Ball spline with lubrication passage

Abstract

A ball spline includes a spline shaft, an outer sleeve, and two circulation elements. The outer sleeve is slidably sleeved on the spline shaft to form a load channel therebetween for installation of balls, and has an oil guide channel inside. The circulation elements are mounted to two outer end surfaces of the outer sleeve and each has an oil filling hole, an oil storage tank communicating with the oil filling hole, the load channel, and the oil guide channel, and an oil guide portion disposed in the oil storage tank and corresponding to the oil filling hole and protruding towards the oil guide channel. Thus, after injecting lubricant into the oil filling hole of one of the circulation elements, the lubricant lubricates the balls on both sides by means of the oil guide portion and the oil guide channel, thus enhancing the lubrication effect.

Claims

1. A ball spline comprising: a spline shaft having a first rolling groove at an outer surface thereof; an outer sleeve slidably sleeved on the spline shaft and having a second rolling groove at an inner surface thereof, the second rolling groove of the outer sleeve and the first rolling groove of the spline shaft forming a load channel, the outer sleeve having a non-load channel and an oil guide channel inside, two ends of the non-load channel and two ends of the oil guide channel passing through two opposite end surfaces of the outer sleeve; two circulation elements mounted to the two end surfaces of the outer sleeve and penetrated by the spline shaft, the circulation elements each having a circulation groove with two ends thereof connected with the load channel and the non-load channel to form a circulation channel, an oil filling hole, an oil storage tank communicating with the oil filling hole, the load channel, and the oil guide channel of the outer sleeve, and an oil guide portion disposed in the oil storage tank and corresponding to the oil filling hole and protruding towards the oil guide channel; and a plurality of balls disposed in the circulation channel.

2. The ball spline as claimed in claim 1, wherein each of the oil guide portions has a first end connected with a periphery wall of the oil storage tank, a second end arranged adjacent to the oil guide channel, and a guide bevel surface facing the oil filling hole and tilting downwards from the first end towards the second end and having a position higher than a bottom surface of the oil guide channel.

3. The ball spline as claimed in claim 2, wherein each of the oil guide portions has a width decreasing from the first end towards the second end.

4. The ball spline as claimed in claim 3, wherein a width of the second end of each of the oil guide portions is smaller than or equal to a width of the oil guide channel.

5. The ball spline as claimed in claim 1, wherein a depression is provided at each of two opposite sides of each of the oil guide portions.

6. The ball spline as claimed in claim 1, wherein each of the two end surfaces of the outer sleeve has a lubrication channel communicating with the second rolling groove and the oil storage tank.

7. The ball spline as claimed in claim 6, wherein the lubrication channel is closer to the spline shaft than the oil guide channel.

8. The ball spline as claimed in claim 1, wherein the oil guide channel extends along an axial direction of the spline shaft.

9. The ball spline as claimed in claim 1, wherein each of the oil guide portions has a pointed cone shape, truncated square pyramid shape or arc shape.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a perspective view of a ball spline of the present invention.

(2) FIG. 2 is an exploded view of the ball spline of the present invention.

(3) FIG. 3 is a sectional view of the ball spline of the present invention.

(4) FIG. 4 is an exploded view of the outer sleeve and the circulation element provided by the ball spline of the present invention.

(5) FIG. 5 is an exploded view from another perspective of the outer sleeve and the circulation element provided by the ball spline of the present invention.

(6) FIG. 6 is a partially enlarged view of the circulation element provided by the ball spline of the present invention.

(7) FIG. 7 is a partially sectional view of the ball spline of the present invention.

(8) FIG. 8 is a sectional view taken along line 8-8 of FIG. 7.

(9) FIG. 9a is similar to FIG. 6, showing the circulation element with another configuration.

(10) FIG. 9b is a plane view of FIG. 9a.

(11) FIG. 10a is similar to FIG. 9a, showing the circulation element with another configuration.

(12) FIG. 10b is a plane view of FIG. 10a.

(13) FIG. 11a is similar to FIG. 10a, showing the circulation element with another configuration.

(14) FIG. 11b is a plane view of FIG. 11a.

(15) FIG. 12a is similar to FIG. 11a, showing the circulation element with another configuration.

(16) FIG. 12b is a plane view of FIG. 12a.

(17) FIG. 13a is similar to FIG. 12a, showing the circulation element with another configuration.

(18) FIG. 13b is a plane view of FIG. 13a.

DETAILED DESCRIPTION OF THE INVENTION

(19) Referring to FIGS. 1 and 2, a ball spline 10 of the present invention comprises a spline shaft 20, an outer sleeve 30, two circulation elements 40, two dustproof elements 50, and a plurality of balls 60.

(20) The outer surface of the spline shaft 20 has two pairs of first rolling grooves 22. Each of the first rolling grooves 22 extends along an axial direction of the spline shaft 20.

(21) The outer sleeve 30 has two opposite outer end surfaces 31 and a shaft hole 32 passing through the outer end surfaces 31. The outer sleeve 30 is sleeved on the spline shaft 20 through the shaft hole 32 and slidable along the axial direction of the spline shaft 20. The periphery wall of the shaft hole 32 has two pairs of second rolling grooves 33. The second rolling groove 33 of the outer sleeve 30 and the first rolling groove 22 of the spline shaft 20 correspond to each other to form a load channel 62 (as shown in FIG. 3). In addition, the outer sleeve 30 further has two pairs of non-load channels 34 and two oil guide channels 35. The non-load channels 34 and the oil guide channels 35 extend along the axial direction of the spline shaft 20 and pass through the outer end surfaces 31 of the outer sleeve 30. As shown in FIGS. 4 and 5, each of the outer end surfaces 31 of the outer sleeve 30 has two opposite lubrication channels 36. The lubrication channel 36 is closer to the spline shaft 20 than the oil guide channel 35, and two ends of the lubrication channel 36 are connected with one pair of the second rolling grooves 33.

