CN116511967A - Ball screw device and machine tool equipment - Google Patents

Abstract

The invention relates to a ball screw device and machine tool equipment. The ball screw device includes: the ball bearings are distributed in the guide grooves of the lead screw; the main nut component and the auxiliary nut component are sleeved on the screw rod and are in rolling connection with the balls, and the auxiliary nut component is in sliding plug connection with the main nut component. The outer sleeve component is fixed on the main nut component and sleeved outside the auxiliary nut component, and a sealed adjusting space is formed among the outer sleeve component, the auxiliary nut component and the main nut component. And the fluid conveying component is used for conveying a fluid medium with adjustable pressure into the adjusting space, and the fluid medium acts on the pretightening force of the main nut component and the auxiliary nut component, which is opposite to each other. The fluid conveying assembly drives the fluid medium to push the main nut assembly and the auxiliary nut assembly to move back, so that the fit clearance between the ball and the screw is automatically adjusted, the rolling clearance between the ball and the screw is always kept flexible, and the transmission precision of the ball screw device is kept.

Description

Ball screw device and machine tool equipment

Technical Field

The invention relates to the technical field of transmission devices, in particular to a ball screw device and machine tool equipment.

Background

The ball screw utilizes a ball and nut pair matching structure to realize a high-precision low-resistance transmission mechanism which converts rotary motion into linear motion or an executive component which converts the linear motion into rotary motion. The surface of the screw rod forms a spiral guide groove, the hole wall of the nut seat forms a matched guide groove, and balls are arranged in a rolling channel formed by the screw rod and the nut seat one by one so as to realize high-speed and high-precision transmission.

With the improvement of the precision requirements of intelligent manufacturing equipment, ball screws are increasingly applied to high-precision machines. However, the high-torque high-precision double-nut ball screw is extremely easy to wear after being used for a period of time, and the degree of wear is small, however, the wear of the ball screw is fed back to the whole machine tool, so that the processing error of the system is increased, the processing precision of equipment is reduced, and the technical problem that the processing precision requirement cannot be met is solved.

The abrasion of the ball screw is mainly focused on the increase of the clearance between the ball and the rolling channel, and the existing repairing mode or adjusting mode of the clearance of the ball screw is as follows:

the hydraulic clearance eliminating ball screw nut comprises a ball screw nut body, sealing rings at two ends of the nut body and a pressing plate as disclosed in Chinese patent CN 111503235A; an oil filling hole is formed in the side wall of one end of the ball screw nut body, the inner end of the oil filling hole is communicated with an inner side raceway of the ball screw nut body, and an oil filling joint is arranged at the outer end of the one-way oil filling hole and can be connected with an oil inlet pipeline of an external pressure source; the other end of the ball screw nut body is provided with a throttling exhaust hole, and the inner end of the throttling exhaust hole is communicated with an inner side raceway of the ball screw nut body.

Chinese patent CN 211371201U discloses a double-nut structure of atmospheric pressure regulation interval, including first nut, establish the second nut in first nut one side, all be equipped with the ball raceway that is the heliciform on first nut and the second nut inner peripheral surface, be equipped with the pneumatic groove in the first nut, be equipped with the through-hole on the pneumatic groove lateral wall, the one end that the pneumatic groove was kept away from to the through-hole is connected with the pneumatic cylinder through the hose, be equipped with mobilizable piston rod in the pneumatic groove, be equipped with the shifting chute on the first nut is close to second nut one side lateral wall, the shifting chute is equipped with the movable rod along shifting chute opening direction removal, movable rod one end and piston rod one end fixed connection, the movable rod other end and second nut lateral wall fixed connection.

The existing ball screw repairing mode has the technical problems that the repairing process has higher requirements on the technical level of personnel and the gap repairing difficulty of the ball screw is high, so that improvement is needed.

Disclosure of Invention

In order to overcome the problems in the related art, embodiments of the present invention provide a ball screw device and a machine tool apparatus.

According to an embodiment of the present invention, a ball screw device includes:

the ball bearings are distributed in the guide grooves of the lead screw;

the main nut component and the auxiliary nut component are sleeved on the screw rod and are in rolling connection with the balls, and the auxiliary nut component is in sliding plug connection with the main nut component;

the outer sleeve component is fixed on the main nut component and sleeved outside the auxiliary nut component, and a sealed adjusting space is formed among the outer sleeve component, the auxiliary nut component and the main nut component;

and the fluid conveying component is used for conveying a fluid medium with adjustable pressure into the adjusting space, and the fluid medium acts on the pretightening force of the main nut component and the auxiliary nut component, which is opposite to each other.

