A static pressure electric spindle

Abstract

The present invention provides a hydrostatic electric spindle, belonging to the field of mechanical technology. It solves the problem of poor service life of existing electric spindles. The hydrostatic electric spindle comprises a housing, a rotor shaft disposed within the housing, and a stator. Hydrostatic bearings are disposed between both ends of the rotor shaft and the housing. Oil inlet and outlet holes are disposed at both ends of the housing to mate with the hydrostatic bearings. Static rings and dynamic rings are disposed between both ends of the stator and the corresponding hydrostatic bearings. The outer wall of the static ring and the inner wall of the dynamic ring are sealed and fixedly connected to the housing and the rotor shaft, respectively. The static ring is sleeved over the dynamic ring without contact between the two rings, forming an annular cavity between the static ring and the dynamic ring. An air duct with an inlet and an outlet is formed within the static ring, the outlet of the air duct connecting to the annular cavity. Two air inlets are formed through the housing, respectively connecting the two air duct inlets. An annular air guide cavity is formed between the housing, the rotor shaft, the hydrostatic bearing, and the static ring and dynamic ring disposed near the hydrostatic bearing. Two exhaust holes are disposed in the housing, respectively connecting the two air guide cavities. The hydrostatic electric spindle has a long service life.

Description

Technical Field

[0001] The invention belongs to the field of mechanical technology and relates to an electric spindle, in particular to a static pressure electric spindle. Background Art

[0002] Most of the existing grinding electric spindles are traditional electric spindle structures, which are difficult to perform long-term grinding of superhard materials. The main manifestation is that long-term, high-hardness grinding is a test for the stability and rigidity of the spindle. In order to solve this problem, the hydrostatic electric spindle was born.

[0003] Existing hydrostatic electric spindles, such as a high-speed ultrasonic liquid hydrostatic grinding electric spindle device disclosed in the China Patent Library (application number: 201911193169.2), include a spindle, a rotor sleeved on the spindle, and a housing with a stator that cooperates with the rotor. The front part of the spindle is supported on the housing by a bearing, and a linkage shaft is installed at its front end through a linkage sleeve; a grinding head is installed at the end of the linkage shaft, which is characterized in that it also includes an ultrasonic vibration device installed at the front of the spindle and used to drive the spindle to perform high-frequency mechanical vibration when the spindle rotates, and a hydraulic floating device installed at the rear of the spindle and used to float the front end of the spindle when the spindle rotates; the hydraulic floating device includes The invention comprises a radial bearing seat which is sleeved on the outer side of the rear part of the main shaft and is provided with an oil passage inside, an oil inlet on the outside of the radial bearing seat which is connected with the above-mentioned oil passage for hydraulic oil to enter the oil passage, an oil sealing flange which is clamped between the front end of the radial bearing seat and the housing and is provided with a boss near the end of the main shaft, and an oil-proof cover which is installed at the rear end of the radial bearing seat by fasteners. The radial bearing seat, the oil-proof cover, the oil-sealing flange and the main shaft together constitute a chamber for the flow of hydraulic oil. The outside of the radial bearing seat is provided with a first oil outlet which is connected with the above-mentioned chamber for the hydraulic oil to flow out of the chamber. The invention also comprises a hydrostatic radial bearing which is installed on the outer side of the main shaft through the shoulder of the main shaft and the first step in the radial bearing seat and is used to float the front end of the main shaft.

[0004] When the above-mentioned electric spindle is in use, the hydraulic oil flows through the oil channel inside the radial bearing seat and enters the first annular oil chamber on the inner surface of the hydrostatic radial bearing and the second annular oil chamber on the inner surface of the hydrostatic radial auxiliary bearing, thereby forming an oil film between the main shaft and the hydrostatic radial bearing and the hydrostatic radial auxiliary bearing, reducing the degree of friction damage to the main shaft and making the transmission smoother. The oil pressure is adjusted to a predetermined value so that the hydraulic oil has sufficient pressure to float the main shaft, thereby effectively solving the above-mentioned problem.

[0005] However, there is still a problem with this electric spindle: in actual use, there is a chance of hydraulic oil leakage. The leaked hydraulic oil comes into contact with the stator, which will cause insulation degradation, and may cause short circuit or performance degradation at any time, affecting the life and working stability of the electric spindle. Summary of the Invention

[0006] The purpose of the present invention is to address the above-mentioned problems in the existing technology and to provide a hydrostatic electric spindle with long service life and stable operation.

