A hand brake mechanism

Abstract

The utility model discloses a hand brake, belongs to rail transit equipment field, including drive shaft, transmission nut, self locking ratchet and drive gear. Drive shaft is provided with the compression part. Transmission nut and drive shaft form the screw pair. Self locking ratchet is limited between compression part and transmission nut. Drive gear and transmission nut can pass through each other transmission torque. Transmission nut and drive shaft are provided with sealing ring between, and sealing ring is located between self locking ratchet and screw pair. Drive shaft and transmission nut form the screw pair structure, are used for realizing the loading and unloading of brake force. Self locking ratchet realizes the self locking function of keeping the brake state, prevents the load rebound. Drive gear and transmission nut realize the mutual transmission of torque force, realize the conversion of external driving force input. Sealing ring sets up in the front end of screw pair, and the abrasive dust is prevented from invading the screw meshing surface, reduces the risk of oil mud cementation, improves the long-term reliability of system.

Description

Technical Field

[0001] This utility model belongs to the field of rail transit equipment, specifically a hand brake. Background Technology

[0002] The handbrake of railway freight cars is a crucial manually operated safety device that ensures the safe stopping of freight cars in situations where there is no power source (such as locomotive traction or air brake failure). The handbrake is operated by the operator who applies torque via a handwheel or handle, ultimately transmitting braking force to the basic braking system, causing the brake shoes to press against the wheels and generate friction. As the last mechanical line of defense against accidental vehicle runaway, its reliability is directly related to railway transportation safety.

[0003] Currently, some handbrake designs employ a ratchet self-locking structure in conjunction with a threaded clutch mechanism. For example, patent CN103569153A discloses a handbrake for heavy-duty freight cars on railways. In addition to braking, this handbrake also has a gradual release function. The specific operation process is as follows: the drive shaft is rotated counterclockwise, causing the threads between the drive shaft and the pinion shaft to loosen. This, in turn, causes a small gap to be created between the ratchet and the friction plates installed at its front and rear ends. The chain in the braking state drives the large gear to rotate, which in turn drives the small gear to rotate. The small gear then drives the key wheel and the pinion shaft to rotate in sequence, causing the ratchet to press against the friction plates at its front and rear ends again and maintain the braking force, thereby achieving controllable and smooth unloading of the braking force.

[0004] However, the continuous pressing and friction of the friction plates inevitably generates particulate wear debris. When the threaded clutch structure performs clamping and releasing functions, there are dynamic meshing gaps between its threaded pairs, which easily allow wear debris to penetrate. More seriously, to ensure smooth operation, lubricating grease is applied to the threaded pairs. When the infiltrated wear debris mixes with the grease, it forms a high-viscosity sludge on the threaded meshing surface. Under prolonged static conditions, temperature changes, and environmental oxidation, the sludge gradually dehydrates, hardens, and solidifies, eventually forming a hard, solidified deposit within the threaded gaps. This solidified sludge can potentially cause the threaded pairs to completely lose their freedom of movement, resulting in the complete loss of the handbrake's core unloading function. Utility Model Content

[0005] The purpose of this invention is to provide a handbrake to solve the problems mentioned in the prior art.

[0006] A handbrake is provided, comprising:

[0007] A drive shaft, which has only one degree of freedom to rotate about its axis at both ends, and a clamping part is provided on the drive shaft;

[0008] The transmission nut forms a threaded pair with the drive shaft;

[0009] A self-locking ratchet, which is confined between the clamping part and the drive nut;

[0010] The drive gear is sleeved around the drive shaft and can transmit torque between itself and the transmission nut.

[0011] A sealing ring is provided between the transmission nut and the drive shaft, and the sealing ring is located between the self-locking ratchet and the threaded pair.

[0012] Furthermore, an isolation ring is provided between the self-locking ratchet and the drive shaft.

