JPH01193139A - Positioning device - Google Patents

Abstract

PURPOSE:To make it possible to perform plural positioning operations with a single drive means so as to reduce the weight and the cost of the device in the caption by properly operating each control means relating to a drive shaft which is driven by the single drive means, CONSTITUTION:While a nut member 22 is allowed to rotate around its axis, and a control means 34 for controlling movement in axial direction is operated, another control means 54 for controlling the movement of a rotary body 30 which is connected to the nut member 22 so as to be integrally rotated, is made non operative. And when a ball thread shaft 18 is rotated by a servo motor 14, the nut member 22 is allowed only to rotate around the axis, so that movement corresponding to the rotation quantity of the servo motor 14 is applied to the connected rotary body 30. On the other hand, when the control means 34 is made non-operative, and the control means 54 is operated, the rotational movement of the rotary body 30 is limited, and the rotation of the nut member 22 is restricted, so that the movement of the ball thread shaft 18 in its extending direction, corresponding to the rotation quantity of the servo motor 14, is applied to the nut member 22, consequently, more than two positioning operations can be attained with the single servo motor 14.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention is a positioning device suitable as a positioning device for machine tools, robot arms, etc., and more specifically, a positioning device that performs multiple positioning operations with a single drive means. The present invention relates to a positioning device that can perform

(Prior Art and its Problems) As a positioning device used for machine tools, robot arms, etc., the ones shown in FIGS. 6(a) to 6(C), for example, are known. The device shown in FIG. 3A positions an arm 2 equipped with a positioning pin 1 at predetermined positions in two directions indicated by arrows A and B, and operates a drive motor 4 connected to a ball screw 3. While moving the table 5 along the guide rail 6, another drive motor 7, which is disposed on the table and includes a speed reducer, is actuated to impart a linear motion A and a rotational motion B to the arm 2. to a predetermined position.

However, to bring the arm 2 into position, separate drive motors were required, a number equal to the number of directions in which it could move, ie each corresponding to a linear movement A and a rotational movement.

This also applies to the devices shown in FIGS. 6(b) and (C). In the device shown in FIG. 6(b), tables 5a and 5b connected to ball screws 3 are moved along guide rails 6. In order to move the two parts individually, respective drive motors 4a and 4b were required. In addition, in the device shown in FIG. 5(C), in order to impart movement in the direction shown by the arrow in the figure to the arm 9 provided to cross the column 8 provided upright on the table 5, it is necessary to 8, and drive motors 4a, 4 that drive the arm 9 in respective directions.
b and 4c were required individually.

For this reason, conventional positioning devices require drive motors corresponding to the number of positioning directions, so as the number of positioning directions increases, the number of drive motors also increases, which only increases costs. However, there was a problem in that the weight of the positioning device also increased.

The present invention was made in view of such problems,
To provide a lightweight and inexpensive positioning device capable of performing a plurality of positioning operations with a single driving means.

(Means for solving the problem) In order to achieve this objective, the positioning device according to the present invention has the following features:
A ball screw shaft rotatably supported by a base material, a nut member that engages with the ball screw shaft to form a ball screw, a driving means connected to one end of the ball screw shaft to drive the ball screw shaft, and a nut member. a guide means for guiding the nut member in its axial direction; a braking means capable of permitting rotational movement of the nut member around its axis and restricting movement in the axial direction; and a braking means connected to the nut member and capable of integrally rotating. It comprises at least a rotating body and other braking means capable of restricting rotation of the rotating body about its axis.

(Function) According to the positioning device configured in this way, the nut member is allowed to rotate around its axis, and the braking means capable of restricting the movement in the axial direction is actuated, while the nut member is rotated around its axis. When the other braking means that restricts the movement of the connected and integrally rotatable rotating bodies are deactivated and the ball screw shaft is rotated by the driving means, the nut member is only allowed to rotate around its axis. , nut member,
As a result, the rotating body connected to the nut member is given a motion corresponding to the amount of rotation of the drive means.

On the other hand, when the braking means is deactivated and the other braking means is activated, the rotational movement of the rotating body connected to the nut member about its axis is restricted, and as a result, the rotation of the nut member is restricted. Therefore, the nut member is given a movement in the direction in which the screw shaft extends along the guide means in accordance with the amount of rotation of the drive means. Therefore, by appropriately operating these braking means, positioning operations in two directions can be performed using a single driving means.

