An oil injection lubricating structure of an electric spindle and an electric spindle

Abstract

The application discloses a kind of electric spindle oil injection lubrication structure and electric spindle, comprising: bearing seat, with axial inner hole, the hole wall of axial inner hole is equipped with axial limit boss;Shaft core, is supported in bearing seat by first bearing, the inner ring of first bearing is installed in shaft core, the outer ring of first bearing is installed in the axial inner hole of bearing seat, and axial interval is left between the outer ring of first bearing and axial limit boss;Pre-tightening spring seat is set in axial interval, and axial pre-tightening spring is equipped between pre-tightening spring seat and axial limit boss, and pre-tightening spring seat is supported in the outer ring of first bearing along axial direction by axial pre-tightening spring, and pre-tightening spring seat is equipped with the first oil injection hole extending to the direction of first bearing, and bearing seat is equipped with the first oil inlet pipeline being communicated with first oil injection hole.The application only passes through pre-tightening spring seat simultaneously bearing pre-tightening, oil path distribution and other functions, reduces independent part, simplifies bearing seat inner cavity structure, and reduces the radial volume of main shaft.

Description

Technical Field

[0001] This invention relates to the field of electric spindles, and in particular to an oil-lubricating structure for an electric spindle and an electric spindle. Background Technology

[0002] High-speed electric spindles are core precision actuators in high-end CNC machine tools. The preload reliability, assembly stability, and lubrication and heat dissipation effects of the spindle bearings directly affect the spindle's rotational accuracy, rigidity, temperature rise control, and overall machine lifespan. Currently, high-speed electric spindles generally adopt a fixed spring preload structure, which uses elastic elements to axially press the bearings, eliminating bearing clearance and ensuring the rigidity and accuracy of the spindle during high-speed operation.

[0003] In existing conventional fixed preload electric spindle structures, the bearing preload spring assembly and the oil injection and return lubrication structure are arranged independently, resulting in significant technical defects during actual assembly and use: First, traditional structures lack dedicated spring limiting and protection structures. During manual assembly, the preload spring is prone to spring misalignment, displacement, and detachment, leading to assembly failure of the preload assembly. Once the spring falls off or becomes misaligned, it directly causes dimensional chain failure, interfering with all sealing structures and severely impacting assembly efficiency. Second, the existing preload area and lubrication return area are structurally separate and fragmented, occupying a large amount of spindle space, and the bearing cavity has an empty interior space without a flow guiding and limiting structure. During oil-jet lubrication, the sprayed lubricating oil splashes haphazardly within the cavity without a directional return channel, easily causing localized oil accumulation and delayed return. Under high-speed conditions, the lubricating oil is violently agitated by the bearing cage and spring assembly, generating a large amount of agitation heat, leading to excessive spindle temperature rise and increased thermal deformation, affecting precision machining accuracy. Simultaneously, the unguided oil flow easily causes uneven lubrication of the bearing raceways, resulting in localized dry friction, abnormal wear, and increased noise over long-term operation. Furthermore, traditional split-type layouts result in dispersed parts and low space utilization. The preload spring mounting position lacks a shielding and limiting structure, leading to extremely low assembly error tolerance and an inability to integrate preload installation protection with lubrication and heat dissipation structures.

[0004] In summary, the problems existing in the relevant technologies urgently need to be solved. Summary of the Invention

[0005] The purpose of this invention is to at least solve one of the technical problems existing in the prior art, and to provide an oil injection lubrication structure for an electric spindle and an electric spindle.

[0006] The technical solution adopted by this invention to solve its technical problem is: In a first aspect, an oil-lubricated structure for an electric spindle includes: The bearing housing has an axial inner hole, and the wall of the axial inner hole has an axial limiting boss. The shaft core is supported on the bearing housing by a first bearing. The inner ring of the first bearing is installed on the shaft core, and the outer ring of the first bearing is installed in the axial inner hole of the bearing housing. An axial gap is left between the outer ring of the first bearing and the axial limiting boss. A preload spring seat is provided at the axial interval. An axial preload spring is provided between the preload spring seat and the axial limiting boss. The axial preload spring supports the preload spring seat axially on the outer ring of the first bearing. The preload spring seat is provided with a first oil injection hole extending toward the first bearing. The bearing seat is provided with a first oil inlet pipe communicating with the first oil injection hole.