(22) The circulation elements 40 are mounted to the outer end surfaces 31 of the outer sleeve 30 and penetrated by the spline shaft 20. Each of the circulation elements 40 has an inner end surface 41 facing towards the outer sleeve 30 and an outer surface 42 facing away the outer sleeve 30. As shown in FIGS. 2, 4, and 5, the inner end surface 41 has four circulation grooves 43 and two opposite oil storage tanks 44. Two ends of each circulation groove 43 are connected with the load channel 62 and the non-load channel 34 to form a circulation channel 64 (see FIG. 3) for circulation of the balls 60. The oil storage tank 44 axially communicates with the oil guide channel 35 of the outer sleeve 30 and radially communicates with the lubrication channel 36 of the outer sleeve 30 (see FIGS. 4, 5, and 7). As shown in FIGS. 4 and 5, the outer surface of the circulation element 40 has two opposite oil filling holes 45 radially communicating with the oil storage tanks 44, respectively. In addition, as shown in FIGS. 6 and 7, each of the circulation elements 40 has two oil guide portions 46 disposed in the oil storage tanks 44, respectively, and protruding towards the oil guide channels 35, and further, each of the oil guide channels 35 corresponds to one of the oil filling holes 45, one of the oil storage tanks 44, and one of the oil guide portions 46. Furthermore, the oil guide portion 46 has a first end 461, a second end 462, and a guide bevel surface 463. The first end 461 is connected with the periphery wall of the oil storage tank 44. The second end 462 is arranged adjacent to the oil guide channel 35, and the width W2 of the second end 462 is smaller than or equal to the width W1 of the oil guide channel 35 (see FIG. 8). The guide bevel surface 463 faces the oil filling hole 45 and tilts downwards from the first end 461 towards the second end 462, and further, the position of the guide bevel surface 463 is higher than the bottom surface 352 of the oil guide channel 35 (see FIG. 7). As shown in FIGS. 6, the oil guide portion 46 has a width decreasing gradually from the first end 461 towards the second end 462, and each of two opposite sides of the oil guide portion 46 has an arc-shaped depression 47. In addition, as shown in FIG. 2, a positioning hole 48 passing through the inner and outer end surfaces 41, 42 is provided at each of two opposite sides of the oil storage tank 44.

(23) Each of the dustproof elements 50 has two pairs of positioning posts 52 at an inner end surface thereof. The dustproof elements 50 uses the positioning posts 52 to insert into the positioning holes 48 of the circulation element 40 and uses screws (not shown) to secure the circulation elements 40 and the outer sleeve together.

(24) It can be seen from the above that when the lubricant is injected into the oil filling hole 45 of the circulation element 40 on one side, as shown in FIG. 7, the lubricant flows down to the lubrication channel 36 through the oil storage tank 44 on the same side, and then flows into the load channel 62 to lubricate the balls 60 on the same side. In another aspect, a part of the lubricant is guided into the oil guide channel 35 by the oil guide portion 46, and then flows along the oil guide channel 35 to the oil storage tank 44 on the other side, and then flows down to the lubrication channel 36, and then flows to the load channels 62 on the other side to lubricate the ball 60 on the other side. During the flow of the lubricant, through the guidance of the guide bevel surface 463 and the size design of W2W1, the lubricant can enter the oil guide channel 35 from the oil storage tank 44 more concentratedly and efficiently. In addition, through the depressions 47 on both sides of the oil guide portion 46, the backflow situation caused by the lubricant flowing from the oil guide channel 35 to the guide bevel surface 463 of the oil guide portion 46 can be reduced, so that the lubricant can flow to the other side more efficiently. Further, through the tapered width of the oil guide portion 46 and the depressions 47 on both sides of the oil guide portion 46, the lubricant can flow down from the oil storage tank 44 to the lubrication channel 36 more efficiently.

(25) What needs to be supplemented here is that the configuration of the oil guide portion 46 can be changeable according to actual needs. For example, the oil guide portion 46 can be designed in a pointed cone shape as shown in FIGS. 9a and 9b. The oil guide portion 46 in FIGS. 9a and 9b still has the guide bevel surface 463 and the depressions 47; alternatively, the oil guide portion 46 can also be designed in a truncated square pyramid shape as shown in FIGS. 10a and 10b or an arc shape as shown in FIGS. 11a and 11b. The oil guide portion 46 in FIGS. 10a, 10b, 11a, and 11b has the guide bevel surface 463 but omits the depressions 47; alternatively, the oil guide portion 46 can also be designed in a truncated square pyramid shape as shown in FIGS. 12a and 12b or an arc shape as shown in FIGS. 13a and 13b. The oil guide portion 46 in FIGS. 12a, 12b, 13a, and 13b omits the guide bevel surface 463 and the depressions 47. However, regardless of the above configuration, the oil guide portion 46 can provide a guiding and steering function for the lubricant, so that a part of the lubricant can smoothly enter the oil guide channel 35 to provide a lubricating effect for the ball 60 on the other side.

(26) As indicated above, through the arrangement of the oil guide channel 35 of the outer sleeve 30 and the oil guide portion 46 of the circulation element 40. As long as the lubricant is injected into the oil filling hole 45 on one side, the balls 60 on both sides can be lubricated to achieve the effect of two-sided lubrication, thereby achieving the purpose of enhancing lubrication efficiency. In addition, since the oil guide channel 35 is provided inside the outer sleeve 30 and passes through the outer sleeve 30 along the axial direction of the spline shaft 20, it can withstand a larger oil injection pressure without causing oil leakage.

(27) The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.