CN112077638A - An integrated hydrostatic nut main drive screw pair linear feed unit - Google Patents

Abstract

The invention discloses a primary driving type screw pair linear feeding unit integrated with a hydrostatic nut, which adopts the technical scheme that: the hydrostatic guide rail is characterized by comprising a hydrostatic lead screw and a hydrostatic guide rail which are parallel to each other, wherein a nut component is axially arranged on the hydrostatic lead screw, and a hollow motor is arranged on one side of the nut component; the nut assembly is arranged below the workbench through a support frame, and the workbench is detachably connected with the hydrostatic guide rail; an oil collecting plate is coated on the outer side of the supporting frame to form an oil collecting space; the static pressure lead screw is arranged above the base, and the base is provided with a plurality of oil discharge grooves for discharging oil for the hydrostatic pressure guide rail and the oil collecting plate. The invention solves the problem that the machining precision is limited easily due to vibration, heating, deformation and the like caused by the fact that the lead screw drives the hydrostatic pressure lead screw pair in the current precision and ultra-precision machining process, and can realize the ultra-high precision linear motion with large stroke, high rigidity and high frequency response in the precision and ultra-precision machining process.

Description

An integrated hydrostatic nut main drive screw pair linear feed unit

technical field

The invention relates to the technical field of precision and ultra-precision machining, in particular to an integrated hydrostatic nut main drive type lead screw pair linear feed unit.

Background technique

As the development support of national defense and high-tech, ultra-precision machining technology plays an increasingly important role in modern manufacturing. As the speed of upgrading of industrial products continues to accelerate, the performance requirements for precision and ultra-precision machine tools are gradually increasing. As an important realization component of ultra-precision machining equipment, the ultra-precision linear motion platform mainly uses the form of linear motor, ball screw pair and hydrostatic screw pair.

Although the linear motor has high stiffness and fast response, there are problems in anti-interference and damping. The ball screw pair uses steel balls as the running load, which has large weight, easy deformation of steel balls, poor bearing capacity, and high lubrication requirements. Due to the fluid lubrication between the hydrostatic screw nut and the screw, the hydrostatic screw pair has the characteristics of high rigidity, low friction and superior damping characteristics, and is currently widely used in precision and ultra-precision machining equipment. The inventor found that the current existing hydrostatic screw pair is usually driven by the rotation of the screw to drive the hydrostatic screw nut to achieve linear motion. When rotating at high speed, it is easy to generate a large inertial force and cause vibration, heat generation, deformation and other phenomena, which seriously affect the feeding accuracy.

SUMMARY OF THE INVENTION

In view of the deficiencies in the prior art, the purpose of the present invention is to provide an integrated hydrostatic nut main drive type lead screw pair linear feed unit, which solves the problem that the lead screw drives the hydrostatic wire in the current precision and ultra-precision machining process. The vibration, heat generation and deformation of the lever pair can easily lead to the problem of limited processing accuracy, which can realize ultra-high-precision linear motion with large stroke, high stiffness and high-frequency response in the process of precision and ultra-precision machining.

In order to achieve the above object, the present invention is realized by the following technical solutions:

The embodiment of the present invention provides an integrated hydrostatic nut main drive type lead screw pair linear feed unit, including a hydrostatic lead screw parallel to each other, a hydrostatic guide rail, an axially mounted nut assembly for the hydrostatic lead screw, and a nut assembly. A hollow motor is installed on one side of the assembly; the nut assembly is installed under the workbench through a support frame, and the workbench is detachably connected to the hydrostatic guide rail; the outer side of the support frame is covered with an oil collecting plate to form an oil collecting space; the The static pressure screw is installed above the base, and the base is provided with a plurality of oil drain grooves for draining oil for the hydrostatic guide rail and the oil collecting plate.

As a further implementation, the nut assembly includes a bearing and a hydrostatic screw nut, and bearings are respectively installed at both ends of the hydrostatic screw nut; the bearing outer ring of one of the bearings is connected to the motor stator of the hollow motor through the bearing flange, and the motor The rotor is mated with the hydrostatic screw nut through the nut flange.