[0007] In conjunction with the first aspect, in some implementations of the first aspect, the axial limiting boss is an annular shape extending circumferentially along the axial inner hole, the preload spring seat is sleeve-shaped, the preload spring seat has a first outer peripheral surface and a second outer peripheral surface, an axial limiting surface is provided between the first outer peripheral surface and the second outer peripheral surface, the axial preload spring is supported between the axial limiting surface and the axial limiting boss, the first outer peripheral surface cooperates with the hole wall of the axial inner hole and is provided with a first sealing ring, and the second outer peripheral surface cooperates with the inner peripheral surface of the axial limiting boss and is provided with a second sealing ring.

[0008] In combination with the first aspect and the above-mentioned implementation methods, some implementation methods of the first aspect further include a circular baffle, which is sleeved on the second outer peripheral surface and supported between the axial limiting boss and the axial preload spring. The preload spring seat is provided with a screw hole extending axially from the end to the axial limiting surface, and the circular baffle is provided with a screw hole corresponding to the screw hole. It also includes screws that can pass through the screw holes and connect to the screw holes of the annular baffle, thereby forming a pre-assembled assembly of the preload spring seat, the axial preload spring, and the annular baffle.

[0009] In combination with the first aspect and the above-described implementations, in some implementations of the first aspect, the preload spring seat is provided with a plurality of axial blind holes on the axial limiting surface, the plurality of axial blind holes are distributed along the circumference of the preload spring seat, and the axial preload spring is disposed in the axial blind holes.

[0010] In combination with the first aspect and the above-described implementations, in some implementations of the first aspect, the preload spring seat is provided with an axial pin hole on the axial limiting surface, and the axial limiting boss is provided with a guide pin that cooperates with the axial pin hole.

[0011] In combination with the first aspect and the above-described implementations, in some implementations of the first aspect, the wall of the axial inner hole is provided with a first oil injection ring groove at a position that mates with the first outer peripheral surface, the first oil inlet pipe is connected to the first oil injection ring groove, and a first sealing ring is provided on both sides of the first oil injection ring groove.

[0012] In combination with the first aspect and the above-described implementations, in some implementations of the first aspect, the preload spring seat is provided with a centrifugal oil return groove on the end face facing the first bearing, and the bearing seat is provided with an oil return pipeline on the outside of the centrifugal oil return groove.

[0013] In combination with the first aspect and the above-mentioned implementation methods, some implementation methods of the first aspect further include a second bearing, the second bearing being disposed on the side of the axial limiting boss away from the first bearing, the inner ring of the second bearing being installed on the shaft core, the outer ring of the second bearing being installed in the axial inner hole of the bearing seat, the preload spring seat being provided with a second oil injection hole extending toward the second bearing, and the bearing seat being provided with a second oil inlet pipe communicating with the second oil injection hole; The inner wall of the axial limiting boss is provided with a second oil injection ring groove at the position that mates with the second outer peripheral surface. The second oil inlet pipe is connected to the second oil injection ring groove, and a second sealing ring is provided on both sides of the second oil injection ring groove.

[0014] In combination with the first aspect and the above-described implementations, in some implementations of the first aspect, the preload spring seat is provided with a sensor mounting hole, and a temperature sensor is provided in the sensor mounting hole.

[0015] In a second aspect, an electric spindle includes an oil-lubricated structure for an electric spindle as described in any implementation of the first aspect.

[0016] One of the above technical solutions has at least one of the following advantages or beneficial effects: In the technical solution of the present invention, a preload spring seat is provided in the axial inner hole of the bearing housing. Under the action of the axial preload spring, the preload spring seat is axially supported on the outer ring of the first bearing, thereby realizing the bearing preload function. At the same time, the preload spring seat is provided with a first oil injection hole. When the electric spindle is working, oil and gas enter the preload spring seat through the first oil inlet pipe, and then are precisely sprayed into the contact area between the rolling elements and the inner ring raceway of the first bearing through the first oil injection hole, realizing oil injection lubrication for the first bearing. The present invention realizes the integrated integration of the spring preload structure and the oil injection lubrication structure, simplifies the cavity layout, and reduces independent parts, simplifies the internal cavity structure of the bearing housing, and reduces the radial volume of the spindle by using only the preload spring seat to perform bearing preload and oil circuit distribution functions.

