Ball screw

Abstract

The utility model provides a ball screw. The ball screw comprises a screw shaft and a nut. The nut is rotatably and displaceably arranged on the screw shaft in a sleeved mode, a first load path for the balls to run is formed between the nut and the screw shaft, the nut is provided with an oil way channel, an oil inlet hole communicated with the oil way channel and an oil outlet hole communicated with the first load path and the oil way channel, and the oil outlet hole corresponds to the external thread groove of the screw shaft. Therefore, the ball screw provided by the utility model can lubricate the screw shaft and the nut at the same time, thereby achieving the effect of uniform lubrication.

Description

Technical Field

[0001] The present utility model relates to a ball screw, and particularly to a ball screw with a lubrication structure. Background Art

[0002] After the lubricating oil is injected into the oil supply hole of the bearing ring of the ball screw disclosed in the utility model patent TWM523025U, the lubricating oil will flow into the annular oil passage and enter the nut through a plurality of oil injection holes. When the annular oil passage is filled with the lubricating oil, the excess lubricating oil will enter the two second load paths through the two axial oil passages, so that the first rolling elements and the second rolling elements can obtain a lubricating effect. However, in the foregoing patent, the process of machining a plurality of oil injection holes in the nut is relatively cumbersome. Moreover, the distance between two adjacent oil injection holes is too close, resulting in the occurrence of easy hole breakage during machining. In addition, for a multi-start screw, the lubrication design of the foregoing patent cannot lubricate the first load path evenly.

[0003] The ball screw disclosed in the invention patent JP1995332456 is provided with a first oil supply hole in the fixed outer ring, and a second oil supply hole is further provided in the nut. The second oil supply hole communicates with the first oil supply hole through an annular gap. When the lubricating oil is injected from the first oil supply hole, it will first flow into the annular gap, and after filling the entire annular gap, it will flow to the ball circulation part between the nut and the screw through the second oil supply hole, so that the balls can obtain a lubricating effect. However, the lubrication design of the foregoing patent provides limited lubrication effect and is difficult to provide a uniform lubrication effect for the ball circulation part. Summary of the Utility Model

[0004] The main object of the present utility model is to provide a ball screw, which can achieve the effect of uniform lubrication.

[0005] To achieve the above main object, the ball screw provided by the present utility model includes a screw shaft, a nut, and a plurality of first balls. The screw shaft has an external thread groove; the nut has a first shaft hole penetrating through two opposite end faces, and the nut is rotatably and displaceably sleeved on the screw shaft with the first shaft hole. The nut further has an internal thread groove, and the internal thread groove is provided on the hole wall of the first shaft hole and forms a first load path for the first balls to run together with the external thread groove of the screw shaft. In addition, the nut has an oil passage, an oil inlet hole, and an oil outlet hole. The oil inlet hole communicates with the oil passage, and the oil outlet hole communicates with the first load path and the oil passage and corresponds to the external thread groove of the screw shaft.

[0006] As can be seen from the above, when the lubricating oil is injected from the oil inlet hole, the lubricating oil flows to the oil passage, and then flows from the oil passage to the first load path through the oil outlet hole, thereby lubricating the first balls. Therefore, the ball screw of the present utility model can lubricate the screw shaft and the nut at the same time, and thus achieve the effect of uniform lubrication.

[0007] Preferably, the number of the oil outlet holes is configured according to the number of the external thread grooves. If there is one external thread groove, there is one oil outlet hole; if there are two external thread grooves, there are two oil outlet holes. In this way, whether the screw shaft is designed with single threads or double threads, the present utility model can meet the lubrication requirements.

[0008] Preferably, the oil outlet holes can be arranged on the same axis or different axes according to actual needs.

[0009] Preferably, the nut further has an external rolling groove, which is annular and arranged on the outer peripheral surface of the nut. The ball screw further includes an outer bearing ring and a plurality of second balls. The outer bearing ring has a second shaft hole, an annular inner rolling groove and an oil supply hole. The second shaft hole penetrates through two opposite end faces of the outer bearing ring. The outer bearing ring is sleeved on the nut with the second shaft hole. The inner rolling groove is arranged on the hole wall of the second shaft hole and jointly forms a second load path with the external rolling groove of the nut. The oil supply hole communicates the second load path and the oil inlet hole of the nut. The second balls are arranged in the second load path. Thereby, when lubricating oil is injected from the oil supply hole, a part of the lubricating oil will flow to the second load path to lubricate the second balls, and another part of the lubricating oil will flow from the oil inlet hole to the oil passage, and then flow from the oil passage to the first load path through the oil outlet hole, so as to lubricate the first balls. In this way, the screw shaft, the nut and the outer bearing ring can be lubricated simultaneously, and the effect of uniform lubrication can be achieved.

