Drum brake and vehicle

Abstract

The utility model relates to the technical field of braking, provide a drum brake and vehicle, drum brake includes brake shoe, brake bottom plate and branch pin, the branch pin is worn in brake bottom plate with brake bottom plate rotation cooperation, brake shoe with branch pin fixed connection, the utility model provides a drum brake for solving the defect that high easily leads to spring recession failure in the prior art, wherein, branch pin and brake bottom plate can rotate each other, branch pin and brake shoe are fixed each other, in the braking process, brake shoe and branch pin can rotate relative to brake bottom plate to realize the brake. In addition, the structure design ensures the movement track of brake shoe in the braking process, in this way, need not set up lower return spring to carry out the location of brake shoe, and then avoid the problem that spring recession failure leads to the temperature of brake drum is too high.

Description

Technical Field

[0001] This utility model relates to the field of braking technology, and in particular to a drum brake and a vehicle. Background Technology

[0002] Drum brakes, also known as block brakes, achieve braking by pressing brake blocks against the brake drum. The mainstream type of drum brake is the internally expanding type, where the brake blocks (brake shoes) are located inside the brake drum. When braking, the brake blocks expand outwards, rubbing against the inside of the brake drum, thereby achieving the purpose of braking.

[0003] Currently, there are two types of support pin structures for drum brakes: gantry type and semi-open type. For semi-open drum brakes, a lower return spring is required to fix the brake shoes. However, if the lower return spring is too close to the brake drum, the temperature of the brake drum will be too high, which can easily lead to the spring's failure due to wear. Utility Model Content

[0004] The first aspect of this utility model provides a drum brake to solve the defect of the prior art that is prone to spring decay failure. The support pin is fixedly connected to the brake shoe. This structural design ensures the movement trajectory of the brake shoe during the braking process. In this way, there is no need to set a lower return spring to limit the brake shoe, thereby avoiding the problem of spring decay failure caused by excessive temperature of the brake drum.

[0005] The second aspect of this utility model provides a vehicle.

[0006] The drum brake provided by this utility model includes a brake shoe, a brake base plate, and a support pin. The support pin passes through the brake base plate and rotates with the brake base plate. The brake shoe is fixedly connected to the support pin.

[0007] According to the drum brake provided by this utility model, the brake shoe includes a first connecting part and a second connecting part, the first connecting part and the second connecting part are disposed opposite to each other at both ends of the brake base plate, one end of the support pin is fixedly connected to the first connecting part, and the other end passes through the brake base plate and is fixedly connected to the second connecting part.

[0008] The drum brake provided by this utility model further includes a bushing and two oil seals. The bushing is rotatably sleeved on the outside of the support pin. The two oil seals are located at both ends of the bushing and sleeved on the support pin. The brake base plate is sleeved on the outside of the bushing and the oil seals.

[0009] According to the drum brake provided by this utility model, the support pin has a first oil passage inside, the oil inlet of the first oil passage is located on one end face of the support pin, and the oil outlet of the first oil passage is located on the side of the support pin.

[0010] According to the drum brake provided by this utility model, the inner wall of the bushing is provided with a second oil passage, the second oil passage extends along the length direction of the bushing and communicates with the first oil passage.

[0011] According to the drum brake provided by this utility model, the inner wall of the first connecting part is provided with an oil unloading groove, and the oil unloading groove is connected to the second oil passage.

[0012] According to the drum brake provided by this utility model, the lips of both oil seals are arranged facing the oil unloading groove.

[0013] According to the drum brake provided by this utility model, the inner wall of the bushing is provided with multiple oil pits.

[0014] The drum brake provided by this utility model also includes two retaining rings, which are respectively disposed at both ends of the support pin, and the retaining rings are used to restrict the axial movement of the support pin.

[0015] The vehicle provided by this utility model includes the drum brake described in any of the preceding claims.