Furthermore, by connecting the rotating body to another drive mechanism, that drive mechanism can also be operated, and in that case, two or more positioning operations can be performed with a single drive means.

(Embodiments) Hereinafter, preferred embodiments of the positioning device of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a cross-sectional view of one embodiment of the positioning device of the present invention, in which a cylindrical housing 10 as a base material is shown.
A servo motor 14 as a driving means is fixed to a bottom wall member 12 attached to one end of the servo motor 14 .

The output shaft of this servo motor 14 is made to protrude in the axial direction of the housing 12 within a recess 12a formed in the bottom wall member 12, while a ball screw shaft 18 is rotatably supported by the bottom wall member via a bearing 16. Similarly, one end thereof protrudes into the recess 12a, and its output shaft and ball screw shaft 18 are coaxially connected to each other via a coupling 20.

A ball screw is formed by screwing onto a ball screw shaft 18 extending within the housing 10 a nut member 22 that removably holds a spherical rolling element (not shown) that engages with a ball groove of the ball screw shaft. do. In this embodiment, this nut member includes a nut member main body 24 that holds a rolling element and is directly screwed onto the ball screw shaft 18, and a nut member body 24 that is disposed coaxially with the ball screw shaft 18 and outside of the nut member 24. and a connecting member 26. Here, the connecting member 26 is a hollow body having a housing recess that accommodates the nut member main body 24 and a part of the ball screw shaft 18, and is integrated with the nut member main body 24 via a connecting bracket 28 fixed to the nut member main body 24. installed. Further, the connecting member 26 is provided with a spline 26 & extending parallel to the axis of the connecting member on the outer periphery of a portion spaced apart from the nut member main body.

A rotating body 30 is attached to the connecting member 26 via a spherical rolling element 28 that engages with the splines 26a, and a so-called ball spline is used as a guide means 32 for guiding the connecting member 26 and, ultimately, the nut member 22 in the axial direction. form.

The inner wall of the housing 10 facing the portion of the connecting member 26 that is spaced apart from the spline 26a is provided with a wall that allows rotational movement of the connecting member, and therefore the nut member 22, about the axis of the pole screw shaft and prevents movement in the axial direction. Restrictive braking means 34 are provided. This braking means is shown in Fig. 2(a).
As shown in an enlarged view in FIG.
The brake body 40 is capable of coming into contact with the outer peripheral surface of the brake body 40. The brake body 40 is rotatably supported by one or more pins 42 that are fixed to the protrusions 38a of the holding member 38 that protrude inward from the housing and extend parallel to and apart from the connecting member 26. The arm 44 is made of a magnetic material. As shown in FIG. 2(b), the arms 44 have a curved shape extending substantially parallel to the outer peripheral surface of the connecting member, and a brake pad is provided on the curved inner surface facing the connecting member 26. 46 is secured and a receiving hole 48 is provided near the free end of the arm. And accommodation hole 4
A compression spring 50 as an elastic means is housed in the spring 8 so that the arm 44 supported by the holding member 38 can be rotated around the pin 42, thereby pressing the brake pad 46 against the connecting member 26. do. On the other hand, the compression spring 50
An electromagnet 52 is provided on the holding member 38 so as to face the curved outer surface of the arm 44, and is an example of a releasing means that rotates the arm 44 in opposition to the brake pad 44 to release the brake pad 44 from the connecting member 26. Note that, considering that the holding member 38 rotates, it is preferable to apply a known method such as a slip ring to supply current to the electromagnet, but the present invention is not limited thereto.

Therefore, in this braking means 34, when the supply of current to the electromagnet 52 is stopped, the arm 44 is pressed in the direction of the connecting member 26, as shown in FIG. 26 and acts to limit the rotation of the connecting member. However, the brake body 4
0 is supported by a holding member 38 attached to the inner ring of the bearing 36. Although the holding member 38 can rotate together with the connecting portion 26, it restricts the movement of the connecting member, and thus the nut member 22, in the axial direction. I will do it.

On the other hand, if a current is supplied to the electromagnet 52 to rotate the arm 44 against the compression spring, and the brake pad 44 attached to the arm is disengaged from the outer surface of the connecting member 26, the connecting member and eventually Movement of the nut member 22 along the ball screw axis is allowed. According to this embodiment, the brake pad can be released only when a current is applied to the electromagnet, so that the nut member does not move unnecessarily even in an emergency such as a power outage.