[0017] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0018] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 This is a schematic diagram of an embodiment of the present invention; Figure 2 This is a schematic diagram of the pre-installed component installation structure according to an embodiment of the present invention; Figure 3 This is a schematic diagram of a temperature sensor and guide pin structure according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the centrifugal oil return groove structure provided on the pre-tightening spring seat according to an embodiment of the present invention; Figure 5 This is a schematic diagram of the return oil pipeline structure according to an embodiment of the present invention. Detailed Implementation

[0019] This section will describe in detail specific embodiments of the present invention. Preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the drawings is to supplement the textual description with graphics, so that people can intuitively and vividly understand each technical feature and overall technical solution of the present invention, but they should not be construed as limiting the scope of protection of the present invention.

[0020] In this invention, when directions (up, down, left, right, front, and back) are described, it is only for the purpose of describing the technical solution of this invention, and does not indicate or imply that the technical features referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this invention.

[0021] In this invention, "several" means one or more, "multiple" means two or more, "greater than," "less than," "exceeding," etc., are understood to exclude the stated number; "above," "below," "within," etc., are understood to include the stated number. In the description of this invention, the terms "first" and "second" are used only to distinguish technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0022] In this invention, unless otherwise explicitly defined, the terms "setting," "installing," and "connecting" should be interpreted broadly. For example, they can refer to a direct connection or an indirect connection through an intermediate medium; a fixed connection, a detachable connection, or an integrally formed connection; a mechanical connection, an electrical connection, or a connection capable of mutual communication; or the internal connection of two components or the interaction between two components. Those skilled in the art can reasonably determine the specific meaning of the above terms in this invention based on the specific content of the technical solution.

[0023] See Figure 1 , Figure 2 This invention provides an oil-lubricated structure for an electric spindle, including a bearing housing 100, a spindle core 200, and a preload spring seat 300. The bearing housing 100 is mounted on a machine body 400 during use. The bearing housing 100 has an axial inner hole 101, and the hole wall of the axial inner hole 101 has an axial limiting boss 102. The axial limiting boss 102 protrudes radially from the hole wall of the axial inner hole 101, thereby forming an axial limiting structure within the axial inner hole 101. The spindle core 200 is supported on the bearing housing 100 by a first bearing 500. One or more first bearings 500 are provided. Specifically, the inner ring of the first bearing 500 is mounted on the spindle core 200, and the outer ring of the first bearing 500 is mounted on the axial inner hole 101 of the bearing housing 100. The spindle core 200 can rotate at high speed under the drive of a motor, thereby outputting power outwards.

[0024] An axial gap exists between the outer ring of the first bearing 500 and the axial limiting boss 102. A preload spring seat 300 is positioned within this axial gap. An axial preload spring 600 is provided between the preload spring seat 300 and the axial limiting boss 102. The axial preload spring 600 axially supports the preload spring seat 300 against the outer ring of the first bearing 500, thereby achieving bearing preload. Simultaneously, the preload spring seat 300 is provided with a first oil injection hole 301 extending towards the first bearing 500. The bearing housing 100 is provided with a first oil inlet pipe 102 communicating with the first oil injection hole 301. External oil and gas can enter through the first oil inlet pipe 102 and, through the first oil injection hole 301, guide the lubricating oil and gas to the contact area between the rolling elements and the inner ring raceway of the first bearing 500, thereby achieving oil and gas lubrication of the first bearing 500.