[0016] In the drum brake provided by this utility model, the support pin and the brake base plate are rotatable relative to each other, and the support pin and the brake shoe are fixed to each other. During braking, the brake shoe and the support pin can rotate relative to the brake base plate, thereby achieving braking. Compared with the prior art, in the drum brake provided by this utility model, the support pin and the brake shoe are fixedly connected. This structural design ensures the movement trajectory of the brake shoe during braking. Thus, there is no need to set a lower return spring to limit the brake shoe, thereby avoiding the problem of spring failure due to excessive temperature of the brake drum. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is an axonal schematic diagram of the drum brake provided in this embodiment of the utility model.

[0019] Figure 2 This is a partial cross-sectional schematic diagram of the drum brake provided in this embodiment of the utility model.

[0020] Figure 3 This is a detailed structural diagram of the first and second oil passages provided in an embodiment of the present invention.

[0021] Figure 4 This is a cross-sectional view of the bushing provided in an embodiment of the present invention.

[0022] Figure 5 This is a schematic diagram of the brake shoe provided in an embodiment of the present invention.

[0023] Figure label:

[0024] 100: Brake shoe; 110: First connecting part; 111: Oil drain groove; 120: Second connecting part; 200: Brake base plate; 300: Support pin; 310: First oil passage; 400: Bushing; 410: Second oil passage; 420: Oil pit; 500: Oil seal; 600: Snap ring; 700: Oil injector. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this utility model clearer, the technical solutions of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0026] In the description of the embodiments of this application, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this application based on the specific circumstances.

[0027] In the embodiments of this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0028] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the embodiments of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0029] Figure 1 This is an axonal schematic diagram of the drum brake provided in this embodiment of the utility model; Figure 2 This is a partial cross-sectional schematic diagram of the drum brake provided in this embodiment of the utility model.

[0030] See Figure 1 and Figure 2 The first aspect of this utility model provides a drum brake, which includes a brake shoe 100, a brake base plate 200, and a support pin 300. The brake shoe 100 and the brake base plate 200 are arranged side by side along a preset direction. The support pin 300 passes through the brake shoe 100 and the brake base plate 200 in sequence. The support pin 300 is rotatably engaged with the brake base plate 200 and is fixedly connected to the brake shoe 100.

[0031] See Figure 1 and Figure 2 It is understood that in the drum brake provided by this embodiment of the present invention, the support pin 300 and the brake base plate 200 are rotatable relative to each other, and the support pin 300 and the brake shoe 100 are fixed to each other. During braking, the brake shoe 100 and the support pin 300 can rotate relative to the brake base plate 200, thereby achieving braking. Compared with the prior art, in the drum brake provided by this embodiment of the present invention, the support pin 300 and the brake shoe 100 are fixedly connected. This structural design ensures the movement trajectory of the brake shoe 100 during braking. Thus, there is no need to set a lower return spring to limit the brake shoe 100, thereby avoiding the problem of spring failure due to excessive temperature of the brake drum.

[0032] Figure 3 This is a detailed structural diagram of the first and second oil passages provided in an embodiment of the present invention.

[0033] Continue reading Figure 1 , Figure 2 and Figure 3In an optional embodiment of the present invention, the brake shoe 100 includes a first connecting part 110 and a second connecting part 120. The first connecting part 110 and the second connecting part 120 are disposed opposite to each other at both ends of the brake base plate 200. One end of the support pin 300 is fixedly connected to the first connecting part 110, and the other end passes through the brake base plate 200 and is fixedly connected to the second connecting part 120.

[0034] Understandably, the design of the first connecting part 110 and the second connecting part 120 makes the connection between the support pin 300 and the brake shoe 100 more stable. During braking, it allows for more uniform stress transmission between the support pin 300 and the brake shoe 100, thereby enabling more effective transmission of braking force and improving the braking performance of the drum brake.

[0035] Continue reading Figure 1 , Figure 2 and Figure 3 In an optional embodiment of the present invention, the drum brake further includes a bushing 400 and two oil seals 500. The bushing 400 is rotatably sleeved on the outside of the support pin 300. The two oil seals 500 are located at both ends of the bushing 400 and sleeved on the pin. The brake base plate 200 is sleeved on the outside of the bushing 400 and the oil seals 500.