In one embodiment, the secondary nut assembly and the outer sleeve assembly are a straight sliding fit.

In one embodiment, the secondary nut assembly includes a secondary nut body slidably defined by the outer sleeve assembly and at least one secondary seal mounted to the secondary nut body, the secondary seal being in resilient sealing engagement with the outer sleeve assembly.

In an embodiment, the auxiliary nut body comprises a first inserting portion, a second inserting portion and an extending portion, the first inserting portion and the second inserting portion are in a step shaft shape, the first inserting portion is in inserting connection with the main nut assembly, the second inserting portion is in inserting connection with the outer sleeve assembly, the auxiliary sealing element is installed on the second inserting portion, the extending portion penetrates out of the outer sleeve assembly, and a step surface between the first inserting portion and the second inserting portion is arranged with an interval between the main nut assembly to form the adjusting space.

In one embodiment, the step surface is tapered.

In one embodiment, two auxiliary sealing elements are arranged, and the two auxiliary sealing elements are distributed at intervals along the axial direction of the screw rod.

In one embodiment, the outer sleeve assembly comprises a sleeve member inserted and fixed with the main nut assembly and a gland frame detachably fixed to the sleeve member, and the sliding part of the auxiliary nut assembly is limited between the gland frame and the main nut assembly.

In an embodiment, the main nut component comprises a mounting end and a pipe body part protruding out of the mounting end in a tubular shape, the outer sleeve component is sleeved on the pipe body part and is locked at the mounting end in a butt joint manner, the auxiliary nut component is inserted into the pipe body part, and the adjusting space is formed among the end face of the pipe body part, the auxiliary nut component and the outer sleeve component.

In an embodiment, the fluid medium is set to be gas, and the fluid delivery assembly includes a gas source, a pressure regulating assembly connected to the gas source, and a joint assembly connected to the pressure regulating assembly, wherein the joint assembly is connected to the outer sleeve assembly and is communicated with the adjusting space, and the pressure regulating assembly is used for regulating the air pressure in the adjusting space.

The invention also discloses machine tool equipment, which comprises an equipment main body and the ball screw device, wherein the ball screw device is arranged on the equipment main body.

The technical scheme provided by the embodiment of the invention can comprise the following beneficial effects: the fluid conveying assembly drives the fluid medium to push the main nut assembly and the auxiliary nut assembly to move back, so that the fit clearance between the ball and the screw is automatically adjusted, the rolling clearance between the ball and the screw is always kept flexible, and the transmission precision of the ball screw device is kept. The outer sleeve assembly, the auxiliary nut assembly and the main nut assembly jointly construct an adjusting space so that the auxiliary nut assembly can reversely move relative to the main nut assembly and is in a controllable moving range.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention as claimed.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and together with the description, serve to explain the principles of the invention.

Fig. 1 is a schematic perspective view of a ball screw device according to an exemplary embodiment.

Fig. 2 is a schematic partial cross-sectional view of a ball screw device according to an example embodiment.

Fig. 3 is an enlarged schematic view in partial cross-section of a ball screw device according to an exemplary embodiment.

Fig. 4 is an enlarged schematic view of the structure at a in fig. 3.

Fig. 5 is a schematic view of another split seal ring of fig. 4.

Fig. 6 is an enlarged schematic view of the structure in fig. 4 in which opposite wall surfaces of the adjustment space are provided as concave curved surfaces.

Fig. 7 is a schematic structural view of a sub-nut assembly according to an exemplary embodiment.

Fig. 8 is a schematic structural view of a main nut assembly according to an exemplary embodiment.

Fig. 9 is a schematic structural view of a sheathing assembly according to an exemplary embodiment.

In the figure, a lead screw 10; a main nut assembly 20; a mounting end 21; a tube body 22; a tube body groove 221; an elastic seal ring 222; an extension 23; a jacket assembly 30; a sleeve member 31; a gland bracket 32; a slide key 33; a positioning groove 34; a fluid delivery assembly 40; a gas source 41; a pressure regulating assembly 42; a pressure regulating knob 421; a joint assembly 43; a pressure gauge 44; a ball 50; a sub-nut assembly 60; a first plug-in portion 61; a positioning groove 611; a front end seal ring 612; a second plug-in portion 62; an extension 63; key slot 631; a secondary seal 64; a rubber seal 641; an open seal 642; a step surface 643; a guide groove 65; an adjustment space 70; a concave curved surface 71.

