JP2010117011A - Spherical bearing - Google Patents

Abstract

A spherical bearing excellent in durability is provided.
SOLUTION: A large sphere (51), a plurality of curved small spheres having a configuration in which a hollow sphere disposed around the large sphere is divided equally by a virtual plane including an axis extending vertically through the center of the sphere. Spherical small sphere holder 52 composed of holding pieces (52a, 52b), a plurality of small spheres (54a, 54b,...) Rotatably held by the spherical small sphere holder, and a spherical small sphere holder. A spherical bearing including a housing (56) having a spherical cavity having an opening in at least one of upper and lower sides accommodated together with a sphere, wherein the plurality of small sphere holding pieces (52a, 52b) A spherical bearing characterized by being joined to each other by a joining means (57) through a split surface.
[Selection] Figure 5

Description

  The present invention relates to a spherical bearing that is advantageously used as a part of a three-dimensional positioning device or an industrial robot.

  The spherical bearing is connected, for example, between a stage of a three-dimensional positioning device or an arm of an industrial robot and its driving device, and is used to move the stage or arm with multiple degrees of freedom.

  FIG. 1 is a cross-sectional view showing a configuration example of a conventional spherical bearing. 2 and 3 are a front view and a plan view, respectively, of a spherical small ball holder 12 provided in the spherical bearing 10 of FIG. 2 and 3, the spherical small ball holder 12 holds a plurality of small balls 14a, 14b,... And the curved small ball holding pieces 12a, 12b are separated from each other around the large ball 11. It is filled in the state that was done.

  The spherical bearing 10 is composed of two small spheres having a structure in which a hollow sphere disposed around the large sphere 11 and the large sphere 11 is equally divided by a virtual plane including an axis extending vertically through the center of the sphere. A spherical small sphere holder 12 composed of sphere holding pieces 12a, 12b, a plurality of small spheres 14a, 14b,... Rotatably held by the spherical small sphere holder 12, and a spherical small sphere holder 12. 14a, 14b,... Is housed together with a housing 16 having a spherical cavity 15 having openings 15a, 15b on the upper and lower sides.

  The large sphere 11 of the spherical bearing 10 is tightly supported by a plurality of small spheres 14a, 14b,... Arranged between the large sphere 11 and the housing 16 in a pressurized state. For this reason, the spherical bearing 10 can smoothly tilt and move the rod 18 together with the large sphere 11 (and / or rotate around the axis of the rod 18).

  Patent Document 1 discloses a spherical bearing including a spherical small ball retainer composed of two curved small ball holding pieces (retainer divided bodies) as in the spherical bearing 10 of FIG. There is disclosed a spherical bearing including a spherical small sphere retainer composed of a single curved small sphere retaining piece (a divided body of the retainer).

In Patent Document 3, the conventional spherical bearing as described above has a large number of parts, and it takes time to assemble, and when the spherical small ball cage is made of a metal material, It is described that the rolling of the small sphere may become unstable due to the influence of the metal powder generated by the friction. And in the same literature, in order to solve said problem, the spherical bearing provided with the spherical small ball holder integrally molded using the resin material is proposed. In this spherical bearing, a small ball (steel ball) is press-fitted from the outer surface side of the cage into a through hole (holding hole) that holds the small ball of the spherical small ball cage.
JP 2002-115710 A (FIG. 4) JP-A-8-338422 (FIG. 4) JP 2002-339947 A

  Normally, the diameter of the opening of the through hole on the outer surface side of the spherical sphere holder of the spherical bearing is set to a value smaller than the diameter of the sphere to prevent the sphere from falling out of the spherical sphere holder. Is done.

  In the spherical bearing disclosed in Patent Document 3, the inner surface of the through hole is easily worn because the small ball made of the metal material contacts the inner surface of the through hole of the spherical small ball cage made of resin material. For this reason, when this spherical bearing is used for a long period of time, the size of the through hole of the spherical small ball cage tends to increase due to the above-mentioned wear, and in extreme cases, the small ball may fall out of the through hole. . In order to suppress such dropout, it is desirable to reduce the diameter of the opening of the through hole on the outer surface side of the spherical small ball cage. However, in this spherical bearing, since it is necessary to press the small spheres into the through holes from the through holes on the outer surface side of the spherical small ball cage, the diameter of the through holes must be made extremely small. Is difficult.

