JP6892752B2 - Free ball bearing - Google Patents

Description

The present invention relates to a free ball bearing having a structure in which one large sphere is placed on a large number of small spheres arranged on a concave spherical surface of a ball accommodating portion of a sphere holder.

A conventional free ball bearing of this type has a structure in which a large number of small spheres that receive a large sphere are arranged in such a manner that they are freely spread on a mere concave sphere of a sphere holder to cover the concave sphere (Patent Documents 1 and 2). ).
This free ball bearing is not generally used when the work moves in one direction because one large sphere supported by a large number of small balls can rotate in any direction. For example, a work such as a plate material can be used. It is mainly used for transport tables and the like that can transport in any horizontal direction. In the case of a transport table, a large number of free ball bearings are arranged in a distributed manner on the upper surface of the table.

Japanese Patent Application Laid-Open No. 2003-184871 Japanese Patent Application Laid-Open No. 07-164078

This type of free ball bearing has a feature that the frictional resistance generated is small because the sphere is supported by a large number of small spheres, unlike the structure in which the sphere that receives the load is directly received by the concave spherical surface. As described above, the bearing may be used for a transport table or the like, and is not generally assumed to be used for rotating a sphere at a remarkably high speed. Further, in the case of a transport table, since a large number of free ball bearings are arranged, it is not generally assumed that a significantly large load is applied to one free ball bearing.

However, this type of free ball bearing can be used in applications where the sphere needs to rotate at a significantly higher speed, or where it needs to bear a significantly larger load, and even when it is rotated at a significantly higher speed and has a significantly larger load. When used in applications that require a burden, frictional resistance increases, which may require greater power than expected to drive the moving body, and may cause seizure of the free ball bearings. ..
When this type of free ball bearing, which is generally used when moving in any direction, is used to support a moving body that moves in one direction, it rotates at a significantly high speed or bears a significantly large load. Furthermore, it may be necessary to rotate at a significantly high speed and bear a significantly large load.

The present invention has been made based on the above background, and as a free ball bearing for supporting a moving body moving in one direction, the frictional resistance to the rotation of the sphere is small, and the sphere is rotated at a remarkably high speed or remarkably. It is an object of the present invention to provide a free ball bearing that can be applied to an application in which a large load is applied to the bearing and the bearing is rotated at a significantly high speed and a significantly large load is required.

The invention of claim 1 that solves the above problems is one in which a large number of small spheres are arranged on the concave sphere of a sphere holder having a ball accommodating portion forming a concave sphere and rotatably supported by the large number of small spheres . A free ball bearing that has a large sphere and movably supports a moving body that moves in one direction in contact with the sphere.
An even-numbered row of track grooves forming the moving body moving direction is formed in at least a central region in the left-right direction orthogonal to the moving body moving direction of the concave spherical surface of the ball accommodating portion, and the even-numbered row of track grooves are shallow grooves and deep grooves. The shallow groove and the deep groove in each set are connected by a connecting passage connecting both ends of each, and the small sphere in the central region is the shallow groove. It is characterized in that it can circulate between the deep groove and the deep groove.
In the present invention, the moving body that moves in one direction is not limited to a moving body whose center of gravity moves, and is a rotating body that rotates without moving its center of gravity, such as a rotation axis. Including. The moving direction of the moving body in this case refers to the moving direction of each point on the outer peripheral surface of the rotating body.

2. The free ball bearing according to claim 1, wherein the sphere holder has a ball accommodating portion and accommodates a large number of small spheres and one large sphere, and an upper surface of the holder body. It is characterized in that it is attached to a lid and holds the sphere so that a part of the sphere is exposed.

According to the third aspect, in the free ball bearing of the second aspect, the even-numbered rows of track grooves on the concave spherical surface of the holder body are located only in the central region in the left-right direction orthogonal to the moving body moving direction, and the outer region in the left-right direction thereof. Is a concave spherical surface directly along the surface of the one large sphere.