[0010] Preferably, the nut further has an oil guiding hole communicating with the oil passage. An annular space is formed between the nut and the outer bearing ring, and the annular space communicates the second load path and the oil guiding hole. In this way, the redundant lubricating oil will enter the annular space through the oil guiding hole, and then flow from the annular space to the second load path, so as to provide a lubricating effect on the second balls.

[0011] Details of the structure, features, assembly or usage method of the ball screw provided by the present utility model will be described in the subsequent detailed description of the embodiments. However, those with ordinary knowledge in the field related to the present utility model should understand that these detailed descriptions and the specific embodiments listed for implementing the present utility model are only used to illustrate the present utility model, and are not used to limit the patent application scope of the present utility model. Description of the Drawings

[0012] Through the following description of the embodiments of the present utility model with reference to the drawings, the above and other objects, features and advantages of the present utility model will become clearer. In the drawings:

[0013] Figure 1 is a perspective view of the ball screw according to the first embodiment of the present utility model;

[0014] Figure 2 Stereo exploded view of the ball screw of the first embodiment of the present utility model, omitting the first ball;

[0015] Figure 3 Axial sectional view of the ball screw of the first embodiment of the present utility model;

[0016] Figure 4 Radial sectional view of the ball screw of the first embodiment of the present utility model;

[0017] Figure 5 Another stereo view of the nut of the first embodiment of the present utility model, mainly showing that the oil holes are located on different axes;

[0018] Figure 6 Stereo view of the ball screw of the second embodiment of the present utility model;

[0019] Figure 7 Axial sectional view of the ball screw of the second embodiment of the present utility model.

[0020] In the above-mentioned drawings, the meanings of the reference numerals are specifically as follows:

[0021] 10. Ball screw;

[0022] 12. Ball screw;

[0023] 20. Screw shaft;

[0024] 22. External thread groove;

[0025] A. Axial direction;

[0026] 30. Nut;

[0027] 31. Inner ring body;

[0028] 32. Inner flange;

[0029] 33. First shaft hole;

[0030] 34. Internal thread groove;

[0031] 35. External rolling groove;

[0032] 36. Oil passage;

[0033] 37. Oil inlet hole;

[0034] 38. Oil outlet hole;

[0035] D. Distance;

[0036] 39. Oil guiding hole;

[0037] 40. First ball;

[0038] 42. First load path;

[0039] 50. Bearing outer ring;

[0040] 51. Outer ring body;

[0041] 52. Outer flange;

[0042] 53. Second shaft hole;

[0043] 54. Annular space;

[0044] 55. Inner rolling groove;

[0045] 56. Oil supply hole;

[0046] 57. Oil seal;

[0047] 60. Second ball;

[0048] 61. Cage;

[0049] 62. Second load path;

[0050] 64. Plug;

[0051] 70. Nut;

[0052] 71. Ring body;

[0053] 72. Flange;

[0054] 73. First shaft hole;

[0055] 74. Inner thread groove;

[0056] 76. Oil passage;

[0057] 77. Oil inlet hole;

[0058] 78. Oil outlet hole;

[0059] 79. Oil seal. Detailed implementation manners

[0060] To make the objectives, technical solutions and advantages of the present utility model clearer and more understandable, the following further describes the present utility model in detail with reference to specific embodiments and the accompanying drawings.

[0061] The terms used herein are merely for describing specific embodiments and are not intended to limit the present utility model. The terms "including", "comprising", etc. used herein indicate the presence of the described features, steps, operations and / or components, but do not exclude the presence or addition of one or more other features, steps, operations or components.

[0062] All terms used herein, including technical and scientific terms, have the meanings commonly understood by those of ordinary skill in the art, unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of this specification, and should not be interpreted in an idealized or overly rigid manner.

[0063] In the case of using expressions such as "at least one of A, B, and C, etc.", generally, it should be interpreted according to the meaning commonly understood by those of ordinary skill in the art. For example, "a system having at least one of A, B, and C" should include, but not be limited to, a system having only A, only B, only C, having A and B, having A and C, having B and C, and / or having A, B, and C, etc. In the case of using expressions such as "at least one of A, B, or C, etc.", generally, it should be interpreted according to the meaning commonly understood by those of ordinary skill in the art. For example, "a system having at least one of A, B, or C" should include, but not be limited to, a system having only A, only B, only C, having A and B, having A and C, having B and C, and / or having A, B, and C, etc.