[0036] Understandably, the presence of bushing 400 reduces the direct friction between pin 300 and brake base plate 200, lowering the wear rate of both and effectively extending their service life. It also ensures smoother rotation of pin 300. Oil seal 500 plays a crucial sealing and protective role, preventing impurities such as mud and water from entering the gaps between pin 300 and bushing 400, and between bushing 400 and brake base plate 200. This reduces the risk of corrosion for braking components, ensures the long-term reliability of the drum brake, and lowers maintenance costs. Furthermore, good sealing helps maintain the lubrication environment inside the drum brake, further improving braking performance.

[0037] Continue reading Figure 1 , Figure 2 and Figure 3 In an optional embodiment of this utility model, a first oil passage 310 is provided inside the support pin 300. The oil inlet of the first oil passage 310 is located on one end face of the support pin 300 facing the dust cover, and the oil outlet of the first oil passage 310 is located on the side of the support pin 300. When lubricating grease is injected from the oil inlet, the grease flows along the first oil passage 310 to the side oil outlet under pressure, thereby lubricating the contact surface between the bushing 400 and the support pin 300.

[0038] Understandably, by providing the first oil passage 310 to lubricate the support pin 300 and the bushing 400, the drum brake can be lubricated in a timely manner during operation, reducing frictional resistance between components. Furthermore, reducing frictional resistance helps improve braking efficiency, reduces braking energy loss, and also reduces heat generated by friction, further protecting the braking components. In addition, the design of the first oil passage 310 ensures that lubricating grease can accurately reach between the support pin 300 and the bushing 400, thereby improving lubrication and extending the service life of the components.

[0039] Continue reading Figure 1 , Figure 2 and Figure 3 In an optional embodiment of this utility model, an oil filling nozzle 700 is further included. The oil filling nozzle 700 is disposed at the oil inlet of the first oil passage 310. The oil inlet of the first oil passage 310 is provided with an internal thread, and the outside of the oil filling nozzle 700 is provided with an external thread that mates with the internal thread. It can be understood that the oil filling nozzle 700 can prevent accidental leakage at the oil inlet of the first oil passage 310, and can also prevent impurities from easily entering the first oil passage 310.

[0040] Continue reading Figure 1 , Figure 2 and Figure 3 In an optional embodiment of this utility model, the inner wall of the bushing 400 is provided with a second oil passage 410, which extends along the length of the bushing 400 and communicates with the first oil passage 310. It is understood that the design of the second oil passage 410 further optimizes the transmission path of the lubricating grease. When lubricating grease is injected from the oil inlet, the grease, under pressure, flows along the first oil passage 310 to the side oil outlet, and then enters the second oil passage 410 of the bushing 400, thereby lubricating the contact surfaces between the bushing 400 and the support pin 300.

[0041] Figure 4 This is a cross-sectional view of the bushing provided in an embodiment of the present invention.

[0042] See Figure 4 In an optional embodiment of this utility model, the second oil passage 410 extends spirally along the length of the bushing 400 on the inner wall of the bushing 400. It can be understood that the spiral second oil passage 410 can form a wider lubrication path on the inner wall of the bushing 400. When the lubricating grease flows from the first oil passage 310 of the support pin 300 into the spiral second oil passage 410, due to its spiral shape, the grease will gradually distribute at different positions on the inner wall of the bushing 400 as the bushing 400 rotates.

[0043] Compared to straight oil passages, the spiral-shaped second oil passage 410 allows grease to more evenly cover the contact surfaces of the bushing 400 and the support pin 300, ensuring effective lubrication at all angles and positions. Specifically, during braking, the bushing 400 rotates along with the movement of the brake shoe 100 and the support pin 300. The spiral-shaped second oil passage 410 cleverly utilizes the rotational force of the bushing 400 to promote grease flow. When the bushing 400 rotates, due to the guiding effect of the spiral structure, the grease will flow axially and circumferentially along the second oil passage 410. This flow helps to deliver newly injected grease to the parts that need lubrication in a timely manner, while also carrying used grease back to the oil reservoir 420 or other suitable locations for storage or discharge. In other words, during the high-speed rotation of the bushing 400, the spiral-shaped second oil passage 410 can guide the grease to better fill the fine gaps in the inner wall of the bushing 400 under the action of centrifugal force, reducing wear caused by insufficient local lubrication.