In the free ball bearing of the present invention, when the moving body moves on the sphere of the free ball bearing, the sphere rotates in the same direction as the moving body on the contact surface with the moving body.
With respect to this sphere, of the pair of track grooves of the shallow groove and the deep groove in the central region, the small sphere in the shallow groove contacts the sphere and receives a load, and the sphere rotates on the contact surface with the sphere. It rotates in the direction opposite to the direction (the direction opposite to the moving direction of the moving body). On the other hand, the small sphere in the deep groove does not come into contact with the sphere, so that it is in a no-load state.
Since the track groove is in the direction of movement of the moving body, the globules in the shallow groove move in the direction opposite to the direction of movement of the moving body while rotating in the direction opposite to the direction of movement of the moving body, and the end thereof. Enter the next deep groove via the connecting passage. The small ball that entered the deep groove pushes the small ball in the deep groove, and the pushed small ball in the deep groove moves in the moving body moving direction (forward direction) in the deep groove and becomes a shallow groove via the connecting passage on the opposite side. enter. The small sphere that has entered the shallow groove from the deep groove contacts the sphere as described above and receives a load, and rotates in the direction opposite to the rotation direction of the sphere (the direction opposite to the movement direction of the moving body) on the contact surface with the sphere. To do.
In this way, the small sphere that circulates between the shallow groove and the deep groove supports the rotation of the sphere while rotating in the opposite direction (the direction opposite to the moving body moving direction) when it is in the shallow groove.
Since the groove direction of the track groove coincides with the moving body moving direction, the small sphere in the shallow groove supporting the sphere rotating in the moving body moving direction has a rotation axis substantially parallel to the rotation axis of the rotating sphere. Rotate in mode (opposite direction but rotate in approximately the same direction). Therefore, there is little unnecessary slip between the sphere and the globules, and the frictional resistance between the sphere and the globules is remarkably small.
In a structure in which a large number of small spheres are arranged on a simple concave sphere, the positions of the small spheres are not fixed and the rotation direction is also irregular, so that the frictional resistance to the supporting sphere is also large. According to the free ball bearing, as described above, the small sphere rotates in the direction correctly opposite to the rotation direction of the sphere (movement direction of the moving body) (in the opposite direction in a manner having a rotation axis substantially parallel to the rotation axis of the rotating sphere). Since it rotates), the slip generated between the sphere and the small sphere is small and the frictional resistance is small.

In a structure in which small spheres that rotatably support a sphere are laid freely on the concave spherical surface of the sphere holder, such as a conventional free ball bearing, the position of each small sphere in the concave spherical surface is not constant. This structure is effective in the case of a transport table or the like that supports the moving body so as to be movable in an arbitrary direction, but is not efficient when the moving body is moved in one direction.
That is, in a structure in which the position of each small sphere supporting the sphere in the concave sphere is not constant, the rotation of the sphere that rotates in the same direction as the moving direction of the moving body does not rotate in the direction correctly opposite to the rotation direction of the sphere. Of course, small balls also occur. Such a small sphere slips with respect to the rotation of the sphere and becomes frictional resistance.
Such frictional resistance is used in applications where the sphere needs to be rotated at a remarkably high speed, or in which a remarkably large load needs to be applied, and further, it is necessary to rotate the sphere at a remarkably high speed and bear a remarkably large load. When used in certain applications, the frictional resistance increases, which may require a large amount of power to drive the moving body, and the free ball bearing may be seized.
However, as in the present invention, a plurality of sets of track grooves forming a pair of deep grooves and shallow grooves forming the moving body moving direction are provided in at least the central region in the left-right direction orthogonal to the moving body moving direction of the concave spherical surface. According to the structure, the small sphere in the shallow groove in the central region does not move its position unnecessarily, so that the sphere always correctly follows the rotation direction of the sphere in the opposite direction (rotation in the opposite direction on the contact surface). ), And there is very little frictional resistance to the rotation of the sphere.
Therefore, it is used for applications that require the sphere to rotate at a significantly high speed, applications that require a significantly large load, and applications that require a remarkably high speed rotation and a significantly large load. Even in this case, a large amount of power is not required to drive the moving body, and there is little risk of seizure of the free ball bearing.

