TWM662997U - Ball Screw - Google Patents

Abstract

The ball screw of the invention comprises a screw shaft and a nut. The nut is rotatably and displaceably sleeved on the screw shaft and forms a first load path for the ball to run between the nut and the screw shaft. The nut has an oil passage, an oil inlet hole connected to the oil passage, and an oil outlet hole connected to the first load path and the oil passage, wherein the oil outlet hole corresponds to the outer thread groove of the screw shaft. In this way, the ball screw of the invention can lubricate the screw shaft and the nut at the same time, thereby achieving the effect of uniform lubrication.

Description

Ball Screw

This work is related to ball screws, and in particular to a ball screw with a lubricated structure.

After the ball screw disclosed in TW M523025 is injected with lubricating oil from the oil supply hole of the bearing ring, the lubricating oil will flow into the annular oil passage and enter the nut through multiple oil filling holes. When the lubricating oil fills the entire annular oil passage, the excess lubricating oil will enter the second load paths from the two axial oil passages, so that the first rolling element and the second rolling element can obtain a lubricating effect. However, in the aforementioned patent case, the process of machining multiple oil injection holes in the nut is relatively cumbersome, and the distance between two adjacent oil injection holes is too close, which makes it easy for holes to be broken during machining. In addition, for multi-thread screws, the lubrication design of the aforementioned patent case cannot evenly lubricate the first load path.

The ball screw disclosed in JP 1995332456 has a first oil supply hole on the fixed outer ring and a second oil supply hole on the nut. The second oil supply hole is connected to 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 then flow through the second oil supply hole to the ball circulation part between the nut and the screw after filling the entire annular gap, so that the ball can obtain a lubricating effect. However, the lubricating effect provided by the lubricating design of the aforementioned patent is limited, and it is difficult to provide a uniform lubricating effect for the ball circulation part.

The main purpose of this invention is to provide a ball screw that can achieve a uniform lubrication effect.

In order to achieve the above main purpose, the ball screw provided by the invention includes a screw shaft, a nut, and a plurality of first balls. The screw shaft has an external threaded groove; the nut has a first axial hole penetrating two opposite end faces, the nut is rotatably and displaceably sleeved on the screw shaft with the first axial hole, the nut also has an internal threaded groove, the internal threaded groove is arranged on the hole wall of the first axial hole and together with the external threaded groove of the screw shaft forms a first load path for the first balls to run, in addition, the nut has an oil passage, an oil inlet hole and an oil outlet hole, the oil inlet hole is connected to the oil passage, the oil outlet hole is connected to the first load path and the oil passage and corresponds to the external threaded groove of the screw shaft.

As can be seen from the above, after the lubricating oil is injected from the oil inlet, the lubricating oil flows to the oil channel, and then flows from the oil channel through the oil outlet to the first load path, thereby lubricating the first balls. Therefore, the ball screw of the invention can lubricate the screw shaft and the nut at the same time, thereby achieving the effect of uniform lubrication.

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, regardless of whether the screw shaft is a single-thread or double-thread design, the invention can meet the lubrication requirements.

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

Preferably, the nut further has an outer rolling groove, which is annular and disposed on the outer circumference of the nut. The ball screw further comprises a bearing outer ring and a plurality of second balls. The bearing outer ring has a second axial hole, an annular inner rolling groove and an oil supply hole. The second axial hole penetrates the two phases of the bearing outer ring. On the opposite end surface, the outer ring of the bearing is sleeved on the nut with the second axial hole, the inner rolling groove is arranged on the hole wall of the second axial hole and forms a second load path together with the outer rolling groove of the nut, the oil supply hole is connected with the second load path and the oil inlet hole of the nut, and the second balls are arranged on the second load path. Thus, when the 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 the other part of the lubricating oil will flow from the oil inlet hole to the oil channel, and then flow from the oil channel to the first load path through the oil outlet hole to lubricate the first balls. In this way, the screw shaft, the nut and the bearing outer ring can be lubricated at the same time, thereby achieving a uniform lubrication effect.