  An object of the present invention is to provide a spherical bearing having excellent durability.

  According to the study of the present inventor, the main cause of the generation of metal powder inside the housing 16 of the spherical bearing 10 in FIG. 1 is the relative relationship between the large sphere 11 and the spherical sphere holder 12 as described below. It was found that there was a proper positional relationship.

  FIG. 1 shows the arrangement of the spherical ball holders 12 immediately after the spherical bearing 10 is assembled. As shown in FIG. 1, the two curved small sphere holding pieces 12 a and 12 b are arranged close to each other to form a spherical small sphere holder 12.

  Even when the rod 18 of the spherical bearing 10 is tilted and moved together with the large sphere 11 and then returned to the vertical arrangement shown in FIG. No problem arises just by repeating the tilting movement while maintaining the above configuration and then returning to the arrangement shown in FIG.

  However, if the rod 18 is tilted and moved together with the large sphere 11 and then returned to the vertical arrangement, the curved small sphere holder 12a and the curved small sphere holding piece of the spherical small sphere holder 12 are held as shown in FIG. The pieces 12b may be separated from each other. The reason why the curved small sphere holding pieces are separated as described above is as follows.

  The distance between the surface of the large sphere 11 of the spherical bearing 10 and the inner surface of the housing 16 is usually small because the large sphere 11 is closely supported by the plurality of small spheres 14a, 14b,. An interval slightly smaller than the diameter of the sphere (depending on the size of the sphere, for example, an interval smaller by about 1 to 5 μm than the diameter of the sphere) is set. For example, when the rod 18 shown in FIG. 1 is tilted to the right in the drawing, the small ball 14 d comes into contact with the edge of the opening 15 b on the lower side of the housing 16, and the inside of the housing 16 enters. Be disturbed. For this reason, the curved small sphere holding piece 12b holding the small sphere 14d moves relatively downward with respect to the large sphere 11. Accordingly, when the spherical bearing 10 repeats the operation of tilting the rod 18 to the right in the drawing together with the large sphere 11 and then returning to the vertical arrangement, the curved small sphere holding piece 12a and the curved small sphere holding piece 12b are moved. , They tend to be separated from each other as shown in FIG.

  Then, as shown in FIG. 4, when the curved small sphere holding piece 12 b moves downward relative to the large sphere 11, for example, the small sphere 14 c is arranged at a position away from the large sphere 11 outside the housing 16. Is done. For this reason, when the rod 18 is returned to the vertical arrangement, the small ball 14 c comes into strong contact with the edge of the opening 15 b on the lower side of the housing 16. Along with this, the small ball 14c comes into strong contact with the inner surface of the through hole 19c of the curved small ball holding piece 12b. In some cases, the curved small ball holding piece 12 b directly contacts the inner surface of the housing 16. Due to these contacts, metal powder (small spheres, spherical sphere cages or housing material powder generated due to wear due to the contact) or resin powder (for example, spherical small particles) is generated inside the housing 16 due to these contacts. (When the ball cage 12 is formed from a resin material).

  Further, for example, when the curved small sphere holding piece 12b moves extremely downward with respect to the large sphere 11 as shown in FIG. 4, the curved small sphere holding piece 12b is moved to the vertical position when the rod 18 is returned to the vertical arrangement. There is a case where it is sandwiched between the housing 18 and the housing 16 and is damaged.

  The inventor prevents separation of the curved small sphere holding piece 12a and the curved small sphere holding piece 12b of the spherical small sphere holder 12 (relative movement of each curved small sphere holding piece with respect to the large sphere 11). As a result, the occurrence of metal powder, resin powder, etc. inside the housing is suppressed, and damage to the spherical small ball cage is also prevented, so that the durability of the spherical bearing is greatly improved. The invention has been reached.