[0025] See Figure 1 , Figure 2In the technical solution of this invention, a preload spring seat 300 is provided in the axial inner hole 101 of the bearing housing 100. The preload spring seat 300 is axially supported on the outer ring of the first bearing 500 under the action of the axial preload spring 600, thereby achieving the bearing preload function. Simultaneously, the preload spring seat 300 is provided with a first oil injection hole 301. When the electric spindle is working, oil and gas enter the preload spring seat 300 through the first oil inlet pipe 102, and are then precisely sprayed through the first oil injection hole 301 onto the contact area between the rolling elements and the inner ring raceway of the first bearing 500, achieving oil lubrication of the first bearing 500. This invention designs a multi-stage through-type dedicated oil and gas passage, allowing the oil and gas medium to be guided step-by-step through the machine body 400, bearing housing 100, and preload spring seat 300, and then directly and precisely sprayed through the dedicated first oil injection hole 301 inside the preload spring seat 300 onto the core friction contact area between the rolling elements and the inner ring raceway of the first bearing 500. Abandoning the traditional spindle oil-gas diffusion lubrication method, the lubricating medium is highly concentrated in the bearing's highest wear and heat-generating working area, effectively improving the lubrication of the bearing friction pair, reducing dry friction and uneven wear between the rolling elements and raceways under high-speed operation, and improving the bearing's smoothness and service life.

[0026] This invention integrates the spring preload structure and the oil injection lubrication structure, simplifying the cavity layout. This invention uses only the preload spring seat 300 to simultaneously perform functions such as bearing preload and oil circuit distribution, reducing independent parts, simplifying the internal cavity structure of the bearing seat 100, and reducing the radial volume of the spindle.

[0027] In some embodiments, see Figure 1 , Figure 2 The axial limiting boss 102 is an annular shape extending circumferentially along the axial inner hole 101. The preload spring seat 300 is sleeve-shaped and has a first outer peripheral surface 302 and a second outer peripheral surface 303. The outer diameter of the first outer peripheral surface 302 is larger than the outer diameter of the second outer peripheral surface 303. An axial limiting surface 304 is provided between the first outer peripheral surface 302 and the second outer peripheral surface 303. The preload spring seat 300 is stepped. The axial preload spring 600 is supported between the axial limiting surface 304 and the axial limiting boss 102. The first outer peripheral surface 302 is fitted with the hole wall of the axial inner hole 101 and is provided with a first sealing ring 305. The second outer peripheral surface 303 is fitted with the inner peripheral surface of the axial limiting boss 102 and is provided with a second sealing ring 306. The axial preload spring 600 is isolated from the oil chamber by a sealing ring, which prevents the release of oil immersion stress in the axial preload spring 600, ensures the long-term stability of the fixed preload force, and extends the service life of the bearing and preload assembly.

[0028] Specifically, relying on the precise mating surfaces of the preload spring seat 300 and the bearing seat 100, and the sealing structure formed by the sealing ring, a completely independent, closed isolation cavity is constructed for the axial preload spring 600. This ensures that the axial preload spring 600 is completely isolated from the oil-lubricated environment, thoroughly preventing stress release caused by micro-cracks on the spring surface due to long-term immersion and contact with lubricating oil. This effectively eliminates problems such as lubricating oil corrosion of the spring and abnormal changes in the spring fatigue coefficient, preventing defects such as spring elasticity decay, preload decay, and uneven elasticity. It ensures a constant and stable preload during long-term high-speed operation of the electric spindle, maintaining long-term consistency in spindle rigidity and rotational accuracy.

[0029] In some embodiments, see Figure 2 The electric spindle oil injection lubrication structure also includes a circular baffle 700, which is sleeved on the second outer peripheral surface 303 and supported between the axial limiting boss 102 and the axial preload spring 600. The preload spring seat 300 is provided with a screw hole that extends axially from the end to the axial limiting surface 304, and the circular baffle 700 is provided with a screw hole corresponding to the screw hole.

[0030] The electric spindle oil injection lubrication structure also includes a screw 701, which can pass through a screw hole and connect to the screw hole of the annular baffle 700, and make the preload spring seat 300, the axial preload spring 600 and the annular baffle 700 form a pre-assembled assembly.

[0031] The preload spring seat 300 has multiple axial blind holes 307 on the axial limiting surface 304. The multiple axial blind holes 307 are distributed along the circumference of the preload spring seat 300, and the axial preload spring 600 is disposed in the axial blind holes 307.

[0032] See Figure 2 During assembly, first place the axial preload spring 600 into the axial blind hole 307 of the preload spring seat 300, then put the annular baffle 700 onto the preload spring seat 300, and connect the annular baffle 700 to the preload spring seat 300 with screws 701. After assembly, slowly press the whole assembly into the bearing seat 100 to the bottom, and then remove screws 701.