It is sectional drawing of the free ball bearing of one Example of this invention. It is a top view which showed the free ball bearing of FIG. 1 in the state which removed the lid body and the sphere. FIG. 2 is a plan view showing a state in which small spheres are removed in FIG. FIG. 3 is a cross-sectional view taken along the line AA of FIG. It is an enlarged view of the main part of FIG. It is a perspective view which showed the free ball bearing of FIG. 1 in the state which removed the lid body. FIG. 6 is a perspective view showing a state in which a sphere is removed in FIG. FIG. 7 is a perspective view showing a state in which small balls are removed in FIG. 7. As an example of the usage mode of the free ball bearing of the present invention, the grooving device in the grooved metal tube manufacturing device for manufacturing the grooved metal tube will be described, and (a) is a side view of the grooving device 10 (b). ) Is a front view (right arrow view) showing the housing 16 with the lid 16c removed in (a), and (c) is a view showing only the free ball bearing 56 of (b). It is sectional drawing of the free ball bearing of another Example of this invention. Another example of the usage mode of the free ball bearing of the present invention is shown, and it is a figure when it is used as a component of a bearing which supports a large-diameter rotating shaft.

Hereinafter, embodiments for carrying out the free ball bearings of the present invention will be described with reference to the drawings.

The free ball bearing of the present invention movably supports a moving body that moves in one direction. FIG. 1 is a cross-sectional view of the free ball bearing 56 of one embodiment, and FIG. 2 is a free ball bearing 56 of FIG. A plan view showing the lid 54c and the sphere 55 removed, FIG. 3 is a plan view showing the small sphere 80 removed in FIG. 2, FIG. 4 is a sectional view taken along the line AA of FIG. 3, and FIG. It is an enlarged view of the main part of FIG. FIG. 6 is a perspective view showing the free ball bearing 56 of FIG. 1 with the lid 54c removed, and FIG. 7 is a perspective view showing the free ball bearing 56 of FIG. 6 with the sphere 55 removed. FIG. 8 is a perspective view showing a state in which the small ball 80 is removed in FIG. 7.
As shown in these figures, the free ball bearing 56 includes one large sphere 55, a sphere holder 54 that accommodates the sphere 55 in a ball accommodating portion 54a forming a concave spherical surface, and a concave spherical surface of the ball accommodating portion 54a. It has a large number of small spheres 80 and which are arranged in the sphere and on which the sphere 55 is placed. The sphere holder 54 includes a holder body 54b having the ball accommodating portion 54a and a lid 54c for holding the sphere 55.
Then, in the ball accommodating portion 54a of the holder body 54b, an even number of rows forming the moving body moving direction is formed in the central region in the Y direction orthogonal to the moving body moving direction (arrow X direction in FIG. 2) of the concave spherical surface. It forms a track groove.
The even-numbered track grooves are composed of a plurality of sets consisting of a pair of shallow grooves 81a and deep grooves 81b, and the shallow grooves 81a and deep grooves 81b in each set are connecting passages 81c which are inclined surfaces at their ends. The globules 80 can circulate between the shallow groove 81a and the deep groove 81b. A circulation path including a shallow groove 81a, a deep groove 81b, and a connecting passage 81c is indicated by 81.
Both the shallow groove 81a and the deep groove 81b are grooves having an arc cross section that matches the shape of the small sphere 80, and the shallow groove 81a, the deep groove 81b, and the boundary wall are indicated by 82a. The boundary wall between the pair of shallow grooves 81a and deep grooves 81b is indicated by 82b.

In this embodiment, two sets of track grooves are formed on both sides of the central position in the direction orthogonal to the moving body moving direction, and the other regions of the concave spherical surface are simply concave spherical regions 83 without grooves. is there. The boundary wall between the grooved region and the non-grooved region is indicated by 82c.
The depth of the shallow groove 81a is a depth of contact with the sphere 55, and the small sphere 80 in the shallow groove 81a rotates and moves while receiving a load while supporting the rotating sphere 55. The depth of the deep groove 81b is a depth that does not come into contact with the sphere 55, and is not subject to the load from the sphere 55.
The diameter of the small sphere 80 of the embodiment is, for example, 4.0 mm with respect to the sphere 55 having a diameter of 40 mm. The gap h between the sphere 55 and the small sphere 80 in the deep groove 81b is 0.5 mm.

