JP2009058116A - Electric cylinder device having speed reducer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that in a conventional motor drive sliding device, a motor arranged in parallel with a rod rotates and its rotation is transmitted to a screw shaft via a gear train, and a nut and the rod slidingly move, so that the conventional motor drive sliding device cannot be used for devices requiring a high accuracy of sliding movement because there are many components and backlash is easily caused owing to the axis of the motor is arranged in parallel with the rod axis, and is not coaxial with each other. <P>SOLUTION: A screw rod is inserted into a hollow shaft motor, and a screw nut A is rotated according to the rotation of the motor via a speed reducer connected to the shaft end portion of the motor. Further, a screw nut B (located in a place different from that of the screw nut A) is rotated via a connecting shaft connected with the speed reducer (requiring a cushioning mechanism). As a result, the screw nuts A and B can be equally rotated, and the screw rod can slide, keeping a high accuracy. Further, the coaxial arrangement of all elements with the screw rod largely contributes to accuracy improvement, machine element simplification, and space simplification. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

The present invention relates to an apparatus for rotating a screw nut and slidingly moving a screw rod through a speed reducer in accordance with the rotational motion of a hollow shaft motor passing through the screw rod.

A conventional motor-driven slide device includes a device in which a nut and a rod slide when a motor arranged in parallel with a rod causes a rotational motion and the rotation is transmitted to a screw shaft by a gear train. (See Patent Document 1)
JP 2005-86932 A

However, in the above device, the motor shaft and rod shaft are parallel at different positions, and the motor, gear, and rod are not on the same straight line. Not a thing. For this reason, it could not be used for a slide that requires high precision. In addition, the moving rod is arranged in a straight line with the solid drive unit, and because of the stacked structure, a large space is dead. Therefore, it is not suitable for efficient ideal slide movement.

The present invention solves the above-described problem. According to the rotational movement of the hollow shaft motor through the screw rod, the screw nut is rotated via the reduction gear attached to the shaft end portion of the motor. It is a device that slides. This will be described below with reference to 0005 to 0008 (see FIG. 1).

The screw rod is passed through the hollow motor, the hollow motor shaft end and the gear reducer are connected on the same line, and the output gear and the screw nut A are connected via the shaft coupling.

The brake and encoder are connected to the housing A which is the fixed side of the motor, and the brake rotating disk is connected to the screw nut A.

A holder having a bearing is installed on the other side of the screw nut A, and is connected to the housing B on the fixed side.

As described above, by rotating the screw nut A through the gear reducer attached to the shaft end of the motor in accordance with the rotational movement of the hollow shaft motor, the screw rod whose rotation is fixed can be slid. I can do it. The gears can be connected in any number of stages, and the same function can be achieved by using a planetary gear speed reducer or other speed reducers in addition to the speed reducer.

As an application of the above device (FIG. 1), a screw nut is attached to the other of the hollow motor via a speed reducer, and power is transmitted from the connecting shaft to the other screw nut via a similar speed reducer. Similarly, by rotating with equal rotation through the buffer portion, the present invention can be made a more accurate device, and the screw nut can be used as a bearing. This will be described below with reference to 0010 to 0013 (see FIG. 2).

The screw rod is passed through the hollow motor, and the hollow motor shaft end and the planetary gear reducer are connected. The screw nut A is connected via the planetary gear reducer and the carrier.

Further, in order to transmit the same rotation speed to the screw nut B located on the other side of the screw nut A, the carrier and the connecting shaft are engaged with each other by a spline, and the connecting shaft and the screw nut B are connected. The screw nut B is connected via the buffer part of the speed reducer and the spline. Since the carrier and the connecting shaft are engaged and connected, they serve as buffer portions in the axial direction and circumferential direction of the screw rod. (See Figure 3)

As described above, the screw nut A rotates through the planetary gear reducer attached to the shaft end of the motor in accordance with the rotational motion of the hollow shaft motor. Further, by rotating the screw nut B via the carrier connected to the speed reducer and the connecting shaft (connected by the buffering portion), the screw nut A and the screw nut B are rotated equally by receiving power from the speed reducer. The screw rod with fixed rotation can be slid and moved. At this time, the screw nut A serves as a power transmission and bearing, and the screw nut B serves as a bearing (with a screw joint). Moreover, the present invention can perform the same function in spur gear reducers and other reducers other than the above reducer.