  Therefore, the present invention provides a large sphere, and a plurality of curved small spheres having a structure in which a hollow sphere disposed around the large sphere is equally divided by a virtual plane including an axis extending vertically through the center of the sphere. A spherical sphere holder made of a piece, a plurality of small spheres rotatably held by the spherical sphere holder, and a spherical sphere holder with a plurality of small spheres. A spherical bearing including a housing having a spherical hollow portion, wherein the plurality of small sphere holding pieces are joined to each other by joining means via respective divided surfaces. .

Preferred embodiments of the spherical bearing of the present invention are as follows.
(1) The joining means is an adhesive.
(2) An annular fixing comprising a groove formed annularly on the outer peripheral surface of each of the plurality of curved small sphere holding pieces across the dividing surface of each piece, and an elastic material inserted into the groove. It is composed of ingredients.
(3) The spherical small sphere holder is composed of 2 to 4 curved small sphere holding pieces.

  The spherical bearing of the present invention exhibits excellent durability because generation of metal powder, resin powder, and the like inside the housing is suppressed, and damage to the spherical small ball cage is also prevented.

  The spherical bearing of the present invention will be described with reference to the accompanying drawings.

  FIG. 5 is a cross-sectional view showing a configuration example of the spherical bearing of the present invention. 6 and 7 are a front view and a plan view, respectively, of a spherical small ball holder 52 provided in the spherical bearing 50 of FIG. 6 and 7, the spherical small ball holder 52 holds a plurality of small balls 54 a, 54 b, and holds the curved small sphere holding piece 52 a and the curved small sphere around the large sphere 51. The pieces 52b are entered in a state where they are joined to each other by the joining means (adhesive) 57.

  The spherical bearing 50 shown in FIG. 5 to FIG. 7 has a structure in which a hollow sphere arranged around the large sphere 51 and the large sphere 51 is equally divided by a virtual plane including an axis extending vertically through the center of the sphere. The spherical small sphere holder 52 composed of two curved small sphere holding pieces 52a, 52b, a plurality of small spheres 54a, 54b-, which are rotatably held by the spherical small sphere holder 52, and the spherical small sphere holder 52. And a plurality of small spheres 54a, 54b,... And a housing 56 having a spherical cavity 55 having openings 55a and 55b on the upper and lower sides, respectively. The spherical bearing 50 is mainly characterized in that the two curved small sphere holding pieces 52a and 52b are joined via an adhesive which is a joining means 57 via the respective divided surfaces.

  The large sphere 51 of the spherical bearing 50 is provided with a rod 58. When the rod 58 is tilted and moved together with the large sphere 51, a plurality of the spheres 51 are arranged around the large sphere 51 as the large sphere 51 is tilted. The small balls 54a, 54b,. Due to the rolling of these small spheres, the rod 58 of the spherical bearing 50 can be smoothly tilted (and / or rotated around the axis of the rod 58) without causing a large frictional resistance with respect to the housing 56. .

  As materials of the housing 56, the rod 58, the large sphere 51, and the small spheres 54a, 54b, constituting the spherical bearing 50, aluminum, copper alloy (eg, brass), steel (eg, high carbon) are usually used. Metal materials such as chrome steel and stainless steel are used. Further, for example, when the spherical bearing is used in an underwater or high temperature environment, a ceramic material can also be used. A resin material can also be used to reduce the weight of the spherical bearing. As the resin material, it is preferable to use a resin material having high mechanical strength, such as polyacetal resin, polyamide resin, polyphenylene sulfide (PPS) resin, or polyether ether ketone (PEEK) resin.

  Each of the housing 56, the rod 58, the large sphere 51, and the small spheres 54a, 54b,... Is preferably made of a metal material (particularly steel) because excellent mechanical strength is obtained.

  The spherical small sphere holder 52 holds a plurality of small spheres 54a, 54b,... To prevent each small sphere from dropping out of the holder 52, and is adjacent when the rod 58 is tilted. The occurrence of wear of small balls due to contact between small balls is suppressed.

  As a material of the spherical small sphere holder 52, the above-described metal materials and resin materials can be used. The spherical small sphere holder 52 can also be formed from a metal material (particularly brass) because excellent mechanical strength can be obtained, and machining to form a through hole for accommodating and holding the small sphere is facilitated. preferable.