As a further implementation, the inner surface of the static pressure screw nut is engaged with the static pressure screw thread, and the two ends of the outer surface of the static pressure screw nut are respectively in interference fit with the inner ring of the bearing; the bearings located at both ends of the static pressure screw nut The inner ring and the bearing outer ring are supported by a liquid oil film.

As a further implementation, the outer ring of the bearing is uniformly provided with a nut oil inlet A in the circumferential direction, an annular inner groove is arranged inside the outer ring of the bearing, and the nut oil inlet A is communicated with the annular inner groove.

As a further implementation, the bearing outer ring is also provided with bearing oil inlets evenly distributed along the circumferential direction, and an annular oil cavity is provided on the side of the bearing outer ring close to the bearing inner ring; between the bearing outer ring and the bearing inner ring An annular oil outlet is provided with a gap left, and the annular oil outlet and the bearing oil inlet are respectively communicated with the annular oil outlet.

As a further implementation, the hydrostatic screw nut is provided with an oil inlet annular groove corresponding to the annular inner groove, and the oil inlet annular groove is connected with a plurality of nut oil inlets arranged along the circumferential direction of the hydrostatic screw nut B; the nut oil inlet B is communicated with the throttle.

As a further implementation manner, an oil outlet annular groove is provided inside the static pressure screw nut at a position close to the inner ring of the bearing, and the oil outlet annular groove communicates with a plurality of nut oil outlet holes distributed along the circumferential direction thereof.

As a further implementation, the side wall of the base is provided with a guide rail oil drain groove, the length direction of the base is provided with a nut assembly oil discharge groove A, and the nut assembly oil discharge groove A is symmetrically provided with a base oil discharge groove on both sides; The oil groove is communicated with the oil discharge groove B of the nut assembly, and the guide rail oil discharge groove is communicated with the base oil discharge groove.

As a further implementation manner, an oil baffle is arranged on the inner surface of the oil collecting plate, and an oil collecting hole is arranged on the bottom surface of the oil collecting plate.

As a further implementation manner, the support frame includes a support plate and a mounting plate that are connected in one piece, the support plate is connected with the worktable, and the mounting plate is connected with the oil collecting plate and the bearing outer ring.

The beneficial effects of the above embodiments of the present invention are as follows:

(1) In one or more embodiments of the present invention, due to the direct main drive of the hydrostatic nut, the problems such as vibration, heat generation, and deformation caused by the traditional driving method are greatly reduced, and the required rotational inertial force is also reduced. The pressure guide rail can realize ultra-high-precision linear motion with large stroke, high rigidity, high efficiency and fast response in precision and ultra-precision machining;

(2) In one or more embodiments of the present invention, the stator of the motor is matched with the outer ring of the bearing through the bearing flange, the rotor of the motor is matched with the static pressure screw nut through the nut flange, and the bearing also plays the role of radial and axial support, Due to the support and transmission through the hydraulic oil film, the friction is greatly reduced;

(3) One or more embodiments of the present invention solve the problem of entanglement of the oil passage of the nut auto-type hydrostatic screw pair, and the hydrostatic bearing and the hydrostatic screw nut in the nut-driven type hydrostatic screw pair feed unit do not need to be Separate oil supply, simple structure of oil passage, reduce cost.

Description of drawings

The accompanying drawings forming a part of the present invention are used to provide further understanding of the present invention, and the exemplary embodiments of the present invention and their descriptions are used to explain the present invention, and do not constitute an improper limitation of the present invention.