[0013] The isolation ring is used to physically block the abrasive generated on the side of the self-locking ratchet away from the threaded pair from being transferred to the side of the self-locking ratchet closer to the threaded pair through the gap between the self-locking ratchet and the drive shaft, thereby reducing the abrasive production around the seal ring and thus reducing the sealing pressure of the seal ring.

[0014] Furthermore, the portion of the drive shaft located between the clamping part and the threaded pair extends radially outward to form a boss.

[0015] When wear debris is generated between the self-locking ratchet and the drive nut, it tends to fall downwards due to the rotation of the components and gravity. By forming a boss, wear debris located at the bottom of the drive nut needs to overcome gravity to penetrate the threaded joint, increasing the difficulty of wear debris intrusion.

[0016] Furthermore, the transmission nut extends toward the self-locking ratchet to form a pressure plate, and the sealing ring is disposed between the inner ring surface of the pressure plate and the outer peripheral surface of the boss.

[0017] After the motion is decomposed, the transmission nut has both rotational and axial movement freedom relative to the drive shaft. By extending the clamping plate and facing the outer circumference of the drive shaft, the clamping force of the sealing ring is transmitted radially, so that the sealing ring can form a sealing surface between the drive shaft and the transmission nut regardless of whether the drive shaft is rotating or axially translating.

[0018] Furthermore, friction plates are provided at both ends of the self-locking ratchet.

[0019] The friction pads achieve the self-locking function of the self-locking ratchet through axial compression, providing a source of frictional torque in braking conditions, and forming the basis for manual torque locking and control.

[0020] Furthermore, the friction plate has a degree of freedom relative to the self-locking ratchet, allowing it to move axially relative to the self-locking ratchet.

[0021] The axial floating structure allows for a partial rotational clamping action between the clamping part and the friction plate when the clamping part and the friction plate are engaged in rotational clamping action. This, in turn, shares the end face internal stress generated by the friction plate during clamping friction, providing a certain degree of protection to the surface of the friction plate, reducing the wear rate of one side of the friction plate, and reducing the generation of wear debris.

[0022] Furthermore, the friction plate is provided with chip grooves.

[0023] The chip groove provides storage space for some of the wear debris, preventing excessive accumulation of debris between the friction surfaces that could cause slippage or abnormal wear. This reduces the risk of wear debris spreading along the friction surfaces to the threaded joint, slowing down the system contamination process.

[0024] Furthermore, the opening diameter of the inner ring of the friction plate gradually increases in the direction away from the self-locking ratchet.

[0025] Under the self-rotation of the friction plate, the conical opening structure helps to discharge the wear debris on the interface outward, reducing its accumulation.

[0026] Furthermore, the diameter of the inner ring of the friction plate is larger than the diameter of the edge portion of the transmission nut near the friction plate end.

[0027] Since wear debris tends to fall downwards and accumulate on the inner ring interface at the bottom of the friction plate, this arrangement forms a boss structure between the transmission nut and the friction plate in the low elevation area, ensuring that the friction plate does not directly interfere with the edge of the transmission nut. The wear debris needs to overcome gravity to contact the sealing ring, reducing the risk of wear debris entering the threaded pair.

[0028] Furthermore, a lubricating plate is provided on the end face of the drive gear that can contact the transmission nut.

[0029] The lubricating plate can reduce the friction between the drive gear and the transmission nut, and prevent the abrasive particles from entering the threaded pair.

[0030] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0031] The drive shaft and transmission nut form a threaded pair structure for loading and unloading braking force. A self-locking ratchet provides a self-locking function to maintain the braking state and prevent load rebound. Torque is transmitted between the drive gear and transmission nut, enabling the conversion of external driving force input. A sealing ring is located at the front end of the threaded pair to prevent wear debris from entering the threaded meshing surface, reducing the risk of sludge buildup and improving the long-term reliability of the system. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of this drawing 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 only some embodiments of this drawing. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0033] Figure 1 This is an exploded structural diagram of a handbrake mechanism;

[0034] Figure 2 This is a cross-sectional structural diagram of a handbrake mechanism;

[0035] Figure 3 for Figure 2 Enlarged view of region A in the middle;

[0036] Figure 4 A schematic diagram of the structure of the friction plate provided by this utility model.