  As described above, in the spherical bearing 50 of the present invention, the two curved small sphere holding pieces 52a and 52b constituting the spherical small sphere holder 52 are joined to each other through the respective dividing surfaces (adhesive). 57 are joined together. Therefore, even when the spherical bearing 50 repeats the operation of tilting and moving the rod 58 together with the large sphere 51 as shown in FIG. The holding piece 52a and the curved small sphere holding piece 52b do not separate (each curved small sphere holding piece moves relative to the large sphere 51). That is, in the spherical bearing 50, the small sphere (eg, the small sphere 54 d) that is disposed outside the housing 56 and does not perform the function of supporting the large sphere 51 is always disposed in close contact with the large sphere 51. Smooth entry into the inside of the housing of the small sphere and the spherical sphere holder 52 is realized. For this reason, the spherical bearing 50 exhibits excellent durability because generation of metal powder or resin powder or the like inside the housing is suppressed, and damage to the spherical small ball cage is also prevented.

  The joining means 57 is not particularly limited as long as the curved small sphere holding piece 52a and the curved small sphere holding piece 52b can be joined and fixed to each other, but each curved small sphere holding piece is specially provided for joining. It is preferable to use an adhesive as described above, because it is not necessary to set the shape to a simple shape.

  As the adhesive used as the joining means 57, a known adhesive can be used. However, since the work of joining the curved small sphere holding piece 52a and the curved small sphere holding piece 52b becomes easy, an anaerobic adhesive is used. It is preferable to use (including an ultraviolet curable anaerobic adhesive).

  In the spherical bearing of the present invention, the number of curved small sphere holders constituting the spherical small sphere holder is not particularly limited. It is preferable to construct from ~ 4 curved small sphere holding pieces. As a configuration example of such a spherical sphere holder, FIG. 9 shows a spherical sphere holder in which three curved sphere holding pieces 92a, 92b, and 92c are joined to each other by a joining means (adhesive) 57. 92 and FIG. 10 show a spherical sphere holder 102 formed by joining four curved sphere holding pieces 102a, 102b, 102c, and 102d to each other by a joining means (adhesive) 57.

  FIG. 11 is a cross-sectional view showing still another configuration example of a spherical small ball cage that can be used in the spherical bearing of the present invention. FIG. 12 is a front view of the spherical ball holder 112 of FIG. FIG. 13 is a plan view of the annular fixture 117b shown in FIG.

  In the spherical small sphere holder 112 shown in FIGS. 11 to 13, the joining means 117 is formed in an annular shape on the outer peripheral surface of the two curved small sphere holding pieces 112 a and 112 b across the divided surface of each piece. It is comprised from the groove | channel 117a and the cyclic | annular fixing tool 117b which consists of an elastic material (typical example, metal material) inserted in the inside of the groove | channel 117a.

  Since the joining means 117 using such an annular fixture 117b does not require the use of an adhesive, the joining of the curved small sphere holding piece 112a and the curved small sphere holding piece 112b can be performed with a simple operation and in a short time. There is an advantage that can be done.

  In the spherical bearing of the present invention, the spherical small ball cage can be formed of a resin material as described above. In such a case as well, the generation of metal powder due to contact between the small sphere and the edge of the opening of the housing when the rod is returned to the vertical arrangement is suppressed, and the small sphere and the spherical sphere holder are not transparent. Generation of resin powder due to contact with the inner surface of the hole or contact between the spherical small sphere holder and the housing is suppressed, and damage to the spherical small sphere holder is also prevented. Further, the spherical spherical ball cage made of a resin material used in the spherical bearing of the present invention is different from the spherical spherical ball cage described in Patent Document 3 above, and is transparent on the outer surface side of the spherical spherical ball cage. There is no need to press the small spheres into the through holes from the opening of the holes. Therefore, the spherical bearing of the present invention having a spherical sphere cage made of resin material has a diameter of the opening of the through hole on the outer surface side of the spherical sphere cage so that the sphere can be sufficiently prevented from falling off. Set a small value, that is, securely hold the small sphere even when the inner surface of the through hole is worn due to contact between the small ball and the inner surface of the through hole of the spherical small ball holder. Because it is possible, it shows excellent durability.

