] 6. The present invention reduces the volume and weight of the main reducer through the gear pair manufacturing process of the main reducer, thereby solving the problem in the prior art that the main reducer is large in volume and heavy in weight, resulting in crowded space and difficulty in assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to facilitate understanding by those skilled in the art, the present invention is further described below with reference to the accompanying drawings.

[0021] Figure 1 It is a partial cross-sectional schematic diagram of the overall structure of the present invention from a main viewing angle;

[0022] Figure 2 It is a partial cross-sectional schematic diagram of the overall structure of the present invention from a top view perspective;

[0023] Figure 3 For the present invention Figure 1 A-axis cross-sectional structural diagram;

[0024] Figure 4 For the present invention Figure 1 A partial enlarged view of point B in the middle;

[0025] Figure 5 For the present invention Figure 3 A partial enlarged view of point C in the middle.

[0026] In the figure: 1, bridge housing; 2, wet brake; 3, wheel hub; 4, half shaft; 5, planetary carrier; 6, ; 201, brake housing; 202, oil pipe; 203, oil inlet; 204, piston rod; 205, breather plug; 206, star ring; 207, clutch plate; 208, static friction plate; 209, dynamic friction plate; 210, brake gear ring; 211, O-ring; 212, rotating shaft lip seal; 213, cassette sealing component. DETAILED DESCRIPTION

[0027] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the specific implementation methods, structures, features and effects of the present invention are described in detail below in conjunction with the accompanying drawings and preferred embodiments.

[0028] See also Figure 1-5 As shown, a 5-12T forklift wet brake system drive axle assembly structure includes an axle housing 1, a main reducer and a differential are arranged in the axle housing 1, wet brakes 2 and wheel hubs 3 are symmetrically arranged on both sides of the axle housing 1, half shafts 4 are arranged on both sides of the differential and the wheel hubs 3 are driven to rotate through the half shafts 4, a planet carrier 5 fixed to the axle housing 1 is sleeved on the outer side of the half shaft 4, and the wet brakes 2 and the wheel hubs 3 are both installed on the planet carrier 5;

[0029] Specifically, the main reducer is a small-volume primary reducer. The traditional spiral bevel gear pair has a large structure size, and an equal-height gear structure design is adopted to reduce the diameter of the gear pair. At the same time, 20MnCr5 material is used to replace the conventional 20CrMnTi material, and the heat treatment adopts nitriding quenching and tempering process, and the yield strength is higher than 1000MPa. With the volume and weight greatly reduced, the output torque and life are increased by more than 8%;

[0030] At the same time, the sun gear and gear ring pair in the wheel reducer in the hub 3 are made of 42CrMo new material, and the heat treatment adopts nitriding and quenching process; the yield strength is over 950MPa. With the significant reduction in volume and weight, the load, output torque and life are increased by more than 10%;

[0031] Specifically, the wet brake 2 includes a brake housing 201, and three oil inlets 203 are evenly arranged at equal angles on one side of the brake housing 201 relative to the axis of the half shaft 4, and one end of each oil inlet 203 is connected to an oil delivery pipe 202; a piston rod 204 is arranged in the brake housing 201 near a corresponding oil inlet 203, and a star ring 206 is arranged between the piston rod 204 and the brake housing 1 to ensure the sealing performance and oil pressure stability during the movement of the piston rod 204; a vent plug 205 is also arranged on the side wall of the brake housing 201 to balance the internal air pressure changes caused;

[0032] Further, one end of the oil delivery pipe 202 away from the oil inlet 203 is connected to a hydraulic pump system;

[0033] The piston rod 204 slides in the slide groove formed inside the brake housing 201 and the ends of the three piston rods 204 are fixedly connected with a clutch plate 207. The clutch plate 207 is installed in the wet brake 2 by spring floating, and the spring force is perpendicular to the plane where the end of the piston rod 204 is located. On one side of the clutch plate 207, static friction plates 208 and dynamic friction plates 209 are arranged alternately at intervals. Each dynamic friction plate 209 and the static friction plate 208 form a friction pair, and the distance between the two friction plates in each friction pair is equal; the number of groups of friction pairs can be adjusted to adjust the braking torque; in this embodiment, the number of groups of friction plates is set to 7 groups; it should be noted that both sides of the dynamic friction plate 209 are set as porous fiber surfaces to ensure that a layer of oil film is formed under the oil bath condition of the coolant to separate the dynamic friction plate 209 from the static friction plate 208, and reduce the friction force to a minimum when the braking work is not performed;

[0034] The clutch plate 207 is fixedly connected to the static friction plate 208, and the wheel hub 3 is fixedly connected to the brake gear ring 210 on the side close to the wet brake 2 by bolts, one end of the brake gear ring 210 extends to the inside of the brake housing 201 and the dynamic friction plate 209 is fixed to the brake gear ring 210;