Similarly, the rotating body 30 constituting the guide means 32 is also provided with further braking means 54 for limiting its rotation about its own axis, as shown in FIG. This braking means 54 also has substantially the same structure as the braking means 34, and is shown enlarged in FIG.
As shown in the figure, the rotating body 30 is rotatably connected to another bottom wall member 58 integrally attached to the open end of the housing 10 via a bearing 56, and the outer circumferential surface of the rotating body 30 is A brake body 60 that can come into contact with the bottom wall member 58 is provided on the bottom wall member 58. Note that the structure of the brake body 60 is similar to that of the second brake body 60.
Since this is the same as that shown in FIG. 3(b), the explanation thereof will be omitted. However, it should be noted here that even if the rotation of the connecting member 26 of the rotating body 30 around the axis is prevented by operating the brake body 60, the rotating body 30 and the connecting member 26 will not be connected via the rolling elements 28. Since a ball spline is formed, the movement of the connecting member 26 in the axial direction is not restricted.

As shown in FIG. 1, in this embodiment, as an example of applying the device of the present invention as a workpiece positioning device, the housing l is placed on the side remote from the servo motor 14.
Although the arm 64 having the locating pin 62 on the distal end side is fixed to the end of the connecting member 26 protruding from the O, the device is not limited to such a device and various modifications are possible.

Next, the operation of the apparatus of the present invention will be explained with reference to FIG. Note that in order to simplify the explanation, the arm 64 having the locating pin is omitted from the drawing.

FIG. 4(a) shows the case where the nut member 22 is given movement in the longitudinal axis direction. When the braking means 34 is deactivated, the other braking means 54 is activated, and the ball screw shaft 18 is rotationally driven by the servo motor 14, the rotating body 30
is substantially fixed relative to the housing 10, the nut member 22 functions as a ball spline and moves in the direction indicated by arrow A in response to rotation of the ball screw shaft.

On the other hand, in FIG. 4(b), the arrow B is attached to the nut member 22.
In this case, the braking means 34 may be activated while the other braking means 54 may be deactivated.

By doing so, the movement of the nut member 22 in the axial direction is restricted by the braking means 34, but rotation around the axis is allowed.

Further, since the rotating body 30 can also rotate together with the nut member 22, the rotational movement shown by the arrow B can be imparted to the nut member 22.

FIG. 5 is a partial cross-sectional view of another embodiment of the apparatus of the present invention, showing an apparatus capable of positioning in three axes orthogonal to each other.

For the sake of simplicity, parts having the same functions as those shown in FIG. 1 are designated by the same reference numerals.

A ball screw shaft 18 is rotatably supported via bearings 16 on upright walls 12 and 12 provided upright at the base play position 0 and spaced apart from each other, respectively, and one end thereof is fixed to the upright wall. It is connected to the servo motor 14 via a coupling 20.

A nut member 22 is attached to the ball screw shaft 18 to removably hold a spherical rolling element that engages with the ball groove.
are screwed together to form a ball screw.

The nut member 22 is integrally mounted on the inner ring of the bearing 36, and the holding member 38 is connected through the bearing so as to be relatively rotatable. A braking means 34 is provided on the holding member 38 on the side facing the base plate 10, and the braking means 34 is shown in FIG. 5(b).
As shown in FIG. 3, a pin 42, which is similarly protruded from the holding member 38, is attached to the free end of the output shaft of the fluid pressure cylinder 68, which is fixed to the holding member 38 and expands and contracts by supplying and discharging pressurized fluid. An arm 44 whose one end is rotatably supported and whose other end is connected to the arm 44 facing the base plate IO
A brake pad 46 is fixed to the end of the brake pad. Note that, for the sake of simplicity, a supply/discharge pipe for supplying and discharging pressurized fluid to and from the fluid pressure cylinder 68 is not shown.

On the other hand, on the side spaced apart from the base plate 10, the holding member 38 has a first
The slide plate 70 of is fixed. In addition, the first slide plate 70, as shown in FIG. 5(C),
It is connected to a first guide means 32 provided on the base plate 10 and extending parallel to the axial direction of the ball screw shaft. As the guide means 32, a so-called L, which has a small coefficient of friction and is suitable for high-precision positioning, is used as a rolling guide means, for example.
Preferably, an M guide is used.

