JPH0314909A - Linearly sliding bearing - Google Patents

Abstract

PURPOSE:To strengthen rigidity in three directional dimensions by forming a pressure chamber conjointly with one surface of a sliding base, providing a braking plate which presses the surface of an orbit base by fluid pressure working upon the above chamber and enabling application of a load in the direction reverse to the press direction of the braking plate. CONSTITUTION:In a braking plate 5 provided in the clearance between the lower surface of the horizontal part of a sliding base 1 and the upper surface of an orbit base 2, an oil pocket 51 is provided to move the braking plate 5 vertically according to the oil pressure from the oil hole 15 of the sliding base 1 and press the surface of the orbit base 2 through a press surface 51. In the event that oil pressure does not work on the braking plate 5, a belleville spring provided on a bolt which holds the braking plate 5 against the sliding base 1 prevents the press surface 52 from touching the upper surface of the orbit base 1. It is thus possible to adjust the sliding resistance of the sliding base 1 and strengthen rigidity in respective three dimensions, so as to make a bearing compact.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applicable to linear motion for linearly guiding a movable body to be activated in a sliding part of a machine tool such as an NC machine or an industrial robot. It concerns bearings.

[Prior art] For example, when machining a workpiece using a machine tool, either the machine tool side or the zero-load workpiece side is fixed and the other is moved. A linear drive bearing is usually used as the mechanism.

The linear motion bearing used for this purpose includes a wayway having a raceway surface on which rolling elements roll along the axial direction, a load raceway surface facing opposite to the raceway surface, and this load raceway surface. A stationary platform equipped with an endless track consisting of a no-load rolling path that communicates and connects both ends of the platform, and a stationary platform that circulates within the endless track between the loaded rolling surface of the active platform and the rolling surface of the way platform. Generally, it consists of a large number of rolling elements that carry a load. and,
In this type of straight line 1 learning bearing, it is possible to apply loads in four directions perpendicular to the axial direction of the way, and by applying preload to the rolling elements, the track of the slide in the four directions can be applied. By increasing the rigidity of the table, it is possible to suppress as much as possible the chatter and vibration that occur between the tool on the machine tool side and the workpiece during carometry, thereby improving the hroe accuracy.

On the other hand, in the axial direction of the way, it is necessary to improve machining accuracy because it is not possible to apply a load for the original purpose of the linear friction bearing, which is to reduce the dynamic resistance and smoothly guide the movable body in a straight line. Regarding the rigidity in the axial direction of the track, it is necessary to rely on the rigidity of the feed drive system that performs linear guide feeding, and in order to obtain high rigidity, it is necessary to increase the size of the device due to the increase in the size of the feed drive system. This has the problem of increased costs and the like.

Therefore, as a solution to these problems, a linear drive bearing disclosed in Japanese Patent Application Laid-Open No. 169241/1983 has been proposed. Specifically, as shown in FIG. 16, a recess is formed in the surface of the group platform a that faces the track b, and within this recess there is a pressing force against the opposing surface of the track b. A pressure vessel C is provided, and this pressure vessel C
By applying an arbitrary pressure to the pressure vessel C, the friction plate d attached to the pressure vessel C presses the track base b, thereby increasing the sliding resistance of the slide base a against the track base b. It is. According to this linear sliding bearing, the driven resistance of the slide table a can be freely adjusted by adjusting the pressure applied to the pressure vessel C, so that the bearing itself can adjust the rigidity arbitrarily in the axial direction of the way table b. This makes it possible to reduce the burden on the feed drive system, which was a problem with the prior art.

[Problems to be Solved by the Invention] By the way, the sliding base of a linear sliding bearing used in the sliding part of a machine tool, etc. has high rigidity because it is subjected to the heavy load of the machine itself and the impact load caused by machining. However, in the above-mentioned proposed linear l-to-movement platform 7 link, an airtight pressure vessel C is housed in a sliding platform a, and a friction plate d in contact with a track platform b is placed inside the pressure vessel. Because it is provided separately from the carcass C, a relatively large recess must be formed in the sliding table a, and as a result, the wall thickness of the carcass table a becomes thinner and the rigidity of the carcass table a itself decreases. This is a factor that hinders the original purpose of increasing rigidity in all three-dimensional directions. Also, if you try to maintain the rigidity of }H moving platform a, the wall thickness of moving platform a will become thicker than necessary, and if the pressure vessel C is installed above track platform b, the bearing cross-sectional height will be high. This leads to an increase in the moment load acting on the moving base 13 (a), and when the bearing is installed on the side of the track base (b), this leads to an increase in the space for installing the bearing.

