A ball screw

Abstract

The present invention discloses a ball screw and its protection device, including a first mounting seat, a second mounting seat and a flexible protective cover. The first mounting seat is used for fixedly connecting with the screw shaft of the ball screw; the second mounting seat is used for fixedly connecting with the spline nut of the ball screw; both ends of the flexible protective cover are respectively connected to the first mounting seat and the second mounting seat, and the length of the flexible protective cover along the axial direction of the screw shaft is telescopic. The ball screw and its protection device of the present invention can not only provide dust protection for the screw shaft, but also have good applicability and low cost.

Description

Technical Field

[0001] The invention relates to the technical field of screw rods, and in particular to a ball screw rod and a protective device thereof. Background Art

[0002] Ball screws are commonly used transmission components in mechanical equipment. As high-precision mechanical transmission components, ball screws need to maintain high transmission accuracy and service life. In particular, the surface roughness and dimensional accuracy of the screw shaft grooves are extremely high, and dust, water vapor, oil and other impurities are not allowed to enter the grooves of the screw shaft. However, during use, when the ball screw rotates at high speed and moves up and down, a part of the screw shaft is usually exposed to the outside, which will cause various impurities from the outside to enter the screw, which will not only hinder the normal operation of the ball, but also increase wear sharply, affecting the transmission accuracy and service life of the ball screw. Therefore, the protection of the ball screw is particularly important.

[0003] Some existing devices for protecting ball screws must be personalized in combination with specific equipment to adapt to the corresponding equipment structure, and installation holes and connecting channels must be reserved on both the protective device and the equipment so that the protective cavity is connected to the hood cavity of the equipment, resulting in major changes to the equipment and high costs. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a ball screw and a protective device thereof, which can not only provide dust-proof protection for the screw shaft but also have good applicability.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0006] A protective device for protecting a ball screw, comprising:

[0007] A first mounting seat, used for fixedly connecting with the screw shaft of the ball screw;

[0008] A second mounting seat, used for fixedly connecting with the spline nut of the ball screw; and

[0009] A flexible protective cover, wherein two ends of the flexible protective cover are respectively connected to the first mounting seat and the second mounting seat, and the length of the flexible protective cover along the axial direction of the screw shaft is retractable.

[0010] In one embodiment, the first mounting seat and the second mounting seat are both annular, the first mounting seat is used to be sleeved to the outside of the screw shaft, the second mounting seat is used to be sleeved to the outside of the spline nut, and the first mounting seat and the second mounting seat are respectively used to block the two end ports of the flexible protective cover;

[0011] An air inlet is provided on the first mounting seat and / or the second mounting seat. The air inlet is used to connect the outside with the inner cavity of the flexible protective cover. A filter component is provided at the air inlet.

[0012] In one embodiment, the filter component is any one of a silencer, filter cotton, and a filter net.

[0013] In one embodiment, the filter component is a silencer, the air inlet hole is a threaded hole, and the silencer is threadedly matched with the air inlet hole.

[0014] In one embodiment, the number of the air inlet holes and the number of the filter components are both more than two, and the more than two air inlet holes are evenly spaced around the center of the first mounting seat; the filter components are arranged one-to-one with the air inlet holes.

[0015] In one embodiment, the air inlet hole is provided on the second mounting seat, and the filter component is provided at the air inlet of the air inlet hole; the second mounting seat is provided with a rib, and the rib extends from the outer side wall of the second mounting seat toward a direction away from the first mounting seat.

[0016] In one embodiment, the protective device further includes a first fixing member and a second fixing member, and the first fixing member and the second fixing member are used to fix two ends of the flexible protective cover to the first mounting seat and the second mounting seat respectively.

[0017] In one embodiment, a first limiting groove is provided on the outer side surface of the first mounting seat, and the first limiting groove is adapted to the shape of the first fixing member;

[0018] A second limiting groove is disposed on the outer side surface of the second mounting seat, and the second limiting groove is adapted to the shape of the second fixing member.

[0019] In one embodiment, the protective device further includes a limiting element, which is disposed in the flexible protective cover and is used to be fixed to the screw shaft.

[0020] In one embodiment, the flexible protective cover is an accordion-type protective cover.

[0021] The present invention also provides a ball screw, including a screw shaft, a first ball and a spline nut. A first groove is provided on the screw shaft, and an extension direction of the first groove is parallel to the axis of the screw shaft. The ball is arranged in the first groove and is located between the screw shaft and the spline nut. The ball screw also includes the protective device described in any one of the above embodiments.

