Limited stroke ball spline

Abstract

The utility model discloses a limited stroke ball spline which comprises a spline shaft, a spline sleeve is connected to the outer side of the spline shaft in a sleeved mode, an extension shaft is fixedly arranged at the end of the spline shaft, a self-expansion hot melting lubricating mechanism is installed on the spline shaft, and a butt joint base is fixedly arranged at the end of the extension shaft. A butt joint hole is formed in the end of the spline shaft, the butt joint seat is inserted into the butt joint hole and connected with the butt joint hole through a fixing bolt, an expansion channel is formed in the self-expansion hot melting lubricating mechanism, and a sealing plug is installed at the end of the expansion channel. According to the limited-stroke ball spline, the extension shafts with different lengths are flexibly selected according to actual installation space or stroke requirements, secondary machining of the spline shaft body is not needed, and the adaptation difficulty caused by size inconsistency is greatly reduced; and for the same spline shaft, the spline shaft can adapt to various scenes by replacing extension shafts with different lengths, and the universality of parts is improved.

Description

Technical Field

[0001] This utility model relates to the field of ball splines, specifically a limited stroke ball spline. Background Technology

[0002] When ball splines are in operation, lubricating oil needs to be added. Due to the compact structure of the spline itself, it is not possible to add a device to monitor the oil level. If the lubricating oil is consumed and not added in time, the spline shaft and the external circulation device will rub against each other, thereby damaging the surface of the spline shaft and making noise during the friction. Adding oil after the above problems have occurred will result in irreversible damage to the ball spline.

[0003] To solve the above problems, after searching, Chinese Patent CN218761198U was found, which discloses a limited stroke ball spline. The patent includes a spline shaft and a circulator. The circulator is sleeved on the outside of the spline shaft. A detection component is provided at one end of the circulator. The detection component includes a roller and a protrusion. The roller and the protrusion are connected in a driving connection. The outer wall of the roller is covered with a friction layer, which is in contact with the outer wall of the spline shaft.

[0004] While the aforementioned device allows operators to quickly observe when the lubricating oil level is low and needs to be increased, and at this point the lubricating oil is not completely consumed, serving as an early warning to prevent damage and noise from occurring before adding more lubricating oil, in actual use, the spline shaft length is fixed. This fixed length cannot adapt to different installation spaces or stroke requirements. When the equipment needs to adjust the stroke or change the installation position, the spline of the corresponding length must be replaced, increasing cost and difficulty of replacement. Utility Model Content

[0005] The purpose of this invention is to provide a limited-stroke ball spline to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, a limited-stroke ball spline is provided, comprising a spline shaft, a spline sleeve sleeved on the outer side of the spline shaft, an extension shaft fixedly provided at the end of the spline shaft, a self-expanding hot-melt lubrication mechanism mounted on the spline shaft, a mating seat fixedly provided at the end of the extension shaft, a mating hole provided at the end of the spline shaft, the mating seat being inserted into the mating hole and connected by a fixing bolt, an expansion channel provided on the self-expanding hot-melt lubrication mechanism, and a sealing plug installed at the end of the expansion channel.

[0007] Furthermore, both the docking seat and the docking hole have rectangular cross-sections. The length of the docking seat is equal to the depth of the docking hole. Four sets of threaded holes are evenly provided on the outer side of the docking seat. Four sets of slots are evenly provided on the outer ring surface of the docking hole. The fixing bolts pass through the slots and are threaded into the inside of the threaded holes.

[0008] Furthermore, the self-expanding hot melt lubrication mechanism also includes a sealing groove, a sealing gasket, an inner cylinder, and a lubrication channel. The sealing groove is provided at the end of the expansion channel, and the sealing groove is adapted to the size of the sealing plug. An inner cylinder is fixedly provided at the end of the sealing plug.

[0009] Furthermore, a sealing gasket is fitted onto the outer side of the inner cylinder, the inner cylinder is inserted into the expansion channel, and the sealing plug is inserted into the sealing groove and sealed by an annular sealing gasket. The sealing plug is screwed and fixed inside the sealing groove.

[0010] Furthermore, four rows of lubrication channels are evenly formed on the outer ring surface of the spline shaft and the extension shaft. The lubrication channels are connected to the expansion channels. The expansion channels inside the spline shaft and the extension shaft are connected to each other through mating seats and mating holes.

[0011] Furthermore, an acceleration channel is provided in the middle of the lubrication channel, the cross-section of the acceleration channel is rectangular, and the cross-section of the lubrication channel is trapezoidal.