1 is a cross-sectional view of the present invention according to one or more embodiments;

2 is a schematic structural diagram of a hydrostatic guide rail according to one or more embodiments of the present invention;

3 is a cross-sectional view of bearing oil supply and hydrostatic screw nut oil inlet according to one or more embodiments of the present invention;

Figure 4 is a sectional view of the oil inlet of the hydrostatic screw nut rotated 45° around the axis of Figure 3;

5 is a cross-sectional view of a bearing and a hydrostatic screw nut assembled according to one or more embodiments of the present invention;

6 is a schematic structural diagram of an oil collecting plate according to one or more embodiments of the present invention;

7 is a schematic structural diagram of a support frame according to one or more embodiments of the present invention;

FIG. 8 is a schematic diagram of a base structure according to one or more embodiments of the present invention;

Among them, 1, the base; 101, the guide rail oil drain; 102, the nut assembly oil drain A; 103, the nut assembly oil drain B; 104, the base oil drain; 2, the bearing inner ring A; 3, the bearing outer ring A; 301, Bearing oil inlet; 302, annular oil cavity; 303, annular oil outlet; 304, nut oil inlet A; 305, annular inner groove; 306, bearing flange; 4, motor stator; 5, motor rotor; 6, Fixed seat A; 7. Static pressure screw; 8. Linear guide rail; 9. Guide rail slider A; 10. Workbench; 11. Support frame; , matching hole; 12, static pressure screw nut; 1201, oil inlet ring groove; 1202, nut oil inlet B; 1203, oil outlet ring groove; 1204, nut oil outlet hole; 1205, nut flange; 1206, section flow device; 13, bearing inner ring B; 14, bearing outer ring B; 15, guide rail slider B; 16, fixing seat B; 17, sealing ring; 18, oil collecting plate; 1801, mounting hole B; 1802, receiving Oil hole; 1803, oil baffle.

Detailed ways

It should be noted that the following detailed description is exemplary and intended to provide further explanation of the application. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

It should be noted that the terminology used herein is for the purpose of describing specific embodiments only, and is not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly dictates otherwise, the singular is intended to include the plural as well, furthermore, it is to be understood that when the terms "comprising" and/or "including" are used in this specification, it indicates that the presence of features, steps, operations, devices, components and/or combinations thereof;

For the convenience of description, if the words "up", "down", "left" and "right" appear in this application, it only means that the directions of up, down, left and right are consistent with the drawings themselves, and do not limit the structure. It is to facilitate the description of the present invention and to simplify the description, rather than indicating or implying that the device or element referred to must have a particular orientation, be constructed and operate in a particular orientation, and therefore should not be construed as a limitation on the application.

Terminology explanation part: Terms such as "installation", "connection", "connection", "fixation" in this application should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integrated; It can be a direct connection, or an indirect connection through an intermediate medium, an internal connection between two elements, or an interaction relationship between two elements. specific meaning.

Example 1:

This embodiment provides an integrated hydrostatic nut main drive type lead screw pair linear feed unit, as shown in FIG. 1 , including a hollow motor, a nut assembly, a hydrostatic lead screw 7 , a hydrostatic guide rail, and a workbench 10 , Static pressure screw fixing seat and base 1, there are two static pressure screw fixing seats, namely fixing seat A6 and fixing seat B16; The nut assembly is threadedly connected with the static pressure screw 7, and the hollow motor is installed on one side of the nut assembly. One end of the static pressure screw 7 is connected to the fixed seat A6, and the other end is connected to the fixed seat B16. The nut assembly is connected to the workbench 10 through the support frame 11, and the workbench 10 is connected to the hydrostatic guide rail.

Specifically, as shown in FIG. 2, the hydrostatic guide rail includes a guide rail slider A9, a guide rail slider B15, and a linear guide rail 8. The linear guide rail 8 and the static pressure screw 7 are parallel to each other. The guide rail slider A9, the guide rail slider B15 and the Linear guides 8 are slidingly connected. The worktable 10 is connected above the guide rail slider A9 and the guide rail slider B15.

The nut assembly includes a bearing and a hydrostatic screw nut 12 , and two ends of the hydrostatic screw nut 12 are respectively installed with a bearing, that is, a bearing A and a bearing B. Bearing A includes a bearing inner ring A2 and a bearing outer ring A3, and bearing B includes a bearing inner ring B13 and a bearing outer ring B14. In this embodiment, the bearing is a hydrostatic composite bearing.