In the apparatus shown in FIG. 2, a spline is used as a method of connecting the carrier and the connecting shaft, but it is also possible to connect with a key. In this case, a buffer (gear meshing) mechanism is provided between the connecting shaft and the screw nut B. Is installed, and the internal teeth to be connected to the connecting shaft and the external teeth to be connected to the screw nut B are installed and connected, so that the same function as that of the device of the present invention can be achieved. (For the buffer mechanism, refer to Japanese Patent Application No. 2007-173705.) It is also possible to provide a gap in the key part and use the sliding key itself as the buffer mechanism.

By combining a motor and a speed reducer as in the present invention, it can be adapted to the output, speed, and purpose of use, and greater efficiency can be produced more economically. Furthermore, since all elements are installed on the same line of the threaded rod, it greatly contributes to improving accuracy, simplifying machine elements, and simplifying space.

By transmitting the power from the reducer to the screw nuts installed on both sides according to the rotation of the hollow motor, the screw nuts A and B rotate equally, and the buffer part that absorbs the error keeps smooth rotation. By continuing, it is possible to slide the screw rod while maintaining higher accuracy.

Since the carrier and connecting shaft are engaged with each other by a spline and the power is transmitted to the screw nut B, when the thread groove of the screw rod and the interval between the leads change due to the temperature displacement of each part, etc. As shown in the figure, the gap existing in the meshing of the splines absorbs the deviation and error, so that the device can maintain a stable slide movement without being affected by the displacement of the element portion.

Hereinafter, embodiments of the present invention will be described with reference to FIGS.

FIG. 1 shows a cylinder device requiring a gear reducer. 2 is passed through 1, the shaft end of 1 and 6 are connected on a straight line, and 6 and 3 are connected via 8. 4 and 5 are connected to 9 which is a fixed side of the motor, and 4 rotating disks are connected to 3. 11 with 10 attached to the other is installed and connected to 12 which is the fixed side.

As described above, according to the rotational movement of 1, by rotating 3 through 6 attached to the end of the shaft 1, it is possible to slide the 2 whose rotation is fixed. The gears can be connected in any number of stages, and the same function can be achieved by using a planetary gear speed reducer or other speed reducers in addition to the speed reducer.

FIG. 2 shows a cylinder device requiring a planetary gear reducer. 2 is passed through 1 and the shaft end 1 and 13 are connected. 3 is connected through 13 and 15. Further, in order to transmit the same rotation to 20 located at the other side of 3, 15 and 16 are engaged by splines and connected, and 16 and 20 are connected, so that 3 and 20 are connected. Since 15 and 16 are meshed and connected, they serve as two axial and circumferential buffer portions.

As described above, 3 rotates through 13 attached to the end of one shaft according to one rotational motion. Further, by rotating 20 through 16 connected to 15, 3 and 20 can transmit power from 15 and rotate equally, and the fixedly-rotated 2 can be slid. At this time, 3 serves as a power transmission and bearing, and 20 serves as a bearing (with a screw joint). Further, the present invention can achieve the same function by using a spur gear reducer or other reducer in addition to the above reducer.

FIG. 3 is a detailed view of the meshing locations 15 and 16. As shown in the figure, by maintaining a space (gap, assembly) that can absorb deviations and errors during rotational movement, smooth transmission is possible, and damage due to overload is also prevented.

2 and 3 uses a spline as a connection method of 15 and 16, but can also be connected by a key. In this case, a buffer (gear engagement) is provided between 15 and 20. By installing the mechanism and meshing and installing the internal teeth connected to 15 and the external teeth connected to 20, the same function as the device of the present invention can be achieved.

Overall view of unit (using gear reducer) Overall view of unit (using planetary gear reducer) Fig. 2-A Detailed view of part A

Explanation of symbols

・ Hollow motor ・ Screw rod Screw nut A
4). 4. Brake Encoder 6. Gear reducer 8. Bracket 9. Housing A
10. Bearing 11. Holder 12. Housing B
13. Planetary gear reducer 15. Carrier 16. Connecting shaft 20. Screw nut B

Claims (5)

A mechanism that attaches a reducer to a device in which a screw nut rotates and a screw rod slides in accordance with the rotation of a hollow motor with a screw rod. 2. The apparatus according to claim 1, wherein power is transmitted to screw nuts mounted on both sides of the hollow motor (through the connecting shaft) via a speed reducer installed at the end of the motor shaft and rotated at an equal rotational speed. The mechanism by which the screw rod slides. 3. The structure according to claim 2, wherein the speed reducer and the screw nut are connected, and a buffer mechanism is provided therebetween. 2. The mechanism according to claim 1, wherein one side of the screw nut mounted on both sides of the hollow motor is a power transmission and bearing, and the other screw nut is a bearing. A mechanism comprising a brake and an encoder in the device of the present invention.

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