JPS6155462A - Driving gear of ball screw - Google Patents

Abstract

PURPOSE:To easily switch a device to automatic and manual operation, by enabling a nut member to be continually moved in a screw shaft direction with a movable structure, in the case of the device which moves the movable structure connected with the nut member in the screw shaft direction by rotating a screw shaft. CONSTITUTION:A device, when it is in automatic operation, supplies air from a pressurizing device 27 to another chamber 22B of a cylinder 22 through a pipe 26. Then a displacement member 24 moves leftward engaging both engaging members 32, 33 of a cubic coupling 22. Here a nut member 7, being integrally connected with a strut, is prevented from rotating. And the nut member 7, being unable to perform the displacement in the direction of a screw shaft 2 by an angular bearing 6, moves in the direction of the screw shaft 2 if it rotates, accordingly moving also the strut 1 in an equal direction. While the device, when it is in manual operation, releases said obth engaging members 32, 33 from engagment, rotatably supporting the nut member 7 to a holder 5 through the angular bearing 6 to be enabled to move integrally with the strut 1.

Description

[Detailed description of the invention] [Industrial application field 1 The present invention relates to a ball screw drive device.

[Background Art and its Problems] Generally, ball screws are widely used in table feed mechanisms of measuring machines and machine tools.

By the way, in a ball screw, the so-called nut member and screw-1111 cannot be separated, so when a table etc. integrated with the nut member is separated from the screw D and manually fed, the nut member and the table etc. cannot be separated. A mechanical or electromagnetic locking device must be provided between them.

However, conventional locking devices, such as those in which a magnetic body is placed on the nut member side and an electromagnet is placed on the table side, and the two are engaged and separated by the magnetic force, have the following problems. There is.

■When the engagement device is released and the table is manually fed, the nut member remains stationary on the screw shaft, so even if you try to integrate the table and nut member again and feed it automatically, the above-mentioned method will not work. In this case, since the magnetic body and the electromagnet are located at separate positions, the engagement device cannot be operated as is.

Therefore, it is necessary to move the table toward the stationary nut member, then make fine adjustments so that the magnetic body and electromagnet correspond, and then activate the locking device, so in order to automatically operate from the previous table position. The problem is that the table must first be returned semi-automatically.

This has the drawback that, especially when used in precision measuring machines such as coordinate measuring machines, it not only significantly reduces work efficiency, but also makes it impossible to perform a series of measurement tasks using a combination of manual and automatic methods. As a result, there was a strong demand for improvement.

(2) Furthermore, in order to maintain the magnetic body and the electromagnet in a predetermined relative positional relationship in the circumferential direction of the screw shaft, the nut member must be supported so as not to rotate relative to the table; Rotation prevention means must be provided separately or in combination with the engagement device.

Since this means must function over the entire length of the threaded member, the structure is complicated, and when used in a three-dimensional measuring machine, etc., the main body structure must be robust to ensure measurement accuracy. , (III).

[Object of the Invention] The object of the present invention is to solve these problems, and is to be small and lightweight, to be able to instantly switch from manual to automatic or from automatic to manual, and to be easy to operate. An object of the present invention is to provide a ball screw drive device that can improve efficiency.

[Means and actions to solve the problem] Therefore,
The present invention provides a drive device for moving a movable body movably guided in the screw axis direction of a ball screw structure and connected to a nut member in the screw axis direction by rotation of the screw shaft. A pair of retaining members are supported on the movable body as being non-displaceable and rotatable in the direction of the screw axis, one of which is fixed to the nut member, and the other is fixed to the movable body, and when both engaging members are engaged, A rotating means having a function of preventing rotation of the nut member around the screw axis is provided, and a displacement member for engaging and disengaging the re-engaging member of the rotation preventing means is provided on the movable body in the direction of the screw axis. The nut member is displaceably but non-rotatably mounted, and is provided with a driving means for moving the displacing member in the direction of the screw axis, so that the nut member can always move in the direction of the screw axis together with the movable body.

[Embodiment 1] The figure shows an embodiment in which the present invention is applied to a three-dimensional measuring machine. In the same figure, the base of a column I as a movable body that supports a probe, etc. is provided on a surface plate (not shown) so as to be movable in one of the three-dimensional directions (for example, the Y-axis direction). , screw shafts 2 having a ball screw structure are supported below the support 1 in parallel with each other along the moving direction of the support 1. A holder 5 is attached to the lower surface of the support 1 via several bolts 3 and pins 4.