Preferably, the nut further has an oil guide hole connected to the oil passage. An annular space is formed between the nut and the outer ring of the bearing, and the annular space is connected to the second load path and the oil guide hole. In this way, excess lubricating oil will enter the annular space through the oil guide hole, and then flow from the annular space to the second load path, thereby providing a lubricating effect to the second balls.

The detailed structure, features, assembly or use of the ball screw provided by this invention will be described in the detailed description of the implementation method in the following. However, those with ordinary knowledge in the field of this invention should understand that such detailed description and specific embodiments listed for implementing this invention are only used to illustrate this invention and are not used to limit the scope of the patent application of this invention.

The applicant first explains that in the entire specification, including the embodiments described below and the claims of the patent application, the terms related to direction are based on the directions in the drawings. Secondly, in the embodiments and drawings to be described below, the same component numbers represent the same or similar components or their structural features.

Please refer to FIG. 1 to FIG. 3 , the ball screw 10 of the first embodiment of the present invention 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 .

In this embodiment, the outer circumferential 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.

The nut 30 has an inner ring body 31 and two inner flanges 32. The two inner flanges 32 are arranged around the outer circumference 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 axial hole 33 penetrating through two opposite end surfaces of the inner ring body 31. The nut 30 is rotatably and displaceably sleeved on the screw shaft 20 through the first axial hole 33. The nut 30 also has an internal threaded groove 34 and two external rolling grooves 35. The internal threaded groove 34 is arranged on the hole wall of the first axial hole 33 and together with the external threaded groove 22 of the screw shaft 20 forms a first load path 42 for the first balls 40 to run. The two external rolling grooves 35 are respectively arranged along the two internal flanges 32 and are annular.

In addition, as shown in FIG. 3 , the nut 30 also has two oil passages 36, two oil inlet holes 37, two oil outlet holes 38, and two oil guide holes 39, wherein the two oil passages 36 are located at two opposite sides of the first axial hole 33 and penetrate the two opposite end surfaces of the inner ring body 31 along the direction parallel to the axial direction A of the screw shaft 20, and the two ends of each oil passage 36 are respectively closed by a plug 64; the two oil inlet holes 37 are located at two opposite sides of the first axial hole 33 and penetrate 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 to respectively connect the two oil passages 36 and the inner ring body 31. The two oil outlet holes 38 are located on the same side of the first shaft hole 33 and connected to the first load path 42 and one of the oil passages 36 and correspond to the two external thread grooves 22 of the screw shaft 20 respectively. The two oil outlet holes 38 can be arranged along the same axis at intervals (as shown in FIG. 3 ) or located on different axes according to actual needs; the two oil guide holes 39 are connected to one of the oil passages 36 and coaxially correspond to the two oil outlet holes 38. Therefore, the two oil guide holes 39 can be located on the same axis as the two oil outlet holes 38 (as shown in FIG. 2 ) or on different axes (as shown in FIG. 5 ). In addition, when the diameters of the oil outlet hole 38 and the oil guide hole 39 are too small, the lubrication effect may be reduced, and when the diameters are too large, the first ball 40 and the second ball 60 may vibrate when passing through. Therefore, the diameters of the oil outlet hole 38 and the oil guide hole 39 are between 1/3 and 1/2 of the ball diameter.

It should be noted that the number of the oil passage 36 and the oil inlet hole 37 is 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, 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.

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 circumference of the outer ring body 51. The bearing outer ring 50 has a second axial hole 53 that penetrates two opposite end surfaces of the outer ring body 51. The bearing outer ring 50 is sleeved with the nut 30 through the second axial hole 53 and an annular space 54 is formed between the bearing outer ring 50 and the nut 30 (as shown in FIGS. 3 and 4). The annular space 54 is connected to the two oil guide holes 39 of the nut 30. The bearing outer ring 50 further has two annular inner rolling grooves 55, which are arranged on the hole wall of the second shaft hole 53 and respectively form a second load path 62 connected to the annular space 54 with the two outer rolling grooves 35 of the nut 30. Each second load path 62 is respectively provided with a retainer 61, and each retainer 61 is provided with a plurality of second balls 60, so that when the nut 30 is driven, on the one hand, it can rotate relative to the screw shaft 20 and the bearing outer ring 50, and on the other hand, it can drive the bearing outer ring 50 to reciprocate along the axial direction A of the screw shaft 20.