The present invention has been made in view of the above problems, and
The purpose is to have rigidity in four directions orthogonal to the wayway (of course, it is possible to arbitrarily add and adjust rigidity in the axial direction of the wayway, and to Our objective is to provide a compact linear translation bearing.

[Means for Solving the Problems] In order to achieve the above object, the linear drive bearing of the present invention has a rolling surface on which rolling elements such as balls or rollers roll along the axial direction. The above-mentioned track is equipped with an endless track consisting of a way fixed to a mechanical device, etc., a loaded raceway facing opposite to the raceway, and a no-load rolling path that communicates and connects both ends of the load raceway. A movable platform that moves along the platform,
In the linear work bearing, which is composed of a large number of rolling elements that circulate within the endless track and apply loads between the load rolling and running surfaces of the group platform and the rolling surfaces of the way platform, The moving platform is equipped with a braking plate that forms a pressure chamber together with one surface of the sliding platform and presses the surface of the track platform in accordance with the fluid pressure acting on this pressure chamber, and also has a braking plate that presses the surface of the track platform in a direction opposite to the pressing direction of the braking plate. It is characterized by being able to carry a load acting on it.

In such a technical means, the sliding platform has an endless track on which rolling elements circulate, and can freely move on the track, and the brake plate presses the track in the direction in which it presses the track. As long as the load can be applied in the opposite direction, the structure may be selected as appropriate.For example, the structure may include a horizontal part and a pair of sleeve parts hanging downward from both sides of the horizontal part. A recessed portion is provided on the lower surface side, and each of the sleeve portions has a load rolling surface along the longitudinal direction of the inner surface and is disposed so as to straddle the track, or a sleeve that hangs down from the horizontal portion and one end thereof. It has a substantially tilted cross section, and has a load rolling surface along the longitudinal direction on the horizontal lower surface side and the sleeve inner surface side, and is arranged so as to hang down from the upper surface of the way. Various structures are conceivable, such as one that is formed into a substantially rectangular strip and has a load rolling surface along the longitudinal direction of the side surface and is disposed on the side surface of the track.

In addition, as for the above-mentioned endless track, the number of threads, the inclination angle of the loaded rolling surface, etc. may be changed as appropriate depending on the intended use of the bearing and the structure of the sliding table. As for the method, any method may be selected as appropriate, such as drilling a no-load rolling hole in the moving table, or attaching a rolling element retainer to the cleaning table from the outside.

Furthermore, the rolling elements that circulate within the endless track may be appropriately selected from cylindrical rollers, barrel-shaped rollers, balls, etc. When using cylindrical rollers, the load rolling surface of the sliding base and the track base are The rolling surface shall be a flat surface, and when barrel-shaped rollers and balls are used, the load rolling surface and rolling surface shall be curved surfaces with a radius slightly larger than the axial curvature of the rollers and balls. is preferred.

Furthermore, as long as the above-mentioned brake plate has a pressing surface that presses the surface of the track base and can form a pressure chamber in conjunction with one surface of the counterfeit base, the design of its configuration and shape may be changed as appropriate. Without any problem, form a recess in the brake plate and connect this recess with }H.
A pressure chamber may be formed by sealing the gap with one surface of the moving table, or conversely, a recess may be formed on the side of the moving table. In addition, from the viewpoint of simplifying the device configuration by omitting the retainer for the loaded rolling elements rolling on the loaded rolling element, the brake plate is suitable for the rolling elements rolling on the loaded rolling element of the slide table. is located in a concave groove formed with one side of the brake plate as a side surface, and the opening width of this concave groove is equal to the length of the rolling element in the rotational axis direction (the diameter for balls, the diameter for rollers). It is preferable that the roller be attached to the sliding table so as to be smaller than the axial length (length in the axial direction) and also have the function of a retainer for the loaded rolling element. Furthermore, the brake plate can press anywhere on the surface of the way, but if a large radial load is applied to the bearing, the brake plate may be pressed against any part of the surface of the way. It is preferable to apply a load in the reverse radial direction to the sliding table by pressing the top surface of the table, and when the brake plate presses the side of the way, the sliding table is displaced laterally with respect to the way. In order to prevent this from happening, it is preferable to press both the left and right sides of the track at the same time.