Description of the embodiments

Wherein the drawings are for illustrative purposes only and are shown in schematic, non-physical, and not intended to be limiting of the present patent; for the purpose of better illustrating embodiments of the invention, certain elements of the drawings may be omitted, enlarged or reduced and do not represent the size of the actual product; it will be appreciated by those skilled in the art that certain well-known structures in the drawings and descriptions thereof may be omitted.

The same or similar reference numbers in the drawings of embodiments of the invention correspond to the same or similar components; in the description of the present invention, it should be understood that, if the terms "upper", "lower", "left", "right", "inner", "outer", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, only for convenience in describing the present invention and simplifying the description, rather than indicating or implying that the apparatus or elements being referred to must have a specific orientation, be constructed and operated in a specific orientation, so that the terms describing the positional relationships in the drawings are merely for exemplary illustration and should not be construed as limiting the present patent, and that the specific meaning of the terms described above may be understood by those of ordinary skill in the art according to specific circumstances.

In the description of the present invention, unless explicitly stated and limited otherwise, the term "coupled" or the like should be interpreted broadly, as it may be fixedly coupled, detachably coupled, or integrally formed, as indicating the relationship of components; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between the two parts or interaction relationship between the two parts. The specific meaning of the above terms in the present invention will be understood in specific cases by those of ordinary skill in the art.

As shown in fig. 1 to 4, the present invention provides a ball screw device including a screw 10, balls 50 disposed in guide grooves 65 of the screw 10, and a main nut assembly 20 and a sub nut assembly 60 fitted over the screw 10 and rolling-coupled with the balls 50. The guide grooves 65 are spirally distributed on the outer peripheral wall of the screw 10, the balls 50 are limited in a nut pair formed by the main nut assembly 20 and the auxiliary nut assembly 60, and the screw 10 can drive the nut pair to linearly move when rotating.

In this embodiment, the secondary nut assembly 60 is slidably plug-connected to the primary nut assembly 20 such that the secondary nut assembly 60 is capable of sliding linearly relative to the primary nut assembly 20. The sub-nut assembly 60 moves in the axial direction of the lead screw 10 with respect to the main nut assembly 20 to fine-tune the gap therebetween. Optionally, the sliding gap between the secondary nut assembly 60 and the primary nut assembly 20 is 0.01 mm-0.5 mm.

The outer sleeve assembly 30 is fixed to the main nut assembly 20 and is sleeved outside the sub nut assembly 60, and a sealed adjustment space 70 is formed among the outer sleeve assembly 30, the sub nut assembly 60 and the main nut assembly 20. The outer sleeve assembly 30 is fixedly connected with the main nut assembly 20 in an integral structure, and the outer sleeve assembly 30 and the main nut assembly 20 are detachably connected, so that the outer sleeve assembly 30 and the main nut assembly 20 jointly define the auxiliary nut assembly 60, the movable range of the auxiliary nut assembly 60 is limited in the movable area defined by the outer sleeve assembly 30 and the main nut assembly 20, and the auxiliary nut assembly 60 is prevented from exceeding the movable area.

The sub nut assembly 60 is inserted and connected to the main nut assembly 20, and an end surface of a mating portion of the sub nut assembly 60 and the outer sleeve assembly 30 and an end surface of an inserted portion of the main nut assembly 20 form an annular groove structure, and the outer sleeve assembly 30 is sleeved outside the sub nut assembly 60 and the main nut assembly 20, so that an opening of the annular groove structure is closed by the outer sleeve assembly 30 to form a sealed adjustment space 70. The outer sleeve assembly 30, the sub-nut assembly 60, and the main nut assembly 20 together construct an adjustment space 70 to enable the sub-nut assembly 60 to move in a reverse direction relative to the main nut assembly 20 and within a controllable range of movement.

The fluid delivery assembly 40 is configured to deliver a fluid medium of adjustable pressure into the adjustment space 70, the fluid medium acting against a relatively deviating pretension of the main nut assembly 20 and the sub nut assembly 60. The fluid delivery assembly 40 communicates with the adjustment space 70, and in particular, the outer jacket assembly 30 provides a flow guide channel in communication with the adjustment space 70, to which the fluid delivery assembly 40 is connected. Alternatively, the fluid medium is provided as a gas or a liquid, preferably, the fluid medium is provided as a gas, such as a nitrogen gas, and the fluid medium pneumatically pushes the secondary nut assembly 60 relative to the primary nut assembly 20 to automatically adjust the clearance of the balls 50. The fluid delivery assembly 40 drives the fluid medium to push the main nut assembly 20 and the auxiliary nut assembly 60 to move back, so that the fit clearance between the ball 50 and the screw 10 is automatically adjusted, the rolling clearance between the ball 50 and the screw 10 is always kept flexible, and the transmission precision of the ball screw device is kept.