[0022] In one embodiment, it further includes a nut and a second ball. The screw shaft is also provided with a second groove, the second groove is spirally arranged along the axis of the screw shaft, and the second ball is arranged in the second groove and is located between the screw shaft and the nut.

[0023] Implementing the embodiments of the present invention will have the following beneficial effects:

[0024] In the present invention, there is no connection between the protective device and the equipment, and there is no need to modify the equipment. The protective device only needs to be installed on the inherent structure of the ball screw. It is easy to use and has better applicability. Moreover, when the screw shaft moves axially, the flexible protective cover can follow the screw shaft to axially expand and contract, so that the screw shaft always remains inside the flexible protective cover, thereby providing better protection for the screw shaft and preventing external dust and oil from entering the screw shaft. In addition, the two ends of the flexible protective cover are respectively fixed to the spline nut and the screw. During use, the two ends of the flexible protective cover can achieve synchronous rotation without distortion. Therefore, there is no need to set bearings like the existing protective devices, and the cost is lower. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0026] in:

[0027] Figure 1 It is a schematic diagram of the partial structure of a ball screw according to an embodiment of the present invention;

[0028] Figure 2 A partial structural cross-sectional view of a ball screw according to an embodiment of the present invention;

[0029] Figure 3 An exploded view of a local structure of a ball screw according to an embodiment of the present invention;

[0030] Description of labels:

[0031] 100, screw shaft;

[0032] 200. Spline mother;

[0033] 300, protective device; 310, first mounting seat 310; 311, first limiting groove; 320, second mounting seat; 321, edge stop; 322, second limiting groove; 330, flexible protective cover; 340, air inlet hole; 350, filtering component; 360, first fixing member; 370, second fixing member; 380, limiting element. Detailed implementation mode

[0034] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0035] It should be noted that all directional indications (such as up, down, left, right, front, back...) in the embodiments of the present invention are only used to explain the relative position relationship and movement conditions between components in a specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indications will also change accordingly.

[0036] In addition, the descriptions involving "first", "second", etc. in the present invention are only for descriptive purposes, and cannot be understood as indicating or implying their relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between various embodiments can be combined with each other, but it must be based on the fact that those of ordinary skill in the art can implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the protection scope required by the present invention.

[0037] Please refer to Figure 1 , an embodiment of the present invention provides a ball screw, which includes a screw shaft 100, a first ball (not shown in the figure) and a spline nut 200. A first groove is formed on the screw shaft 100, and the extending direction of the first groove is parallel to the axis of the screw shaft 100. The number of the first grooves can be multiple, and the multiple first grooves are arranged at intervals on the outer side surface of the screw shaft 100. It can be understood that the number of the first balls is also multiple, and each first groove is provided with multiple first balls, and the first balls are located between the screw shaft 100 and the spline nut 200. The spline nut 200 can axially move relative to the screw shaft 100 through the rolling of the first balls in the first groove.

[0038] In some embodiments, the ball screw further includes a nut and second balls (the nut and the second balls are not shown in the figure). A second groove is also formed on the lead screw shaft 100, and the second groove extends spirally along the axis of the lead screw shaft 100. The second balls are disposed in the second groove and located between the lead screw shaft 100 and the nut. The number of the second grooves can be one or more, and a plurality of second balls are disposed in each second groove. The nut can perform a helical upward movement relative to the lead screw shaft 100 by rolling of the second balls in the second groove. In this embodiment, by cross - arranging the first groove and the second groove on one lead screw shaft 100, and arranging the spline nut 200 and the nut on the lead screw shaft 100, three forms of motion, namely rotation, linear motion and helical motion, can be realized, and it can be widely applied to various devices.

[0039] During the use of the ball screw, when the lead screw shaft 100 axially moves relative to the spline nut 200 and the nut, a part of the lead screw shaft 100 will extend out of the housing of the device, so that the lead screw shaft 100 is exposed, and external impurities or oil stains are likely to contaminate the first groove and the second groove of the lead screw shaft 100, thereby affecting the transmission accuracy of the lead screw shaft 100. Based on this, the ball screw of the present invention is further provided with a protection device 300, and the protection device 300 can protect the lead screw shaft 100 and prevent external impurities or oil stains from entering the lead screw shaft 100.