The static pressure screw 7 is threadedly engaged with the hydrostatic pressure nut 12, and the two ends of the outer surface of the static pressure screw nut 12 are respectively in interference fit with the bearing inner ring A2 and the bearing inner ring B13, and the bearing inner ring A2 and the bearing outer ring A3 pass through Supported by liquid oil film; bearing inner ring B13 and bearing outer ring B14 are supported by liquid oil film. The bearing outer ring A3 is detachably connected to one side of the support frame 11 , and the bearing outer ring B14 is detachably connected to the other side of the support frame 11 .

The hollow motor includes a motor stator 4 and a motor rotor 5 . The motor stator 4 is in the form of a hollow cylinder, and the static pressure screw 7 can pass through the hollow part of the motor stator 4 . As shown in FIGS. 3-5 , the motor stator 4 is matched with the bearing outer ring A3 through the bearing flange 306 , and the motor rotor 5 is connected with the static pressure screw nut 12 through the nut flange 1205 . The structure of the motor stator 4 and the motor rotor 5 forms a closed-loop servo drive control. Since the two bearings themselves play a radial and axial support role for the hydrostatic screw nut 12, the hollow motor itself does not need to install bearings.

The bearing outer ring A3 is provided with a nut oil inlet A304, the nut oil inlet A304 is evenly distributed along the circumferential direction of the bearing outer ring A3, and the opening direction of each nut oil inlet A304 is along the radial direction of the bearing outer ring A3. An annular inner groove 305 is provided inside the bearing outer ring A3, and the nut oil inlet A304 communicates with the annular inner groove 305. The bearing outer ring A3 is also provided with bearing oil inlets 301 evenly distributed along the circumferential direction, and the opening direction of the bearing oil inlets 301 is along the radial direction of the bearing outer ring A3.

An annular oil cavity 302 is provided on the side of the bearing outer ring A3 close to the bearing inner ring A2. The annular oil cavity 302 may be an annular cavity, or a plurality of fan-shaped cavities may be arranged in an annular shape at intervals. The annular oil cavity 302 forms a certain angle with the axis of the bearing outer ring A3 , and provides radial and axial support for the static pressure screw nut 12 .

There is a gap between the bearing outer ring A3 and the bearing inner ring A2, and an annular oil outlet 303 is provided. The annular oil outlet 303 and the bearing oil inlet 301 communicate with the annular oil outlet 303 respectively. The bearing outer ring A3 supplies oil to the annular oil cavity 302 through the bearing oil inlet 301 , and discharges the oil to the oil collecting plate 18 through the annular oil outlet 303 for recovery.

The bearing outer ring B14 has no bearing flange 306, and other structures are the same as the bearing outer ring A3, which will not be repeated here.

The hydrostatic screw nut 12 is provided with an oil inlet annular groove 1201 having the same width as the annular inner groove 305 . Both the bearing outer ring A3 and the bearing outer ring B14 are equipped with a sealing ring 17 to ensure good sealing, so as to realize the oil supply from the nut oil inlet A304 to the nut oil inlet B1202.

The inside of the static pressure screw nut 12 is further provided with a nut oil inlet B1202 , and the nut oil inlet B1202 is evenly distributed along the circumferential direction of the static pressure screw nut 12 . An end of the nut oil inlet B1202 away from the oil inlet annular groove 1201 is provided with a restrictor 1206, and the number of the restrictors 1206 and the nut oil inlet B1202 is the same and corresponding. The nut oil inlet A304, the annular inner groove 305, the oil inlet annular groove 1201, the nut oil inlet B1202 and the restrictor 1206 are connected in sequence, and finally the hydraulic oil is transmitted to both sides of the thread of the static pressure screw nut 12, which is a static pressure wire Lever nut 12 supplies oil.

