CN115889829A - Static pressure centre - Google Patents
Static pressure centre Download PDFInfo
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- CN115889829A CN115889829A CN202110918401.5A CN202110918401A CN115889829A CN 115889829 A CN115889829 A CN 115889829A CN 202110918401 A CN202110918401 A CN 202110918401A CN 115889829 A CN115889829 A CN 115889829A
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
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Abstract
The invention relates to a static pressure center, which comprises a shaft sleeve and a center shaft inserted in the shaft sleeve, wherein the center of the center shaft extends out of the front end of the shaft sleeve, and the tail end of the center shaft extends out of an end cover fixed at the tail end of the shaft sleeve; bearing oil grooves are formed in the shaft sleeve on the outer ring surface of the center shaft, and oil inlet oil passages communicated with the bearing oil grooves and the tail end of the center shaft are formed in the center shaft; a bearing oil cavity is formed between the bearing oil groove and the inner hole surface of the shaft outer sleeve, so that the center shaft is arranged in the shaft outer sleeve in a hydrostatic bearing supporting mode; an oil return hole for outputting static pressure oil is formed in the side wall of the shaft sleeve; a front-end oil seal structure is arranged between the part of the shaft outer sleeve close to the front end and the center shaft, and a tail-end oil seal structure is arranged at the matching part of the end cover and the center shaft; the tail end of the center shaft is provided with an axial clamping mechanism which enables the center to be pressed on the workpiece. The static pressure center has the advantages of high supporting rigidity, high rotation precision, low abrasion and good precision durability.
Description
Technical Field
The invention belongs to the technical field of auxiliary supporting of workpieces for processing or measurement, and relates to a movable center structure, in particular to a static pressure center.
Background
The centre is an auxiliary supporting structure commonly adopted on a processing machine tool, is mainly used for auxiliary clamping and supporting of a long-shaft part non-main shaft, and has great influence on processing quality due to rotation precision and rigidity. At present, the centre is divided into a fixed centre and a live centre supported by a rolling bearing. The supporting precision of the fixed center is high and is generally 1-2 μm, but the precision is easy to lose because the contact surface of the fixed center and the workpiece is dry friction and is quickly abraded. The live center is supported by a rolling bearing, so that the abrasion is reduced, but the moving part is in point or line contact, so that the rigidity is low, and the precision level is about 5 mu m generally.
Aiming at the advantages and the defects of the existing fixed center and the movable center, the center structure with high rigidity and high precision is designed, and is very necessary for processing high-precision parts.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provides the static pressure center with high supporting rigidity, high rotation precision and low abrasion.
One of the above objects of the present invention is achieved by the following technical solutions:
the utility model provides a static pressure is top, includes axle overcoat and cartridge apex axle in the axle overcoat, and the apex of apex axle stretches out from the front end of axle overcoat, and the tail end of apex axle stretches out its characterized in that from the end cover that is fixed in the axle overcoat tail end: bearing oil grooves are formed in the shaft sleeve on the outer ring surface of the center shaft, and oil inlet oil passages communicated with the bearing oil grooves and the tail end of the center shaft are formed in the center shaft; a bearing oil cavity is formed between the bearing oil groove and the inner hole surface of the shaft outer sleeve, so that the center shaft is arranged in the shaft outer sleeve in a hydrostatic bearing supporting mode; an oil return hole for outputting static pressure oil is formed in the side wall of the shaft sleeve;
a front end oil seal structure is arranged between the part of the shaft outer sleeve close to the front end and the center shaft, and a tail end oil seal structure is arranged at the matching part of the end cover and the center shaft;
the tail end of the center shaft is provided with an axial clamping mechanism which enables the center to be pressed on the workpiece.
Further: a throttler is arranged in the position, corresponding to each bearing oil groove, of the oil inlet oil way, so that oil enters the corresponding bearing oil groove through the throttler.
Further: the bearing oil grooves arranged on the tip shaft are symmetrically arranged in one group or a plurality of groups, each bearing oil groove is internally provided with a throttling area, and an oil inlet hole is arranged in each throttling area and is communicated with an oil inlet oil way; the throttling area of each bearing oil groove is communicated with the part outside the throttling area in the other bearing oil groove in the same group through a feedback oil circuit arranged in the center shaft, and the two bearing oil grooves symmetrically arranged are communicated through the feedback oil circuit to form a static pressure circulating oil circuit.