In addition, in the form in which the above-mentioned brake plate presses the track, the brake plate and the first sliding base are engaged so that they can freely come into contact with and separate from each other, and one side of the brake plate facing the track base is The brake plate may be in full contact with the track base to apply a pressing force, or both ends of the brake plate may be fixed to the sliding base and fluid pressure may be applied to the center to deflect the brake plate in the longitudinal direction. Alternatively, only the central region may be brought into contact with the track base to apply a pressing force.

[Function] The brake plate provided on the underground platform presses the surface of the track platform in response to the fluid pressure acting on the pressure chamber. The sliding base can apply a load in the direction opposite to the direction in which the brake plate presses the wayway, so the brake plate comes into pressure contact with the surface of the wayway, creating a frictional force between the brake plate and the wayway, which causes the brake plate to press against the wayway. Increased resistance when the platform moves on the track platform.

In this case, the pressure chamber is formed with one side of the sliding table as its pressure bulkhead, so a pressing mechanism for pressing the way can be constructed by simply arranging a brake plate in the gap between the sliding table and the way. There is no need to provide a special space for arranging the suppression mechanism.

[Example] Hereinafter, the linear sliding bearing of the present invention will be described in detail based on the accompanying drawings.

◎First Embodiment As shown in Figs. 4 and 5, the linear drive bearing in this embodiment has a horizontal portion 1a and left and right sleeve portions 1b hanging from both ends, and has a substantially inverted C-shape in cross section. A sliding table 1 having a recessed portion on the lower surface thereof, a pair of ball retainers 6 attached to the lower ends of the left and right sleeve portions 1b of the sliding table 1, and fixed to a mechanical device or the like using a fixing bolt as a fixing means. a track base 2, a large number of balls 4 that circulate within the ball track formed on the slide base 1 and apply a load between the abuse base 1 and the track base 2, and the horizontal portion 1a. It consists of a brake plate 5 located in the gap between the lower surface and the body of the track base 2, which moves up and down as appropriate according to the pressure of the fluid introduced from the sliding base 1 side to press the surface of the track base 2. ing.

As shown in FIG. 5 and FIG. 6, the above-mentioned 1 locomotion table 1 has an upper ball endless track and a lower ball track along the axial direction on the lower surface side of the horizontal portion 1a and on the inner side of the left and right sleeve portions 1b, respectively. Load rolling surfaces 11 and 12 of the endless track are formed into curved surfaces with a radius of curvature larger than the radius of the balls 4. In addition, an upper ball endless track and a lower ball endless track 4' are provided on the left and right sleeves 1b.
A non-load rolling hole 13 corresponding to 7 tons of loaded rolling surfaces 11 and 12 is formed. In addition, the four load rolling surfaces 11 mentioned above
, 12 are inclined at a predetermined angle so as to face the upper raceway surface 21 and the lower raceway surface 22 of the track base 2 when the bearing is assembled. In addition, a mounting portion 1C is provided protruding from both widthwise ends of the exercise table 1, and a mounting hole 14 through which a mounting bolt passes from the lower surface to the upper surface of the mounting portion 1C.
is formed. }f The lower surface of the horizontal portion 1a of the moving table 1 serves as an attachment part for the brake plate 5 to the sliding table 1, and in the center thereof there is an oil hole 15 through which oil that applies pressure to the brake plate 5 enters and exits. A mounting hole 16 is formed which extends vertically from the upper surface to the lower surface, and into which a screw 9 passing through the brake plate 5 is engaged.

At each end in the longitudinal direction of the moving table 1, there is a lid 3 made of resin.
is fixed with a fixing bolt 31.

The lid body 3 also has a grooved ball turning portion (not shown) that communicates and connects the loaded rolling surfaces 11 and 12 formed on the 1f@stand 1 and the corresponding no-load rolling hole 13. } is formed.