[0012] Compared with the prior art, the beneficial effects of this utility model are:

[0013] 1. This solution uses four sets of bolts to fix the extension shaft and spline shaft inside the screw hole through the slot. Different lengths of extension shaft can be flexibly selected according to the actual installation space or stroke requirements, without the need for secondary processing of the spline shaft body, which greatly reduces the difficulty of adaptation due to size incompatibility. For the same spline shaft, by changing the extension shaft of different lengths, it can adapt to a variety of scenarios, improving the versatility of the components.

[0014] 2. This solution utilizes the principle that as the temperature of the splined shaft increases, the lubricating oil inside expands due to heat and overflows through the lubrication channels to the outer surface of the splined shaft. When the temperature of the splined shaft rises due to rolling friction, the lubricating oil in the expansion channels expands synchronously and automatically overflows through the lubrication channels to contact the balls inside the raceway and spline sleeve, precisely matching the real-time lubrication needs of the friction parts. The higher the temperature of the splined shaft, the greater the expansion of the lubricating oil, and the more timely the grease replenishment, avoiding the problem of insufficient lubrication at high temperatures in traditional lubrication methods, thus forming a dynamic balance. It eliminates the need for frequent manual lubrication, making it particularly suitable for enclosed spaces, high-speed operation, or inaccessible working conditions, reducing maintenance costs and downtime. Attached Figure Description

[0015] Figure 1 This is a front view schematic diagram of the structure of this utility model;

[0016] Figure 2 This is a front view of the structure of this utility model;

[0017] Figure 3 This is a rear view of the structure of this utility model;

[0018] Figure 4 This is a schematic diagram of the spline shaft structure of this utility model;

[0019] Figure 5 This is a cross-sectional view of the spline shaft of the present invention;

[0020] Figure 6 This is a schematic diagram of the connection structure of the spline shaft and extension shaft of this utility model;

[0021] Figure 7 This is a schematic diagram of the external structure of the ball spline of this utility model;

[0022] Figure 8 This is a cross-sectional view of the lubrication channel structure of this utility model.

[0023] The following are the labeling elements in the diagram: 1. Splined shaft; 2. Splined sleeve; 3. Self-expanding hot melt lubrication mechanism; 31. Expansion channel; 32. Sealing groove; 33. Sealing gasket; 34. Inner sleeve; 35. Sealing plug; 36. Lubrication channel; 361. Acceleration channel; 4. Extension shaft; 41. Connecting seat; 411. Connecting hole; 42. Slot; 43. Threaded hole. Detailed Implementation

[0024] Please see Figure 1-8 This utility model provides a limited stroke ball spline, including a spline shaft 1, a spline sleeve 2 sleeved on the outside of the spline shaft 1, an extension shaft 4 fixedly provided at the end of the spline shaft 1, a self-expanding hot melt lubrication mechanism 3 installed on the spline shaft 1, a mating seat 41 fixedly provided at the end of the extension shaft 4, a mating hole 411 opened at the end of the spline shaft 1, the mating seat 41 is inserted into the interior of the mating hole 411 and connected by fixing bolts, an expansion channel 31 is opened on the self-expanding hot melt lubrication mechanism 3, and a sealing plug 35 is installed at the end of the expansion channel 31.

[0025] Working principle: In actual use, when the length of the spline shaft 1 cannot meet the installation space or stroke requirements, the extension shaft 4 of the appropriate size can be inserted into the mating hole 411 opened at the end of the spline shaft 1 through the mating seat 41. At the same time, the fixing bolt passes through the slot hole 42 and is screwed into the screw hole 43. Using four sets of bolts, the extension shaft 4 and the spline shaft 1 are fixedly installed. The extension shaft 4 of different lengths can be selected according to the actual installation space or stroke requirements.

[0026] In a preferred embodiment, both the docking seat 41 and the docking hole 411 have rectangular cross sections. The length of the docking seat 41 is equal to the depth of the docking hole 411. Four sets of screw holes 43 are evenly provided on the outer side of the docking seat 41, and four sets of slots 42 are evenly provided on the outer ring surface of the docking hole 411. The fixing bolt passes through the slot 42 and is screwed and fixed inside the screw hole 43.