[0044] Furthermore, during vehicle braking, the rotation of the bushing 400 causes the grease to circulate dynamically within the spiral oil passages, ensuring timely and effective lubrication. Specifically, straight oil passages may cause grease to accumulate in localized areas under certain circumstances, affecting the uniformity of lubrication. The spiral oil passage design avoids this situation. Its spiral structure causes the grease to continuously change direction and speed during flow, preventing grease from stagnating or excessively accumulating in any one place. This ensures that the entire inner wall of the bushing 400 receives a continuous and adequate supply of lubricating grease, maintaining a stable lubrication state.

[0045] Furthermore, during the lubrication process, the spiral structure creates a certain flow resistance within the oil passages, extending the residence time of the grease within the bushing 400. This allows the grease to perform its lubricating function more fully, improving its utilization rate. Even with a relatively limited grease supply under conditions such as frequent braking or prolonged driving, the spiral oil passages can maintain good lubrication by optimizing grease distribution and utilization, reducing friction and wear between components.

[0046] Figure 5 This is a schematic diagram of the brake shoe provided in an embodiment of the present invention.

[0047] See Figure 1 , Figure 2 , Figure 3 and Figure 5 In an optional embodiment of this utility model, the inner wall of the first connecting part 110 is provided with an oil unloading groove 111, which is connected to the second oil passage 410. It should be noted that the oil unloading groove 111 is located on the same side as the oil inlet of the first oil passage 310 and is located on the side of the brake shoe 100 facing the dust cover, so as to facilitate the observation of the oil filling situation.

[0048] Understandably, without the oil drain groove 111, it would be difficult to accurately determine when to stop grease injection during the grease injection process on a drum brake. The presence of the oil drain groove 111 provides a clear and intuitive location for grease overflow. When the amount of injected grease reaches a certain level, excess grease will overflow through the oil drain groove 111, which is connected to the second oil passage 410. In this way, the operator can stop the grease injection operation in time based on the grease overflow at the oil drain groove 111, thereby accurately controlling the amount of grease injected and preventing excessive accumulation of grease in the drum brake due to over-injection. Compared with existing technologies, the operator can determine whether the grease has filled the parts that need lubrication and whether it is about to be over-injected without the need for complex detection equipment. This simple and effective observation method helps to improve the accuracy and efficiency of the grease injection operation.

[0049] In addition, if grease overflows from the unloading groove 111 too quickly or too slowly during the grease injection process, the operator can adjust the grease injection pressure, speed, and other parameters accordingly. For example, if the grease overflows too quickly, it may indicate a blockage or other abnormality in the lubrication system, and the operator can stop grease injection and check the system. If the overflow is too slow, it may be necessary to increase the grease injection pressure appropriately or check whether the grease supply is normal. By observing the grease overflow from the unloading groove 111, problems during the grease injection process can be identified and resolved in a timely manner.

[0050] In addition, during vehicle operation, the amount of grease in the drum brake needs to be maintained within a suitable range. It should not be too little, which would lead to insufficient lubrication, nor should it affect braking performance too much. As the brake components move and the temperature changes, the distribution and state of the grease will also change. Due to the presence of the unloading groove 111, the unloading groove 111 can discharge excess grease, which can adapt to these changes to a certain extent and help maintain the balance of the amount of grease inside the drum brake, ensuring that the drum brake is always in good lubrication and working condition.