Further, the method comprises the following steps: set up and bear the oil groove and be two sets of on the apical axis, two sets of oil grooves that bear are arranged from top to bottom along the axial of apical axis, and a set of oil groove that bears that is located upper portion and a set of oil groove that bears that is located the lower part are the setting of misplacing in the circumferencial direction.
Further, the method comprises the following steps: axial oil return grooves are formed in the outer ring surface of the center shaft between two oil grooves of the upper bearing oil groove group and between two oil grooves of the lower bearing oil groove group; circumferential oil return grooves communicated with all axial oil return grooves are formed in the outer ring surface of the tip shaft between the upper group of bearing oil grooves and the lower group of bearing oil grooves; and when the tip shaft is in an axial clamping state, the circumferential oil return groove is aligned and communicated with an oil return hole in the shaft outer sleeve.
Further: the part of the shaft outer sleeve positioned at the tail end is provided with a piston cavity, the part of the center shaft close to the tail end is provided with a piston head, the piston head and the piston cavity form piston fit, an oil hole is formed in an end cover or the side part of the tail end of the shaft outer sleeve, and the oil hole is communicated with the piston cavity to form a hydraulic cylinder type axial clamping mechanism acting on the center shaft.
Further, the method comprises the following steps: the rear extending end of the center shaft is sleeved with an inherent shaft end head, and a return spring sleeved on the center shaft is pressed between the shaft end head and the end cover.
Further, the method comprises the following steps: the inner hole of the shaft outer sleeve consists of a small-diameter inner hole section and a large-diameter inner hole section coaxially arranged at the tail end of the small-diameter inner hole section; the small-diameter inner hole section is matched with the oil bearing groove of the tip shaft, the large-diameter inner hole section forms the piston cavity, and an axial limiting table top is formed between the large-diameter inner hole section and the small-diameter inner hole section.
The second objective of the present invention is achieved by the following technical solutions:
a processing machine tool is characterized in that: the processing machine tool is provided with the static pressure center.
The third purpose of the invention is realized by the following technical scheme:
a test apparatus, characterized by: the testing equipment is provided with the static pressure tip.
The invention has the advantages and positive effects that:
1. the static pressure center has high support rigidity; the tip stiffness is mainly dependent on the stiffness of the tip shaft and the stiffness of the bearing support. Hydrostatic bearing stiffness can be improved by adjusting bearing structure and design parameters. The hydrostatic bearing has a small radial dimension, further increasing the diameter of the tip shaft. Therefore, the static pressure center achieves two purposes, the rigidity of the center shaft and the rigidity of the bearing are increased, the rigidity can reach 6 times of that of the rolling support center, and the level of a dead center is reached.
2. The static pressure center has high rotation precision: the static pressure oil film in the bearing oil cavity has error equalization function, and can realize precision evolution, and the common error is about 1/3-1/5 of the precision of a matching piece. The static pressure center can realize the rotation precision higher than the precision of an original part; the rotation precision of the processed workpiece can be higher than that of a machine tool by about one level.
3. The static pressure center has low abrasion and good precision durability: the centre revolving parts are separated by hydraulic oil, and theoretically, the possibility of abrasion does not exist. Practical experience shows that the static pressure bearing can still see the processing tool marks on the moving surface after being used for ten years, so that the precision retentivity of the static pressure center is far higher than that of a common dead center and a common live center. The rotation precision can reach about 10 to 20 times of that of the fixed center.
4. The static pressure center is easy to control intelligently, and intelligent clamping with optimal clamping force is realized. If the clamping hydraulic cylinder arranged at the tail part is controlled by adopting a proportional valve or a servo valve, the pressing force is adjusted at any time according to the cutting condition of the part, and the optimal clamping can be realized.
5. The processing machine tool adopting the static pressure center can realize high-precision and high-rigidity clamping and positioning of the workpiece, thereby being beneficial to realizing long-time heavy cutting and precision processing of the rotary workpiece.
6. The test equipment adopting the static pressure center can improve the positioning precision of the workpiece, thereby being beneficial to improving the test precision of the workpiece. The friction force of the static pressure center is about 1/10 of that of the live center, so that the possibility of creeping when the part to be measured rotates is reduced, and the measurement precision is improved.