[0033] This invention employs a pre-assembly auxiliary structure of temporary baffles and temporary screws to solve the process problems of easy scattering, dislocation, and misalignment during the assembly of fixed axial preload springs 600. The invention adds a circular baffle 700 to radially wrap around and axially constrain the axial preload springs 600, maintaining the overall neatness of the springs throughout the assembly process, reducing assembly errors, and improving batch assembly consistency. Specifically, multiple sets of axial preload springs 600 can be pre-fixed inside the preload spring seat 300 to prevent spring displacement, detachment, and misalignment caused by impact during press-fitting through the oil return and spray grooves. After the entire assembly is press-fitted in place, the temporary screws can be removed to complete the assembly. This solves the problems of high assembly difficulty, poor assembly consistency, and easy assembly defects associated with traditional axial preload springs 600, significantly reducing manual assembly difficulty, improving batch assembly efficiency, and ensuring the symmetry and uniform force distribution of multiple sets of axial preload springs 600, thus guaranteeing the accuracy of the spindle preload foundation.

[0034] In some embodiments, see Figure 3 The preload spring seat 300 has an axial pin hole on the axial limiting surface 304, and the axial limiting boss 102 has a guide pin 308 that cooperates with the axial pin hole. The pin is used to ensure that the preload spring seat 300 will not rotate relative to the axial pin hole.

[0035] In some embodiments, see Figure 1 , Figure 2 The inner wall of the axial bore 101 is provided with a first oil injection ring groove 103 at the position where it mates with the first outer peripheral surface 302. The first oil injection ring groove 103 has a certain groove width to ensure that the preload spring seat 300 can still achieve oil and gas conduction after a certain displacement along the axial direction. The first oil inlet pipe 102 is connected to the first oil injection ring groove 103, and the first oil injection ring groove 103 is provided with first sealing rings 305 on both sides. During operation, the oil and gas pass through the machine body 400 to the first oil inlet pipe 102 of the bearing seat 100, then enter the small cavity formed by the first oil injection ring groove 103 and the preload spring seat 300, and then are precisely sprayed into the contact area between the bearing rolling element and the inner ring raceway through the first oil injection hole 301 inside the preload spring seat 300.

[0036] In some embodiments, see Figure 4 , Figure 5 The preload spring seat 300 has a centrifugal oil return groove 309 on the end face facing the first bearing 500, and the bearing seat 100 has an oil return pipe 104 on the outside of the centrifugal oil return groove 309. When the bearing is running at high speed, the oil vapor and condensed lubricating oil will flow along the centrifugal oil return groove 309 on the end face to the oil return pipe 104 due to centrifugal force. The combination of the negative pressure oil return pipe 104 and the oil return groove that makes reasonable use of centrifugal force effectively improves the oil return efficiency, thereby increasing the oil injection volume. The increase in oil injection volume means that the oil vapor can carry away more heat, effectively optimizing the bearing cooling problem.

[0037] This invention features multiple evenly distributed centrifugal oil return grooves 309 on the bearing mating end face of the pre-tightened spring seat 300. Combined with the overall negative pressure oil return pipeline system 104, the centrifugal force generated by the high-speed rotation of the bearing quickly removes condensed lubricating oil and excess oil vapor from the end face. This, combined with the negative pressure suction, significantly improves the overall oil return efficiency. With the greatly improved oil return flow, the bearing lubrication spray volume can be increased without causing oil accumulation, blockage, or spillage. A larger flow of circulating oil vapor can continuously remove the frictional heat generated by the high-speed operation of the bearing, effectively improving bearing heat dissipation, suppressing abnormal temperature rise and high-temperature heat accumulation, and solving the defects of overheating, thermal drift, and high-temperature degradation in high-speed electric spindle bearings. This significantly improves the stability and limiting speed performance of the spindle during high-speed continuous operation.