An oil outlet annular groove 1203 is formed in the hydrostatic screw nut 12 near the end surfaces of the bearing inner ring A2 and the bearing inner ring B13, respectively. The oil outlet annular groove 1203 communicates with a plurality of nut oil outlet holes 1204 distributed along its circumference. The hydraulic oil in the static pressure screw nut 12 flows out to the oil outlet annular groove 1203 through the tiny gap between the static pressure screw 7 and the static pressure screw nut 12. When the hydrostatic pressure nut 12 rotates, due to the centrifugal force, the oil outlet ring The liquid oil in the groove 1203 is easily discharged to the oil collecting plate 18 through the oil outlet hole 1204 of the nut.

As shown in FIG. 6 , the oil collecting plate 18 is U-shaped, and the inner surface of the oil collecting plate 18 is provided with an oil baffle 1803 suitable for its shape. In this embodiment, two oil baffles 1803 are provided, and an oil receiving hole 802 is provided between the oil baffles 1803 . A mounting hole B1801 is formed on the side of the oil collecting plate 18 near the end to connect with the support frame 11 . The oil collecting plate 18 is positioned axially through the oil baffle plate 1803. The oil collecting hole 1802 is located on the lowermost side of the oil collecting plate 18 (the side away from its open end is the lower side), and the hydraulic oil flows to the oil collecting plate by its own gravity. At the bottom of 18, oil collection is realized.

In order to ensure the coaxiality, the support frame 11 is designed as an integral structure. As shown in FIG. 7 , the supporting frame 11 includes a supporting plate 1102 and a mounting plate 1103 that are connected as a whole. In this embodiment, there are two mounting plates 1103, and the two mounting plates 1103 are vertically connected to the side surfaces of the supporting plate 1102; the supporting plate 1102 is a rectangular plate. It can be understood that, in other embodiments, the support plate 1102 may also have other shapes. There is a certain distance between the two mounting plates 1103 , and the distance between the two is adapted to the size of the oil collecting plate 18 .

Further, the shape of the mounting plate 1103 is adapted to the oil collecting plate 18, the mounting plate 1103 is provided with a matching hole 1104, the diameter of the matching hole 1104 is adapted to the bearing inner ring A2 (bearing inner ring B13), the bearing outer ring A3 (bearing outer ring Ring B14) is connected to the mounting plate 1103 by means of bolts. A mounting hole A1101 is formed on the side of the mounting plate 1103. The mounting hole A1101 corresponds to the mounting hole B1801 of the oil collecting plate 18, and the two are fixed by bolts. The oil collecting plate 18 is covered on the axial outer side of the mounting plate 1103, and the support frame 11 cooperates with the oil collecting plate 18 to form an oil collecting space.

As shown in Fig. 8, the longitudinal section of the base 1 is U-shaped, the side wall of the base 1 is provided with a guide rail oil drain groove 101, the inner surface of the base 1 is provided with a nut assembly oil discharge groove A102, a nut assembly oil discharge groove B103, a base oil discharge groove 104, and a nut assembly oil discharge groove A102. The oil discharge grooves A102 of the assembly are arranged along the length direction of the base 1, and the oil discharge grooves 104 of the base are symmetrically arranged on both sides of the oil discharge grooves A102 of the nut assembly. The nut assembly oil discharge groove B103 is perpendicular to the nut assembly oil discharge groove A102 and the base oil discharge groove 104, and communicates with them; the guide rail oil discharge groove 101 communicates with the base oil discharge groove 104.

The hydraulic oil discharged from the hydrostatic guide rail is discharged to the base oil discharge groove 104 through the guide oil discharge groove 101. When the nut assembly moves axially along the hydrostatic screw 7, the oil collecting plate 18 discharges the recovered oil to the nut through the oil collecting hole 1802. The assembly oil discharge groove A102 is then converged to the base oil discharge groove 104 through the nut assembly oil discharge groove B103, and then the hydraulic oil recovery is completed.

The above descriptions are only preferred embodiments of the present application, and are not intended to limit the present application. For those skilled in the art, the present application may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of this application shall be included within the protection scope of this application.