[0007] The objectives of the present invention can be achieved through the following technical solutions: A hydrostatic electric spindle comprises a housing, a rotor shaft horizontally arranged in the housing, and a stator arranged between the rotor shaft and the housing, hydrostatic bearings are provided between both ends of the rotor shaft and the housing, and the stator is located between the two hydrostatic bearings, and oil inlet and oil outlet holes are provided at both ends of the housing for cooperating with the corresponding hydrostatic bearings, characterized in that a static ring and a dynamic ring are provided between both ends of the stator and the corresponding hydrostatic bearings, the static ring, the dynamic ring and the rotor shaft are coaxially arranged, and the outer wall of the static ring and the inner wall of the dynamic ring are respectively sealed and fixedly connected to the housing and the rotor shaft; the static ring is sleeved outside the dynamic ring and the two do not contact each other, an annular cavity is formed between the static ring and the dynamic ring, an air duct with an inlet and an outlet is formed in the static ring, the air duct outlet is connected to the above-mentioned annular cavity, and two air inlets are penetrated through the housing to respectively connect the two air duct inlets; an annular air guide cavity is formed between the housing, the rotor shaft, the hydrostatic bearing, the static ring and the dynamic ring arranged near the hydrostatic bearing, and two exhaust holes are provided on the housing to respectively connect the two air guide cavities.

[0008] During use, the gas enters the annular cavity through the air inlet through the air channel, and flows to both ends of the cavity. Part of the gas wraps around the stator, and the other part enters the air guide cavity and is finally discharged through the exhaust hole.

[0009] Among them, the gas-filled air guide cavity forms pressure on the side of the hydrostatic bearing close to the stator, effectively preventing the hydraulic oil at the hydrostatic bearing from leaking toward the stator. At the same time, the space between the static ring and the dynamic ring is also filled with gas, which can effectively extend the air sealing path, thereby further avoiding contact between the stator and the hydraulic oil, thereby improving the working stability and life of the electric spindle.

[0010] Part of the gas flowing into the annular cavity flows toward the stator and wraps around the stator, playing a role of air cooling, thereby effectively reducing the working temperature of the stator part and further improving the working stability and life of the electric spindle.

[0011] In the aforementioned hydrostatic electric spindle, the annular cavity comprises coaxially arranged and annular cavity 1 and cavity 2. Cavity 1 is narrower than cavity 2, with one cavity 1 exceeding cavity 2 by one. Cavities 1 and 2 are arranged alternately and continuously along the axial direction of the rotor shaft, and the air passage connects to one of the cavities 2. The annular cavity is formed by alternating multiple cavities 1 and 2, with cavity 1 being narrower than cavity 2. This allows cavity 1 to be narrowed during actual machining, ensuring normal gas flow while enhancing the annular cavity's interception capability, further preventing hydraulic oil leakage and contact with the stator.

[0012] In the above-mentioned static pressure electric spindle, the width of the cavity 1 is 0.2 mm to 0.4 mm.

[0013] In the above-mentioned hydrostatic electric spindle, the static ring includes an inner ring and an outer ring that are coaxially arranged, the inner ring is fixedly connected to the casing, and the outer ring is located between the inner ring and the stator; the outer side surfaces of the inner ring and the outer ring are both attached to the inner side surface of the casing to form a seal, and the above-mentioned annular cavity is formed between the inner side surface of the inner ring and the dynamic ring; the inner wall of the casing has a limiting surface that is annular and coaxial with the casing, and the two end surfaces of the outer ring are respectively pressed tightly against the limiting surface and the inner ring; the above-mentioned air duct is composed of a strip flow channel formed in the outer ring and a strip hole formed in the inner ring, the two ends of the strip hole are respectively connected to the annular cavity and the strip flow channel, and the above-mentioned air inlet hole is connected to the strip flow channel. The static ring adopts a split structure consisting of an inner ring and an outer ring, and the strip flow channel and the strip hole that constitute the air duct are respectively formed in the outer ring and the inner ring, which has the advantages of simple structure and easy assembly.

[0014] In the above-mentioned hydrostatic electric spindle, the inner ring includes a main body with an L-shaped axial cross-section, one end of the main body is fixedly connected to the casing, the outer ring is sleeved on the outside of the other end of the main body, and the inner side surface of the outer ring and the outer side surface of the main body are abutted to form a seal, so as to effectively enhance the positioning effect of the outer ring.

