JP2005321106A - Single shaft table feeder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high-speed single shaft table feeder with a feeding screw shaft having an improved critical speed by putting an auxiliary movable body of the single shaft table feeder in engagement with the feeding screw shaft so as to be integrally associative with a table. <P>SOLUTION: The single shaft table feeder comprises a movable body supported by a guide rail 31 and movable with the feeding screw shaft 35 in the axial direction and the auxiliary movable body 34 having the feeding screw shaft 35 passing through an inner diameter portion, supported by the guide rail 31 and movable in the axial direction. The inner diameter portion 38a of the auxiliary movable body 34 has slide contact with the feeding screw shaft 35. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a uniaxial table feeding device including a movable body and an auxiliary movable body, and in particular, a uniaxial table feeding device that improves the critical speed of a feed screw shaft by providing the auxiliary movable body with a role of an intermediate support. It is about.

  There are various types of table feeders using a feed screw shaft. A single-axis table feed device is one of them, and is a feed screw-integrated linear motion guide device in which a feed screw device is integrally assembled with a linear motion guide device (linear guide). In particular, the single-shaft table feed device to be improved according to the present invention includes a screw nut portion to improve load resistance in addition to a single movable body having a screw nut portion screwed with the feed screw shaft. This is a uniaxial table feeding device to which an auxiliary movable body not having a shaft is attached. Recently, there is an increasing demand for higher feed rates of this type of single-axis table feeder.

  By the way, in a table feeding device using a feed screw shaft, when the rotation speed of the feed screw shaft approaches the natural frequency of the feed screw shaft, a so-called dangerous speed occurs and resonance occurs. Since the critical speed is inversely proportional to the square of the support interval of the feed screw shaft, shortening the support interval as much as possible to increase the natural frequency of the screw shaft is effective for increasing the critical speed. Therefore, in the case of a long feed screw shaft, as shown in FIG. 7, an intermediate support 2 that is in sliding contact with the feed screw shaft 1 is generally installed on the base at an intermediate position of the support interval of the screw shaft. Yes. In this case, in order to avoid interference between the nut 4 attached to the table 3 by screwing with the screw shaft 1 and the intermediate support 2, a limit switch 5 is provided so that the intermediate support 2 is retracted when the table 3 passes. ing.

  Japanese Patent No. 2526816 shows another example of the intermediate support. As shown in FIG. 8, two table linear motion bearings (table sliders) 8 are fitted to guide rails 7 fixed in parallel with each other on both sides of the base so as to be axially movable. The table 3 is fixed on the table slider 8. The feed screw shaft 1 is disposed in parallel between the guide rails 7 and 7, one end connected to the drive motor 13 is supported by the support unit 11, and the opposite end is supported by the support bearing 12. The intermediate support 14 is arranged at an intermediate portion between the table nut 4 and the support bearing 12 screwed to the feed screw shaft 1 via a ball, and is connected to the guide rails 7 and 7 respectively. The intermediate support frame 16 supported by the dynamic bearings (intermediate support sliders) 15 and 15 and movable in the axial direction is screwed to the feed screw shaft 1 via a ball, and is moved relative to the intermediate support frame 16 in the axial direction. An intermediate support nut 17 is provided that is rotatably and rotatably supported. On the other hand, between the feed screw shaft 1 and one guide rail 7, an auxiliary feed screw 18 having an axis parallel to the feed screw shaft 1 and supported by the base is screwed to the auxiliary feed screw. An auxiliary feed screw device 20 having an intermediate support feed nut 19 is also provided. An intermediate support feed nut 19 is fixedly attached to the intermediate support frame 16 of the intermediate support 14, and the auxiliary feed screw 18 and the feed screw shaft 1 having the same pitch are composed of a timing belt and a timing pulley. The auxiliary feed screw 18 is connected by the auxiliary feed screw driving means 21 so that the auxiliary feed screw 18 is rotated at half the rotational speed of the feed screw shaft 1. In the case of this intermediate support 14, when the feed screw shaft 1 is rotationally driven by the drive motor 13, the table nut 4 moves, and the intermediate support 14 moves in conjunction with the table nut 4. Therefore, the intermediate support 14 always supports the feed screw shaft 1 at substantially the center between the table nut 4 and the support bearing 12, and the critical speed of the feed screw shaft 1 is increased. .