Claims (10)

1. An integrated hydrostatic nut main drive type lead screw pair linear feed unit, characterized in that it comprises a hydrostatic lead screw and a hydrostatic guide rail that are parallel to each other, the hydrostatic lead screw is axially installed with a nut assembly, and the nut assembly A hollow motor is installed on one side; the nut assembly is installed under the worktable through a support frame, and the worktable is detachably connected to the hydrostatic guide rail; the outer side of the support frame is covered with an oil collecting plate to form an oil collecting space; the static The pressure screw is installed above the base, and the base is provided with a plurality of oil drain grooves for draining oil for the hydrostatic guide rail and the oil collecting plate. 2. An integrated hydrostatic nut main drive type lead screw pair linear feed unit according to claim 1, wherein the nut assembly comprises a bearing and a hydrostatic lead screw nut, and the hydrostatic lead screw nut has two parts. Bearings are installed at the ends respectively; the bearing outer ring of one of the bearings is connected with the motor stator of the hollow motor through the bearing flange, and the motor rotor is matched with the static pressure screw nut through the nut flange. 3. An integrated hydrostatic nut main drive type lead screw pair linear feed unit according to claim 2, characterized in that the inner surface of the hydrostatic lead screw nut is threadedly engaged with the hydrostatic lead screw, and the static pressure The two ends of the outer surface of the screw nut are respectively in interference fit with the inner ring of the bearing; the inner ring of the bearing located at both ends of the static pressure screw nut and the outer ring of the bearing are supported by a liquid oil film. 4. An integrated hydrostatic nut main drive type lead screw pair linear feed unit according to claim 2, wherein the outer ring of the bearing is evenly provided with a nut oil inlet A in the circumferential direction, and the outer ring of the bearing is provided with a nut oil inlet A evenly in the circumferential direction. There is an annular inner groove inside, and the nut oil inlet A is communicated with the annular inner groove. 5 . The integrated hydrostatic nut main drive type linear feed unit of the lead screw pair according to claim 4 , wherein the bearing outer ring is further provided with bearing oil inlets evenly distributed along the circumferential direction. 6 . , the outer ring of the bearing is provided with an annular oil cavity on the side close to the inner ring of the bearing; there is a gap between the outer ring of the bearing and the inner ring of the bearing with an annular oil outlet, and the annular oil outlet and the bearing oil inlet are respectively connected with the annular oil outlet. Connected. 6 . An integrated hydrostatic nut main drive type lead screw pair linear feed unit according to claim 4 , wherein the hydrostatic lead screw nut is provided with an oil inlet corresponding to the annular inner groove. 7 . An annular groove, the oil inlet annular groove is connected with a plurality of nut oil inlets B arranged along the circumferential direction of the static pressure screw nut; the nut oil inlet B is communicated with the restrictor. 7 . The integrated hydrostatic nut main drive type linear feed unit of the lead screw pair according to claim 6 , wherein an oil outlet annular groove is provided inside the hydrostatic lead screw nut at a position close to the inner ring of the bearing. 8 . , the oil outlet annular groove is communicated with a plurality of nut oil outlet holes distributed along its circumferential direction. 8. An integrated hydrostatic nut main drive type lead screw pair linear feed unit according to claim 1, wherein the side wall of the base is provided with a guide rail oil drain groove, and the length direction of the base is provided with a nut assembly row Oil tank A and nut component oil drain tank A are symmetrically provided with base oil drain tanks on both sides; nut component oil drain tank A and base oil drain tank are connected with nut component oil drain tank B, and the guide rail oil drain tank is connected with the base oil drain tank. 9 . The integrated hydrostatic nut main drive type linear feed unit of the lead screw pair according to claim 1 , wherein an oil baffle is provided on the inner surface of the oil collecting plate, and a bottom surface of the oil collecting plate is provided with an oil baffle plate. 10 . There are oil collecting holes. 10. An integrated hydrostatic nut main drive type lead screw pair linear feed unit according to claim 1, wherein the support frame comprises a support plate and a mounting plate that are connected as a whole, the support plate and the worktable The mounting plate is connected with the oil collecting plate and the outer ring of the bearing.

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