[0037] In the diagram: 1. Drive shaft; 11. Clamping part; 12. Boss; 2. Transmission nut; 21. Clamping plate; 3. Self-locking ratchet; 31. Friction plate; 32. Chip groove; 33. Ratchet stop; 34. Torsion spring; 4. Drive gear; 41. Lubricating plate; 5. Sealing ring; 6. Isolating ring; 71. Linkage gear; 72. Chain winding wheel; 8. Clutch pulley; 81. Return spring; 9. Hand-held clutch mechanism. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of this application clearer, the application is described and illustrated below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application. All other embodiments obtained by those skilled in the art based on the embodiments provided in this application without inventive effort are within the scope of protection of this application.

[0039] Obviously, the accompanying drawings described below are merely some examples or embodiments of this application. Those skilled in the art can apply this application to other similar scenarios based on these drawings without any inventive effort. Furthermore, it is understood that although the efforts made in this development process may be complex and lengthy, for those skilled in the art related to the content disclosed in this application, any changes to design, manufacturing, or production based on the technical content disclosed in this application are merely conventional technical means and should not be construed as insufficient disclosure of the content of this application.

[0040] However, there may be instances where unnecessary detailed descriptions are omitted. For example, detailed descriptions of well-known matters or repetitive descriptions of essentially the same structures may be omitted. This is to avoid unnecessarily lengthy descriptions and to facilitate understanding by those skilled in the art. Furthermore, the accompanying drawings and the following description are provided to enable those skilled in the art to fully understand this application and are not intended to limit the subject matter of the claims.

[0041] Please see Figures 1-3 As shown in the embodiment of this utility model, a handbrake includes a drive shaft 1, a transmission nut 2, a self-locking ratchet 3, and a drive gear 4. The drive shaft 1 has only one degree of freedom for rotation about its axis at both ends, and a clamping part 11 is provided on the drive shaft 1. A threaded pair is formed between the transmission nut 2 and the drive shaft 1. The self-locking ratchet 3 is confined between the clamping part 11 and the transmission nut 2. The drive gear 4 is sleeved around the drive shaft 1 and can transmit torque between itself and the transmission nut 2. A sealing ring 5 is provided between the transmission nut 2 and the drive shaft 1, and the sealing ring 5 is located between the self-locking ratchet 3 and the threaded pair.

[0042] The drive shaft 1 is supported at both ends by gears within the housing of the handbrake assembly. One end of the drive shaft 1 passes through the housing and engages with the square hub of the rotating handwheel, securing the handwheel to the drive shaft 1 with fasteners. The transmission nut 2 meshes with the chain operating mechanism of the brake. The chain operating mechanism has a linkage gear 71 and a chain winding wheel 72 designed from the inside out. The outer edge of the linkage gear 71 has linkage teeth that mesh with the drive gear 4 above the linkage gear 71, thereby reliably transmitting the torque from the drive shaft 1 to the chain operating mechanism.

[0043] A self-locking ratchet 3, a sealing ring 5, a transmission nut 2, and a drive gear 4 are sequentially assembled on the drive shaft 1, and are limited by a retaining ring and a pin. Rotating the handwheel clockwise towards the handbrake engages the threaded connection between the transmission nut 2 and the drive shaft 1. Since the drive shaft 1 has no axial displacement, the transmission nut 2 moves towards the self-locking ratchet 3 under the constraint of the thread. Ultimately, both sides of the self-locking ratchet 3 press against the clamping part 11 and the transmission nut 2, respectively, achieving locking under friction and ensuring continuous torque transmission. When rotating counterclockwise, the threaded connection between the transmission nut 2 and the drive shaft 1 loosens. At this point, the self-locking ratchet 3 is no longer pressed against the drive shaft 1, and the threads of the transmission nut 2 and the drive shaft 1 loosen slightly. However, under the torque drive of the chain mechanism, the transmission nut 2 tends to re-tighten, and the threads immediately return to a tightened state, gradually relieving the braking force.