In one embodiment, the fluid delivery assembly 40 includes a gas source 41, a pressure regulating assembly 42 coupled to the gas source 41, and a connector assembly 43 coupled to the pressure regulating assembly 42, the connector assembly 43 coupled to the housing assembly 30 and in communication with the regulated space 70, the pressure regulating assembly 42 for regulating the gas pressure within the regulated space 70. The air source 41 may be provided as a high pressure air source 41, such as the air source 41 may be provided as a high pressure air pump, a high pressure air bottle, or the like.

The pressure regulating assembly 42 is configured as a pressure reducing valve or the like to regulate the gas pressure of the output pressure regulating assembly 42 and to maintain the stability of the gas pressure. Optionally, the line connecting the pressure regulating assembly 42 to the air supply 41 is a high pressure line to maintain stability of the line. Optionally, the pipeline to which the pressure regulating assembly 42 and the joint assembly 43 are connected is a high pressure pipe to maintain the stability of the pipeline. Optionally, the joint assembly 43 is threadably coupled to the jacket assembly 30 to maintain the reliability and convenience of the coupling. Preferably, the coupling assembly 43 is configured for threaded tubular connection with the outer housing assembly 30.

Preferably, the pressure regulating assembly 42 is connected to the control platform, so that the air pressure of the output pressure regulating assembly 42 can be automatically regulated by the control platform, and the output pressure of the pressure regulating assembly 42 can be adapted to the acting force between the main nut assembly 20 and the auxiliary nut assembly 60, so that the clearance adjustment of the balls 50 is convenient.

The ball 50 clearance adjustment is adjusted through the steady pressure of pressure regulating assembly 42 output, wherein, ball screw device parameter calculates the interaction force between main nut subassembly 20 and vice nut subassembly 60, and the high-pressure nitrogen gas of air supply 41 output is through the high-pressure pipe entering pressure regulating assembly 42. The fluid medium of the pressure regulating assembly 42 forms a preload between the main nut assembly 20 and the sub nut assembly 60 of the adjustment space 70, and the conventional ball screw device is set with an axial preload, and the preload effect generated by the input of the fluid medium through the pressure regulating assembly 42 can be maintained to 2 to 4 times of the preload. In this embodiment, 10% of the basic rated load (Ca) of the ball screw device is used as a reference for the maximum preload.

In the ball screw device, the pre-compression amount of the balls by the main nut assembly 20 and the auxiliary nut assembly 60 is calculated, and the screw precision and the basic rated load are screw factory setting parameters.

The pressure regulating assembly 42 regulates the thrust required by the pre-compression amount to output nitrogen pressure, and then the distance between the main nut assembly 20, the auxiliary nut assembly 60 and the adjusting space 70 formed by the outer sleeve assembly 30 is regulated through nitrogen which is a fluid medium, the main nut assembly 20 and the auxiliary nut assembly 60 form relatively deviating and balanced and stable pre-compression force, and the gap between the ball 50 and the screw rod 10 is kept stable.

The thrust formula of the sub nut assembly 60 is: f1 =3.14× (D/2) f/1000; where F1 is the thrust, D is the inner diameter of the jacket assembly 30, and F is the nitrogen pressure.

Preferably, the fluid delivery assembly 40 further includes a pressure gauge 44 coupled to the pressure regulating assembly 42, the pressure gauge 44 visually outputting a pressure value of the output pressure of the pressure regulating assembly 42. Optionally, the pressure regulating assembly 42 is provided with a pressure regulating knob 421, and the pressure regulating knob 421 is used for regulating the pressure value output by the pressure regulating assembly 42. Preferably, the fluid medium is provided as nitrogen to facilitate transport of the fluid medium without risk of leakage. Preferably, the pressure regulating assembly 42 is configured as an automatic regulating valve that automatically regulates the output pressure based on a control command or a built-in program.