[0035] O-rings 211 are installed at the mounting surfaces of the wheel hub 3 and the brake gear ring 210, and at the mounting surfaces of the wet brake 2 and the bridge body, and are coated with sealant to ensure the sealing performance of the wet drive axle; the traditional installation method only coats sealant, which has poor sealing performance and cannot be sealed for a long time;

[0036] Furthermore, the joint between the brake gear ring 210 and the brake housing 201 is provided with a rotating shaft lip seal 212 and a cartridge oil seal 213 for double sealing to prevent the coolant from escaping from the joint between the brake gear ring 210 and the brake housing 201; it should be noted that due to the high working temperature of the wet brake 2, the rotating shaft lip seal 212 is made of fluororubber material, which is resistant to high temperature, and the cartridge oil seal 213 is installed on its outer side to enhance the sealing performance and is easy to install.

[0037] When the present invention is in use, the operator steps on the foot brake, and the forklift hydraulic pump system works, pushing the hydraulic oil into the wet brake 2 from the oil inlet 203; the hydraulic oil pushes the three piston rods 204 through the oil pipe 202 through the oil inlet 203, thereby driving the clutch plate 207 to move, and the static friction plate 208 moves accordingly, and causes the dynamic friction plate 209 and the static friction plate 208 to be squeezed to generate friction force, preventing the dynamic friction plate 209 from rotating, and a large amount of heat generated during the friction process is absorbed by the coolant; because the dynamic friction plate 209 is fixed on the brake gear ring 210, and the brake gear ring 210 is connected to the wheel hub 3, after the dynamic friction plate 209 stops rotating, it drives the wheel hub 3 to stop rotating, thereby achieving the effect of forklift braking;

[0038] When restarting, the forklift hydraulic pump system stops working. Since there is no oil pressure, the spring rebound in the wet brake 2 drives the clutch plate 207 back to its original position. The clutch plate 207 then pushes the three piston rods 204 back to their original position, returning the hydraulic oil to the hydraulic pump system. The dynamic friction plate 209 separates from the static friction plate 208, and the brake is released.

[0039] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technical personnel in this field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A 5-12T forklift wet brake system drive axle assembly structure, comprising a bridge housing (1) and brakes and wheel hubs (3) symmetrically arranged on both sides thereof, characterized in that The bridge housing (1) is provided with a main reducer and a differential, and half shafts (4) are installed on both sides of the differential, and the output end of the half shaft (4) drives the corresponding wheel hub (3) to rotate; the brake adopts a wet brake (2) to brake the wheel hub (3); A brake gear ring (210) is fixed to a side of the wheel hub (3) close to the wet brake (2), and the brake gear ring (210) is frictionally braked by a friction pair in the wet brake (2), thereby braking the wheel hub (3); a rotating shaft lip seal ring (212) and a box oil seal (213) are arranged between the brake gear ring (210) and the wet brake (2) for double sealing.

2. A 5-12T forklift wet brake system drive axle assembly structure according to claim 1, characterized in that: The wet brake (2) is provided with a closed friction pair installation chamber, in which a plurality of groups of friction pairs are arranged in parallel, each group of friction pairs comprises a static friction plate (208) and a dynamic friction plate (209), and the gap between the two friction plates in each group of friction pairs is consistent.

3. A 5-12T forklift wet brake system drive axle assembly structure according to claim 2, characterized in that: Three piston rods (204) capable of horizontal movement are evenly distributed at equal angles on one side of the installation chamber around the axis of the half shaft (4), and a clutch plate (207) parallel to the friction pair is fixedly installed on the output ends of the three piston rods (204), the clutch plate (207) is fixedly connected to a plurality of static friction plates (208), and a plurality of dynamic friction plates (209) are fixedly connected to a brake gear ring (210).

4. A 5-12T forklift wet brake system drive axle assembly structure according to claim 3, characterized in that: The wet brake (2) is provided with an oil inlet (203) at a position of the housing relative to the three piston rods (204), and the oil inlet (203) is connected to a hydraulic pump system via an oil delivery pipe (202), and hydraulic oil enters from the oil inlet (203) and acts on the piston rod (204).

5. The 5-12T forklift wet brake system drive axle assembly structure according to claim 3 is characterized in that: A star ring (206) is installed in the slide groove where each piston rod (204) is located to ensure the stability and sealing of the oil pressure of the piston rod (204) during movement.

6. A 5-12T forklift wet brake system drive axle assembly structure according to claim 1, characterized in that: O-rings (211) are installed at the mounting surfaces of the wheel hub (3) and the brake gear ring (210), and at the mounting surfaces of the wet brake (2) and the bridge body, and are coated with sealant.

7. The 5-12T forklift wet brake system drive axle assembly structure according to claim 1, characterized in that: The reduction gear pair of the main reducer adopts a uniform gear structure design and uses 20MnCr5 material, and also adopts nitriding quenching and tempering heat treatment processes.

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