The ball retainer 6 is formed into an oval shape in cross section by pressing a metal plate or extruding a hard synthetic resin, and the tip of the ball retainer 6 has an oval shape in cross section. A locking pawl 61 is provided to prevent the ball 4 rolling on the surface 12 from falling off.

The ball holder 6 is screwed to the lower ends of the left and right sleeves 1b of the pigeon-holding stand 1 by screws 62, and has a load rolling surface 12 and a no-load rolling hole 13 formed at the lower ends of the left and right sleeves 1b, respectively. Together with the ball rotating portion formed on the lid body 3, a ball endless track is formed to guide each ball 4.

On the other hand, the track base 2 has a cross-sectional shape in which both sides of a rectangle are cut out in a trapezoidal shape, and both left and right shoulders are cut out, and the downwardly inclined surface of these trapezoidal cut arrows is the inner surface of the 1f moving base sleeve part 1b. The upper inclined surface of both shoulder notches corresponds to the upper ball endless track provided on the lower surface side of the horizontal part 1a of the slide table. It is located on the running surface 21. Further, fixing bolt mounting holes 23 through which fixing bolts screwed to the fixing portion pass through the center of the way 2 are drilled perpendicularly to the top surface of the way 2 and at appropriate intervals in the longitudinal direction of the way 2. It is set up.

As shown in FIGS. 5 and 6, the braking plate 5 is a substantially rectangular flat plate located in the gap between the lower surface of the horizontal section 1a of the 1st swing platform and the upper surface of the track platform 2 during assembly. It is made of a softer metal material and has the function of pressing the surface of the wayway 2 as necessary and the function of preventing and holding the balls 4 rolling on the left and right upper raceway surfaces 21 of the wayway 2 from falling off. ing. As shown in FIGS. 7, 8, and 9, the upper surface of the brake plate 5 has a concave oil pocket that fills the oil hole 14 formed in the center of the horizontal portion 1a of the slide table. 51 is formed, and the lower surface of the brake plate 5 serves as a pressing surface 52 that contacts the upper surface of the track base 2 as appropriate.

Further, in the center in the width direction, a through hole 54 is perpendicularly bored from the lower surface to the upper surface, through which a screw 9 screwed to the lower surface of the moving table horizontal portion 1a passes.

As shown in FIG. 10, the brake plate 5 formed in this manner is constructed by fitting an O-ring 7 to the inner peripheral edge of the oil pocket 51 to prevent oil leakage, and then inserting a disc spring washer 8 therein. The screw 9 is passed through the through hole 54 from the lower surface side thereof, and the screw 9 is engaged with the mounting hole 15 provided on the lower surface of the horizontal portion 1a of the slide table 1 to be attached to the exercise table 1. At this time, the screw 9 is configured such that the disc spring washer 8 interposed between the top of the screw 9 and the bottom of the brake plate 1 can be elastically deformed freely by the pressure of the fluid acting on the brake plate 5. , when the O-ring 7 is tightened to such an extent that it is always in close contact with the lower surface of the horizontal part 1a of the slide table, and when no pressure is applied to the brake plate 5, the elastic force of the disc spring washer 8 causes the brake plate 5 to keep the slide table horizontal. It should be in a state where it is pushed up towards the lower surface side of the portion 1a. By attaching the brake plate 5 to the moving table 1, the load rolling surface 11 of the upper ball endless track is formed into a recess whose opening width is smaller than the diameter of the balls 4 rolling on the load rolling surface 11. The ball 4 is located within the groove, and when the activity table 1 is removed from the track base 2, the ball 4 is locked in the opening of the groove and prevented from falling off.

In the linear slaughter bearing of this embodiment constructed as described above, the track base 2 is fixed to a mechanical device etc. with fixing bolts, and various machines are mounted on the movable base 1 that moves along the track base 2. Attach the table on which the equipment is placed using mounting bolts, and
A hydraulic device (not shown) that is driven based on a command signal output from a control device (not shown) is connected to the oil hole 15 of the track platform 1 at a required location on the track platform 2. Brake plate 5
It is used by applying arbitrary hydraulic pressure to the oil pocket 51 of.