[0015] In the above-mentioned hydrostatic electric spindle, the outer walls of the inner ring and the outer ring are sealed with the casing through a sealing ring, and the above-mentioned strip flow channel is located between the two sealing rings to further strengthen the sealing effect formed between the casing and the inner ring and the outer ring, and further improve the airtight sealing effect.

[0016] Compared with the existing technology, this hydrostatic electric spindle has the following advantages:

[0017] 1. The gas-filled air guide cavity forms pressure on the side of the hydrostatic bearing close to the stator, effectively preventing the hydraulic oil at the hydrostatic bearing from leaking toward the stator. At the same time, the space between the static ring and the dynamic ring is also filled with gas, which can effectively extend the gas sealing path, thereby further avoiding contact between the stator and the hydraulic oil, thereby improving the working stability and life of the electric spindle.

[0018] 2. Part of the gas flowing into the annular cavity flows toward the stator and wraps the stator, playing a role of air cooling, so as to effectively reduce the working temperature of the stator part and further improve the working stability and life of the electric spindle.

[0019] 3. The annular cavity is composed of multiple cavities 1 and 2 that are alternately distributed, and the width of cavity 1 is smaller than that of cavity 2. In this way, during actual processing, the width of cavity 1 can be set narrower. Under the premise of ensuring the normal flow of gas, the interception ability of the annular cavity can be enhanced, thereby further preventing the hydraulic oil from leaking and contacting the stator. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a front view structural diagram of the hydrostatic electric spindle.

[0021] Figure 2 It is a schematic diagram of the cross-sectional structure of the hydrostatic electric spindle.

[0022] Figure 3 yes Figure 2 Schematic diagram of the enlarged structure at point A in the middle.

[0023] In the figure, 1, casing; 1a, oil inlet hole; 1b, oil outlet hole; 1c, air inlet hole; 1d, exhaust hole; 1e, limit surface; 2, rotor shaft; 3, stator; 4, hydrostatic bearing; 5, thrust bearing; 6, static ring; 6a, air channel; 6b, inner ring; 6b1, main body; 6c, outer ring; 6d, strip flow channel; 6e, strip hole; 6f, sealing ring 1; 7, dynamic ring; 8, annular cavity; 8a, cavity 1; 8b, cavity 2; 9, air guide cavity; 10, sealing ring 2. DETAILED DESCRIPTION

[0024] The following are specific embodiments of the present invention and the accompanying drawings to further describe the technical solutions of the present invention, but the present invention is not limited to these embodiments.

[0025] like Figure 1 and Figure 2 As shown, the static pressure electric spindle includes a housing 1, a rotor arranged in the housing 1, and a stator 3 arranged in the rotor and the housing 1. The rotor includes a rotor shaft 2 horizontally arranged in the housing 1, and the front end of the rotor shaft 2 extends out of the barrel.

[0026] Specifically,

[0027] Both ends of the rotor shaft 2 are connected to the housing 1 via hydrostatic bearings 4, with the stator 3 positioned between the two hydrostatic bearings 4. Both ends of the housing 1 are equipped with oil inlet holes 1a and oil outlet holes 1b that mate with the corresponding hydrostatic bearings 4. The hydrostatic bearings 4 are existing products, and the connection between the oil inlet holes 1a and oil outlet holes 1b and the hydrostatic bearings 4 is well-known and will not be described in detail here. In actual production, the rotor shaft 2 is also connected to the housing 1 via thrust bearings 5, with both hydrostatic bearings 4 positioned in front of the thrust bearings 5.

[0028] like Figure 2 As shown, a static ring 6 and a dynamic ring 7 are provided between both ends of the stator 3 and the corresponding hydrostatic bearing 4. The static ring 6, the dynamic ring 7 and the rotor shaft 2 are coaxially arranged, and the outer wall of the static ring 6 and the inner wall of the dynamic ring 7 are sealed and fixedly connected to the casing 1 and the rotor shaft 2 respectively.

[0029] in,

[0030] The stationary ring 6 is sleeved over the dynamic ring 7 without contacting the two rings. At this time, an annular cavity 8 is formed between the stationary ring 6 and the dynamic ring 7. An air passage 6a with an inlet and an outlet is formed in the stationary ring 6. The outlet of the air passage 6a is connected to the annular cavity 8. Two air inlet holes 1c are respectively connected to the inlets of the two air passages 6a. Figure 2 and Figure 3 As shown, an annular air guide cavity 9 is formed among the casing 1, the rotor shaft 2, the hydrostatic bearing 4, and the static ring 6 and the dynamic ring 7 arranged near the hydrostatic bearing 4. At this time, the annular cavity 8 is connected to the air guide cavity 9, and two exhaust holes 1d are provided on the casing 1 to respectively connect the two air guide cavities 9.