[0027] like Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown: Different lengths of extension shaft 4 can be flexibly selected according to actual installation space or stroke requirements, eliminating the need for secondary processing of the spline shaft 1 body and significantly reducing the difficulty of adaptation due to size mismatches; for the same spline shaft 1, by replacing with extension shafts 4 of different lengths, it can adapt to various scenarios, improving the versatility of the components; adopting a plug-in structure, the extension shaft 4 is inserted into the mating hole 411 of the spline shaft 1 through the mating seat 41 and fixed with bolts, allowing for quick assembly without complex tools or professional skills, improving installation efficiency; the symmetrical distribution of the four sets of bolts can evenly transmit force, reducing stress concentration at the connection points and ensuring that the extension shaft 4 and spline shaft 1 rotate synchronously during operation, avoiding slippage or loosening; the plug-in fit between the mating seat 41 and the mating hole 411 can play a positioning role, ensuring the spline shaft 1 rotates synchronously. The coaxiality of the key shaft 1 and the extension shaft 4 reduces vibration or wear caused by eccentricity, extending the service life of the components. There is no need to customize the spline shaft 1 for different size requirements; only standard-length spline shaft 1 and various specifications of extension shaft 4 need to be mass-produced, reducing customized production costs. If the extension shaft 4 needs to be replaced due to wear or length discrepancies, only the extension shaft 4 needs to be replaced, without replacing the entire spline shaft 1, saving materials and replacement costs. During later equipment modifications or stroke adjustments, size changes can be achieved by replacing the extension shaft 4 with a longer or shorter one, without redesigning the spline shaft 1 system, improving the flexibility of equipment upgrades. The modular extension structure balances the adaptability, stability, and economy of ball splines, making it particularly suitable for mechanical transmission systems that require frequent length adjustments or diverse installation scenarios.

[0028] As a preferred embodiment, the self-expanding hot melt lubrication mechanism 3 further includes a sealing groove 32, a sealing gasket 33, an inner cylinder 34, and a lubrication channel 36. The sealing groove 32 is provided at the end of the expansion channel 31. The sealing groove 32 is adapted to the size of the sealing plug 35. The inner cylinder 34 is fixedly provided at the end of the sealing plug 35.

[0029] A sealing gasket 33 is fitted onto the outer side of the inner tube 34. The inner tube 34 is inserted into the inside of the expansion channel 31. At the same time, the sealing plug 35 is inserted into the inside of the sealing groove 32 and sealed by the annular sealing gasket 33. The sealing plug 35 is screwed and fixed inside the sealing groove 32.

[0030] Four rows of lubrication channels 36 are evenly provided on the outer ring surface of the spline shaft 1 and the extension shaft 4. The lubrication channels 36 are connected to the expansion channels 31. The expansion channels 31 inside the spline shaft 1 and the extension shaft 4 are connected to each other through the mating seat 41 and the mating hole 411.

[0031] An acceleration channel 361 is provided in the middle of the lubrication channel 36. The cross-section of the acceleration channel 361 is rectangular, and the cross-section of the lubrication channel 36 is trapezoidal.

[0032] like Figure 5 , Figure 6 , Figure 7 and Figure 8 As shown: Splined shaft 1 and splined sleeve 2 achieve relative sliding or rotation through internal balls. When the balls roll between the raceway of splined shaft 1 and the corresponding track of splined sleeve 2, rolling friction is generated due to contact pressure, causing the temperature of splined shaft 1 to increase. Sufficient lubricating oil can be filled in the expansion channel 31 inside splined shaft 1 beforehand. As the temperature of splined shaft 1 rises, the lubricating oil inside will expand due to heat and overflow to the outer surface of splined shaft 1 through lubrication channel 36. When the temperature of splined shaft 1 rises due to rolling friction, the expansion channel 31... The lubricating oil inside expands synchronously with heat and automatically overflows through the lubrication channel 36 to contact the balls inside the raceway and spline sleeve 2, precisely matching the real-time lubrication needs of the friction parts. The higher the temperature of the spline shaft 1, the greater the expansion of the lubricating oil, and the more timely the grease replenishment, avoiding the problem of insufficient lubrication at high temperatures in traditional lubrication methods, thus forming a dynamic balance. Frequent manual lubrication is not required, making it particularly suitable for enclosed spaces, high-speed operation, or inaccessible working conditions, reducing maintenance costs and downtime. The lubricating oil is stored in the internal channel of the spline shaft 1, reducing external contamination. The risk of lubrication failure due to contamination is reduced, extending the effective life of the lubrication system. Lubricating oil overflows directly from the internal channels of the spline shaft 1 to the raceway surface without external conduction, resulting in a short and precise lubrication path. This allows for the rapid formation of an effective oil film between the balls and raceways, reducing the rolling friction coefficient. Compared to open lubrication systems, the internally stored lubricating oil is less likely to be ejected due to centrifugal force or vibration, leading to higher utilization and reduced lubricant waste. Overflowing lubricating oil can carry away some of the heat generated by friction during lubrication, indirectly helping to dissipate heat from the spline shaft 1 and alleviating overheating issues. The lubrication channels are integrated inside the spline shaft 1, eliminating the need for external lubrication lines or pumps and saving external installation space, making it particularly suitable for equipment requiring high structural compactness. The system cleverly utilizes the physical property of thermal expansion of lubricating oil, deeply binding the lubrication system to the working state of the spline shaft 1. This achieves advantages such as on-demand grease replenishment, automatic response, low maintenance, and high efficiency, improving the operational stability of the ball spline and reducing long-term operating costs, especially in high-load, high-frequency, or maintenance-inconvenient scenarios.