As shown in fig. 3 to 9, in an embodiment, the sub nut assembly 60 and the outer sleeve assembly 30 are linearly slidably engaged, thereby enabling the sub nut assembly 60 to be linearly moved with respect to the outer sleeve assembly 30 without deflection, and improving the accuracy of linear adjustment of the clearance between the balls 50 by the movement of the sub nut assembly 60. Alternatively, the sub nut assembly 60 is engaged with the outer sheathing assembly 30 through a guide structure of a guide groove and a guide protrusion, to achieve a linear movement. Preferably, the sub nut assembly 60 is provided with a key slot 631 and a sliding key 33 mounted to the key slot 631, and the sleeve assembly 30 is provided with a positioning groove 34 matching the sliding key 33 such that the sliding key 33 defines both the sub nut assembly 60 and the sleeve assembly 30.

Alternatively, the linear mating portions of the secondary nut assembly 60 and the outer sleeve assembly 30 are spaced apart from the primary nut assembly 20, and preferably the outer sleeve assembly 30 projects toward the secondary nut assembly 60 to define a linear sliding distance of the secondary nut assembly 60. The auxiliary nut assembly 60 is inserted into the outer sleeve assembly 30 and is slidably connected with the outer sleeve assembly 30, so as to realize a sliding insertion structure, and combines with the sliding key 33 structure to realize linear guiding.

In one embodiment, the secondary nut assembly 60 includes a secondary nut body slidably defined in the outer sleeve assembly 30 and at least one secondary seal 64 mounted to the secondary nut body, the secondary seal 64 being in resilient sealing engagement with the outer sleeve assembly 30. The sub nut body has a hollow shaft structure which is sleeved outside the screw 10, and a guide groove 65 is provided on the inner wall surface of the shaft hole to cooperate with the screw 10 to define the ball 50. The sub-nut body is of a stepped shaft construction and a sub-seal 64 is provided at a sliding mating surface of the sub-nut body and the outer jacket assembly 30 adjacent to the adjustment space 70 to maintain a sealing arrangement of the mating surface between the sub-nut body and the outer jacket assembly 30.

In an alternative embodiment, the secondary seal 64 is provided as an annular elastomeric seal 222 with a sealing groove formed in the peripheral wall of the secondary nut body, the secondary seal 64 being positioned within the sealing groove and resiliently sealing against the mating surface under compression of the outer sleeve assembly 30. Preferably, the number of the sub-seals 64 may be set to one or more. When two or more sub-seals 64 are provided, the sub-seals 64 form a multi-stage seal with respect to the sub-nut body, thereby improving the sealing performance. In an alternative embodiment, two secondary seals 64 are provided, with the two secondary seals 64 being spaced apart along the axial direction of the lead screw 10. The two secondary seals 64 may be provided as the same type of sealing ring, for example, both seals may be provided as sealing rings having circular cross-sections.

Preferably, the two secondary seals 64 are provided as differently shaped sealing rings. Specifically, the sub seal 64 includes a rubber seal 641 and an open seal 642 that are fitted around the sub nut body, and the size of the open seal 642 from the adjustment space 70 is smaller than the size of the rubber seal 641 from the adjustment space 70. The open seal 642 has a deformation notch, and the opening direction of the deformation notch faces the direction of the adjustment space 70. Preferably, the elastic deformation capacity of the split seal ring 642 on the two side wall surfaces of the deformation notch is larger than the elastic deformation strength of the middle part of the split seal ring 642, and the two side wall surfaces of the split seal ring 642 are respectively attached and tensioned to the auxiliary nut main body and the outer sleeve assembly 30 under the pressure action of the fluid medium, so that a sealing tensioning structure is formed. For example, the split seal 642 has a structure similar to a "C", and the split seal 642 includes a main body, a first curved portion and a second curved portion that are formed by protruding from the main body, the first curved portion is attached to the bottom of the deformation notch, and the second curved portion is attached to the wall of the jacket assembly 30. The first bending part and the second bending part are respectively clung to the corresponding wall surfaces under the pressure action of the fluid medium, and the pressure deformation of the fluid medium is utilized to form a stable tensioning sealing structure. Preferably, the second bending portion has a cross-sectional dimension gradually decreasing from the main body portion toward the distal end. Optionally, the end of the first bending portion is provided with an annular rib, so as to strengthen the end strength of the first bending portion and improve the tightness of the middle portion of the first bending portion. Alternatively, the first curved portion gradually decreases in cross-sectional dimension from the main body portion in the distal direction.

In an alternative embodiment, the secondary nut body includes a first socket portion 61, a second socket portion 62, and an extension portion 63, and the first socket portion 61 and the second socket portion 62 are stepped shaft-like. The first plug portion 61, the second plug portion 62 and the extension portion 63 are different regions of the secondary nut body distributed in the axial direction, wherein the outer diameter of the second plug portion 62 is larger than the outer diameter of the first plug portion 61 so as to form a stepped shaft structure. The outer diameter of the second socket portion 62 is larger than the outer diameter of the extension portion 63, that is, the second socket portion 62 is the maximum outer diameter portion of the sub nut body.