At this time, if hydraulic pressure is not acting on the oil pocket 51, the braking plate 5 is pushed up toward the lower surface of the horizontal part 1a of the slide table 5 by the elastic force of the spring washer 8, and the lower surface of the braking plate 5 is pushed up by the elastic force of the spring washer 8. Since the pressing surface 52 does not come into contact with the physical body of the track base 2, the driven resistance of the slide base 1 that moves on the track base 2 is only the rolling resistance of the load balls 4, and the national motion base 1 has only a slight driven resistance. It becomes possible to move around on the track platform 2 (see Figure 11).

Further, when the oil pressure P is acting on the oil pocket 51, the brake plate 5 is pushed down by the oil pressure, and the suppression surface 5
2 is in pressure contact with the top surface of the way base 2, a frictional force is generated between the suppressing surface 52 and the top surface of the way base 2, and this frictional force is applied to the sliding resistance pile 1, causing the sliding base 1 to press against the top surface of the way base 2. A large causal resistance will come into play when causing (see Figure 12).

In this way, in the linear drive bearing of this embodiment, a pressure chamber is formed by sealing with the O-ring 7 between the inner peripheral edge of the oil pocket 51 of the brake plate 5 and the lower surface of the horizontal section 1a of the dark motion table. At the same time, the brake plate 5 forming the partition wall of the pressure chamber moves up and down and comes into direct contact with the track base 2.

Therefore, by simply forming a slightly wider gap between the lower surface of the horizontal portion 1a of the slide table 1a and the physical structure of the track table 2, a suppression mechanism that can adjust the pressing force can be provided on the exercise table 1. It is possible to increase the rigidity of the linear drive bearing in the two axial directions of the track base while maintaining the rigidity of the slide base 1 itself.

Although balls were used as the rolling elements in the linear group bearing in this embodiment, the same effect can be obtained by using cylindrical rollers as the rolling elements, as shown in FIG. .

◎Second Embodiment This embodiment shows another embodiment of the manner in which the brake plate 5 is attached to the sliding base 1.

In the first embodiment described above, the braking plate 5 is screwed to the sliding base 1 using screws 9 with spring washers 8 interposed therebetween. Although there are differences due to rigidity, etc., the brake plate 5 is slightly bent when hydraulic pressure is applied, and only the central part of the suppression surface 52 is bent by the track base 2.
It has been found that there is a tendency to press against the top surface of the

Therefore, in this embodiment, the braking plate 5 is designed so that the entire surface of the suppressor 52 comes into contact with the track base 2 when hydraulic pressure is applied.
Both longitudinal ends of the brake plate 5 are attached to the slide table 1 using leaf springs 10 (see FIG. 13).

As shown in FIG. 14, the brake plate 5 used in this embodiment is basically the same as that used in the first embodiment, but has notches on both sides in the longitudinal direction for incorporating the leaf springs 10. Part 5
5 is formed, and a step portion 56 for fixing the side end portion 10a of the leaf spring 10 is further provided.

In this brake plate 5, the side part 10a of the leaf spring 10 is fixed to the step part 56 by laser welding, and the other side end part 10b of the leaf spring 10 is fixed to the step part 56 by laser welding.
By fixing it to the lower surface of the horizontal portion 1a of the moving table 1, it is movably held on the sliding table 1.

In this embodiment, the main parts other than those related to the support of the brake plate 5 described above, such as the sliding table 1 and the track base 2, are the same as in the first embodiment, so the drawings do not include the first embodiment. The same reference numerals will be given and the explanation will be omitted.

The function of the linear group bearing of this embodiment constructed as described above is exactly the same as that of the first embodiment, that is,
Oil pocket 51 of brake plate 5 and horizontal portion 1a of sliding table 1
By applying a desired hydraulic pressure to the pressure chamber formed by the lower body, the brake plate 5 moves up and down to press the upper surface of the track base 2 with a pressure corresponding to the hydraulic pressure.

Although balls were used as the rolling elements in the linear and dynamic bearings in each of the above embodiments, the same effect can be obtained by using cylindrical rollers as the rolling elements, as shown in Figure 15. It is.