[0064] It should also be noted that the directional terms mentioned in the embodiments, such as "upper", "lower", "front", "rear", "left", "right", etc., are only for reference to the directions in the drawings and do not limit the protection scope of the present utility model. Throughout the drawings, the same elements are represented by the same or similar reference numerals. When it may cause confusion in the understanding of the present utility model, the conventional structures or configurations will be omitted.

[0065] The applicant hereby states first that throughout the specification, including the embodiments introduced below and the claims in the scope of the patent application, the directional nouns are based on the directions in the drawings. Secondly, in the embodiments and drawings to be introduced below, the same reference numerals represent the same or approximate elements or their structural features.

[0066] Please refer to Figures 1 to 3 , the ball screw 10 of the first embodiment of the present utility model includes a screw shaft 20, a nut 30, a plurality of first balls 40, a bearing outer ring 50, and a plurality of second balls 60.

[0067] In this embodiment, the outer peripheral surface of the screw shaft 20 has two external thread grooves 22, and the two external thread grooves 22 extend along the axial direction A of the screw shaft 20.

[0068] The nut 30 has an inner ring body 31 and two inner flanges 32. The two inner flanges 32 are disposed around the outer peripheral surface of the inner ring body 31 and are located at the front and rear ends of the inner ring body 31. The nut 30 has a first shaft hole 33 penetrating through two opposite end faces of the inner ring body 31. The nut 30 is rotatably and displaceably sleeved on the screw shaft 20 with the first shaft hole 33. The nut 30 further has an internal thread groove 34 and two outer rolling grooves 35. The internal thread groove 34 is disposed on the hole wall of the first shaft hole 33 and together with the external thread groove 22 of the screw shaft 20 forms a first load path 42 for the first balls 40 to run. The two outer rolling grooves 35 are respectively arranged along the two inner flanges 32 and are annular.

[0069] In addition, as Figure 3 shown, the nut 30 further has two oil passage channels 36, two oil inlet holes 37, two oil outlet holes 38, and two oil guiding holes 39. Among them, the two oil passage channels 36 are located on two opposite sides of the first shaft hole 33 and penetrate through two opposite end faces of the inner ring body 31 along the direction parallel to the axial direction A of the screw shaft 20. Both ends of each oil passage channel 36 are respectively closed by a plug 64; the two oil inlet holes 37 are located on two opposite sides of the first shaft hole 33 and penetrate through the inner ring body 31 and one of the inner flanges 32 along the direction perpendicular to the axial direction A of the screw shaft 20 and respectively communicate with the two oil passage channels 36; the two oil outlet holes 38 are located on the same side of the first shaft hole 33 and communicate with the first load path 42 and one of the oil passage channels 36 and respectively correspond to the two external thread grooves 22 of the screw shaft 20. The two oil outlet holes 38 can be arranged at intervals along the same axis according to actual needs (as Figure 3 shown) or are located on different axes; the two oil guiding holes 39 communicate with one of the oil passage channels 36 and are coaxially corresponding to the two oil outlet holes 38. Therefore, the two oil guiding holes 39 can be located on the same axis as the two oil outlet holes 38 (as Figure 2 shown) or are located on different axes (as Figure 5 shown). In addition, when the diameters of the oil outlet holes 38 and the oil guiding holes 39 are too small, the lubrication effect may be reduced, and when the diameters are too large, the first balls 40 and the second balls 60 may shake when passing through. Therefore, the diameters of the oil outlet holes 38 and the oil guiding holes 39 are between 1 / 3 of the ball diameter and 1 / 2 of the ball diameter.

[0070] It should be supplemented and explained here that the number of the oil passage channels 36 and the oil inlet holes 37 only needs to be at least one. In addition, the number of the oil outlet holes 38 is configured according to the number of the external thread grooves 22. That is to say, if there is one external thread groove 22, there is one oil outlet hole 38, and if there are two external thread grooves 22, there are two oil outlet holes 38. In this case, the distance D between the two oil outlet holes 38 is equal to the pitch of the external thread groove 22.