  Conventionally, in the uniaxial table feed device provided with the auxiliary movable body which is the subject here, the feed is provided between the movable body having a screw nut portion screwed with the feed screw shaft and the bearing supporting the end portion of the feed screw shaft. Since the auxiliary movable body that is not in contact via the screw shaft and the hole is sandwiched, the span between the screw nut portion of the movable body and the support bearing becomes long. As a result, the natural frequency of the feed screw shaft is lowered, that is, the critical speed is lowered, and there is often a problem that the use in high speed feed is limited. As a countermeasure, it is conceivable to provide an intermediate support for the single-axis table feeder.

  However, the conventional intermediate support 2 shown in FIG. 7 has the following drawbacks. That is, when the table 3 or the table nut 4 passes through the intermediate support 2, a retracting mechanism for retracting the intermediate support 2 is necessary, and the structure is complicated. It is unsuitable for use as an intermediate support for the device in terms of cost and space.

On the other hand, in the case of the conventional intermediate support 14 shown in FIG. 8, the auxiliary feed screw device 20 for moving the intermediate support 14 in the axial direction in conjunction with the table nut 4 is necessary, and its structure is complicated. As described above, it is not suitable for use as an intermediate support of a compact single-shaft table feeder in terms of cost and space.
The inventors of the present invention have studied a uniaxial table feeding device that includes a movable body and an auxiliary movable body and easily causes a reduction in dangerous speed, and how to achieve the speed increase. In the past, it has been found that the critical speed can be improved if the auxiliary movable body that is in non-engagement with the feed screw shaft has the role of an intermediate support. Therefore, the problem to be solved by the present invention is to obtain a single-axis table feed device capable of increasing the critical speed of the feed screw shaft and performing high-speed feed with an inexpensive and compact structure.

  A uniaxial table feed device according to the present invention that solves the above-described problems includes a movable body that is supported by a guide rail and is movable in the axial direction by a feed screw shaft, and the guide screw shaft passes through an inner diameter portion and the guide. In a uniaxial table feeding device comprising an auxiliary movable body supported by a rail and movable in the axial direction, the inner diameter portion of the auxiliary movable body is in sliding contact with the feed screw shaft or when the feed screw shaft vibrates. The auxiliary movable body is fixed to a table that can be brought into contact with and driven by the movable body, and the auxiliary movable body receives a load applied to the table together with the movable body.

  Here, in order to make the auxiliary movable body slidably contact with the feed screw shaft, a sliding contact member that is lightly in contact with the feed screw shaft may be interposed in the inner diameter portion of the auxiliary movable body. The sliding member is preferably cylindrical, but the cylinder may be divided in the circumferential direction and tightened with a spring or the like for easy attachment. Further, the cylinder may be divided into a plurality of parts in the axial direction and attached to the inner diameter portion of the auxiliary movable body. Or you may attach to the internal-diameter part of an auxiliary | assistant movable body in spiral shape. In this case, the sliding contact member may be screwed onto the feed screw shaft by matching the spiral winding direction with the spiral of the thread groove of the feed screw shaft. In addition, the sliding contact member with a spiral can be made rotatable on the auxiliary movable body, and in this case, the auxiliary movable body can be fixed at an arbitrary position in the axial direction of the feed screw shaft, so that it is necessary as an intermediate support. It becomes possible to arbitrarily determine the distance and adjust the critical speed appropriately.

  Examples of the material for the sliding contact member include a fluororesin having a good sliding property, a crystalline polymer such as nylon, POM, PBT, PET, PPS, and PEEK, and a polymer alloy (a multi-component system including two or more kinds of polymers). ), Composite plastics containing reinforcing fibers and the like can be suitably used. In addition, a material having lubricity, for example, a lubricant containing resin or a solid lubricant such as molybdenum sulfide can be used. In this case, the critical speed can be improved and the feed screw can be lubricated.