A nut member 7 is rotatably supported in the holder 5 through two angular bearings 6 at the center thereof through which the screw shaft 2 passes, and cannot be displaced in the axial direction of the screw shaft 2.
An end plate 8 is attached to one end surface via several bolts, and an outer cylinder 9 is attached to the other end surface via several bolts.

A spacer 12 is inserted into the outer peripheral surface of the nut member 7 between the angular bearing 6 and a flange portion 11 integrally formed on the other end surface, and the angular bearing 6 is inserted into the outer peripheral surface of one end surface. A clamp l-13 held between the spacer 12 and the spacer 12 is screwed together. As a result, the nut member 7 is tightened with the spacer 12.
Since the angular bearing 6 is sandwiched between the screw shaft 2 and the shaft 13, the screw shaft 2 is mounted in such a manner that movement in the axial direction is restricted. Furthermore, the flange portion 11 includes:
The access plate 14 is attached via several bolts.
Ru.

A through hole 20 is formed in the center of the outer cylinder 9 through which the screw shaft 2 passes, and a through hole 20 with an outer diameter smaller than that of the through hole 20 is formed through several holes on the other end surface. A cylindrical inner tube 21 having an inner diameter slightly larger than the screw shaft 2 is attached. Between the outer peripheral surface of the inner cylinder 21 and the through hole 20 of the outer cylinder 9 (here, an annular cylinder 22 is formed, and a displacement member 24 made of a cylindrical member is displaced in the axial direction of the screw shaft 2). The other end of the displacement member 24 is integrally formed with a piston 23 that is slidably housed within the cylinder 22.
3 is integrally formed with an internal gear 42 that meshes with an external gear 41 that is integrally formed at a substantially central position on the outer peripheral surface of the inner cylinder 21 . Thereby, the displacement member 24 can be displaced in the axial direction of the screw shaft 2 while being prevented from rotating. The outer cylinder 9 also has a pipe 2 for supplying air as pressurized fluid to one chamber 22A of the cylinder 22.
5, the inner cylinder 21 has the other chamber 2 of the cylinder 22.
Pipes 26 for supplying air as pressurized fluid to 2B are connected to each other, and these pipings 25.2
6 is connected to a pressurizing device 27 via a switching valve (not shown). Here, the pressurizing device 27, the cylinder 2
2 and the piston 23, the drive device 28 of this embodiment
is configured.

Further, between one end surface of the displacement member 24 and the other end surface of the mounting plate 14, a curvic coupling is provided as a rotation prevention means for selectively preventing rotation of the nut member 7 around the threaded foot 2. 31 are provided. The curvic coupling 31 is composed of one engaging member 32 attached to the other end surface of the mounting plate 14 and the other engaging member 33 attached to one end surface of the displacement member 24. When both the engaging members 32 and 33 engage with each other as the member 24 is displaced, the threaded shaft 2 of the nut member 7
It is designed to prevent rotation.

Next, the operation of this embodiment will be explained. First, in the case of automatic operation, when air from the pressurizing device 27 is supplied to the other chamber 22B of the cylinder 22 through the pipe 26, the displacement member 24 is displaced to the left in the figure, and as a result, the curvic coupling 31 is Both engaging members 32,33 are engaged with each other. In this state, the nut member 7 engages both engaging members 32 and 33 of the curvic coupling 3, and engages the displacement member 24.
The internal gear 42 of the inner cylinder 21 meshes with the external gear 41 of the inner cylinder 21, and is integrally connected to the support l through the outer cylinder 9 and the holder 5.
In other words, since the nut member 7 is prevented from rotating and cannot be displaced in the axial direction of the screw shaft 2 by the angular bearing 6, when the screw shaft 2 rotates, the nut member 7 can move in the axial direction of the screw shaft 2. . Therefore, the support column 1 also moves in the axial direction of the screw shaft 2.

On the other hand, in the case of manual operation, when air from the pressurizing device 27 is supplied to one chamber 22A of the cylinder 22 through the piping 25, the displacement member 24 is displaced to the right in the figure, and as a result, the curvic coupling 31 is The other engaging member 33 is disengaged from the one retaining member 32. Then, the nut member 7
is rotatably supported by the holder 5 via the angular bearing 6. Therefore, even if the support l is moved by hand, the nut member 7 can be freely rotated accordingly, and can eventually be rotated with respect to the screw shaft 2 as well. Therefore, the nut member 7 can move together with the support l.