By the way, a pulley 72 is integrally fixed to the nut member 22, and this pulley 72 is rotatably supported by an upright wall 74 provided on the first plate 70 via a bearing 76, and is parallel to the ball screw shaft 18. The pulley 80 is connected via a belt 82 to another pulley 80 fixed to one end of a shaft 78 extending in the direction of the shaft 78 . Further, a bevel gear 84 is fixed to the other end of the shaft 78. This bevel gear 84 meshes with another bevel gear 88 fixed to one end of another ball screw shaft 86 that extends substantially perpendicular to the shaft 78 and parallel to the first slide plate 70 . Here, each end of the other ball screw shaft 86 is rotatably supported via a bearing 92 by upstanding walls 74 and 90 provided on the first slide plate 70 at a distance from each other.

Another ball screw shaft 86 is screwed with another nut member 94 that rotatably holds a spherical rolling element supplied to the ball groove, thereby forming another ball screw.

Then, another nut member 94 is integrally fixed to the inner ring of the bearing 96, and another holding member 98 is relatively rotatably connected via this bearing 96, and the holding member 94 is attached on the side facing the first slide plate 70. At 98, another braking means 54 having the same structure as that shown in FIG. 5(b) is provided. Further, the second slide plate 100 is fixed to another holding member 98 on the side separated from the first slide plate 70. This second slide plate 100 is connected to the first guide means 32
A second guide means 102 having a similar structure allows movement in the extending direction of the second ball screw shaft 86. It should be noted here that the movement transmitted to the pulley 72 connected to the nut member 22 is
is transmitted to the pulley 80 through the bevel gears 34 and 88 that mesh with each other, and is further transmitted to the other ball screw shaft 86 and the nut member 94, so that these members rotate as shown in FIG. It is essentially equivalent to the body.

By the way, the braking means 34 is deactivated and the other braking means 5
4, the servo motor 14 drives the ball screw shaft 1.
8 is rotationally driven, the movement of the other holding member 98 in the axial direction of the other ball screw shaft 86 is restricted, and rotation there is simply allowed. However, the holding member 38 is 86, so that the first slide plate connected thereto is moved along the guide means 32 in the direction indicated by arrow X.

In response to this, the braking means 34 is activated, and the other braking means 54
When the holding member 38 is deactivated, the movement of the holding member 38 in the axial direction is restricted by the braking means 34, and only rotational movement is permitted. This rotational movement is transmitted to the other ball screw 86 via the pulleys 72, 78, and the other holding member 9
8 is movable in its axial direction, so that the second slide plate 100 can be moved along the second guide means 102 in the direction indicated by the arrow Y.

Furthermore, in this embodiment, the above-mentioned two directions, that is, X, 7
In addition to being able to perform positioning operations in both directions, as shown in FIG. 5(C), the positioning operation can be performed in the Z direction, that is, in the directions orthogonal to both the X and 7 directions, as described below.

Another pulley 104 is integrally fixed to a nut member 94 screwed onto another ball screw shaft 86 disposed on the first slide plate 70, while an upstanding wall provided on the second slide plate 100 A pulley 112 is fixed to one end of a shaft 110 which is rotatably supported by a shaft 106 via a bearing 108 and extends parallel to the other ball screw shaft 86.
These pulleys 104 and 112 are connected via 4.

In addition, a bevel gear 118 is fixed to the other end of the shaft 110 with the pulley 112 fixed to one end, and the ball screw shafts 18 and 86
substantially orthogonal to the second slide plate 1
Another base plate 120 provided substantially perpendicular to 00
The third ball screw shaft 122 is meshed with a gear 124 fixed to one end of a third ball screw shaft 122 that extends parallel to the third ball screw shaft 122 .

One end of the third ball screw shaft 122 is rotatably supported by the upright wall 106 via a bearing 126.

Further, the third ball screw shaft has a nut member 128 that removably holds a spherical rolling element that engages with the ball groove.
are screwed together to form a ball screw.

Then, this nut member 128 is attached to the nut members 22 and 9.
4, it is integrally fixed to the inner ring of the bearing, and connected to the holding member 130 via this bearing so as to be relatively rotatable. This holding member 130 is provided with a braking means 132 similar to that shown in FIG. 5(b) on the side facing the other base plate 120, and a third slide plate 134 is fixed on the side separated from the other base plate 120. .

The slide play eye 34 is attached to the base plate 120, for example, as shown in FIG. 5(d).
Guide means 136, such as an M-guide, allow movement parallel to the third ball screw axis 122. Note that a locking ring 13 is provided at the free end of the third ball screw shaft 122.
8 is preferably fixed to prevent the nut member 128 from falling off the ball screw shaft.