[0040] The protection device 300 includes a first mounting seat 310, a second mounting seat 320 and a flexible protective cover 330. Among them, the first mounting seat 310 is used for fixedly connecting with the lead screw shaft 100 of the ball screw; the second mounting seat 320 is used for fixedly connecting with the spline nut 200 of the ball screw; both ends of the flexible protective cover 330 are respectively connected to the first mounting seat 310 and the second mounting seat 320, and the length of the flexible protective cover 330 along the axial direction of the lead screw shaft 100 is telescopic.

[0041] There is no connection relationship between the protection device 300 of the present invention and the device. There is no need to transform the device. Only the protection device 300 needs to be installed on the inherent structure of the ball screw, which is convenient to use and has better applicability, and can be used on different types of devices; moreover, when the lead screw shaft 100 axially moves, the flexible protective cover 330 can axially expand and contract following the lead screw shaft 100, so that the lead screw shaft 100 is always kept inside the flexible protective cover 330, thereby providing good protection for the lead screw shaft 100 and preventing external dust and oil stains from entering the lead screw shaft 100; in addition, both ends of the flexible protective cover 330 are respectively fixed to the spline nut 200 and the lead screw. During the use process, both ends of the flexible protective cover 330 can rotate synchronously and will not be distorted. Therefore, there is no need to set bearings like the existing protection device 300, and the cost is lower.

[0042] In one embodiment, both the first mounting seat 310 and the second mounting seat 320 are annular. The first mounting seat 310 is used to be sleeved outside the lead screw shaft 100, and the second mounting seat 320 is used to be sleeved outside the spline nut 200. The flexible protective cover 330 is a hollow cylindrical structure. After the two ends of the flexible protective cover 330 are respectively fixed to the first mounting seat 310 and the second mounting seat 320, the first mounting seat 310 and the second mounting seat 320 can respectively block the two end ports of the flexible protective cover 330. The outer diameters of the annular first mounting seat 310 and the annular second mounting seat 320 respectively match the sizes of the two end ports of the flexible protective cover 330, so as to block the two ends of the flexible protective cover 330, preventing external impurities, oil stains, etc. from entering the lead screw shaft 100 inside the flexible protective cover 330, and can play a better protective role for the lead screw shaft 100.

[0043] The fixed connection between the first mounting seat 310 and the lead screw shaft 100 can be achieved by means of screw clamping. Specifically, one or more threaded holes can be drilled in the circumferential direction of the first mounting seat 310, and the extending direction of the threaded holes is perpendicular to the axial direction of the lead screw shaft 100. Then, screws are screwed into the threaded holes to make them abut against the lead screw shaft 100, so as to realize the fixation of the first mounting seat 310 on the lead screw shaft 100. It can be understood that, in order to increase the connection sealing performance between the first mounting seat 310 and the lead screw shaft 100, sealant can be applied or a sealing ring can be provided at the connection between the first mounting seat 310 and the lead screw shaft 100. It can be understood that the fixed connection between the first mounting seat 310 and the lead screw shaft 100 can also be in the form of clamping, bonding or welding.

[0044] The fixed connection manner between the second mounting seat 320 and the spline nut 200 can also be in the form of screw clamping, clamping, bonding or welding. Among them, for the screw clamping connection manner, reference can be made to the connection manner between the first mounting seat 310 and the lead screw shaft 100 above, and details will not be repeated here.

[0045] In one embodiment, an air inlet hole 340 is provided on the second mounting seat 320. The air inlet hole 340 is used to communicate the outside with the inner cavity of the flexible protective cover 330. A filtering component 350 is provided at a position on the second mounting seat 320 corresponding to the air inlet hole 340. After the first mounting seat 310 and the second mounting seat 320 block the two end ports of the flexible protective cover 330, air can freely enter and exit the inner cavity of the flexible protective cover 330 through the air inlet hole 340. This enables the flexible protective cover 330 to axially expand and contract while following the movement of the lead screw shaft 100, without being severely deformed due to a huge change in internal pressure, and can avoid contact between the flexible protective cover 330 and the lead screw shaft 100. At the same time, by providing the filtering component 350 at the air inlet hole 340, the outside air can be filtered when it enters the inner cavity of the flexible protective cover 330, preventing impurities in the outside air from entering the inside of the flexible protective cover 330, and ensuring that the lead screw shaft 100 inside the flexible protective cover 330 always has a good environment.