[Effects of the Invention] As explained above, according to the linear motion bearing according to the present invention, when the sliding base moves vertically on the track base without providing a special installation space on the motion base, Since the suppression mechanism that adjusts the movement resistance can be mounted on the movement table, it is possible to strengthen the rigidity in all three-dimensional directions, which is required for linear movement bearings, without compromising the rigidity of the movement table. ,
A compact straight line bearing can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a front view showing a first embodiment of the linear motion bearing according to the present invention, FIGS. 2 and 3 are side views and plan views thereof, and FIG. 4 is a linear motion bearing according to the first embodiment. FIG. 5 is a perspective view showing the bearing, FIG. 5 is a sectional view taken along line II in FIG. Plan view, Figure 8 is a cross-sectional view taken from ■-■ of Figure 7, Figure 9 is a cross-sectional view of IV-IV of Figure 7, and Figure 10 is a cross-sectional view of Figure 7.
The figure is a diagonal exploded view showing the assembled state of the brake plate according to the first embodiment, Figure 11 is a sectional view of the main part showing the state where no pressure is applied to the brake plate, and Figure 12 is the brake plate. FIG. 13 is a perspective view showing a second embodiment of the linear & dynamic bearing according to the present invention; FIG. 14 is a cross-sectional view of a main part showing a state in which hydraulic pressure is applied; FIG. 14 is a diagram showing a brake plate according to the second embodiment. Fig. 15 is a front sectional view showing the linear motion bearings according to the first and second embodiments in which rollers are used as rolling elements; Fig. 16 is a perspective view showing the assembled state; Fig. 16 shows the pressure applied to the track base; FIG. 2 is a front sectional view showing a conventional linear motion bearing equipped with a mechanism. [Explanation of symbols] 1: Moving base 2: Way base 3: M body 4: Pole (rolling element) 5: Braking plate
6: Ball retainer 720 ring 8: Disc spring washer 10: Leaf spring 11, 12: Load raceway surface 13: No-load raceway hole (no-load raceway path) 21.22: Raceway surface

Claims (8)

[Claims] (1) A track base fixed to a mechanical device, etc., having a raceway surface on which rolling elements such as balls or rollers roll along the axial direction, and a load raceway surface facing oppositely to the raceway surface. It is equipped with an endless track consisting of a no-load rolling path that communicates and connects both ends of the loaded rolling surface, and a sliding base that moves along the way, and a load on the sliding base that circulates within the endless track. In a linear sliding bearing that is composed of a large number of rolling elements that apply a load between the raceway surface and the raceway surface of the way, the above-mentioned slide table works together with one surface of the slide table to reduce pressure. A straight line comprising a brake plate that forms a chamber and presses the surface of the track base in accordance with the fluid pressure acting on the pressure chamber, and is capable of applying a load that acts in a direction opposite to the pressing direction of the brake plate. Sliding bearing. (2) The linear sliding bearing according to claim 1, wherein the brake plate has a recessed portion for forming a pressure chamber together with one surface of the sliding table. (3) The brake plate is movably attached to the sliding base to form a pressure chamber, and is separated from the sliding base and presses the surface of the track base according to the fluid pressure acting on the pressure chamber. The linear sliding bearing according to claim 1. (4) The linear sliding bearing according to claim 3, wherein both sides of the brake plate are supported by the sliding base via leaf springs. (5) The braking plate is fixed near both ends in the longitudinal direction to the sliding base to form a pressure chamber, and presses the surface of the track base by deflection in the longitudinal direction that occurs in response to the fluid pressure acting on the pressure chamber. The linear sliding bearing according to claim 1, characterized in that: (6) The sliding table has a horizontal portion and a pair of sleeve portions hanging downward from both sides of the horizontal portion, and has a recessed portion on the lower surface side, and the sleeve portions have a recessed portion along the inner surface longitudinal direction. The linear slide according to claim 1 or 4, wherein the linear slide has a pair of upper load area and lower load area, and a brake plate is disposed on the lower surface side of the horizontal portion and presses the opposing upper surface of the track. dynamic bearings. (7) When the load rolling surface constituting the endless track is provided in a groove formed with one side of the brake plate as a side surface, and the rolling element rolling in this groove is a ball, the groove 2. The linear sliding bearing according to claim 1, wherein the opening width of the groove is formed to be smaller than at least the diameter of the ball. (8) When the load rolling surface constituting the endless track is provided in a groove formed with one side of the brake plate as a side surface, and the rolling element rolling in this groove is a roller, the groove The linear sliding bearing according to claim 1, wherein the opening width of the groove is formed to be smaller than at least the axial length of the roller.