[0044] Friction plates 31 are respectively provided at both ends of the self-locking ratchet 3. The two friction plates 31 can contact the clamping part 11 and the transmission nut 2 respectively. Since the friction plates 31 will generate powdery abrasives during use, they can easily enter between the threaded pair of the transmission nut 2 and the drive shaft 1, and combine with the lubricating grease in the thread structure to form grease. After the grease solidifies, it will cause the threaded pair to jam, causing the thread structure to malfunction. Therefore, a sealing ring 5 is designed between the transmission nut 2 and the drive shaft 1 to effectively prevent the powdery abrasives from entering the thread structure.

[0045] In addition, please see Figure 4 As shown, the friction plate 31 is designed with several chip grooves 32 to collect wear debris, which reduces the risk of wear debris spreading to the threaded pair along with the friction surface and slows down the system contamination process.

[0046] A ratchet stop 33 is designed above the self-locking ratchet 3. The ratchet stop 33 is mounted on the brake housing via a pin. A torsion spring 34 is installed on the ratchet stop 33, which can press the ratchet stop 33 against the teeth of the self-locking ratchet 3. This allows the self-locking ratchet 3 to rotate in one direction while the rotation of the self-locking ratchet 3 is limited by the ratchet stop 33 and the teeth, thus realizing the self-locking function of the handbrake.

[0047] An isolation ring 6 is provided between the self-locking ratchet 3 and the drive shaft 1. The isolation ring 6 is located between the self-locking ratchet 3 and the drive shaft 1, but it does not impede the relative rotation between the drive shaft 1 and the self-locking ratchet 3. Structurally, the isolation ring 6 forms a physical barrier, sealing off the wear debris generated on the side of the self-locking ratchet 3 away from the threaded pair, preventing the wear debris from migrating along the axial clearance of the drive shaft 1 to the side of the self-locking ratchet 3 near the threaded pair, especially in the area where the sealing ring 5 is located.

[0048] The drive shaft 1 extends radially outward from the portion between the clamping part 11 and the threaded pair to form a boss 12, and the self-locking ratchet 3 is fitted around the boss 12. A step or shoulder, higher than the threaded structure, is formed on the outer circumference of the boss 12, creating a height difference relative to the periphery. When friction debris is generated between the self-locking ratchet 3 and the drive nut 2, this debris may settle downwards under the influence of gravity and rotational inertia. The boss 12 geometrically forms an upward obstacle, ensuring that debris falling below the drive nut 2 must overcome the boss 12 to enter the threaded pair meshing surface. This means that the debris must overcome gravitational potential energy to move upwards into the threaded pair gap, significantly reducing the probability of debris intrusion.

[0049] Furthermore, the transmission nut 2 extends towards the self-locking ratchet 3 to form a clamping plate 21. The clamping plate 21 is a cylindrical structure formed by extending from the transmission nut 2 towards the self-locking ratchet 3. A sealing ring 5 is arranged between the inner ring surface of the clamping plate 21 and the outer circumferential surface of the boss 12. During braking and releasing, the transmission nut 2 has two degrees of freedom relative to the drive shaft 1: rotation and axial movement. When the transmission nut 2 rotates, the sealing ring 5 forms a rotational sealing interface between the moving ring and the stationary ring; when the transmission nut 2 moves axially, the sealing ring 5 forms an axial floating sealing interface in the radial fit. The two superimposed achieve dynamic multi-degree-of-freedom sealing.