In addition, as shown in FIG. 3 , the bearing outer ring 50 also has two oil supply holes 56 , which penetrate the outer ring body 51 and the outer flange 52 in a direction perpendicular to the axial direction A of the screw shaft 20 and are connected to a second load path 62 adjacent to the outer flange 52 , and one of the oil supply holes 56 is simultaneously connected to the oil inlet hole 37 of the nut 30 .

As can be seen from the above, as shown in FIG4, after 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 near the outer flange 52 to lubricate the second ball 60 there, 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 the two oil outlet holes 38, thereby lubricating the first balls 40. After the lubricating oil fills the oil passage 36, the excess lubricating oil will enter the annular space 54 through the two oil guide holes 39, and then flow from the annular space 54 to the second load path 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, an oil seal 57 is respectively disposed on two opposite end surfaces of the bearing outer ring 50 . The two oil seals 57 are used to prevent lubricating oil from flowing out of the bearing outer ring 50 .

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

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

In this embodiment, the outer circumferential 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.

The nut 70 has a ring body 71 and a flange 72. The flange 72 is disposed around the outer circumference of the ring body 71 and is located at the front end of the ring body 71. The nut 70 has a first axial hole 73 that passes through two opposite end surfaces of the ring body 71. The nut 70 is rotatably and displaceably sleeved on the screw shaft 20 through the first axial hole 73. The nut 70 also has an internal thread groove 74. The internal thread groove 74 is disposed on the hole wall of the first axial hole 73 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.

In addition, the nut 70 also has an oil passage 76, an oil inlet hole 77, and two oil outlet holes 78, wherein the oil passage 76 is located on one side of the first axial hole 73 and passes through two opposite end surfaces of the ring body 71 along a direction parallel to the axial direction A of the screw shaft 20, and the two ends of the oil passage 76 are respectively sealed by an oil seal 79; the oil inlet hole 77 passes through the ring body 71 and the flange 72 along a direction perpendicular to the axial direction A of the screw shaft 20 and is connected to the oil passage 76; the two oil outlet holes 78 are located on the same side of the first axial hole 73 and are connected to the first load The path 42 and the oil passage 76 correspond to two external thread grooves 22 of the screw shaft 20 respectively. The two oil outlet holes 78 can be arranged along the same axis at intervals or on different axes according to actual needs. In addition, the number of oil outlet holes 78 is configured according to the number of external thread grooves 22. That is, 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.

As can be seen from the above, as shown in FIG. 7 , after the lubricating oil is injected from the oil inlet hole 77 , the lubricating oil first flows to the oil passage 76 , and then flows from the oil passage 76 through the two oil outlet holes 78 to the first load path 42 , thereby lubricating the first balls 40 .

In summary, the ball screw 12 of the second embodiment of the present invention can lubricate the screw shaft 20 and the nut 70 at the same time, thereby achieving uniform lubrication. Furthermore, 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 than 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, regardless of whether the screw shaft 20 is a single-thread or double-thread design, the present invention can meet the lubrication requirements.