Drawings
FIG. 1 is a schematic perspective view of the present invention;
FIG. 2 is a longitudinal cross-sectional view of the present invention;
FIG. 3 isbase:Sub>A cross-sectional view A-A of FIG. 2;
FIG. 4 is a schematic exterior view of the tip shaft of the present invention;
FIG. 5 is a left side view of FIG. 4;
FIG. 6 is a schematic view of the tip shaft configuration of the present invention employing a small bore restrictor;
fig. 7 is a schematic diagram of the present invention employing a capillary restrictor in the tip shaft.
Detailed Description
The structure of the present invention will be further described by way of examples with reference to the accompanying drawings. It is to be understood that this embodiment is illustrative and not restrictive.
A static pressure centre comprises a shaft outer sleeve 2 and a centre shaft 3 inserted in the shaft outer sleeve. The shaft outer sleeve is used for integrally mounting the hydraulic center on a machine tool or equipment used. The center shaft is matched with the shaft outer sleeve, and the workpiece is compressed through axial movement of the center shaft. The center 3.1 of the center shaft stretches out from the front end of the shaft sleeve, the tail end of the center shaft stretches out from the end cover 1 fixed on the tail end of the shaft sleeve, and the invention point is that:
the outer ring surface of the center shaft is provided with bearing oil grooves in the shaft outer sleeve, the tail end of the center shaft is provided with a main oil inlet, and the center shaft is internally provided with an oil inlet oil path 9 for communicating each bearing oil groove with the tail end of the center shaft. A bearing oil cavity 13 is formed between the bearing oil groove and the inner hole surface of the shaft sleeve, and a bearing oil film is formed in the bearing oil cavity by introducing oil, so that the tip shaft is arranged in the shaft sleeve in a hydrostatic bearing supporting mode. An oil return hole 2.1 for outputting static pressure oil is arranged on the side wall of the shaft sleeve.
The normal work of the static pressure center requires a throttle arranged in the center shaft. There are two ways that can be used:
the first method is as follows: the throttling structure without feedback is as follows: a throttler is arranged in the position, corresponding to each bearing oil groove, of the oil inlet oil way, so that oil enters the corresponding bearing oil groove through the throttler. The restrictor may be a small orifice restrictor 17 or a capillary restrictor 18. The construction of the orifice restrictor or capillary restrictor is shown in fig. 6 and 7, respectively.
The second method comprises the following steps: internal clearance feedback type throttle, it is specific: the bearing oil grooves arranged on the center shaft are symmetrically arranged in one group or multiple groups, each bearing oil groove is internally provided with a throttling area 14, and each throttling area is provided with an oil inlet hole 15 and is communicated with an oil inlet oil way; the throttling area of each bearing oil groove is provided with a feedback oil hole 16, and the feedback oil hole is communicated with the part outside the throttling area in the other bearing oil groove in the same group through a feedback oil path 10 arranged in the tip shaft, and the two bearing oil grooves which are symmetrically arranged are communicated through the feedback oil path to form a static pressure circulating oil path. Further, it is preferable that the bearing oil grooves arranged on the center shaft are two sets, referring to fig. 4 and 5, the two sets of bearing oil grooves are arranged up and down along the axial direction of the center shaft, and a set of bearing oil grooves located at the upper portion and a set of bearing oil grooves located at the lower portion are arranged in a staggered manner in the circumferential direction. Because the center shaft is usually a slender shaft structure, the two groups of bearing oil grooves which are arranged in a staggered mode in the vertical direction are adopted, on one hand, the arrangement and the processing of the bearing oil grooves and the internal feedback oil circuit are facilitated, on the other hand, the formation of a uniform static pressure oil film in the whole circumferential direction is ensured, and therefore the coaxiality of the center shaft and the shaft outer sleeve is accurately ensured. Theoretically, the revolving precision of the static pressure center can reach 0.1 μm or even higher.
In the case of adopting the preferable structure of the second aspect, the preferable configuration of the oil return structure is as follows:
and axial oil return grooves 11 are formed between two oil grooves of a group of bearing oil grooves on the upper part and between two oil grooves of a group of bearing oil grooves on the lower part on the outer ring surface of the center shaft. And a circumferential oil return groove 12 communicated with all axial oil return grooves is formed between the upper group of bearing oil grooves and the lower group of bearing oil grooves on the outer ring surface of the center shaft. And when the center shaft is in an axial clamping state, the circumferential oil return groove is aligned and communicated with an oil return hole in the shaft outer sleeve.