[0031] During use, the gas enters the annular cavity 8 through the air inlet 1c via the air channel 6a, and flows to both ends of the cavity. Part of the gas wraps around the stator 3, and the other part enters the air guide cavity 9 and is finally discharged through the exhaust hole 1d.

[0032] Among them, the gas-filled air guide cavity 9 forms pressure on the side of the hydrostatic bearing 4 close to the stator 3, effectively preventing the hydraulic oil at the hydrostatic bearing 4 from leaking toward the stator 3. At the same time, the space between the static ring 6 and the dynamic ring 7 is also filled with gas, which can effectively extend the air sealing path, thereby further avoiding contact between the stator 3 and the hydraulic oil, thereby improving the working stability and life of the electric spindle.

[0033] Part of the gas flowing into the annular cavity 8 flows toward the stator 3 and wraps around the stator 3, which can play a role in air cooling, thereby effectively reducing the operating temperature of the stator 3 and further improving the working stability and life of the electric spindle.

[0034] In this embodiment,

[0035] The outer wall of the dynamic ring 7 is sealed with the rotor shaft 2 through the sealing ring 2 10 . Preferably, there are two sealing rings 10 and they are distributed axially along the rotor shaft 2 .

[0036] The stationary ring 6 comprises a coaxially arranged inner ring 6b and outer ring 6c. The inner ring 6b is fixedly attached to the housing 1, while the outer ring 6c is positioned between the inner ring 6b and the stator 3. The outer surfaces of the inner and outer rings 6b and 6c seal against the inner surface of the housing 1, forming the aforementioned annular cavity 8. The inner surface of the inner ring 6b forms a coaxial stop surface 1e on the inner wall of the housing 1. The end surfaces of the outer ring 6c press against the stop surface 1e and the inner ring 6b, respectively.

[0037] The air channel 6a is composed of a strip-shaped flow channel 6d formed in the outer ring 6c and a strip-shaped hole 6e formed in the inner ring 6b. The two ends of the strip-shaped hole 6e are connected to the annular cavity 8 and the strip-shaped flow channel 6d, respectively, and the air inlet 1c is connected to the strip-shaped flow channel 6d. The static ring 6 adopts a split structure consisting of an inner ring 6b and an outer ring 6c, and the strip-shaped flow channel 6d and the strip-shaped hole 6e that constitute the air channel 6a are respectively formed in the outer ring 6c and the inner ring 6b, which has the advantages of simple structure and easy assembly. In the actual product, the outer walls of the inner ring 6b and the outer ring 6c are sealed with the housing 1 through the sealing ring 6f, and the strip-shaped flow channel 6d is located between the two sealing rings 6f to further strengthen the sealing effect formed between the housing 1 and the inner ring 6b and the outer ring 6c, and further improve the airtightness.

[0038] To further illustrate, the inner ring 6b includes a main body 6b1 with an L-shaped axial cross-section, one end of the main body 6b1 is fixedly connected to the housing 1, and the outer ring 6c is sleeved on the other end of the main body 6b1, and the inner side surface of the outer ring 6c and the outer side surface of the main body 6b1 are in contact with each other to form a seal, so as to effectively enhance the positioning effect of the outer ring 6c.

[0039] like Figure 3 As shown, the annular cavity 8 comprises coaxially arranged cavity 1 8a and cavity 2 8b, both of which are annular. The width of cavity 1 8a is smaller than that of cavity 2 8b. There is one more cavity 1 8a than cavity 2 8b, and these two are continuously and alternately distributed along the axial direction of the rotor shaft 2. The aforementioned strip-shaped hole 6e connects to one of the cavities 2 8b. The annular cavity 8 is formed by alternating multiple cavities 1 8a and 8b, with the width of cavity 1 8a being smaller than that of cavity 2 8b. This allows cavity 1 8a to be narrowed during actual processing, ensuring proper gas flow while enhancing the interception capability of the annular cavity 8, further preventing hydraulic oil leakage and contact with the stator 3. In this embodiment, the width of cavity 1 8a is preferably 0.2 mm to 0.4 mm.