10: Ball screw 12: Ball screw 20: Screw shaft 22: External thread groove A: Axial 30: Nut 31: Inner ring 32: Inner flange 33: First shaft hole 34: Inner thread groove 35: External rolling groove 36: Oil channel 37: Oil inlet hole 38: Oil outlet hole D: Distance 39: Oil guide hole 40: First ball 42: First load path 50: Bearing outer ring 51: Outer ring 52: Outer flange 53: Second shaft hole 54: Annular space 55: Inner rolling groove 56: Oil supply hole 57: Oil seal 60: Second ball 61: Cage 62: Second load path 64: Plug 70: Nut 71: Ring 72: Flange 73: First shaft hole 74: Inner threaded groove 76: Oil channel 77: Oil inlet hole 78: Oil outlet hole 79: Oil seal

Figure 1 is a three-dimensional view of the ball screw of the first embodiment of the present invention. Figure 2 is a three-dimensional exploded view of the ball screw of the first embodiment of the present invention with the first ball omitted. Figure 3 is an axial cross-sectional view of the ball screw of the first embodiment of the present invention. Figure 4 is a radial cross-sectional view of the ball screw of the first embodiment of the present invention. Figure 5 is another three-dimensional view of the nut of the first embodiment of the present invention, mainly showing that the oil holes are located on different axes. Figure 6 is a three-dimensional view of the ball screw of the second embodiment of the present invention. Figure 7 is an axial cross-sectional view of the ball screw of the second embodiment of the present invention.

20: Screw shaft

22: External thread groove

A: Axial

30: Nut

31: Inner ring body

32: Neifalan

34: Internal thread groove

35: Outer rolling groove

36: Oil channel

37: Oil inlet hole

38: Oil outlet hole

D: Distance

39: Oil guide hole

40: First Roll

42: First load path

50: Bearing outer ring

51: Outer ring

52: Outer France

54: Ring space

55: Inner rolling groove

56: Oil supply hole

60: Second Roller

62: Second load path

64: Plug

Claims (10)

A ball screw comprises: a screw shaft having an external threaded groove; a nut having a first axial hole, the first axial hole penetrating two opposite end surfaces of the nut, the nut being rotatably and displaceably sleeved on the screw shaft with the first axial hole, the nut having an internal threaded groove, an oil passage, an oil inlet hole and an oil outlet hole, the internal threaded groove being arranged on the hole wall of the first axial hole and forming a first load path together with the external threaded groove of the screw shaft, the oil inlet hole being connected to the oil passage, the oil outlet hole being connected to the first load path and the oil passage and corresponding to the external threaded groove of the screw shaft; and A plurality of first rollers are arranged on the first load path. A ball screw as described in claim 1, wherein the number of the oil outlet holes is configured according to the number of the external thread grooves. A ball screw as described in claim 1 or 2, wherein the nut has two oil outlet holes, and the distance between the oil outlet holes is equal to the pitch of the external thread groove. A ball screw as described in claim 3, wherein the oil outlet holes are located on the same axis. A ball screw as described in claim 3, wherein the oil outlet holes are located on different axes. The ball screw as described in claim 1, wherein the ball screw further comprises a bearing outer ring and a plurality of second balls, the nut further comprises an outer rolling groove, the outer rolling groove is annular and disposed on the outer circumference of the nut, the bearing outer ring has a second axial hole, an annular inner rolling groove and an oil supply hole, the second axial hole penetrates the shaft The bearing outer ring has two opposite end faces, the bearing outer ring is sleeved on the nut with the second axial hole, the inner rolling groove is arranged on the hole wall of the second axial hole and forms a second load path together with the outer rolling groove of the nut, the oil supply hole is connected with the second load path and the oil inlet hole of the nut, and the second balls are arranged on the second load path. The ball screw as described in claim 6, wherein the nut further has an oil guide hole connected to the oil passage; an annular space is formed between the nut and the outer ring of the bearing, and the annular space is connected to the second load path and the oil guide hole. A ball screw as described in claim 7, wherein the oil guide hole and the oil outlet hole are coaxially corresponding. A ball screw as described in claim 6, wherein the extension direction of the oil inlet hole is perpendicular to the axial direction of the screw shaft, the extension direction of the oil supply hole is perpendicular to the axial direction of the screw shaft, and the extension direction of the oil passage is parallel to the axial direction of the screw shaft. A ball screw as described in claim 7, wherein the diameters of the oil outlet hole and the oil guide hole are between 1/3 and 1/2 of the ball diameter.

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