The oil return structure is reasonably arranged, and the specific oil return process is as follows: a set of oil return that bears the weight of the oil groove in upper portion flows into the diaxon on upper portion through the clearance between oil groove limit portion and the axle overcoat hole in, and the oil return that the lower part a set of oil groove that bears flows into the diaxon of lower part through the clearance between oil groove limit portion and the axle overcoat hole in, flows into the oil return in four axial oil galleries, converges in the circumference oil gallery, discharges through the oil gallery on the overcoat at last.
A front-end oil seal structure is arranged between the part of the shaft sleeve close to the front end and the center shaft, a tail-end oil seal structure is arranged at the matching part of the end cover and the center shaft, and the front-end oil seal structure and the tail-end oil seal structure avoid the oil inlet entering the bearing oil groove from flowing out of the two ends of the center shaft, so that the necessary condition for establishing static pressure between the shaft sleeve and the center shaft is provided. The front end oil seal structure and the tail end oil seal structure can adopt the structures described in figures 2 and 3: the front end part and the tail end part of the center shaft are provided with sealing ring grooves, and the sealing ring grooves are internally provided with sealing rings, and can be realized by other modes, and the invention is not limited in the invention.
The tail end of the center shaft is provided with an axial clamping mechanism which enables the center to be pressed on the workpiece. The axial clamping mechanism can be realized by adding a separate structure at the tail end of the center shaft, such as a hydraulic cylinder or an air cylinder. The axial clamping mechanism can also be realized by arranging a matching structure between the tail end of the centre shaft and the tail end of the shaft sleeve. In the invention, the axial clamping mechanism preferably comprises:
the piston cavity 7 is arranged at the tail end part in the shaft outer sleeve, the piston head 8 is arranged at the tail end part of the center shaft close to the tail end, the piston head can be integrally formed on the center shaft, the piston head and the piston cavity form piston fit, an oil hole 6 is formed in the end cover or the tail end side part of the shaft outer sleeve and communicated with the piston cavity, and the oil hole is connected with an oil supply device through an external oil pipe to form a hydraulic cylinder type axial clamping mechanism acting on the center shaft. In order to simplify an external oil circuit and realize quick reset of the center shaft, an inherent shaft end head 4 is sleeved at the rear extending end of the center shaft, and a reset spring 5 sleeved on the center shaft is pressed between the shaft end head and an end cover.
In the above structure, further: the inner hole of the shaft outer sleeve consists of a small-diameter inner hole section and a large-diameter inner hole section coaxially arranged at the tail end of the small-diameter inner hole section; the small-diameter inner hole section is matched with the oil bearing groove of the tip shaft, the large-diameter inner hole section forms the piston cavity, and an axial limiting table top is formed between the large-diameter inner hole section and the small-diameter inner hole section. The axial limiting table top has the following functions: the center shaft is limited in the front, so that the center shaft is prevented from sliding out of the front end of the shaft outer sleeve.
The static pressure center is a novel live center structure, combines the existing live center and live center, and overcomes the defects of the existing live center. A combination of high stiffness, high accuracy and high accuracy retention is achieved. The device can be applied to various processing machines in an expanded way, for example, grinding machines (including vertical or horizontal), lathes, gear processing machines and the like, and can also be applied to measuring equipment. The axial clamping positioning can be carried out on the machined workpiece, and the radial positioning and the like can also be carried out on the workpiece by adopting a mode of uniformly arranging a plurality of centers on the ring frame.
Although the embodiments of the present invention and the accompanying drawings are disclosed for illustrative purposes, those skilled in the art will appreciate that: various substitutions, changes and modifications are possible without departing from the spirit of the invention and the scope of the appended claims, and therefore the scope of the invention is not limited to the disclosure of the embodiments and the accompanying drawings.