[0050] A certain floating clearance or sliding fit structure exists between the friction plate 31 and the self-locking ratchet 3, allowing for axial follow-up pressing due to changes in external clamping force. During hand braking, the drive shaft 1 drives the clamping part 11 to rotate, simultaneously generating a combined force of rotation and axial clamping. Under the axial floating structure, the friction plate 31 can partially follow the clamping action and adjust its force position. This allows the friction plate 31 to not only generate frictional clamping action with the clamping part 11, but also form auxiliary clamping action with the end face of the self-locking ratchet 3 under floating conditions. The clamping action changes from single-point force to multi-faceted force distribution. After the torque is distributed among multiple contact surfaces, a single contact surface of the friction plate 31 will not bear the entire clamping stress, resulting in an expansion of the wear area and a reduction in pressure, which significantly reduces material spalling. Similarly, the working principle between the friction plate 31 and the transmission nut 2 in this structural form is the same as that between the friction plate 31 and the clamping part 11, and will not be described in detail here.

[0051] The opening diameter of the inner ring of the friction plate 31 gradually increases in the direction away from the self-locking ratchet 3. When the friction plate 31 rotates around its axis during operation, the wear debris on the contact interface tends to fall downwards under the influence of gravity. The geometric feature of the conical structure is that it gradually opens from the inside out. The opening shape can induce wear debris to enter axially and slide along the conical surface to the bottom, which helps to form a wear debris guidance path. This can effectively prevent wear debris from accumulating in the sealing area of ​​the friction pair, avoid further entering the sealing area or generating compressive load on the sealing ring 5, thereby reducing the wear and pressure burden on the sealing ring 5.

[0052] Similarly, wear debris tends to fall downwards under gravity and accumulate between the outer circumference of the drive shaft 1 and the inner ring surface of the friction plate 31, especially at the bottom, adjacent to the sealing ring 5. Therefore, the diameter of the inner ring of the friction plate 31 is set to be larger than the diameter of the edge of the transmission nut 2 near the end of the friction plate 31. This structure, by forming a shoulder structure between the bottom interface of the inner ring of the friction plate 31 and the transmission nut 2, makes it more likely that the falling wear debris will accumulate in the interface area of ​​the inner ring of the friction plate 31 below the shoulder, and is less likely to spread upwards to the sealing ring 5. Subsequently, the wear debris can be discharged when the friction plate 31 and the transmission nut 2 are in a clearance fit stage.

[0053] A lubricating plate 41 is provided on the end face of the drive gear 4 that can contact the transmission nut 2. During transmission, there is relative rotational motion between the drive gear 4 and the transmission nut 2, and direct contact will lead to high friction. The presence of the lubricating plate 41 can form a low-friction interface between the drive gear 4 and the transmission nut 2, effectively reducing frictional resistance, reducing the generation of wear debris, and keeping the inside of the threaded pair clean.

[0054] In one specific embodiment, the handbrake also includes a clutch pulley 8, which is mounted around the transmission nut 2. The clutch pulley 8 and the transmission nut 2 are connected by a spline, allowing the clutch pulley 8 to have only axial sliding freedom on the transmission nut 2 and to transmit torque. The clutch pulley 8 and the drive gear 4 are engaged by convex and concave teeth, allowing torque transmission when engaged and torque separation when disengaged. The engagement of the clutch pulley 8 and the drive gear 4 is the commonly used operating state, so a return spring 81 is designed between the transmission nut 2 and the clutch pulley 8. Under normal conditions, the return spring 81 is in a pre-compressed state, passively keeping the clutch pulley 8 engaged with the drive gear 4.

[0055] The handbrake is also equipped with a hand-operated clutch mechanism 9, which is used to control the sliding state of the clutch pulley 8 on the transmission nut 2. The hand-operated clutch mechanism 9 is existing technology, and its specific structure will not be described in detail here.

