JPH0155936B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Application Field) The present invention provides a method in which a movable table is slidably disposed on a track via a ball bearing, and the movable table is driven by a rack and pinion transmission mechanism. Concerning conveyance devices, these are used for micron tables, conveyance robots, etc.

(Prior Art) As a conventional example of this type of conveyance device, for example,
A pair of left and right tracks are arranged and fixed on a fixed bed at a predetermined interval, and a movable table is slidably mounted on the tracks via ball bearings.
This movable table is linearly driven by a rack and pinion transmission mechanism.

Problems to be Solved by the Invention) However, according to the configuration of this conventional example, there may be an axial backlash between the rack and the pinion (a problem that occurs along the longitudinal direction of the rack) depending on the machining accuracy and mounting accuracy. If a gap (between pinions) occurs, the phase of the movable table will be delayed when the table starts or stops, resulting in a decrease in responsiveness and the inconvenience that precision feeding using a micron table or the like cannot be performed. Another problem was that dynamic loads were applied when the table started or stopped, causing uneven wear and damage to unit parts.

Therefore, the present invention has been made to solve the above-mentioned problems, and its purpose is to:
To prevent axial backlash from occurring between a rack on the track side and a pinion on the movable table side, and to ensure responsive and smooth linear movement of the movable table.

(Means for Solving the Problems) In order to achieve the above object, the present invention includes first and second tracks fixed to the fixed bed at a predetermined interval, In a conveying device comprising a movable table that runs on the track via a second ball bearing, a second ball bearing is brought into contact with one side surface of the second track, and the second ball bearing is brought into contact with the second ball bearing. A rack in the longitudinal direction is formed on the side surface opposite to the side surface, a pinion is provided on the rotating shaft of the drive means provided on the movable table to mesh with the rack, and an adjustment member provided behind the second ball bearing is further provided with a pinion that engages with the rack. Therefore, the second ball bearing is pressed toward the second track, and the reaction force is used to bring the pinion into close contact with the rack via the movable table.

(First Embodiment) The present invention will be described below based on illustrated embodiments. In FIGS. 1 to 3 showing the first embodiment of the conveying device according to the present invention, 1 is a fixed bed. On the fixed bed 1, a pair of left and right first tracks 2 and second tracks 3 are fixed with vertical bolts 40, 41 so as to be parallel to each other with a predetermined interval. Here, in order to achieve parallelism between the first track base 2 and the second track base 3, in this embodiment, the first track base 2 and the second track base 3 are
With the wayway 2 in contact with the stopper 1a of the fixed bed 1, it is permanently fixed with the vertical bolts 40 and horizontal bolts 42, and while maintaining parallelism with this fixed first wayway 2 as a reference, A second track 3 is bolted onto the fixed bed 1. Therefore, the first
The wayway 2 has a total of four ball rolling grooves 21 to 24 on both sides thereof, which extend over the entire length of the wayway.
Articles are provided. On the other hand, the second track 3 has a rack 30 extending over the entire length of the track on its inner surface (the side on the same side as the central axis X passing through the center between the first and second tracks 2 and 3). In addition, on its outer surface (the side opposite to the central axis X), there are two upper and lower ball rolling grooves 3 extending over the entire length.
It has a total of 2 articles of 1 and 32. In addition, the first and second
Ball rolling grooves 21 to 24 and 3 of track bases 2 and 3
1 and 32 are constituted by circular arc grooves having a slightly larger curvature than the spherical ball B and contacting the ball B at one point.

Next, 5 is a pair of left and right ball bearings 6, 7.
A movable table is slidably disposed on the first and second track bases 2 and 3 via the movable table 5, and a motor 50 as a driving means is mounted on the movable table 5. A pinion 51 is provided on the spindle 52 of the motor 50 and is adapted to mesh with the rack 30 of the second track 3.

6 and 7 are a pair of first and second ball bearings interposed between the first and second tracks 2 and 3 and the movable table 5 as described above, and are arranged so as to straddle the first track 2. The first ball bearing 6 is directly fixed to the lower surface of the movable table 5 by bolts 43 and 44. The bearing main body 60 constituting the first ball bearing 6 has a substantially U-shaped cross-sectional shape, and has inner circumferential surfaces of both skirts corresponding to the ball rolling grooves 21 to 24 of the first track 2. It is provided with a total of four ball rolling grooves 61 to 64, two upper and lower, extending the entire length in the axial direction, and ball rolling holes 65 to 68, which extend the entire length and have a slightly larger diameter than the ball diameter, in the solid part of both skirts. 2 rows on top and bottom, total 4
I have a contract. As clearly shown in FIGS. 2 and 3, a pair of front and rear side covers 8, 8 consisting of a set of an outer guide member 80 and an inner guide member 81 are attached to the front and rear end surfaces of the bearing body 60. and
Direction changing grooves 82, . . . are formed between the members 80, 81, which connect the ball rolling grooves 61 to 64 and the end portions of the same side of the ball rolling holes 65 to 68, respectively. As a result, four sets of ball circulation paths (1
The set of ball circulation paths is formed, for example, by connecting the ball rolling groove 64 on the lower left side of the bearing body and the ball rolling hole 68 on the lower left side of the bearing body through direction changing grooves 82, 82 on the side cover. . The same goes for the others. ) is configured.