[0071] The bearing outer ring 50 has an outer ring body 51 and an outer flange 52. The outer flange 52 is disposed around the outer peripheral surface of the outer ring body 51. The bearing outer ring 50 has a second shaft hole 53 that penetrates through two opposite end faces of the outer ring body 51. The bearing outer ring 50 sleevingly mounts the nut 30 with the second shaft hole 53 and forms an annular space 54 between the bearing outer ring 50 and the nut 30 (as shown in Figure 3 and Figure 4 ). The annular space 54 communicates with two oil guiding holes 39 of the nut 30. The bearing outer ring 50 further has two annular inner rolling grooves 55. The two inner rolling grooves 55 are disposed on the hole wall of the second shaft hole 53 and respectively form a second load path 62 communicating with the annular space 54 with two outer rolling grooves 35 of the nut 30. Each second load path 62 is respectively provided with a cage 61. Each cage 61 is provided with a plurality of second balls 60. When the nut 30 is driven, on the one hand, the nut 30 can rotate relative to the screw shaft 20 and the bearing outer ring 50, and on the other hand, the nut 30 can drive the bearing outer ring 50 to reciprocate along the axial direction A of the screw shaft 20.

[0072] In addition, as shown in Figure 3 , the bearing outer ring 50 further has two oil supply holes 56. The two oil supply holes 56 penetrate through the outer ring body 51 and the outer flange 52 along the direction perpendicular to the axial direction A of the screw shaft 20 and communicate with the second load path 62 adjacent to the outer flange 52. One of the oil supply holes 56 also communicates with the oil inlet hole 37 of the nut 30.

[0073] As can be seen from the above, as shown in Figure 4 , when the lubricating oil is injected from the oil supply hole 56, a part of the lubricating oil will flow to the second load path 62 adjacent to the outer flange 52 to lubricate the second balls 60 here, and the other part of the lubricating oil will flow from the oil inlet hole 37 to the oil passage 36, and then flow from the oil passage 36 to the first load path 42 through two oil outlet holes 38, thereby lubricating the first balls 40. After the oil passage 36 is filled with the lubricating oil, the excess lubricating oil will enter the annular space 54 through two oil guiding holes 39, and then flow from the annular space 54 to the second load paths 62 at the front and rear ends, thereby providing a lubricating effect for the second balls 60 at the front and rear ends. In addition, two oil seals 57 are respectively disposed on two opposite end faces of the bearing outer ring 50. The two oil seals 57 are used to prevent the lubricating oil from flowing out of the bearing outer ring 50.

[0074] In summary, the ball screw 10 of the first embodiment of the present invention can simultaneously lubricate the screw shaft 20, the nut 30 and the bearing outer ring 50, thereby achieving the effect of uniform lubrication. Furthermore, the oil passage 36, the oil inlet hole 37, the oil outlet hole 38, the oil guiding hole 39 and the oil supply hole 56 are all formed by drilling, which is simpler and more convenient in processing compared with the prior art. In addition, since the number of the oil outlet holes 38 is configured according to the number of the external thread grooves 22, the present invention can meet the lubrication requirements regardless of whether the screw shaft 20 is a single-thread or double-thread design.

[0075] Please refer to again Figures 6 to 7 Figures 6 to 7 , the ball screw 12 of the second embodiment of the present utility model is substantially the same in structure as the above embodiment, except that the configuration of the bearing outer ring 50 and the second ball 60 is omitted, that is, it includes a screw shaft 20, a nut 70, and a plurality of first balls 40.

[0076] In this embodiment, the outer peripheral surface of the screw shaft 20 also has two external thread grooves 22, and the two external thread grooves 22 extend along the axial direction A of the screw shaft 20.

[0077] The nut 70 has an annular body 71 and a flange 72. The flange 72 is disposed around the outer peripheral surface of the annular body 71 and is located at the front end of the annular body 71. The nut 70 has a first shaft hole 73 passing through two opposite end faces of the annular body 71. The nut 70 is rotatably and displaceably sleeved on the screw shaft 20 with the first shaft hole 73. The nut 70 also has an internal thread groove 74, and the internal thread groove 74 is disposed on the hole wall of the first shaft hole 73 and forms a first load path 42 for the first balls 40 to run together with the external thread groove 22 of the screw shaft 20.

[0078] In addition, the nut 70 also has an oil passage 76, an oil inlet hole 77, and two oil outlet holes 78. Among them, the oil passage 76 is located on one side of the first shaft hole 73 and penetrates through two opposite end faces of the annular body 71 along the direction parallel to the axial direction A of the screw shaft 20. Both ends of the oil passage 76 are closed by an oil seal 79; the oil inlet hole 77 penetrates through the annular body 71 and the flange 72 along the direction perpendicular to the axial direction A of the screw shaft 20 to communicate with the oil passage 76; the two oil outlet holes 78 are located on the same side of the first shaft hole 73 and communicate with the first load path 42 and the oil passage 76 and respectively correspond to the two external thread grooves 22 of the screw shaft 20. The two oil outlet holes 78 can be arranged at intervals along the same axis or located on different axes according to actual needs. In addition, the number of the oil outlet holes 78 is configured according to the number of the external thread grooves 22. That is to say, if there is one external thread groove 22, there is one oil outlet hole 78; if there are two external thread grooves 22, there are two oil outlet holes 78. In this case, the distance D between the two oil outlet holes 78 is equal to the pitch of the external thread groove 22. The diameter of the oil outlet hole 78 is between 1 / 3 of the ball diameter and 1 / 2 of the ball diameter.

