CN2156343Y - Rolling bearing screw arbor - Google Patents

Abstract

The utility model relates to a rolling bearing type screw, which comprises a screw and screw cap, wherein, external screw threads are arranged on the external wall of the screw; at least one pair of bearings are arranged on the internal wall of the screw cap; every bearing has a structure that two external rings are designed separately and an opposite effect of precompression in an oblique angle can be generated between the internal wall and an internal ring; the internal ring of each bearing has a plurality of annular molding grooves corresponding to the guide distance of the external screw threads of the screw; the internal diameter of the internal ring is longer than the external diameter of the screw; all the bearing are arranged in a state of mutual eccentricity, i.e. the mesh position between the internal ring of each bearing and the screw is respectively positioned on the opposite side of the screw, so that the swivel motion of the screw can be conveniently converted into the rectilinear motion of the screw cap.

Description

Rolling bearing screw arbor

The utility model is about a kind of rolling bearing type screw rod, be by at least one pair of bearing of the eccentric configuration of nut inwall and the meshing relation of screw rod maintenance part especially, make it have low temperature rise, low noise and be applicable to speed up, heavy load, little helical pitch and the characteristics in increase life-span.

By in the existing mechanical industry, ball screw is one of quite important element, and is used in national defence boat nothing science and technology (as aircraft, ships, fly bomb guidance system), industrial machine and computer numerical control (CNC) toolroom machine etc. in a large number.Basically, ball screw is screw rod, nut and falls between and can heavily cover the circulation steel ball and form, and can divide into two kinds of outer circulation type (External Recirculation) and inner circulation types (Internal Recirculation) according to the difference of its endless form.Outer circulation type system utilizes and is located at the circulation road of the reflow pipe (Return Tube) of nut outside as steel ball, so its volume is bigger; Inner circulation type then has and can reduce the volume of nut, but its price be than outer circulation type person costliness for the groove of steel ball circulation in the nut inwall.Though the application area of ball screw is quite extensive, but still there is the following disappearance of work:

(a) thread groove of screw rod and nut is semicircle camber or Goethe's type (Gothic), on worker's reason, when manufacture process, if it is comparatively difficult to desire to make on the thread groove every bit all to have identical curvature, thereby increased manufacture cost, and precision also is difficult to promote.

(b) design of ball screw is to utilize steel ball to roll in thread groove, so chute adopts circular arc type or Gothicism wrapping angle more.No matter be to adopt which kind of mode, all can reduce the area of contact between steel ball and screw rod and nut, cause and reduce its load carrying capacity.

(c) load carrying capacity of ball screw system is directly proportional with total area of contact of rolling element, so in order to increase the load carrying capacity of ball screw, then need increase steel ball quantity, and nut length also relatively increases thereupon, but within the single nut thread groove in make have length restriction because of disturbing, so can't promote the load carrying capacity of ball screw effectively.

(d) the net pearl between ball screw and nut need be cooked circulating rolling, when steel ball has its unreasonable mechanical efficiency when releasing with insertion screw thread track, the sliding phenomenon that is produced because of load at a high speed for example, to cause serious abrasion, and can't make it that speed up motion (even more serious than the sliding phenomenon of rolling screw), noise are big, temperature rise, easily produce thermal distortion and steel ball and push phenomenon mutually and cause steel ball wearing and tearing etc.

Other has a kind of design kenel of roller screw, and main system is engaged between screw rod and the nut and with a plurality of roller of uniformly-spaced configuration by screw rod, nut and one group and is formed.The load carrying capacity of this kind roller screw is much larger than ball screw, but the application of rolling type screw rod on the order institute former world adopts the ball-type person to account for more than 90%, and institute is mechanical to be added up and the roller-type person grinds not as good as 10%(worker), its reason is too high and manufacturing technology is difficult for except cost, and details are as follows in addition:

(a) roller has good rolling effect in the thread groove domestic demand, and so according to existing design, when the axial motion excessive velocities, roller can produce sliding phenomenon and then destroy structure, so the thread helix angle of roller can not be too big, so helical pitch is less.In order to overcome this kind sliding phenomenon, be the design that develops a kind of gear type rolling element, make it can do wandering star type and roll, but relatively cost is higher.

(b) when roller is used in big helical pitch, the area of contact of roller and screw rod and nut is less, and its load carrying capacity is also lower.Again, the roller diameter can't strengthen arbitrarily under the restriction that is subjected to usage space, if deepen the screw thread of roller, then easily makes roller construction understrressing.Therefore, the roller screw of big helical pitch will cause overall structure understrressing.