On the other hand, the second ball bearing 7 is fixed to the lower surface of the movable table 5 with bolts 45 via the guide plate 10, and is located on the anti-easy side of the second track 3, that is, on the opposite side to the central axis X. are doing. The bearing body 70 constituting the second ball bearing 7 has a substantially square cross-sectional shape, and the ball rolling groove 31 of the second track 3 is formed on the inner surface (the side surface on the same side as the central axis X). ,3
Corresponding to 2, it is provided with a total of two ball rolling grooves 71 and 72, two upper and lower, extending the entire length in the axial direction, and a ball rolling hole extending the entire length and having a diameter slightly larger than the ball diameter in the solid part. It has 2 rows of 73 and 74 on the top and bottom. A pair of front and rear side covers (not shown) having the same structure as the side covers 8, 8 attached to the first ball bearing 6 are attached to the front and rear end surfaces of the bearing body 70. The inner surface of this side cover is also provided with a direction changing groove (not shown) that interconnects the ball rolling grooves 71, 72 and the ball rolling holes 73, 74 to form two sets of ball circulation paths. There is.

The ball rolling grooves 61 to 64 and 71, 72 of the first and second ball bearings 6, 7 are also circular arc grooves that have a slightly larger curvature than the spherical ball B and contact the ball B at one point. It is structured as follows.

A guide plate 9 is integrally fixed to the lower surface of the movable table 5 by bolts 46, and is provided with a mounting flange 90 behind the second ball bearing 7, that is, on the opposite side of the central axis X. Reference numeral 91 denotes a screw hole drilled through the mounting flange 90.

Reference numeral 10 denotes a clearance adjustment bolt screwed into the screw hole 91 of the guide plate 9, which is located behind the second ball bearing 7, and the end of the bolt abuts against the side surface of the second ball bearing 7. I'm being forced to do it. Therefore, by operating this bolt 10 and pressing the second ball bearing 7 toward the second track 3 located on the inside (center axis X side) with a pressing force P, the movable table integrated with the guide plate 9 can be moved. 5 removes the reaction force N from the second ball bearing 7 and moves to the left in the drawing, and along with this, the pinion 51, which is operatively connected to the motor 50 mounted on the movable table 5, also moves to the left in the drawing and moves from the fixed state to the left in the drawing. Since it is in close contact with the rack 30, the rack 30 and pinion 51
It is possible to eliminate the axial backlash G between
(see figure).

Furthermore, in the conveying device according to the present invention, when operating the clearance adjusting bolt 10 to eliminate axial backlash between the rack 30 and the pinion 51, 1. Preload (preliminary compression) can be applied to the load ball B interposed between the second ball bearings 6 and 7 at the same time. That is, when the clearance adjustment bolt 10 is operated, the second ball bearing 7 is first moved to the second track base 3.
By pressing sideways, a preload is applied to the load ball B interposed therebetween. At the same time, the movable table 5 also removes the reaction force from the second ball bearing 7 side, moves to the left in the drawing, pulls the first ball bearing 6 in the same direction, and moves the first ball bearing 6 into the first orbit. It is possible to simultaneously apply preload to the load ball B disposed on the right side of the first track base 2 by pressing it toward the base 2 side.

In this way, by simply operating the clearance adjustment bolt 10, the backlash between the rack 30 and the pinion 51 can be eliminated, and at the same time, the movable table 5
It is also possible to apply a preload to the load balls B located on both outer sides of the ball.

In addition, 100 in the drawing is a retainer attached to the first and second ball bearings 6 and 7, and is attached to the first track base 2.
and the load balls B interposed between the corresponding ball rolling grooves 21 to 24 and 61 to 64 of the first ball bearing 6, and the corresponding ball rolling grooves 31 of the second track 3 and the second ball bearing 7. ,32
The load balls B interposed between and 71 and 72 are designed not to fall off even if each track base is removed.