As shown in fig. 3 to 9, the first plug portion 61 is plug-connected to the main nut assembly 20, the second plug portion 62 is plug-connected to the outer sleeve assembly 30, and a step surface 643 between the first plug portion 61 and the second plug portion 62 is spaced from the main nut assembly 20 to form an adjustment space 70. The outer peripheral wall of the first inserting portion 61, the step surface 643 and the end surface of the main nut assembly 20 form a ring groove structure, the second inserting portion 62 is inserted into the outer sleeve assembly 30, and the inner wall of the outer sleeve assembly 30 distributes openings of the ring groove structure to form a closed adjusting space 70. The second socket 62 is movably defined between the outer sleeve member 30 and the main nut member 20, and maintains the balls 50 to fit the movable gap of the screw 10, thereby preventing the sub nut member 60 from being separated from the outer sleeve member 30 and maintaining the accuracy of rotation of the screw 10.

Further, in order to improve the sealing performance at the peripheral fit-in gap of the adjustment space 70, a sealing structure is provided at the fit-in surface between the main nut assembly 20, the sub nut assembly 60 and the outer sleeve assembly 30 to maintain the sealing performance of the adjustment space 70. The secondary seal 64 is mounted on the second plug portion 62, wherein the secondary seals 64 are spaced apart along the axial direction of the second plug portion 62.

Further, the mating surface between the first mating portion 61 and the main nut assembly 20 is sealed by at least one sealing ring to maintain tightness of the seal. Preferably, the main nut assembly 20 includes a mounting end 21 and a tubular body portion 22 of the tubular projecting mounting end 21, and the jacket assembly 30 is sleeved on the tubular body portion 22 and is abutted and locked to the mounting end 21. The tube body 22 is of a tubular structure, the outer diameter of the tube body 22 is smaller than that of the mounting end 21, and the tube body 22 is connected with the jacket assembly 30 in a plugging manner so as to keep the assembly accuracy of the tube body 22 and the jacket assembly. Further, the fastener lockingly connects the main nut assembly 20 and the outer sleeve assembly 30 to further maintain the tightness of the bond therebetween. Further, the main nut assembly 20 is formed with an elongated portion 23 extending from the mounting end 21 in a direction away from the pipe body 22, and the elongated portion 23 enlarges the coupling area between the main nut assembly 20 and the screw 10, thereby improving stability.

Preferably, at least one pipe groove 221 is provided on the outer peripheral wall of the pipe portion 22, and an elastic seal ring 222 is installed in the pipe groove 221, and the elastic seal ring 222 is elastically deformed by pressing, so that an elastic seal is formed between the outer peripheral wall of the pipe portion 22 and the inner wall surface of the jacket assembly 30. Alternatively, the pipe body groove 221 may be provided in one or more, and when the pipe body groove 221 is provided in a plurality, a multi-stage sealing structure is formed. Preferably, when the elastic seal ring 222 is provided in plurality, the elastic seal ring 222 may be provided as an O-ring having a circular cross section, or a part of the elastic seal ring 222 may be provided as an open seal ring 642 having an opening. Wherein, the size of the opening seal 642 from the adjusting space 70 is smaller than the size of the O-ring distance adjusting space 70.

Further, the sub nut assembly 60 is inserted into the pipe body 22, that is, the first insertion portion 61 is inserted into the hole wall of the pipe body 22, and an adjustment space 70 is formed between the end surface of the pipe body 22, the step surface 643 of the sub nut assembly 60, and the jacket assembly 30.

Preferably, the mating surface between the first plug portion 61 and the pipe body portion 22 is provided with an elastic seal for further improving the sealing of the mating surface between the first plug portion 61 and the pipe body portion 22. At least one pipe wall groove is formed in the inner peripheral wall of the pipe body 22, and an elastic sealing member is installed in the pipe wall groove and is elastically deformed by extrusion, so that an elastic seal is formed between the inner wall of the pipe body 22 and the outer wall surface of the first plug-in portion 61. Alternatively, the pipe wall grooves can be arranged in one or more, and when the pipe wall grooves are arranged in a plurality, the multi-section sealing structure is formed. Preferably, when a plurality of elastic seals are provided, the elastic seals may be all provided as O-rings having circular cross sections, or a part of the elastic seals may be provided as split seal rings 642 having openings. Wherein, the size of the opening seal 642 from the adjusting space 70 is smaller than the size of the O-ring distance adjusting space 70.