[0051] In addition, when grease accumulates excessively in the drum brake, it may attract more dust and impurities. These impurities may enter key mating parts such as the bushing 400 and the support pin 300 as the grease flows, which will aggravate the wear of the parts. The oil drain groove 111 can drain excess grease in time, which can reduce the amount of grease accumulated in the system, thereby reducing the risk of impurities entering, protecting the braking parts, and extending the service life of the drum brake.

[0052] It should be noted that if too much grease accumulates inside the drum brake, it may overflow onto the brake friction surface. The brake friction surface needs to maintain a certain coefficient of friction to ensure effective braking. If it is contaminated by grease, it will lead to a decrease in the coefficient of friction, an increase in braking distance, and a serious impact on braking performance. The oil drain groove 111 guides the excess grease to a suitable location to overflow, avoiding contamination of critical parts such as the brake friction surface and ensuring the normal operation of the drum brake.

[0053] Continue reading Figure 1 , Figure 2 and Figure 3 In an optional embodiment of this utility model, the oil seal 500 is a one-way oil seal 500, and the lips of both oil seals 500 are set towards the oil discharge port. It can be understood that during the operation of the drum brake, when excess grease seeps out from the gap between the bushing 400 and the support pin 300, the design of the oil seal 500 lips facing the oil discharge groove 111 can utilize its sealing and guiding function to guide this excess grease towards the oil discharge groove 111.

[0054] This ensures that the grease is discharged along a predetermined path, preventing it from flowing freely within the drum brake and thus preventing grease contamination of critical parts such as the brake friction surfaces. For example, when the vehicle brakes frequently, the grease between the bushing 400 and the support pin 300 may leak out under pressure. The lip of the oil seal 500 can accurately guide this leaked grease to the oil discharge groove 111, ensuring that braking performance is not affected.

[0055] Continue reading Figure 4 In an optional embodiment of this utility model, the inner wall of the bushing 400 is provided with a plurality of oil pits 420. The oil pits 420 can be evenly distributed or spaced apart according to certain requirements, and can be adapted to the actual situation.

[0056] Understandably, during vehicle operation, especially under conditions of frequent braking or prolonged driving, the lubricating grease between the bushing 400 and the support pin 300 will gradually be consumed. The oil sump 420 can store a certain amount of lubricating grease. When the lubricating grease between the bushing 400 and the support pin 300 decreases due to use, the grease in the oil sump 420 can be gradually released under the action of centrifugal force, vibration, and other factors to replenish lubrication to the contact surfaces of the bushing 400 and the support pin 300. This ensures that the bushing 400 and the support pin 300 can always receive a certain degree of lubrication during the interval between two oiling operations, reducing the risk of wear and jamming caused by insufficient lubrication.

[0057] Compared to a bushing 400 without an oil well 420, a bushing 400 with an oil well 420 can create a more stable lubrication environment during the lubrication process. Specifically, the oil well 420 can buffer the flow of grease to a certain extent, reducing grease fluctuations caused by factors such as vehicle vibration and speed changes. A stable lubrication environment helps maintain good lubrication between the bushing 400 and the support pin 300, reduces changes in the coefficient of friction, and improves the consistency and stability of braking.

[0058] Furthermore, the oil pit 420 reduces ineffective grease loss by storing and optimizing grease distribution. Specifically, during normal operation, some grease may lose its lubricating effect due to leakage, evaporation, or contamination. The grease in the oil pit 420 can compensate for these losses to some extent, allowing the grease in the lubrication system to be utilized more effectively, thereby extending the service life of the grease and correspondingly extending the lubrication interval. A longer lubrication interval means fewer lubrication maintenance operations required during vehicle use. This not only saves on grease usage but also reduces labor costs and vehicle downtime caused by frequent lubrication. For large fleets or commercial vehicles, reducing lubrication frequency can significantly improve operational efficiency and lower overall maintenance costs.