As means for fixing the sliding contact member to the inner diameter portion of the auxiliary movable body, a fixing screw for fastening from the outside of the auxiliary movable body can be used. Moreover, you may utilize the end cap mounted | worn with the both ends of the axial direction of an auxiliary | assistant movable body like embodiment mentioned later.
In the present invention, the inner diameter portion of the auxiliary movable body to which the sliding contact member is attached is not limited to the inner diameter portion of the main body of the auxiliary movable body (for example, the sub-slider main body). For example, it also means an inner diameter portion of end caps at both ends of the sub-slider body. Therefore, this invention also includes making the sliding contact member slidably contact the feed screw shaft by attaching it to the inner diameter portion of the auxiliary member of the auxiliary movable body.
In addition, the present invention provides a configuration in which the feed screw shaft vibrates in the gap between the inner diameter portion of the auxiliary movable body and the outer diameter surface of the feed screw shaft without causing the inner diameter portion of the auxiliary movable body to be in sliding contact with the feed screw shaft. The auxiliary movable body can also serve as an intermediate support by having a size that allows contact with the auxiliary movable body.

  According to the uniaxial table feed device of the present invention, the auxiliary movable body has the function of an intermediate support, so that the critical speed of the feed screw shaft can be improved and the speed can be easily increased.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
Embodiment 1
A first embodiment of the present invention will be described with reference to FIGS.
1 to 4 show the configuration of a first embodiment of a uniaxial table feeding device according to the present invention. FIG. 1 is an overall plan view, FIG. 2 is a side view thereof, and FIG. 3 is an auxiliary movable body. FIG. 4 is a perspective view showing the structure of the movable body with a part cut away. As is apparent from the figure, this single-axis table feeding device has a substantially U-shaped cross section and has ball rolling grooves 31a on both inner surfaces thereof, and is extended in the axial direction. A slider 33 serving as a movable body and a sub-slider 34 serving as an auxiliary movable body, which are movably fitted in a direction, extend along the axis of the guide rail 31, and both ends are rotatable via a rolling bearing (not shown). A ball screw shaft 35 is provided as a supported feed screw shaft. One shaft end 35a of the ball screw shaft 35 protrudes outward from the guide rail 31 and can be connected to an output shaft of a drive motor (not shown).

  The slider 33 and the sub-slider 34 have end caps 33b and 34b removably attached to both ends of the main bodies 33a and 34a. Then, ball rolling grooves 33c and 34c facing the ball rolling groove 31a of the guide rail 31 are provided on both side surfaces of the main bodies 33a and 34a, respectively. A large number of linear motion guiding balls 32 are interposed between the ball rolling grooves 31a of the guide rail 31 and the ball rolling grooves 33c and 34c of the slider and sub-slider opposed thereto. Further, the end caps 33b and 34b on the front and rear end faces of each main body are provided with a circulation path for making these balls 32 U-turn and infinitely circulate. By rolling of these balls 32, the slider 33 and the sub-slider 34 are guided by the guide rail 31 while being shared with a load from a table (not shown) attached to the upper surface of the sub-slider 34 and smoothly in the axial direction. Can be moved to.