In addition, the load balls B are arranged in the corresponding ball rolling grooves 21 to 24 and 61 to 64 of the first way 2 and the first ball bearing 6, as well as the ball rolling grooves 21 to 24 and 61 to 64 of the second way 3 and the second ball bearing 7. Running groove 31, 3
2, 71, and 72 at a contact angle of approximately 45 degrees (the angle formed by the line connecting the contact points of the ball and the horizontal axis) at two points. As a result, when a load is applied, the contact area due to elastic deformation between the surface of the loaded ball and the rolling surface of the ball rolling groove increases, so each part on the contact surface bears less load. Therefore, the load capacity will increase.

In the above configuration, when the transfer device according to the present invention is used for a micron table, a transfer robot, etc., the movable table 5 is connected to a pair of tracks provided on the fixed bed 1 via first and second ball bearings 6 and 7. In this case, the movable table 5 transfers the rotational force from the motor 50 mounted on it more easily than the pinion 51.
0 side, and moves by taking the reaction force from the rack 30 side. Therefore, if there is a backlash G in the axial direction between the rack 30 and the pinion 51, the movable table 5 will be delayed in phase by the amount of the backlash when the table starts or stops, and the responsiveness will decrease by that amount. .

Therefore, by operating the gap adjustment bolt 10 to move the pinion 51 in the direction of the rack 30 and bring the pinion 51 into close contact with the rack 30, the axial backlash between the rack and the pinion can be reduced to zero. At the same time, a preload can be applied to the load balls B located on both outer sides of the movable table 5.

(Second Embodiment) FIG. 5 shows a second embodiment of the conveying device according to the present invention. In the second embodiment, a leaf spring 11 is used as the gap adjustment member, and this point differs from the first embodiment in which a bolt 10 is used. That is, to describe the differences between the two, the back side of the second track 3, that is, the side opposite to the rack, and the mounting flange 9 of the guide plate 9.
An axial space S is provided between the
Two disc-shaped leaf springs 11, 11 are housed in this space S facing each other. Note that 92 is a cover for storing the leaf spring. The leaf springs 11, 11 remove the reaction force from the second ball bearing 7, urge the movable table 5 to the left in the drawing, and bring the pinion 51 into close contact with the fixed rack 30, thereby creating a space between the rack and the pinion. The axial vibration is made zero.

In this way, in the conveying device of the second embodiment, the elastic force of the leaf spring 11 is used to constantly absorb the axial backlash between the rack and the pinion, so that In this way, not only is there no need to worry about having to adjust the gap by operating bolts each time, but also the rack 30 and pinion 51 can be brought into contact with each other with appropriate surface pressure. In the illustrated embodiment, the leaf springs are composed of two leaf springs, but if necessary, a plurality of leaf springs may be arranged in the axial direction, or a single leaf spring may be used.

Also in this second embodiment, a preload is applied to the load balls B located on both outer sides of the movable table 5 at the same time as the buckling is eliminated. Descriptions of other configurations and functions will be omitted.

(Effects of the Invention) Since the conveyance device according to the present invention has the above-described configuration and operation, the axial backlash between the rack and pinion can be reduced to zero, so that the relative relationship between the track base and the movable table can be reduced to zero. There is no play in the axial direction, and therefore responsiveness is excellent when the movable table moving in the axial direction starts or stops. Furthermore, even when the movable table changes direction, there is no play in the axial direction, so followability is good.
Furthermore, since the responsiveness and followability are improved, dynamic loads are not applied when the table starts or stops, and there is no risk of uneven wear or damage to the unit parts, etc. This has various effects.

[Brief explanation of drawings]

Fig. 1 is a longitudinal sectional front view showing a conveying device according to the present invention, Fig. 2 is a plan view taken along the line shown in Fig. 1, Fig. 3 is a cross sectional view taken along the line taken in Fig. 1, and Fig. 4 shows the rack and pinion. FIG. 5 is a longitudinal sectional front view showing another embodiment of the conveying device according to the present invention. Explanation of symbols: 1...Fixed bed, 2...First track, 3...Second track, 30...Rack, 5...
...Movable table, 50...Motor (driving means),
51... Pinion, 6... First ball bearing, 7... Second ball bearing, 10... Bolt (gap adjustment member), 11... Leaf spring (gap adjustment member).

Claims (1)

[Claims] 1. Consists of first and second tracks fixed to a fixed bed at a predetermined interval, and a movable table that travels on the tracks via first and second ball bearings. In the conveyance device, a second ball bearing is brought into contact with one side of the second track, a longitudinal rack is formed on the side opposite to the side with which the second ball bearing comes into contact, and a movable table is provided. A pinion that meshes with the rack is provided on the rotating shaft of the driving means provided in A conveying device characterized in that the pinion is brought into close contact with the rack via a movable table by force.