[0056] Rotating the handwheel clockwise on the handbrake engages the drive shaft 1, locking the threaded connection between the drive shaft 1 and the transmission nut 2. The transmission nut 2 gradually approaches the self-locking ratchet 3, eventually clamping it between the clamping part 11 and the clamping plate 21 via the friction plate 31. The drive shaft 1 continuously transmits torque to the drive gear 4 and the linkage gear 71, pulling the chain upwards via the chain winding wheel 72, thus gradually tightening the brake chain until the required braking tension is achieved. When the handwheel stops rotating, the ratchet stop 33 engages the self-locking ratchet 3, ensuring that the transmission nut 2 does not rotate in the opposite direction, thus achieving self-locking. When the handbrake is turned counterclockwise, the threaded connection between the drive shaft 1 and the transmission nut 2 is loosened. The transmission nut 2 is limited by the lubricating plate 41, so that the threaded connection between the drive shaft 1 and the transmission nut 2 can only be loosened at a certain angle. After loosening, the self-locking ratchet 3 between the drive shaft 1 and the transmission nut 2 loosens and loses its self-locking effect. The tightened brake chain sequentially drives the chain winding wheel 72, the linkage gear 71, the drive gear 4, the clutch pulley 8, and the transmission nut 2 to rotate, thus releasing the brake. Since the self-locking ratchet 3 is only slightly loose, the degree of release is limited. The brake chain, which is still under the braking tension, causes the transmission nut 2 to rotate counterclockwise, thereby reconnecting and locking the threaded connection between the drive shaft 1 and the transmission nut 2. Correspondingly, the self-locking ratchet 3 is re-clamped and no longer releases the brake. By rotating the handwheel counterclockwise in sequence, the gradual release function of the handbrake is achieved.

[0057] It should be noted that this application is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this application are included in the technical scope of this application. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of this application, are also included in the scope of this application.

Claims

1. A handbrake, characterized in that, include: The drive shaft (1) has only one degree of freedom to rotate around its axis at both ends, and a clamping part (11) is provided on the drive shaft (1). The transmission nut (2) forms a threaded pair with the drive shaft (1); The self-locking ratchet (3) is confined between the clamping part (11) and the transmission nut (2); The drive gear (4) is sleeved around the drive shaft (1) and can transmit torque to each other with the transmission nut (2); A sealing ring (5) is provided between the transmission nut (2) and the drive shaft (1), and the sealing ring (5) is located between the self-locking ratchet (3) and the threaded pair.

2. A handbrake according to claim 1, characterized in that, An isolation ring (6) is provided between the self-locking ratchet (3) and the drive shaft (1).

3. A handbrake according to claim 1, characterized in that, The drive shaft (1) extends radially outward at the part between the clamping part (11) and the threaded pair to form a boss (12).

4. A handbrake according to claim 3, characterized in that, The transmission nut (2) extends toward the self-locking ratchet (3) to form a pressure plate (21), and the sealing ring (5) is disposed between the inner ring surface of the pressure plate (21) and the outer circumferential surface of the boss (12).

5. A handbrake according to claim 1, characterized in that, Friction plates (31) are provided at both ends of the self-locking ratchet (3).

6. A handbrake according to claim 5, characterized in that, The friction plate (31) has a degree of freedom relative to the self-locking ratchet (3) that can move axially on the self-locking ratchet (3).

7. A handbrake according to claim 5, characterized in that, The friction plate (31) is provided with a chip groove (32).

8. A handbrake according to claim 5, characterized in that, In the direction away from the self-locking ratchet (3), the opening diameter of the inner ring of the friction plate (31) gradually increases.

9. A handbrake according to claim 5, characterized in that, The diameter of the inner ring of the friction plate (31) is greater than the diameter of the edge portion of the transmission nut (2) near the end of the friction plate (31).

10. A handbrake according to claim 1, characterized in that, A lubricating plate (41) is provided on the end face of the drive gear (4) that can contact the transmission nut (2).

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