Next, the operation of this embodiment will be explained. Each braking means 3
4.54 and 132 to restrict the axial movement of the associated nut members 22,94,128, the servo motor 14 will only rotate the associated ball screw shaft. Yes, each slide plate 70. 100.134 is kept at the initial position.

When it is desired to move the first slide plate 70, the braking means 34 is deactivated, and the remaining braking means 54 and 13
2 should be activated. In this case, the movement of the nut members 94 and 128 in the axial direction is restricted, and the nut members 2
Since only movement in the axial direction of the nut member 22 is allowed, the nut member 22 moves in the extending direction of the ball screw shaft 18, and the first slide plate 70 connected thereto is moved along the guide means 32. can be done.

On the other hand, the second slide plate 100 is guided by the guide means 102.
When it is desired to move along the braking means 34 and 132
The rotational motion of the servo motor 14 transmitted to the pulley 72 by activating the brake means 34 is transmitted to the pulley 80 via the belt 82 connected thereto. is transmitted to the second ball screw 86 and thus allows the nut member 94 threaded thereto to be moved along the guide means 102. At this time, since the braking means 132 restricts the movement of the nut member 128 in the axial direction, the third slide plate does not move.

Further, the third slide plate 134 is moved to the guide means 13.
6, the braking means 34 and 54 are actuated and the braking means associated with the third slide plate is deactivated, and the nut members 22 and 54 whose movement in the axial direction is restricted are Associated pulleys 72 and 10
4. Furthermore, the ball screw shaft 128 is connected via the pulley 112.
The rotational movement of the servo motor 140 is transmitted to move the nut member 128 in its axial direction, so that the slide plate 134 connected to the nut member moves along the guide means 136.

Note that the present invention is not limited to these examples (
By adding another transmission mechanism, it is possible to perform positioning operations at four or more positions, and various modifications are possible within the scope of the claims.

(Effects of the Invention) As detailed above, according to the positioning device of the present invention, by appropriately operating each control means related to a drive shaft driven by a single drive means, Since the positioning operation can be performed, there is no need for a number of drive means corresponding to the number of drive shafts, and therefore the structure of the device can be simplified. Therefore, the weight of the device can be reduced compared to conventional devices, and it has many advantages such as being advantageous in terms of cost.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing the positioning device of the present invention, FIG. 2(a) is an enlarged view showing the braking means of the positioning device shown in FIG. 1, and FIGS. 2(b) and (C) is an exploded perspective view of the braking means shown in FIG. 2(a) and an explanatory diagram showing its operation, and FIG. 3 is an exploded perspective view of the braking means shown in FIG.
4(a) and (b) are explanatory diagrams showing the operation of the device shown in FIG. 1. FIGS. 5(a) to (d) ) is a front cross-sectional view showing another embodiment of the device of the present invention, and a perspective view, a side cross-sectional view, and a plan view showing a braking means suitable for the device, and FIGS. 6(a) to (C) are a conventional positioning device. FIG. 10, 120...housing (base plate) 1
2, 58...Bottom wall member 14...Servo motor 18, 86.122...Ball screw shaft 22, 94...
・Nut member 24... Nut member body 26...
Connecting member 26a... Splines 32, 10
2.136...Guide means 34, 59.132...Brake means 38, 98.130...Holding members 40, 60...Brake body 44...Arm 46
... Brake pad 50 ... Compression spring 52 ...
・Electromagnet 62... Locate pin 70,
100. 134...Slide plate 72, 80
．． 104. 112...Bouli Figure 3 Figure 4 Figure 5 (a) Figure 5 (d) Figure 6 (a) 8 (b)

Claims (1)

[Claims] 1. Ball screw shaft (18) rotatably supported on a base material
a nut member (22) that engages with the ball screw shaft to form a ball screw; a drive means (14) connected to one end of the ball screw shaft to drive the ball screw shaft; and a drive means (14) that guides the nut member in the axial direction thereof. a guide means (32); a braking means (34) capable of permitting rotational movement of the nut member around its axis and restricting movement in the axial direction; and a rotary member connected to the nut member and capable of integrally rotating A positioning device characterized in that it comprises at least a body (30) and further braking means (54) capable of limiting the rotation of the rotating body about its axis.