Claims (10)
1. The utility model provides a static pressure is top, includes axle overcoat and cartridge apex axle in the axle overcoat, and the apex head of apex axle stretches out from the front end of axle overcoat, and the tail end of apex axle stretches out its characterized in that from the tail end lid that is fixed in the axle overcoat tail end: bearing oil grooves are formed in the shaft sleeve on the outer ring surface of the center shaft, and oil inlet oil passages communicated with the bearing oil grooves and the tail end of the center shaft are formed in the center shaft; a bearing oil cavity is formed between the bearing oil groove and the inner hole surface of the shaft outer sleeve, so that the center shaft is arranged in the shaft outer sleeve in a hydrostatic bearing supporting mode; an oil return hole for outputting static pressure oil is formed in the side wall of the shaft sleeve;
a front-end oil seal structure is arranged between the part of the shaft outer sleeve close to the front end and the center shaft, and a tail-end oil seal structure is arranged at the matching part of the tail end and the center shaft;
the tail end of the center shaft is provided with an axial clamping mechanism which enables the center to be pressed on the workpiece.
2. The static tip of claim 1, wherein: a throttler is arranged in the position, corresponding to each bearing oil groove, of the oil inlet oil way, so that oil enters the corresponding bearing oil groove through the throttler.
3. The static pressure center according to claim 1, wherein: the bearing oil grooves arranged on the tip shaft are symmetrically arranged in one group or a plurality of groups, each bearing oil groove is internally provided with a throttling area, and each throttling area is provided with an oil inlet hole and communicated with an oil inlet oil way; the throttling area of each bearing oil groove is communicated with the part outside the throttling area in the other bearing oil groove in the same group through a feedback oil circuit arranged in the center shaft, and the two bearing oil grooves which are symmetrically arranged are communicated through the feedback oil circuit to form a static pressure circulating oil circuit.
4. The static pressure center according to claim 3, wherein: set up and bear the oil groove and be two sets of on the apical axis, two sets of oil grooves that bear are arranged from top to bottom along the axial of apical axis, and a set of oil groove that bears that is located upper portion and a set of oil groove that bears that is located the lower part are the setting of misplacing in the circumferencial direction.
5. The static pressure center according to claim 4, wherein: axial oil return grooves are formed in the outer ring surface of the center shaft between two oil grooves of the upper bearing oil groove group and between two oil grooves of the lower bearing oil groove group; a circumferential oil return groove communicated with all axial oil return grooves is formed between the upper bearing oil groove and the lower bearing oil groove on the outer ring surface of the center shaft; and when the center shaft is in an axial clamping state, the circumferential oil return groove is aligned and communicated with an oil return hole in the shaft outer sleeve.
6. The static pressure center according to claim 1, wherein: the piston cavity is arranged at the position, located at the tail end, in the shaft outer sleeve, the piston head is arranged at the position, close to the tail end, of the center shaft, the piston head and the piston cavity form piston fit, an oil hole is formed in the tail end or the side portion of the tail end of the shaft outer sleeve, and the oil hole is communicated with the piston cavity to form a hydraulic cylinder type axial clamping mechanism acting on the center shaft.
7. The static tip of claim 6, wherein: the rear extending end of the center shaft is sleeved with a fixed shaft end, and a return spring sleeved on the center shaft is pressed between the shaft end and the end cover.
8. The static pressure center according to claim 6, wherein: the inner hole of the shaft outer sleeve consists of a small-diameter inner hole section and a large-diameter inner hole section coaxially arranged at the tail end of the small-diameter inner hole section; the small-diameter inner hole section is matched with the oil bearing groove of the tip shaft, the large-diameter inner hole section forms the piston cavity, and an axial limiting table top is formed between the large-diameter inner hole section and the small-diameter inner hole section.
9. A kind of processing machine tool, its characterized in that: the machine tool is provided with a static center according to any one of claims 1-8.
10. A test apparatus, characterized by: the test apparatus is provided with a static pressure tip according to any one of claims 1 to 8.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110918401.5A CN115889829A (en) | 2021-08-11 | 2021-08-11 | Static pressure centre |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110918401.5A CN115889829A (en) | 2021-08-11 | 2021-08-11 | Static pressure centre |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN115889829A true CN115889829A (en) | 2023-04-04 |
Family
ID=86471414
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202110918401.5A Pending CN115889829A (en) | 2021-08-11 | 2021-08-11 | Static pressure centre |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN115889829A (en) |
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2021
- 2021-08-11 CN CN202110918401.5A patent/CN115889829A/en active Pending
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