[0059] Continue reading Figure 1 , Figure 2 and Figure 3 In an optional embodiment of this utility model, the drum brake further includes two retaining rings 600, which are respectively disposed at both ends of the support pin 300. The retaining rings 600 are used to restrict the axial movement of the support pin 300. It is understood that during vehicle operation, various complex forces, such as vibration, braking impact force, and steering force, may cause the support pin 300 to tend to move axially. The presence of the retaining rings 600 can effectively restrict the axial movement of the support pin 300, ensuring that the support pin 300 maintains a stable axial position between the brake backing plate 200 and the brake shoe 100. For example, when the vehicle travels over a bumpy road, strong vibrations may cause the support pin 300 to be subjected to axial impact force. The retaining rings 600 can withstand and resist this impact force, preventing the support pin 300 from axially shifting, thereby ensuring that the relative positional relationship between the brake shoe 100 and the brake backing plate 200 remains correct and maintaining the normal operation of the drum brake.

[0060] In addition, if the support pin 300 is axially displaced, it may squeeze or pull the oil seal 500, causing the oil seal 500 to deform, be damaged, or have reduced sealing performance. In this embodiment, since the retaining ring 600 restricts the axial movement of the support pin 300, the oil seal 500 can be protected from such additional force. This ensures that the oil seal 500 can maintain a sealing state effectively for a long time, prevents impurities from entering the drum brake, extends the service life of the oil seal 500, and reduces the risk of drum brake failure due to oil seal 500 failure.

[0061] A second aspect of this utility model provides a vehicle that includes the drum brake described in any of the foregoing embodiments. It is understood that the vehicle provided in this embodiment, because it includes the drum brake described in any of the foregoing embodiments, also has the beneficial effects of the drum brake described in any of the foregoing embodiments. For specific beneficial effects, please refer to the foregoing description.

[0062] It should be noted that the technical solutions in the various embodiments of this utility model can be combined with each other, but the basis for such combination is that they can be implemented by those skilled in the art. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist, that is, it is not within the protection scope of this utility model.

[0063] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and not to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.

Claims

1. A drum brake, characterized in that, It includes a brake shoe (100), a brake base plate (200) and a support pin (300). The support pin (300) passes through the brake base plate (200) and rotates with the brake base plate (200). The brake shoe (100) is fixedly connected to the support pin (300).

2. The drum brake according to claim 1, characterized in that, The brake shoe (100) includes a first connecting part (110) and a second connecting part (120). The first connecting part (110) and the second connecting part (120) are disposed opposite to each other at both ends of the brake base plate (200). One end of the support pin (300) is fixedly connected to the first connecting part (110), and the other end passes through the brake base plate (200) and is fixedly connected to the second connecting part (120).

3. The drum brake according to claim 2, characterized in that, It also includes a bushing (400) and two oil seals (500), the bushing (400) being rotatably fitted on the outside of the support pin (300); the two oil seals (500) are respectively located at both ends of the bushing (400) and fitted on the support pin (300), and the brake base plate (200) is fitted on the outside of the bushing (400) and the oil seals (500).

4. The drum brake according to claim 3, characterized in that, The support pin (300) has a first oil passage (310) inside. The oil inlet of the first oil passage (310) is located on one end face of the support pin (300), and the oil outlet of the first oil passage (310) is located on the side of the support pin (300).

5. The drum brake according to claim 4, characterized in that, The inner wall of the bushing (400) is provided with a second oil passage (410), which extends along the length of the bushing (400) and communicates with the first oil passage (310).

6. The drum brake according to claim 5, characterized in that, The inner wall of the first connecting part (110) is provided with an oil unloading groove (111), which is connected to the second oil passage (410).

7. The drum brake according to claim 6, characterized in that, The lips of both oil seals (500) are positioned facing the oil unloading groove (111).

8. The drum brake according to claim 5, characterized in that, The inner wall of the bushing (400) is provided with multiple oil pits (420).

9. The drum brake according to any one of claims 1 to 8, characterized in that, It also includes two retaining rings (600), which are respectively disposed at both ends of the support pin (300), and the retaining rings (600) are used to restrict the axial movement of the support pin (300).

10. A vehicle, characterized in that, Includes the drum brake as described in any one of claims 1 to 9.

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