[0079] As can be seen from the above, as Figure 7 shown, when the lubricating oil is injected from the oil inlet hole 77, the lubricating oil will first flow to the oil passage 76, and then flow from the oil passage 76 to the first load path 42 through the two oil outlet holes 78, thereby lubricating the first balls 40.

[0080] In summary, the ball screw 12 of the second embodiment of the present utility model can lubricate the screw shaft 20 and the nut 70 simultaneously, thereby achieving the effect of uniform lubrication. Moreover, the oil passage 76, the oil inlet hole 77 and the oil outlet hole 78 are all formed by drilling, which is simpler and more convenient in processing compared with the prior art. In addition, since the number of the oil outlet holes 78 is configured according to the number of the external thread grooves 22, the present utility model can meet the lubrication requirements regardless of whether the screw shaft 20 is a single-start or double-start design.

[0081] The embodiments of the present utility model have been described above. However, these embodiments are for illustrative purposes only and are not intended to limit the scope of the present utility model. Although the embodiments have been described separately above, this does not mean that the measures in the respective embodiments cannot be used advantageously in combination. The scope of the present utility model is defined by the appended claims and their equivalents. Without departing from the scope of the present utility model, those skilled in the art can make various substitutions and modifications, and these substitutions and modifications should all fall within the scope of the present utility model.

Claims

1. A ball screw, characterized in that, Comprising: A screw shaft having an external thread groove; A nut having a first shaft hole that penetrates two opposite end faces of the nut. The nut is rotatably and displaceably sleeved on the screw shaft with the first shaft hole. The nut has an internal thread groove, an oil passage, an oil inlet hole, and an oil outlet hole. The internal thread groove is provided on the hole wall of the first shaft hole and forms a first load path together with the external thread groove of the screw shaft. The oil inlet hole communicates with the oil passage. The oil outlet hole communicates with the first load path and the oil passage and corresponds to the external thread groove of the screw shaft; and A plurality of first balls provided in the first load path.

2. The ball screw according to claim 1, characterized in that, The number of the oil outlet holes is configured according to the number of the external thread grooves.

3. The ball screw according to claim 1 or 2, characterized in that, The nut has two of the oil outlet holes, and the distance between the oil outlet holes is equal to the pitch of the external thread groove.

4. The ball screw according to claim 3, wherein, The oil outlet holes are located on the same axis.

5. The ball screw according to claim 3, wherein, The oil outlet holes are located on different axes.

6. The ball screw according to claim 1, wherein The ball screw further comprises an outer bearing ring and a plurality of second balls. The nut further has an outer rolling groove that is annular and provided on the outer peripheral surface of the nut. The outer bearing ring has a second shaft hole, an annular inner rolling groove, and an oil supply hole. The second shaft hole penetrates two opposite end faces of the outer bearing ring. The outer bearing ring is sleeved on the nut with the second shaft hole. The inner rolling groove is provided on the hole wall of the second shaft hole and forms a second load path together with the outer rolling groove of the nut. The oil supply hole communicates with the second load path and the oil inlet hole of the nut. The second balls are provided in the second load path.

7. The ball screw according to claim 6, wherein, The nut further has an oil guiding hole that communicates with the oil passage; an annular space is formed between the nut and the outer bearing ring, and the annular space communicates with the second load path and the oil guiding hole.

8. The ball screw according to claim 7, characterized in that, The oil guiding hole and the oil outlet hole are coaxially corresponding.

9. The ball screw according to claim 6, characterized in that, The extending direction of the oil inlet hole is perpendicular to the axial direction of the screw shaft, the extending direction of the oil supply hole is perpendicular to the axial direction of the screw shaft, and the extending direction of the oil passage is parallel to the axial direction of the screw shaft.

10. The ball screw according to claim 7, wherein, The diameters of the oil outlet hole and the oil guiding hole are between 1 / 3 of the ball diameter - 1 / 2 of the ball diameter.

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