[0040] The specific embodiments described herein are merely illustrative of the spirit of the present invention. Persons skilled in the art may make various modifications, additions, or substitutions to the described specific embodiments without departing from the spirit of the present invention or exceeding the scope of the appended claims.

Claims

1. A hydrostatic electric spindle, comprising a housing (1), a rotor shaft (2) arranged horizontally in the housing (1), and a stator (3) arranged between the rotor shaft (2) and the housing (1), hydrostatic bearings (4) being provided between both ends of the rotor shaft (2) and the housing (1), and the stator (3) being located between the two hydrostatic bearings (4), and an oil inlet hole (1a) and an oil outlet hole (1b) being provided at both ends of the housing (1) for cooperating with the corresponding hydrostatic bearings (4), characterized in that: A stationary ring (6) and a moving ring (7) are provided between the two ends of the stator (3) and the corresponding static pressure bearing (4). The stationary ring (6), the moving ring (7) and the rotor shaft (2) are coaxially arranged, and the outer wall of the stationary ring (6) and the inner wall of the moving ring (7) are sealed and fixedly connected to the housing (1) and the rotor shaft (2) respectively; the stationary ring (6) is sleeved outside the moving ring (7) and the two do not contact, and an annular cavity (8) is formed between the stationary ring (6) and the moving ring (7), and a cavity with an inlet and an outlet is formed in the stationary ring (6). The air passage (6a) is connected to the annular cavity (8), and the housing (1) is provided with two air inlet holes (1c) respectively connected to the inlets of the two air passages (6a); an annular air guide cavity (9) is formed among the housing (1), the rotor shaft (2), the static pressure bearing (4), and the static ring (6) and the dynamic ring (7) arranged near the static pressure bearing (4), and the housing (1) is provided with two air exhaust holes (1d) respectively connected to the two air guide cavities (9); The annular cavity (8) includes a coaxially arranged cavity 1 (8a) and a cavity 2 (8b) both in an annular shape. The width of the cavity 1 (8a) is smaller than the width of the cavity 2 (8b). The number of the cavity 1 (8a) is one more than the number of the cavity 2 (8b). The cavity 1 (8a) and the cavity 2 (8b) are continuously and alternately distributed along the axial direction of the rotor shaft (2). The air passage (6a) is connected to one of the cavities 2 (8b). The air guide cavity (9) is connected to the annular cavity (8) through cavity one (8a), and the air flow direction of the air guide cavity (9) is perpendicular to the air flow direction of the annular cavity (8).

2. The hydrostatic electric spindle according to claim 1, characterized in that: The width of cavity 1 (8a) is 0.2mm to 0.4mm.

3. The hydrostatic electric spindle according to claim 1 or 2, characterized in that: The stationary ring (6) comprises an inner ring (6b) and an outer ring (6c) which are coaxially arranged. The inner ring (6b) is fixedly connected to the housing (1), and the outer ring (6c) is located between the inner ring (6b) and the stator (3). The outer side surfaces of the inner ring (6b) and the outer ring (6c) are both attached to the inner side surface of the housing (1) to form a seal, and the inner side surface of the inner ring (6b) and the moving ring (7) form the above-mentioned annular cavity (8). The inner wall of the housing (1) has an annular ring which is in contact with the housing. (1) A coaxial limiting surface (1e), and the two end surfaces of the outer ring (6c) are respectively pressed against the limiting surface (1e) and the inner ring (6b); the above-mentioned air channel (6a) is composed of a strip flow channel (6d) formed in the outer ring (6c) and a strip hole (6e) formed in the inner ring (6b), and the two ends of the strip hole (6e) are respectively connected to the annular cavity (8) and the strip flow channel (6d), and the above-mentioned air inlet hole (1c) is connected to the strip flow channel (6d).

4. The hydrostatic electric spindle according to claim 3, characterized in that: The inner ring (6b) comprises a main body (6b1) having an L-shaped axial cross section, one end of the main body (6b1) being fixedly connected to the housing (1), and the outer ring (6c) being sleeved on the outside of the other end of the main body (6b1), with the inner side surface of the outer ring (6c) and the outer side surface of the main body (6b1) abutting against each other to form a seal.

5. The hydrostatic electric spindle according to claim 4, characterized in that: The outer walls of the inner ring (6b) and the outer ring (6c) are sealed with the housing (1) via a sealing ring (6f), and the strip-shaped flow channel (6d) is located between the two sealing rings (6f).

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