  A ball screw shaft 35 is inserted through the axis of the sub-slider 34. Therefore, the sub-slider main body 34a is provided with a cylindrical screw shaft through-hole 37 in a so-called “fool hole” shape. Also, the end caps 34b, 34b at both ends of the sub-slider are provided with a screw shaft through hole 36 having a slightly smaller diameter than the screw shaft through hole 37 in the shape of a “blow hole”. As shown in FIG. 3, a cylindrical sliding contact member 38 is attached to the inner diameter surface of the through-hole 37 of the sub-slider main body 34a by means of, for example, press fitting, and is restrained in the axial direction by end caps 34b at both ends. doing. The sliding contact member 38 has an inner diameter portion 38 a in sliding contact with the outer peripheral surface of the ball screw shaft 35. This is for providing a function as an intermediate support for supporting the middle of the ball screw shaft 35 to the sub-slider 34 provided to improve the load resistance, and supports the ball screw shaft 35. Any size that is sufficient is sufficient. Therefore, it is not always slidably contacted with the entire circumference of the ball screw shaft 35. A part of the cylindrical shape is cut open in the axial direction and is not slidably contacted with a part of the circumferential surface of the screw shaft. A partial sliding contact structure is also possible.

  In the case of the uniaxial table feeding device of the present invention, it is desirable to move the slidable contact member 38 while slidably contacting the ball screw shaft 35 in conjunction with the movement of the table. Therefore, for example, a fluororesin having good slidability is formed as a material. In addition, it is also possible to use a material made of a crystalline polymer such as nylon, POM, PBT, PET, PPS, or PEEK, a polymer alloy, or composite plastics to which reinforcing fibers are added as necessary. . Further, when a sliding contact member 38 using, for example, a lubricant-containing resin obtained by mixing lubricating oil and synthetic resin is used, the lubricant begins to bleed out from the sliding contact member 38 over a long period of time. 35, the critical speed can be improved and the ball screw shaft can be automatically lubricated.

  The structure of the slider 33 may be the same as that of the ball screw nut in the conventional uniaxial table feeder. That is, as shown in FIG. 4, the slider body 33a has a through hole 39 through which the ball screw shaft 35 is inserted, and the inner peripheral surface thereof has a ball screw groove 35a of the ball screw shaft 35. Correspondingly, a spiral ball screw groove 39a is provided. Further, screw shaft through holes 40 are provided in end caps 33b, 33b fixed with bolts at both ends of the slider body 33a. A ball screw system that guides and circulates a ball screw ball 41 that rolls in the ball screw groove 35a of the ball screw shaft 35 and the ball screw groove 39a on the inner diameter surface of the slider main body facing the ball screw shaft 35 on the upper portion of the slider body 33a. As a ball circulation path, a U-shaped ball circulation tube 42 is incorporated. The ball 41 is lifted up from the ball screw groove 35a to the ball circulation tube 42, runs obliquely over the land portion of the ball screw shaft 35 along the tube, returns to the ball screw groove 35a again, and is infinitely circulated. It has a formula circulation structure. In addition, the structure of the ball circulation path of the ball screw system of the slider 33 which is a movable body in the uniaxial table feeder of the present invention is not limited to the above-described tube-type circulation structure, and may be a circulation piece type, an end cap type, or the like. Other known ball circulation path structures may be used.

  In the single-axis table feeder configured as described above, a common table is attached to the upper surfaces of the slider 33 and the sub-slider 34 in advance. In this state, when the ball screw shaft 35 is driven to rotate, the slider 33 acts as a ball screw nut and starts moving in the axial direction in accordance with the rotation of the screw shaft. Since the sub-slider 34 is connected to the slider 33 via the table, the sub-slider 34 moves similarly in accordance with the movement of the slider 33. The sub-slider 34 moves while receiving the load applied to the table in a shared manner with the slider 33. At the same time, the ball screw shaft 35 is slidably contacted and supported via the slidable contact member 38 mounted on the inner diameter surface, thereby serving as an intermediate support. That is, in the conventional uniaxial table feeding device, an intermediate support cannot be installed between the slider 33 and the bearing that supports the end of the ball screw shaft 35, and therefore the support interval of the ball screw shaft 35 is increased. Since it becomes long and the critical speed is kept low, it has been difficult to increase the speed of feeding the slider 33. However, in this embodiment, the sub-slider 34 itself becomes an intermediate support, so that the ball screw shaft The support interval of 35 is shortened and the critical speed is improved. Therefore, the high speed of the single-axis table feeding device can be easily realized.