[0038] In some embodiments, see Figure 1 , Figure 2 It also includes a second bearing 800, one or more of which are provided. The second bearing 800 is located on the side of the axial limiting boss 102 away from the first bearing 500. The inner ring of the second bearing 800 is mounted on the shaft core 200, and the outer ring of the second bearing 800 is mounted on the axial inner hole 101 of the bearing seat 100. The preload spring seat 300 is provided with a second oil injection hole 310 extending toward the second bearing 800, and the bearing seat 100 is provided with a second oil inlet pipe 105 communicating with the second oil injection hole 310.

[0039] The inner wall of the axial limiting boss 102 is provided with a second oil injection ring groove 106 at the position where it mates with the second outer peripheral surface 303. The second oil inlet pipe 105 is connected to the second oil injection ring groove 106. The second sealing ring 306 is provided on both sides of the second oil injection ring groove 106.

[0040] During operation, the oil and gas pass through the machine body 400 to the second oil inlet pipe 105 of the bearing housing 100, then enter the small cavity formed by the second oil injection ring groove 106 and the preload spring seat 300, and then are precisely sprayed through the second oil injection hole 310 inside the preload spring seat 300 to the contact area between the bearing rolling element and the inner ring raceway, so as to achieve oil and gas lubrication for the second bearing 800.

[0041] In some embodiments, see Figure 3The preload spring seat 300 is provided with a sensor mounting hole, in which a temperature sensor 311 is installed. In this embodiment, a sensor mounting hole for placing the temperature sensor 311 is opened in the preload spring seat 300, allowing the temperature sensor 311 to be closer to the bearing. Conventional spindle bearing thermistors are generally located in the area of ​​extensive heat exchange between the cooling water and the bearing, resulting in significant feedback lag and data deviation. This patent integrates the bearing thermistor into the preload spring seat 300, placing it closer to the bearing and further away from the heat exchange area. This avoids the drawbacks of traditional spindle sensors located in the core area of ​​heat exchange between the cooling water and the bearing, effectively optimizing the industry problems of feedback lag, temperature data distortion, and large thermal interference deviation of the temperature sensor 311. It can collect the actual operating temperature of the bearing in real time and accurately, providing fast, accurate, and effective raw data for thermal error compensation and temperature rise control of the spindle electronic control system, greatly improving the thermal stability of the electric spindle, reducing thermal deformation errors under high-speed and long-term machining, and improving workpiece machining accuracy.

[0042] The core highlight of this invention is the multi-functional combination of the preload spring seat 300 and the annular baffle 700, integrating four functions: radial and axial limiting and anti-dislodgement of the spring, circumferential flow equalization of lubricating oil, oil guiding and converging, and temperature feedback. Existing technologies use separate protective sleeves and flow dividers; this solution replaces multiple sets of parts with a single component, a groundbreaking structure that significantly improves integration. A second highlight is the design of a fully enclosed limiting structure for the fixed, non-adjustable axial preload spring 600. The inner wall of the preload spring seat 300 encircles the outer ring of the axial preload spring 600, and the annular baffle 700 provides axial limiting. This prevents the spring from falling off during press-fitting and installation, eliminating the need for auxiliary tooling. A single person can complete the installation of the bearing and the axial preload spring 600, significantly reducing assembly difficulty, rework rate, and improving mass production efficiency. A third highlight is the separation of the axial preload spring 600 from the oil chamber by a sealing ring, preventing stress release from the spring oil immersion and ensuring long-term stability of the fixed preload force, thus extending the service life of the bearing and preload assembly. Highlight four is its strong compatibility; it requires no modification to the original spindle preload scheme and is compatible with all fixed-spring preload high-speed electric spindles, making modification easy. Highlight five is the placement of the temperature sensor 311 closer to the bearing, solving the problem of lag in temperature feedback and providing high-quality raw data for thermal error compensation. Highlight six is ​​the evenly spaced, obliquely oriented centrifugal oil return grooves 309 on the end face of the oil injection sleeve, improving the oil return performance within the spindle bearing cavity and allowing for a larger volume of low-temperature oil-air injection, effectively removing heat at its source.

[0043] Embodiments of the present invention also provide an electric spindle, including the electric spindle oil injection lubrication structure of any of the above embodiments.

[0044] In the description of this specification, references to terms such as "example," "embodiment," or "some embodiments" indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, 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.