In another embodiment, the inner wall of the pipe body 22 is a flat wall, a positioning groove 611 is provided on the outer peripheral wall of the first plugging portion 61, and a front end sealing ring 612 is installed in the positioning groove 611, and the front end sealing ring 612 elastically abuts against the inner wall of the pipe body 22 to realize sealing.

The opposite wall surfaces of the main nut assembly 20 and the auxiliary nut assembly 60 in the construction adjustment space 70 are set to be non-parallel wall surfaces, so that automatic guiding of the movement process of the auxiliary nut assembly 60 after the construction gas directly enters the adjustment space 70 is realized, the movement precision and the movement direction control of the auxiliary nut assembly 60 are improved, and the gap change of the balls 50 caused by errors is further reduced.

In one embodiment, the step surface 643 has a tapered surface shape, wherein the tapered surface of the step surface 643 is inclined from the first inserting portion 61 to the second inserting portion 62. The fluid medium acts on the whole step surface 643, and the step surface 643 is a conical surface, so that the stress area can be enlarged, and centripetal force components can be formed, thereby improving the centripetal direction convergence of the ball 50, and improving the concentration and stress balance. Preferably, the cone apex angle of the step surface 643 is 120-180 degrees to maintain a large axial force and centripetal force component. The cone apex angle of the step surface 643 is 120 degrees, 130 degrees, 140 degrees, 150 degrees, 160 degrees, 180 degrees, etc.

In an alternative embodiment, the main nut assembly 20 and the sub nut assembly 60 are provided with concave curved surfaces 71 on opposite walls constituting the adjustment space 70, and the center of the concave curved surfaces 71 is the center of the adjustment space 70. The concave curved surface 71 is set to be an arc curved surface or a concave structure such as a triangular groove, and air pressure is automatically centered at the concave curved surface 71, so that the problems of offset and unidirectional abrasion are reduced by automatically centering the auxiliary nut assembly 60 relative to the main nut assembly 20. Preferably, the concave curved surface 71 is configured as an arc curved surface, and two ends of the arc curved surface are edges of the opposite wall surface. Specifically, the step surface 643 and the end surface of the pipe body 22 constitute opposite wall surfaces of the adjustment space 70, and the concave curved surface 71 is provided on the step surface 643 and the end surface of the pipe body 22, respectively.

In one embodiment, the outer sleeve assembly 30 includes a sleeve member 31 inserted and fixed with the main nut assembly 20 and a gland frame 32 detachably fixed to the sleeve member 31, and a sliding portion of the sub nut assembly 60 is defined between the gland frame 32 and the main nut assembly 20. The sleeve member 31 has a tubular structure, the sleeve member 31 is sleeved on the tube body 22, the end of the sleeve member 31 is abutted against the end face of the mounting end 21, and the insertion depth of the sleeve member 31 is accurate. Preferably, the mounting end 21 is circumferentially provided with spaced locking holes, and the sleeve member 31 is provided with counter bores matching the locking holes, and the fastener shuttles the counter bores and locks to the locking holes to lock the sleeve member 31 in a unitary structure with the main nut assembly 20. Preferably, a gasket or seal ring is provided between the end of the sleeve member 31 and the end face of the mounting end 21 to further improve sealability.

The gland bracket 32 is removably attached to the other end of the sleeve member 31 for cooperatively defining the secondary nut assembly 60. Specifically, the second plug portion 62 of the secondary nut assembly 60 is slidably coupled to the sleeve member 31, and the extension portion 63 extends out of the outer sleeve assembly 30. Wherein the gland frame 32 is provided with a through hole, from which the extension 63 passes. Wherein the outer diameter of the second plug portion 62 is greater than the inner diameter of the through bore such that the second plug portion 62 is defined between the gland frame 32 and the mounting end 21. A movement space is provided between the end of the second insertion portion 62 and the gland holder 32, so that the sub nut assembly 60 can slide laterally in the axial direction of the screw 10. The sub nut assembly 60 is moved in a floating manner by the fluid medium, and can automatically correct the combination of the ball 50 and the screw 10 while maintaining the tightness. It should be noted that, the second plugging portion 62 is plugged with the sleeve member 31, and the first plugging portion 61 is plugged with the tube body 22, the auxiliary nut assembly 60 forms a double sliding guiding limiting structure, so that the sliding stability of the auxiliary nut assembly 60 is greatly improved, and the problem of single-side eccentricity is reduced. The outer sleeve assembly 30 and the main nut assembly 20 are integrally fixed, and the whole material or a plurality of materials can be integrally processed, so that the auxiliary nut assembly 60 is well limited and has good guiding performance.