(c) the axial motion speed of nut system is directly proportional with the screw rod helical pitch in the roller screw, for answering actual demand, screw flight can be designed to multiple tooth form, and for example, screw rod is made 2 multiple teeth, and the roller of correspondence still keeps single start thread, and then whole helical pitch is 2 units.Only this kind increases screw thread bar number to increase the mode of roller screw axial motion speed, will make manufacture cost form the multiple increase with the increase of work bar number.

By above-mentioned analysis as can be known, the precision of roller screw and load carrying capacity system is determined by the engagement degree of the screw thread of the screw thread of roller and screw rod and nut.Again screw design is become multiple tooth form, and roller is a single start thread, then the finished product of this kind roller screw its prices are rather stiff, except being difficult for making, though also to obtain highi degree of accuracy, so the utilization rate of roller screw is on the low side.

Based on the aforementioned disappearance of commonly using ball screw and roller screw, more because the development trend of CNC science and technology, make the mechanism of tradition can't mate the more speed up that utilizes servo-drive to reach, be to impel the inventor constantly to study and improve, and according to the Zi Dinglv (design theory that Hertz ' sLaw) is the most desirable, finally design a kind of rolling bearing type screw rod, its main purpose is to provide a kind of low temperature rise that has, low noise, vibrate little and be applicable to speed up, the novel screw rod of characteristics such as heavy load and small helical pitch, comprise the nut that screw rod with outside thread and inwall are provided with pair of bearings, ring has a plurality of moulding annular recess (non-threaded formula) corresponding to screw rod outside thread lead within each bearing, and the part is meshed with screw rod.Footpath system is greater than footpath outside the screw rod within each bearing inner ring again, and each bearing keeps the state of eccentric configuration each other, and promptly the engaging position of ring and screw rod is each positioned at the opposite side of screw rod within each bearing.

Another purpose of the utility model is to provide a kind of rolling bearing type screw rod, wherein screw rod and nut system is in the pre-pressing engagement of circular arc type of part, its arc contact surface amasss the summation greater than the line area of contact of roller in the some area of contact of steel ball in the conventional ball bearings and the roller bearing, so can bear bigger load.

The another purpose of the utility model is to provide a kind of rolling bearing type screw rod, owing to be located at the bearing of nut inwall, directly be greater than footpath outside the screw rod within ring in it, so when screw rod rotates a circle, because of the relation of girth, bearing inner ring rotates less than a circle, therefore, under the situation that does not change helical pitch, can reach the decelerating effect of nut.If the footpath number of threads is adopted suitable cooperating with bearing inner ring outside the screw rod, promptly applicable to fine helical pitch.The characteristics that this can't reach for traditional ball screw also are one of important breakthrough of the utility model.

Be feature and the function that more clearly demonstrates the utility model, Zi Zuo describes the structure function of the utility model in detail and uses situation as follows with diagram:

The diagram part:

The partial cross-sectional perspective view of the ball screw that Fig. 1 system commonly uses;

The partial cross-sectional perspective view of the roller screw that Fig. 2 system commonly uses;

Fig. 3 is the utility model one embodiment's a sectional drawing;

Fig. 4 is another embodiment's of the utility model a sectional drawing;

Fig. 5 is the another embodiment's of the utility model a sectional drawing

The roller in the roller screw that Fig. 6 system commonly uses and the area of contact schematic representation of screw rod; And

Fig. 7 is the screw rod in the utility model and the area of contact schematic representation of bearing.

As shown in Figure 1, be the ball screw of commonly using, comprise screw rod 10 and have internal thread and the nut 12 that can be meshed with screw rod 10 with outside thread.Nut 12 system usually is linked on the frame of machine (not shown), and screw rod 10 then is used to regulate the axial internal clearance of nut 12 on nut 10.One group of (a plurality of) steel ball 14 is to place in the spiral path of 10 of nut 12 and screw rods, and at least one reflow pipe 16 be oblique cutting on nut 12, and fix it with pressing plate 18.When screw rod 10 rotates, by the guiding of reflow pipe 16, make steel ball 14 be circulated to the other end of nut 12 by one of nut 12 end, and the axial motion that nut 12 is produced with respect to screw rod 10.The endless form of this kind steel ball 14 only, no matter it is to enter reflow pipe 16 by thread groove, or push in the thread groove by reflow pipe 16, steel ball all advances with the angular transformation path of swashing row, therefore, big energy be can consume, unnecessary noise and temperature rise produced, and cause the loss of efficient, the emphasis that this also all is difficult to breakthrough for whole world advanced country.