[0045] Of course, the present invention is not limited to the above-described embodiments. Those skilled in the art can make equivalent modifications or substitutions without departing from the spirit of the present invention, and these equivalent modifications or substitutions are all included within the scope defined by the claims of this application.

Claims

1. An oil-spraying lubrication structure for an electric spindle, characterized in that, include: The bearing housing has an axial inner hole, and the wall of the axial inner hole has an axial limiting boss. The shaft core is supported on the bearing housing by a first bearing. The inner ring of the first bearing is installed on the shaft core, and the outer ring of the first bearing is installed in the axial inner hole of the bearing housing. An axial gap is left between the outer ring of the first bearing and the axial limiting boss. A preload spring seat is provided at the axial interval. An axial preload spring is provided between the preload spring seat and the axial limiting boss. The axial preload spring supports the preload spring seat axially on the outer ring of the first bearing. The preload spring seat is provided with a first oil injection hole extending toward the first bearing. The bearing seat is provided with a first oil inlet pipe communicating with the first oil injection hole.

2. The electric spindle oil injection lubrication structure according to claim 1, characterized in that, The axial limiting boss is an annular shape extending circumferentially along the axial inner hole. The preload spring seat is sleeve-shaped and has a first outer peripheral surface and a second outer peripheral surface. An axial limiting surface is provided between the first outer peripheral surface and the second outer peripheral surface. The axial preload spring is supported between the axial limiting surface and the axial limiting boss. The first outer peripheral surface mates with the hole wall of the axial inner hole and is provided with a first sealing ring. The second outer peripheral surface mates with the inner peripheral surface of the axial limiting boss and is provided with a second sealing ring.

3. The electric spindle oil injection lubrication structure according to claim 2, characterized in that, It also includes a circular baffle, which is sleeved on the second outer peripheral surface and supported between the axial limiting boss and the axial preload spring. The preload spring seat is provided with a screw hole extending axially from the end to the axial limiting surface, and the circular baffle is provided with a screw hole corresponding to the screw hole. It also includes screws that can pass through the screw holes and connect to the screw holes of the annular baffle, thereby forming a pre-assembled assembly of the preload spring seat, the axial preload spring, and the annular baffle.

4. The electric spindle oil injection lubrication structure according to claim 3, characterized in that, The preload spring seat has multiple axial blind holes on the axial limiting surface. The multiple axial blind holes are distributed along the circumference of the preload spring seat, and the axial preload spring is disposed in the axial blind holes.

5. The electric spindle oil injection lubrication structure according to claim 3, characterized in that, The preload spring seat has an axial pin hole on the axial limiting surface, and the axial limiting boss has a guide pin that mates with the axial pin hole.

6. The electric spindle oil injection lubrication structure according to claim 2, characterized in that, The axial inner hole has a first oil injection ring groove at a position that mates with the first outer peripheral surface. The first oil inlet pipe is connected to the first oil injection ring groove, and a first sealing ring is provided on both sides of the first oil injection ring groove.

7. The oil injection lubrication structure for an electric spindle according to claim 1, characterized in that, The preload spring seat has a centrifugal oil return groove on the end face facing the first bearing, and the bearing seat has an oil return pipeline on the outside of the centrifugal oil return groove.

8. The electric spindle oil injection lubrication structure according to claim 2, characterized in that, It also includes a second bearing, which is disposed on the side of the axial limiting boss away from the first bearing. The inner ring of the second bearing is installed on the shaft core, and the outer ring of the second bearing is installed in the axial inner hole of the bearing seat. The preload spring seat is provided with a second oil injection hole extending toward the second bearing, and the bearing seat is provided with a second oil inlet pipe communicating with the second oil injection hole. The inner wall of the axial limiting boss is provided with a second oil injection ring groove at the position that mates with the second outer peripheral surface. The second oil inlet pipe is connected to the second oil injection ring groove, and a second sealing ring is provided on both sides of the second oil injection ring groove.

9. The oil injection lubrication structure for an electric spindle according to claim 1, characterized in that, The preload spring seat is provided with a sensor mounting hole, and a temperature sensor is installed in the sensor mounting hole.

10. An electric spindle, characterized in that, The electric spindle includes the oil-lubricated structure according to any one of claims 1 to 9.

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