Therefore, according to this embodiment, regardless of automatic operation or manual operation, as the column 1 moves, the nut member 7 also moves at the same time, so switching from manual operation to automatic operation can be performed without adjusting the positions of both. As a result, work efficiency can be improved.

Further, switching from automatic operation to manual operation or from manual operation to automatic operation requires only switching the air to the cylinder 22, so that the switching operation can be performed instantaneously. This fact, that is, the fact that it is only necessary to switch the air, is suitable for remote control and therefore suitable for automation.

In addition, since the switching is performed by displacing the displacement member 24 in the axial direction of the screw shaft 2, compared to the conventional method, the force in the direction of bending the screw shaft 2, that is, the force in the direction perpendicular to the axis of the screw shaft 2, is applied to the screw shaft 2. Since no additional energy is added, there is an advantage that the entire device can be made smaller and lighter.

In addition, in the embodiment mentioned above, the curvic coupling 31 was used as the rotation prevention means, but mechanical or electromagnetic type other than the above may be used as long as it can selectively prevent the rotation of the nut member 7. good.

Also, one engagement member 3 of the curvic coupling 31
2 on the mounting plate 14 side, and the other engaging member 33 on the displacement member 2.
However, the other engaging member 33 is provided on the support column 1 side including the outer cylinder 9 and the inner cylinder 21 so as to be non-rotatable and movable in the axial direction of the screw shaft 2. Even if the screw shaft 2 is displaced in the axial direction by the displacement member 24, the same effect as described above can be achieved.

Further, as means for making the displacement member 24 non-rotatable but displaceable in the axial direction of the screw shaft 2, in addition to the configuration of the external gear 41 and the internal gear 42 described in the embodiment 1, the key and the key It may also be a groove or the like.

Further, as the driving means, the cylinder 22 described in Example 22. In addition to the device using the piston 23 and the pressurizing device 27, any device that can displace the displacement member 24 may be used, such as an electromagnetic drive device such as a solenoid.

Further, in the embodiment described in "--," the present invention is applied to a three-dimensional measuring machine, but the present invention can also be applied to, for example, moving a table in a machine tool.

[Effects of the Invention] As described above, the present invention provides a ball screw drive device that is small and lightweight, can quickly switch from manual to automatic or automatic to manual, and can be expected to improve work efficiency. can do.

[Brief explanation of drawings]

The figure is a sectional view showing one embodiment of the present invention. l... Support as a movable body, 2... Screw shaft, 7...
- Nut member, 22... Cylinder, 23... Piston, 24... Displacement member, 27... Pressure device, 28...
... Drive means, 31... Curbic coupling as rotation prevention means, 32... One retaining member, 33.
...The other engaging member, 41...External gear, 42...
Internal gear.

Claims (4)

[Claims] (1) In a drive device for moving a movable body movably guided in the direction of a screw shaft of a ball screw structure and connected to a nut member in the direction of the screw shaft by rotation of the screw shaft, the nut member is moved in the direction of the screw shaft. It is supported by the movable body as being non-displaceable and rotatable in the axial direction, and includes a pair of engaging members, one of which is fixed to the nut member and the other to the movable body, and when both engaging members are engaged, the nut is fixed. A rotation prevention means having a function of preventing rotation of the member around the screw axis is provided, and a displacement member for engaging and disengaging both engaging members of the rotation prevention means is displaceable in the direction of the screw axis on the movable body. The nut member is mounted in a non-rotatable manner and is provided with a driving means for moving the displacement member in the direction of the screw axis, so that the nut member can always move in the direction of the screw axis together with the movable body.
A ball screw drive device characterized by: (2) The ball screw drive device according to claim 1, wherein the rotation preventing means is constituted by a curvic coupling. (3) In claim 1 or 2, the displacement member is formed from a cylindrical member having an internal gear that meshes with an external gear provided on the movable body. Ball screw drive device. (4) In any one of claims 1 to 3, the driving means includes a piston provided on the displacement member, a cylinder containing the piston and provided on the movable body, and a cylinder provided on the movable body. and a pressurizing device for supplying pressurized fluid to the ball screw.