[0046] The number of the air inlet holes 340 on the second mounting seat 320 can be one or multiple. In one embodiment, a plurality of air inlet holes 340 are provided on the second mounting seat 320, and the plurality of air inlet holes 340 are evenly spaced around the central axis of the lead screw shaft 100 (the central axis of the lead screw shaft 100 coincides with the central axes of the first mounting seat 310 and the second mounting seat 320). Correspondingly, the number of the filtering components 350 is also multiple, and the multiple filtering components 350 are respectively arranged in one-to-one correspondence with the multiple air inlet holes 340.

[0047] The filtering component 350 can be arranged inside the air inlet hole 340 or at the air inlet of the air inlet hole 340. In this embodiment, the filtering component 350 is arranged at the external air inlet of the air inlet hole 340, and the filtering area of the filtering component 350 is larger than the cross-sectional area of the air inlet hole 340, which can make the contact area between the air and the filtering component 350 larger, enabling a better filtering effect. At the same time, arranging the filtering component 350 on the outside facilitates the replacement of the filtering component 350.

[0048] A retaining edge 321 is also provided on the second mounting seat 320. The retaining edge 321 extends from the outer side wall of the second mounting seat 320 in a direction away from the first mounting seat 310. Preferably, the retaining edge 321 is annular. The filtering component 350 is located between the retaining edge 321 and the spline nut 200. The retaining edge 321 can reduce the area of the filtering component 350 exposed outside, preventing oil stains and the like from the outside from splashing onto the filtering component 350 and affecting the filtering performance of the filtering component 350.

[0049] In another embodiment, the air inlet hole 340 can be provided on the first mounting seat 310, and a filtering component 350 is provided at a position corresponding to the air inlet hole 340 on the first mounting seat 310. In other embodiments, the air inlet hole 340 can also be provided on both the first mounting seat 310 and the second mounting seat 320, and filtering components 350 are respectively provided at positions corresponding to the air inlet hole 340 on the first mounting seat 310 and the second mounting seat 320, so that air can enter and exit from both ends of the flexible protective cover 330 simultaneously.

[0050] The filtering component 350 can be any one of a silencer, filter cotton, and filter net, as long as it can filter dust and allow air to flow through. In one embodiment, the filtering component 350 is a silencer, which can not only play a filtering role but also reduce the noise caused by air entering and exiting the air inlet hole 340. The silencer is in threaded cooperation with the air inlet hole 340, that is, the air inlet hole 340 is a threaded hole, and the silencer is provided with an external thread adapted to the air inlet hole 340. During installation, the silencer can be directly screwed into the air inlet hole 340. To prevent the silencer from loosening, thread sealant can also be applied at the threaded connection between the silencer and the air inlet hole 340.

[0051] Furthermore, the protective device 300 further includes a first fixing member 360 and a second fixing member 370. The first fixing member 360 and the second fixing member 370 are respectively used to fix both ends of the flexible protective cover 330 to the first mounting seat 310 and the second mounting seat 320, preventing the flexible protective cover 330 from loosening from the first mounting seat 310 and the second mounting seat 320. When the first mounting seat 310 and the second mounting seat 320 are annular, the first fixing member 360 and the second fixing member 370 can be hose clamps, that is, the first hose clamp and the second hose clamp. The first hose clamp and the second hose clamp are respectively sleeved on the outer side surfaces of both ends of the flexible protective cover 330, thereby pressing both ends of the flexible protective cover 330 against the first mounting seat 310 and the second mounting seat 320 respectively.

[0052] A first limiting groove 311 is provided on the outer side surface of the first mounting seat 310. The shape of the first limiting groove 311 is adapted to the shape of the first fixing member 360, and the first fixing member 360 can press one end of the flexible protective cover 330 into the first limiting groove 311. A second limiting groove 322 is provided on the outer side surface of the second mounting seat 320. The shape of the second limiting groove 322 is adapted to the shape of the second fixing member 370, and the second fixing member 370 can press the other end of the flexible protective cover 330 into the second limiting groove 322. The first limiting groove 311 and the second limiting groove 322 can respectively limit the first fixing member 360 and the second fixing member 370, preventing the first fixing member 360 and the second fixing member 370 from sliding along the axial direction of the lead screw, thereby causing the flexible protective cover 330 to loosen.