In the above-mentioned free ball bearing 56, the sphere 55 of the free ball bearing 56 rotates in the same direction as the moving body of the moving body with respect to the moving body moving in one direction.
With respect to the sphere 55, the small sphere 80 in the shallow groove 81a of the pair of track grooves of the shallow groove 81a and the deep groove 81b in the central region comes into contact with the sphere 55 and receives a load from the sphere 55. It rotates in the direction opposite to the rotation direction (the direction opposite to the moving direction of the moving body). On the other hand, the small sphere 80 in the deep groove 81b does not come into contact with the sphere 55, so that it is in a no-load state.
Since the track groove is in the moving direction of the moving body, the globules 80 in the shallow groove 81a move in the shallow groove 81a in the direction opposite to the moving direction of the moving body while rotating, and pass through the connecting passage 81c at the end thereof. After that, it enters the next deep groove 81b. The globules 80 in the deep groove 81b push the globules 80 in the deep groove 81b, and the pushed globules 80 in the deep groove 81b move in the deep groove 81b in the moving body moving direction (forward direction) on the opposite side. Enter the shallow groove 81a via the connecting passage 81c. The small sphere 80 that has entered the shallow groove 81a from the deep groove 81b rotates in the direction opposite to the rotation direction of the sphere 55 (the direction opposite to the movement direction of the moving body) while being in contact with the sphere 55 and receiving a load as described above. ..
In this way, the small sphere 80 that circulates between the shallow groove 81a and the deep groove 81b supports the rotation of the sphere 55 while rotating in the opposite direction when it is in the shallow groove 81a.
Since the groove direction of the track groove coincides with the moving body moving direction, the small sphere 80 in the shallow groove 81a supporting the sphere 55 rotating in the moving body moving direction is substantially parallel to the rotation axis of the rotating sphere 55. It rotates in a mode with a rotation axis (the direction is opposite, but it rotates in almost the same direction). Therefore, there is little unnecessary slip between the sphere 55 and the globules 80, and the frictional resistance between the spheres 55 and the globules 80 is remarkably small. (
Since the frictional resistance to the rotation of the sphere 55 can be reduced as described above, the power for driving the moving body can be reduced as much as possible. In addition, seizure of free ball bearings can be prevented as much as possible.
Therefore, a free ball bearing for supporting a moving body moving in one direction is rotated at a remarkably high speed in an application in which the sphere 55 needs to be rotated at a remarkably high speed, a use in which an extremely large load needs to be applied, or a remarkably high speed. Moreover, when used in an application requiring an extremely large load, it was effective for minimizing the power for driving the moving body or for preventing seizure of the free ball bearing.

FIG. 9 shows an example of using the free ball bearing 56 of the present invention, for example, in a square metal pipe 8 ”installed on the downstream side of a sizing roll stand in an electric sewing pipe manufacturing apparatus and continuously fed and driven. On the other hand, it is a figure explaining the case which used for the grooving apparatus 10 which forms the concave groove on the four surfaces.
The grooving device 10 includes four outer pipe mechanisms 19 provided with a reduction adjustment mechanism 57 and provided with a free ball bearing 56 at intervals in the circumferential direction in a manner of pushing the sphere 55 on the outer surface of the pipe, and a cross section along the inner surface of the pipe. With the core 20 which has a short rod shape and is arranged in the pipe at a position in the longitudinal direction of the pipe corresponding to the outside mechanism 19 and in a manner which does not receive a binding force other than contacting the inner surface of the pipe in the illustrated example. Is provided in the housing 16.
The reduction adjustment mechanism 57 adjusts the position of the free ball bearing 56 (the position of the sphere 55) to adjust the reduction of the sphere 55. In this grooving device 10, when the metal pipe 8 "before grooving is driven in the direction of the arrow in FIG. 9 (a), the pipe wall becomes the outer surface including the sphere 55 and the groove-shaped recess 20a of the core 20. By passing between them, concave grooves are continuously formed on the four surfaces of the metal tube. During this grooving process, the sphere 55 of the free ball bearing 56 receives a significantly large load and at high speed. Although it rotates, the frictional resistance between the small sphere 80 and the sphere 55 is small and seizure does not occur, so that it can withstand such a usage environment.
The shape of the lower surface portion (the dovetail groove portion) of the holder body 54b in the free ball bearing 56 shown in FIGS. 1 to 8 is different from the shape of the holder body 54b in the free ball bearing 56 shown in FIG. However, it does not matter.