[0033] An acceleration channel 361 is provided in the middle of the lubrication channel 36. The inner diameter of the acceleration channel 361 is smaller than that of the lubrication channel 36. When lubricating oil flows from the coarser lubrication channel 36 into the smaller-diameter acceleration channel 361, according to Bernoulli's principle in fluid mechanics, the fluid velocity will increase as the channel cross-section decreases, and the pressure will also increase. The high-pressure, high-speed lubricating oil can be sprayed more forcefully from the end of the channel, accurately impacting the contact area between the ball and the raceway, avoiding lubrication blind spots caused by insufficient flow velocity. In particular, it has a compensating effect on the centrifugal force oil slinging phenomenon when the spline shaft 1 is running at high speed. When the compressed lubricating oil is sprayed out, it is in a jet state, which can spread more quickly on the raceway surface, forming a uniform oil film with a certain thickness. It is less likely to be damaged by the force generated by the rolling of the ball or the rotation of the spline shaft 1, thus improving the lubrication durability.

Claims

1. A finite-stroke ball spline, comprising a spline shaft (1), characterized in that: A spline sleeve (2) is sleeved on the outside of the spline shaft (1). An extension shaft (4) is fixedly provided at the end of the spline shaft (1). A self-expanding hot melt lubrication mechanism (3) is installed on the spline shaft (1). A mating seat (41) is fixedly provided at the end of the extension shaft (4). A mating hole (411) is opened at the end of the spline shaft (1). The mating seat (41) is inserted into the inside of the mating hole (411) and connected by a fixing bolt. An expansion channel (31) is opened on the self-expanding hot melt lubrication mechanism (3). A sealing plug (35) is installed at the end of the expansion channel (31).

2. The finite stroke ball spline according to claim 1, characterized in that: The cross-sections of the docking seat (41) and the docking hole (411) are both rectangular. The length of the docking seat (41) is equal to the depth of the docking hole (411). Four sets of screw holes (43) are evenly opened on the outer side of the docking seat (41). Four sets of slots (42) are evenly opened on the outer ring surface of the docking hole (411). The fixing bolt passes through the slot (42) and is screwed and fixed inside the screw hole (43).

3. The finite stroke ball spline according to claim 1, characterized in that: The self-expanding hot melt lubrication mechanism (3) also includes a sealing groove (32), a sealing gasket (33), an inner cylinder (34), and a lubrication channel (36). The sealing groove (32) is provided at the end of the expansion channel (31). The sealing groove (32) is adapted to the size of the sealing plug (35). The inner cylinder (34) is fixedly provided at the end of the sealing plug (35).

4. A finite-stroke ball spline according to claim 3, characterized in that: The inner tube (34) is fitted with a sealing gasket (33) on its outer side. The inner tube (34) is inserted into the expansion channel (31). At the same time, the sealing plug (35) is inserted into the sealing groove (32) and sealed by the annular sealing gasket (33). The sealing plug (35) is screwed and fixed inside the sealing groove (32).

5. A finite-stroke ball spline according to claim 1, characterized in that: Four rows of lubrication channels (36) are evenly provided on the outer ring surface of the spline shaft (1) and the extension shaft (4). The lubrication channels (36) are connected to the expansion channels (31). The expansion channels (31) inside the spline shaft (1) and the extension shaft (4) are connected to each other through the docking seat (41) and the docking hole (411).

6. A finite-stroke ball spline according to claim 5, characterized in that: An acceleration channel (361) is provided in the middle of the lubrication channel (36). The cross-section of the acceleration channel (361) is rectangular, and the cross-section of the lubrication channel (36) is trapezoidal.

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