Optionally, the sleeve member 31 is provided with a threaded bore, and the gland bracket 32 abuts the end of the sleeve member 31. The fastener is connected to the threaded hole after passing through the gland frame 32 to lock the gland frame 32 to the sleeve member 31. The direction of inserting the fastener into the sleeve member 31 is the same as the direction of inserting the locking member into the sleeve member 31, and the assembling direction of the outer sleeve assembly 30 is the same, so that the assembly of operators can be facilitated, the adjustment of each assembling gap can be maintained, and the tightness of the adjusting space 70 can be improved.

The invention also discloses a machine tool device, which comprises a device main body and the ball screw device disclosed in the embodiment, wherein the ball screw device is arranged on the device main body to execute high-precision power transmission and displacement. For example, the equipment is a high-precision numerical control machine tool, a processing machine tool, and the like.

Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the disclosure disclosed herein. This application is intended to cover any variations, uses, or adaptations of the invention following, in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice within the art to which the invention pertains. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.

It is to be understood that the invention is not limited to the precise arrangements and instrumentalities shown in the drawings, which have been described above, and that various modifications and changes may be effected without departing from the scope thereof. The scope of the invention is limited only by the appended claims.

Claims (10)

1. A ball screw device, comprising:

the ball bearings are distributed in the guide grooves of the lead screw;

the main nut component and the auxiliary nut component are sleeved on the screw rod and are in rolling connection with the balls, and the auxiliary nut component is in sliding plug connection with the main nut component;

the outer sleeve component is fixed on the main nut component and sleeved outside the auxiliary nut component, and a sealed adjusting space is formed among the outer sleeve component, the auxiliary nut component and the main nut component;

and the fluid conveying component is used for conveying a fluid medium with adjustable pressure into the adjusting space, and the fluid medium acts on the pretightening force of the main nut component and the auxiliary nut component, which is opposite to each other.

2. The ball screw device according to claim 1, wherein said sub nut assembly and said outer sleeve assembly are linearly slidably engaged.

3. The ball screw device of claim 1, wherein the secondary nut assembly includes a secondary nut body slidably defined by the jacket assembly and at least one secondary seal mounted to the secondary nut body, the secondary seal being in resilient sealing engagement with the jacket assembly.

4. The ball screw device according to claim 3, wherein the sub-nut body includes a first insertion portion, a second insertion portion, and an extension portion, the first insertion portion and the second insertion portion are in a stepped shaft shape, the first insertion portion is inserted and connected to the main nut assembly, the second insertion portion is inserted and connected to the jacket assembly, the sub-seal is mounted to the second insertion portion, the extension portion penetrates through the jacket assembly, and a stepped surface between the first insertion portion and the second insertion portion and the main nut assembly are disposed at an interval therebetween to form the adjustment space.

5. The ball screw device according to claim 4, wherein the step surface is tapered.

6. A ball screw device according to claim 3, wherein two of the auxiliary seals are provided, the two auxiliary seals being spaced apart along the axial direction of the screw.

7. The ball screw device according to claim 1, wherein the outer sleeve assembly includes a sleeve member inserted and fixed with the main nut assembly and a gland bracket detachably fixed to the sleeve member, and the sliding portion of the sub nut assembly is defined between the gland bracket and the main nut assembly.

8. The ball screw device according to claim 1, wherein the main nut assembly comprises a mounting end and a tube portion protruding from the mounting end in a tubular shape, the outer sleeve assembly is sleeved on the tube portion and is locked at the mounting end in an abutting manner, the auxiliary nut assembly is inserted into the tube portion, and the adjusting space is formed among an end face of the tube portion, the auxiliary nut assembly and the outer sleeve assembly.

9. The ball screw device according to claim 1, wherein the fluid medium is provided as a gas, and the fluid delivery assembly includes a gas source, a pressure regulating assembly connected to the gas source, and a joint assembly connected to the pressure regulating assembly, the joint assembly being connected to the housing assembly and in communication with the adjustment space, the pressure regulating assembly being configured to regulate the gas pressure in the adjustment space.

10. A machine tool apparatus comprising an apparatus main body and the ball screw device according to any one of claims 1 to 9, wherein the ball screw device is mounted to the apparatus main body.