  In the spherical bearing of the present invention, the rod does not necessarily have to be fixed to the large sphere. That is, the spherical bearing of the present invention may have a configuration in which, for example, a hole for attaching a rod (for example, a drive shaft of an external mechanical device) to a large sphere is formed. In the spherical bearing of the present invention, the rod may be provided on each of the upper and lower sides of the large sphere. Such a spherical bearing can be advantageously used, for example, as a part of various industrial robots (for example, a joint for connecting a driving device and a driving object).

[Example 1]
In Example 1, the spherical bearing 50 shown in FIG. 5 was produced according to the following procedure.

  First, the main body 56b and the lid 56a of the housing 56, which are parts constituting the spherical bearing 50, were prepared as a large ball 51 having a rod 58, and a plurality of small balls 54a, 54b, 54c,. As these parts, known spherical bearing parts each made of high carbon chromium steel were used. And the two curved small sphere holding pieces 52a and 52b which comprise the spherical small sphere holder | retainer 52 shown in FIG. 5 were produced by cutting the metal material made from a brass, respectively.

  Next, from the inner peripheral surface side of the curved small sphere holding piece 52a, the small sphere was temporarily fixed inside each through hole by accommodating the small sphere having grease attached to each through hole of the holding piece 52a. . Similarly, small spheres (eg, small spheres 54a, 54b, 54c,...) Were temporarily fixed inside the respective through holes of the curved small sphere holding piece 52b using grease. And after apply | coating a commercially available anaerobic adhesive to the division | segmentation surface of each curved small ball holding piece, the curved small ball holding piece 52a and the curved small ball holding piece 52b are mutually mutually received in the state which accommodated the large ball between both. Adhered and allowed to stand until the adhesive was cured. Thereby, the curved small sphere holding piece 52 a and the curved small sphere holding piece 52 b are joined to each other, and the spherical small sphere holder 52 is formed around the large sphere 51.

  Then, the main body 56b of the housing 56 is disposed on a support base provided with a space at a position corresponding to the opening 55b. Inside the main body 55b, the large sphere 51 having the rod 58 and having the spherical small sphere holder 52 attached thereto as described above was accommodated. As a result, the rod 58 is disposed in the space of the support base, and the large sphere 51 is housed via a plurality of small spheres (eg, small spheres 54c, 54d,...) Held by the spherical small sphere holder 52. It is supported by the main body 56b. A lid 56a is fixed on the upper side of the main body 56b of the housing with a bolt 56c, and then the grease for lubrication is filled between the large sphere 51 and the housing 56, thereby producing the spherical bearing 50 shown in FIG.

  The rod 58 of the spherical bearing 50 thus manufactured is inclined and moved at an angle of 40 degrees in one direction from the vertically disposed state, and then disposed again vertically, and then at an angle of 40 degrees in the opposite direction. The operation of tilting and arranging again vertically was repeated 2.4 million times. Then, the lid 56a of the housing 56 of the spherical bearing 50 is removed from the main body 56b, and the inner surface of the housing 56 and the outer surface of the spherical sphere holder 52 are visually observed. There were no scratches and metal powder was not generated.