[0053] The protective device 300 further includes a limiting element 380 which is arranged in the inner cavity of the flexible protective cover 330 and is used to be fixed on the lead screw shaft 100. Specifically, the limiting element 380 and the lead screw shaft 100 can also be connected by means such as screw clamping, bonding, snap connection, welding, etc. When the lead screw has an error after being used for a period of time, or when there is a control error, the movement of the lead screw shaft 100 may exceed the limit stroke. At this time, the limiting element 380 can play a role in mechanical limit. When the lead screw shaft 100 exceeds the limit stroke, the limiting element 380 can abut against the second mounting seat 320, so that the lead screw shaft 100 stops moving, which can avoid the lead screw hitting other structures and reduce the risk of equipment loss. In addition, by arranging the limiting element 380 on the lead screw shaft 100, that is to say, the lead screw of the present invention can perform stroke limit by itself, and there is no need to additionally arrange a limiting device on the equipment to perform stroke limit on it.

[0054] In each of the above embodiments, the flexible protective cover 330 can be a bellows-type protective cover with a multi-layer foldable structure and can be stretched and compressed. Of course, the flexible protective cover 330 can also be other flexible structures that can be telescopic. The material of the flexible protective cover 330 can be selected from heat-resistant, oil-resistant, wear-resistant and other materials, and the maximum stretching length of the flexible protective cover 330 minus the shortest compression length must be greater than the effective stroke of the lead screw shaft 100.

[0055] The above are only the embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. All equivalent transformations made by using the content of the specification and drawings of the present invention, or directly or indirectly applied in related technical fields, are equally included in the patent protection scope of the present invention.

Claims

1. A ball screw, comprising a screw shaft, a first ball, a spline nut, a nut and a second ball. A first groove is formed on the screw shaft, and the extending direction of the first groove is parallel to the axis of the screw shaft. The ball is arranged in the first groove and is located between the screw shaft and the spline nut. A second groove is also formed on the screw shaft, and the second groove is spirally arranged along the axis of the screw shaft. The second ball is arranged in the second groove and is located between the screw shaft and the nut. Characterized in that, The ball screw further comprises a protection device for protecting the ball screw; The protection device includes: A first mounting seat for fixedly connecting with the screw shaft of the ball screw; A second mounting seat for fixedly connecting with the spline nut of the ball screw; and A flexible protective cover, both ends of the flexible protective cover are respectively connected to the first mounting seat and the second mounting seat, the length of the flexible protective cover along the axial direction of the screw shaft is telescopic, and driven by the screw shaft, both ends of the flexible protective cover rotate synchronously; The first mounting seat is used for sleeving outside the screw shaft, the second mounting seat is used for sleeving outside the spline nut, and the first mounting seat and the second mounting seat are respectively used for blocking both ends of the flexible protective cover; The protection device further includes a first fixing member and a second fixing member, and the first fixing member and the second fixing member are respectively used for fixing both ends of the flexible protective cover to the first mounting seat and the second mounting seat.

2. The ball screw according to claim 1, Characterized in that, Both the first mounting seat and the second mounting seat are annular, and air inlet holes are arranged on the first mounting seat and / or the second mounting seat. The air inlet holes are used for communicating the outside and the inner cavity of the flexible protective cover, and a filtering component is arranged at the air inlet holes.

3. The ball screw according to claim 2, Characterized in that, The filtering component is any one of a silencer, filter cotton and a filter net.

4. The ball screw according to claim 3, Characterized in that, The filtering component is a silencer, the air inlet hole is a threaded hole, and the silencer is in threaded fit with the air inlet hole.

5. The ball screw according to claim 2, Characterized in that, The number of both the air inlet holes and the filtering components is more than two, and the more than two air inlet holes are evenly spaced around the center of the first mounting seat; the filtering components are arranged in one-to-one correspondence with the air inlet holes.

6. The ball screw according to any one of claims 2-5, Characterized in that, The air inlet holes are arranged on the second mounting seat, and the filtering components are arranged at the air inlets of the air inlet holes; a retaining edge is arranged on the second mounting seat, and the retaining edge extends from the outer side wall of the second mounting seat towards the direction away from the first mounting seat.

7. The ball screw according to claim 6, Characterized in that, A first limiting groove is arranged on the outer side surface of the first mounting seat, and the shape of the first limiting groove is adapted to that of the first fixing member; The outer side surface of the second mounting seat is provided with a second limiting groove, and the second limiting groove is adapted to the shape of the second fixing member.

8. The ball screw according to any one of claims 1-5, characterized in that the protection device further includes a limiting element, the limiting element is arranged in the flexible protective cover and is used for being fixed to the screw shaft.

9. The ball screw according to any one of claims 1-5, characterized in that the flexible protective cover is a bellows type protective cover.

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