FIG. 10 shows a free ball bearing 56'of another embodiment of the present invention.
In this free ball bearing 56', even-row track grooves on the concave spherical surface of the holder body 54 are located only in the central region in the left-right direction (Y direction) orthogonal to the moving body moving direction, and the outer region 54d in the left-right direction is It is just a concave sphere directly along the surface of the sphere 55.
In the region 54d on the outer side in the left-right direction of the central region, even if the sphere 55 is in direct contact with a mere concave sphere without the presence of a small sphere, a large load does not act on the concave sphere, so that the frictional resistance is small. Sometimes it doesn't matter too much. In such a case, a free ball bearing having a structure as shown in FIG. 10, which is easy to manufacture without deteriorating the performance, was obtained.

As shown in FIG. 11, for example, the free ball bearing of the present invention is a free ball bearing 56 as a component which is arranged around a large-diameter rotating shaft 90 at intervals to form a bearing 91. Can also be applied.
That is, in the present invention, the moving body that moves in one direction is not limited to the moving body that moves the center of gravity position like the metal tube in the above-described embodiment, and the rotating shaft that rotates without moving the center of gravity position ( Including the case of a rotating body). In this case, the moving body moving direction refers to the moving direction of each point on the outer peripheral surface of the rotating shaft 90, and each point on the outer peripheral surface of the rotating shaft 90 moves in one direction with respect to the sphere of the free ball bearing 56.

8 Grooved metal tube 10 Grooving device 19 Outer tube mechanism 20 Core 20a Grooved recess 54 Sphere holder 54a Ball accommodating part (concave spherical surface)
54b Holder body 54c Lid 55 Sphere 56 Free ball bearing 57 Reduction adjustment mechanism 80 Small sphere 81 Circulation path (shallow groove, deep groove and connecting passage)
81a Shallow groove 81b Deep groove 81c Communication passage 82a Shallow groove, deep groove and boundary wall 82b Boundary wall between a pair of shallow groove and deep groove 82c Boundary wall between grooved area and non-grooved area 83 Simple concave without groove Spherical area 90 Rotating shaft 91 Bearing

Claims (3)

A large number of small spheres are arranged on the concave sphere of a sphere holder having a ball accommodating portion forming a concave sphere, and the sphere has one large sphere rotatably supported by the large number of small spheres and is in contact with the sphere. A free ball bearing that movably supports a moving body that moves in one direction.
Even-numbered rows of track grooves forming the moving body moving direction are formed in at least the central region in the left-right direction orthogonal to the moving body moving direction of the concave spherical surface of the ball accommodating portion, and the even-numbered rows of track grooves are shallow grooves and deep grooves. The shallow groove and the deep groove in each set are connected by a connecting passage connecting both ends of each, and the small sphere in the central region is the shallow groove. A free ball bearing characterized in that it can circulate between deep grooves. The sphere holder is attached to a holder main body having the ball accommodating portion and accommodating the large number of small spheres and the one large sphere, and an upper surface of the holder main body so that a part of the sphere is exposed. The free ball bearing according to claim 1, further comprising a lid that holds the sphere. An even row of track grooves on the concave spherical surface of the holder body is located only in the central region in the left-right direction orthogonal to the moving body moving direction, and the outer region in the left-right direction is a concave spherical surface directly along the surface of the one large sphere. The free ball bearing according to claim 2, wherein the free ball bearing is provided.

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