It is sectional drawing which shows the structural example of the conventional spherical bearing. However, the spherical bearing 10 of FIG. 1 is filled in with the housing 16 and the spherical small ball holder 12 cut. It is a front view of the spherical small ball holder 12 with which the spherical bearing 10 of FIG. 1 is provided. However, the spherical small ball holder 12 is filled with a plurality of small balls 14a, 14b,... And the curved small ball holding pieces 12a, 12b are separated from each other around the large ball 11. is there. It is a top view of the spherical small ball holder 12 with which the spherical bearing 10 of FIG. 1 is provided. However, the spherical small ball holder 12 is filled with a plurality of small balls 14a, 14b,... And the curved small ball holding pieces 12a, 12b are separated from each other around the large ball 11. is there. The figure which shows arrangement | positioning of the spherical small ball holder 12 at the time of repeating the operation which makes the rod 18 of the spherical bearing 10 of FIG. It is sectional drawing which shows the structural example of the spherical bearing of this invention. However, the spherical bearing 50 in FIG. 5 is shown in a state where the housing 56 and the spherical small ball holder 52 are cut. It is a front view of the spherical small ball holder 52 with which the spherical bearing 50 of FIG. 5 is provided. However, the spherical small sphere holder 52 holds a plurality of small spheres 54a, 54b,..., And the curved small sphere holding piece 52a and the curved small sphere holding piece 52b are joined to each other around the large sphere. Agent) 57 is entered in a state of being joined to each other. It is a top view of the spherical small ball holder | retainer 52 with which the spherical bearing 50 of FIG. 5 is provided. However, the spherical small sphere holder 52 holds a plurality of small spheres 54 a, 54 b, and the curved small sphere holding piece 52 a and the curved small sphere holding piece 52 b around the large sphere 51 are joined means ( It is written in a state of being bonded to each other by an adhesive) 57. The figure which shows arrangement | positioning of the spherical small ball holder 52 at the time of repeating the operation which inclines and moves the rod 58 of the spherical bearing 50 of FIG. It is a top view which shows another structural example of the spherical small sphere holder | retainer which can be used for the spherical bearing of this invention. However, the spherical small sphere holder 92 holds a plurality of small spheres 54a, 54b,... And three curved small sphere holding pieces 92a, 92b, 92c around the large sphere 51. Agent) 57 is entered in a state of being joined to each other. It is a top view which shows another structural example of the spherical small sphere holder | retainer which can be used for the spherical bearing of this invention. In this spherical small ball holder 102, a plurality of small balls 54a, 54b,... Are held, and around the large ball 51, four curved small ball holding pieces 102a, 102b, 102c, 102d are joined means ( It is written in a state of being bonded to each other by an adhesive) 57. It is sectional drawing which shows another structural example of the spherical small ball holder | retainer which can be used for the spherical bearing of this invention. However, the spherical small sphere holder 112 holds a plurality of small spheres 54 a, 54 b, and the two curved small sphere holding pieces 112 a and 112 b are joined to each other by the joining means 117 around the large sphere 51. It is filled in the state that was done. It is a front view of the spherical ball holder 112 of FIG. It is a top view of the cyclic | annular fixing tool 117b shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Spherical bearing 11 Large ball 12 Spherical small ball holder 12a, 12b Curved small ball holding piece 14a, 14b, 14c, 14d Small ball 15 Cavity 15a, 15b Opening 16 Housing 18 Rod 19c Through-hole 50 Spherical bearing 51 Large ball 52 Spherical small ball holder 52a, 52b Curved small ball holding piece 54a, 54b, 54c, 54d Small ball 55 Cavity 55a, 55b Opening 56 Housing 56a Lid 56b Main body 56c Bolt 57 Joining means (adhesive)
58 Rod 59b, 59c Through-hole 92 Spherical small sphere retainer 92a, 92b, 92c Curved small sphere retainer 102 Spherical small sphere retainer 102a, 102b, 102c, 102d Curved small sphere retainer 112 Spherical small sphere retainer 112a, 112b Curved sphere holding piece 117 Joining means 117a Groove 117b Ring-shaped fixture

Claims (4)

  A spherical ball comprising a plurality of curved small ball holding pieces having a configuration in which a hollow sphere is arranged evenly by a virtual plane including an axis extending through the center of the sphere and extending up and down. A sphere holder, a plurality of small spheres rotatably held by the spherical sphere holder, and a spherical shape having an opening in at least one of the upper and lower sides, containing the spherical sphere holder together with the plurality of spheres A spherical bearing including a housing having a hollow portion, wherein the plurality of small sphere holding pieces are joined to each other by joining means via respective divided surfaces.   The spherical bearing according to claim 1, wherein the joining means is an adhesive.   The joining means includes a groove formed in an annular shape on the outer peripheral surface of each of the plurality of curved small sphere holding pieces across the dividing surface of each piece, and an annular fixture made of an elastic material inserted into the groove. The spherical bearing according to claim 1.   The spherical bearing according to any one of claims 1 to 3, wherein the spherical small ball holder is composed of 2 to 4 curved small ball holding pieces.

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