Embodiment 2
A second embodiment will be described with reference to FIG.
FIG. 5 is a perspective view of the sub-slider 34 showing the second embodiment. The sub-slider 34 is different from the first embodiment in that a fixing screw 45 is used as a fixing means for the sliding member 38. According to this fixing means, it is not necessary to restrict the axial movement of the sliding contact member 38 by the end cap 34b, and the entire length of the sliding contact member 38 does not have to be matched to the length of the sub slider body 34a. Therefore, there is an advantage that a shorter sliding contact member 38 can be used. Other functions and effects are the same as in the first embodiment.

Embodiment 3
A third embodiment will be described with reference to FIG.
FIG. 6 is a perspective view of the sub-slider 34 showing the third embodiment. The sub-slider 34 divides a cylindrical sliding contact member 38 into a plurality of parts in the circumferential direction, and arranges the same so as to surround the outer periphery of the ball screw shaft 35 and tightens it with an elastic body 46 such as a garter spring. The difference from the above-described embodiments is that the slider body 34a is mounted on the inner diameter surface of the through hole 37 for the screw shaft. There is an advantage that the mounting of the cylindrical sliding contact member 38 can be made easier than the case of press-fitting into the screw shaft through hole 37. Further, in the case where the sliding contact member is a lubricant-containing member, the inner surface of the sliding contact member is pressed against the outer surface of the ball screw shaft by the action of the elastic body, so that the lubricant is effectively applied to the ball screw shaft. There is an advantage of being supplied. Other functions and effects are the same as those of the first embodiment.

  In each of the above embodiments, the sliding contact member 38 is mounted on the inner diameter surface of the screw shaft through hole 37 of the sub-slider main body 34a. However, the mounting position of the sliding contact member 38 of the present invention is described here. Not exclusively. If the load resistance of the uniaxial table feeder is not affected, it may be attached to the inner diameter surface of the through hole 36 for either one or both of the end caps 34b attached to the front and rear ends of the sub slider body 34a. .

  In each of the above embodiments, the example in which the inner diameter of the auxiliary movable body is slidably contacted with the outer diameter surface of the feed screw shaft has been shown. However, the intermediate support can be provided without being slidably contacted. . That is, the clearance between the inner diameter portion of the auxiliary movable body and the outer diameter surface of the feed screw shaft is such that the outer diameter surface of the feed screw shaft can contact the inner diameter portion of the auxiliary movable body when the feed screw shaft vibrates. Also by setting the size, resonance of the feed screw shaft can be prevented and the role of an intermediate support can be provided.

1 is an overall plan view of Embodiment 1. FIG. 1 is an overall side view of Embodiment 1. FIG. FIG. 3 is a perspective view showing a structure of the auxiliary movable body according to Embodiment 1 with a part cut away. FIG. 3 is a perspective view showing a structure of the movable body of Embodiment 1 with a part cut away. 6 is a perspective view of an auxiliary movable body according to Embodiment 2. FIG. 10 is a perspective view of an auxiliary movable body according to Embodiment 3. FIG. It is the schematic which shows an example of the conventional intermediate support. It is a top view which shows the other example of the conventional intermediate support.

Explanation of symbols

31 Guide rail 33 Movable body (slider)
34 Auxiliary movable body (sub-slider)
35 Feed screw shaft (ball screw shaft)
36 Screw shaft through hole (for sub-slider end cap)
37 Screw shaft through hole (sub slider body)
38 Sliding member 38a Inner diameter part

Claims (1)

  A movable body supported by the guide rail and movable in the axial direction by the feed screw shaft, and an auxiliary movable body that is movable in the axial direction by the feed screw shaft passing through the inner diameter portion and supported by the guide rail. A table in which an inner diameter portion of the auxiliary movable body can be brought into contact with the feed screw shaft during sliding contact with the feed screw shaft or when the feed screw shaft vibrates, and is fed and driven by the movable body. The auxiliary movable body is fixed, and the auxiliary movable body shares and receives a load applied to the table together with the movable body.

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