As shown in Figure 2, be the roller screw of commonly using, comprise screw rod 20 with outside thread and nut 22 with internal thread.One group of (being generally 6 or 8) roller 24, its surface has outside thread, is uniformly-spaced to dispose and be engaged between screw rod 20 and the nut 22, and the two ends of each roller 24, plant is located at the round nut lid 26 at nut 22 two ends and is located it respectively.By the rotation of screw rod 20, the combination that can drive nut 22 and roller 24 axially moves.This kind roller screw, though applicable to less helical pitch, only cost is too high and be difficult for being fabricated to the disappearance of its maximum.

Now seeing also Fig. 3, is the utility model rolling bearing type screw rod, comprises a screw rod 30, one nuts 32 and a pair of ball bearing 31, and the preferably is to adopt the biserial angular ball bearing.Wall within the nut 32 has the circular hole 321 of eccentric configuration each other, uses and holds this to ball bearing 31.The two ends of nut 32 are revolved respectively and are established round nut lid 36, and side-line is resisted against indivedual ball bearing 31 within each nut cap 36, in order to do ball bearing 31 is remained in the circular hole 321 of nut 32.Each ball bearing 31 is two outer shrouds 311 that adopt the separated type design, and its inwall system and interior ring 312 bevel subtend precompressed effects.Each ball bearing 31 is two outer shrouds 311 that adopt the separated type design, and its inwall system and interior ring 312 bevel subtend precompressed effects.Encircle the 312 non-threaded formulas of a plurality of moulding annular recess 313(that have corresponding to screw rod 30 outside thread leads within each ball bearing 31), and the footpath is greater than screw rod 30 external diameters within the interior ring 312.Screw rod 30 is to be placed through in the ball bearing 31, and because of each ball axle 31 is the maintenance state of off-centre each other, and promptly ring 312 and the engaging position of screw rod 30 are each positioned at the opposite side of screw rod 30 within each ball bearing 31, screw rod 30 can be folded in therebetween.Again, a capping 38 can be inserted in the centre among each nut cap 36, and 38 of cappings have the screw 381 corresponding to screw rod 30 outside threads, and the lubricant oil in can keeping nut 32 also can prevent that the pollution sources in the external world from entering in the nut 32 being difficult for flowing out.

As shown in Figure 4, be another embodiment of the utility model, wherein screw rod 40 has Ai Kemu (ACME) screw thread, is disposed at nut 42 interior circular holes and then is biserial oblique angle roller bearing 41.Other, are stated so no longer apply also as aforementioned as the mounting type of nut cap 46 and capping 48.Enumerate this embodiment's purpose, mainly the also applicable Acme thread of the utility model being described and using roller bearing instead, to cooperate the working load of different demands.

Shown in Figure 5, be the another embodiment of the utility model, show that the utility model also can adopt the double nut formula as the screw rod of commonly using.For example respectively there is a pair of roller bearing 51 to be installed on one of two nuts 52, then separate between each nut 52 with a distance piece 53, and according to the mode of commonly using with connecting plate 55 lockings, installation as for four oblique angle roller bearings 51 of two nuts, 52 inside, then dispose in the mode that staggers mutually in regular turn, to obtain the rarest load.

Press, the roller screw system of commonly using belongs to the rolling screw combination of bearing heavy load, and as shown in Figure 6, it is the mode that adopts the line contact around the roller of screw rod periphery.As for the quantity of roller, be generally 6 or 8, be to look load and size requirements and determine.As shown in Figure 7, the screw rod that shows the utility model is in circular arc type with nut system and contacts, and its arc contact surface amasss the summation greater than the line area of contact of roller in the roller bearing, so according to the analysis of Hertz law, can bear bigger load.

Structure of the utility model and feature; after above-mentioned detailed description and illustration; to be more clear and definite; will be appreciated that; this concrete example system is only as the usefulness that illustrates the preferable serviceability of the utility model; but not to limit to the scope of the utility model, any following of the utility model spirit that do not break away from improves for it and changes, and all belongs to the utility model intention Protector.

Claims (4)

1, a kind of rolling bearing type screw rod is characterized in that comprising:

One screw rod has outside thread;

One nut, its inwall have two circular holes of eccentric configuration; And

Pair of bearings, system is installed on respectively in this circular hole, ring has a plurality of moulding annular recess corresponding to this screw rod outside thread lead within each bearing, and footpath system was meshed with this screw rod in order to do the mode that makes each bearing with biasing each other greater than footpath outside this screw rod within should interiorly encircling.

2, rolling bearing type screw rod according to claim 1 is characterized in that encircling within this bearing the opposite side that is positioned at screw rod with the engaging position system of this screw rod.

3, rolling bearing type screw rod according to claim 1 is characterized in that this bearing is a two row ball bearing.

4, rolling bearing type screw rod according to claim 1 is characterized in that this bearing is a double-row roller bearing.

Images