JPS63163059A - Bearing device - Google Patents

Abstract

PURPOSE:To provide a bearing device for supporting always the central portions of a driven body and an end of a feed screw by providing the bearing device rotated by a half the rotational frequency of a screw in the same direction as the feed screw. CONSTITUTION:A bearing device 4 is disposed intermediate shaft ends 3a, 3b and a driven body 2. A nut 5b is engaged by a feed screw 1 and pivotably mounted on a frame body 6 of bearing device 4. And a gear 8b is mounted on one side surface of the nut. A gear 8 is mounted on the input shaft of a speed change gear 9 to mesh with a rack 7. Here, total speed change ratio of gears 8a-8c and speed change gear 9 is set such that 1/2 rotation is given to the nut 5b in the same direction as that of feed screw while the bearing device 4 is moved by 1/2 of lead of the feed screw 1. Thus, the bearing device is located always intermediate the shaft end and the driven body to increase danger speed about 4 times.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a moving device that rotates a feed screw to move a driven body, and particularly relates to a bearing device that supports the feed screw.

(Conventional technology) When rotating the feed screw to move the driven object.

Attach the nut 5a to the driven body 2 as shown in Figs.
The feed screw 1 is rotated by a motor 13.

(Problem that the invention attempts to solve) In this bearing device, if the feed screw 1 is made longer.

As shown in the formula, the critical speed Nc decreases, and the rotational speed of the feed screw 1 must be decreased.

On the other hand, if the shaft diameter of the feed screw 1 is increased, the inertia increases and the motor capacity increases. That is, in order to rotate the feed screw at high speed, the shaft diameter of the feed screw 1 must be increased or the shaft length must be shortened.

60・λ2P and Nc" 2. Nc: Critical speed (rpm) L: Distance between support points Cm) E: Young's modulus (kgt/■2) Work: Minimum moment of inertia of feed screw (m++'1A
: Cross-sectional area of the feed screw (am”) g: Gravitational acceleration [ma+/sac”) γ: Specific gravity of the feed screw (kgt/n++n”) λ: Coefficient depending on the mounting method of the feed screw. An object of the present invention is to obtain a bearing device capable of driving a driven body with a small-diameter feed screw even at high speed rotation.

[Structure of the invention]

(Means for Solving the Problem) The present invention provides a guide rail parallel to a feed screw whose both ends are supported by support frames, and a rack is provided between the support frames.
In a moving device with a driven body in the middle of the feed screw,
The feed screw is movably passed between the driven body of the feed screw and the support frame, and the feed screw and nut are rotatably passed through the middle part, and a gear is fixed to one side of the nut, and a gear is fixed between the gear and the rack. A gearbox with a pinion that rotates the nut and gear by 172 of the rotation amount of the feed screw and moves the nut in the same direction by 172 of the feed screw is installed, so that even if the driven body moves, the driven body and the feed screw are always connected. This is a bearing device that supports the center portion between the end portions.

(Function) In the bearing device of the present invention, when the feed screw rotates, the nut rotates in the same direction as the screw by 1/2 of the rotation speed of the screw due to the gear ratio between the pinion and the gear attached to the nut. moves in the same direction by 172 the feed amount of the feed screw, and the bearing device installed at the center between the screw end and the driven part during assembly always supports the center even if the driven part moves. .

(Example) This will be explained below using the drawings.

1 to 3 show an embodiment of a bearing device according to the present invention.

In FIG. 1, the bearing devices 4 are arranged so as to be located between the shaft ends 3a, 3b and the driven body 2, respectively.

In FIGS. 2 and 3, a nut 5b is engaged with a feed screw 1 and rotatably mounted on a frame 6 of a bearing device 4 by a rolling bearing 10, and a gear 8b is mounted on one side. Frame body 6
A transmission 9 is attached to the output shaft, and a gear 8b is attached to the output shaft and meshes with the gear 8a.

On the other hand, a gear 8C is attached to the input shaft of the transmission 9 and meshes with the rack 7. Here, while the bearing device 4 moves by 1/2 of the lead of the feed screw 1, the nut 5b is rotated by 1/2 rotation in the direction of rotation of the feed screw 1. Set to apply in the same direction. The guide block 11 is attached to the frame 6 and slides on the guide rail 12.

When the feed screw 1 rotates and the bearing device 4 moves, the nut 5b is rotated in the same direction as the feed screw 1 by the gear 8c, the transmission 9, and the gears 8b and 8a that are transferred on the rack 7, so that the bearing device 4 is rotated. has the effect of pulling back 172 of the amount that should be moved.
work.

If the moving speed of the driven body 2 due to the rotation of the feed screw 1 is defined as ge, then the bearing device 4 is given a moving speed of 1, and the bearing device 4 is always connected to the shaft end 3a or 3b and the driven body 2. This is an intermediate position.

Therefore, the distance between the support points of the feed screw is 21 or Q2
Compared to the Qo without this bearing device, it becomes 7 or less, and the critical speed Nc increases by about 4 times as determined by the P formula.

(Other Embodiments) In the embodiments described above, one bearing device 4 is placed between each of the shaft ends 3a, 3b and the driven body 2, but a plurality of bearing devices 4 may be placed at equal intervals.

Figure 4 shows bearing devices 48 to 4c placed at equal intervals.
The total gear ratio of the gears 88 to 8c and the transmission 9 is set in each of the bearing devices 4a to 4c so that the moving speed is 4,4.4 times the moving speed V of the driven body 2, respectively.

As a result, the distance between the support points can be increased compared to the case without the present bearing devices 48 to 4c (the critical speed is approximately 16 times greater).

〔Effect of the invention〕

As described above, if the bearing device according to the present invention is used to construct a feed device using a feed screw, it can be used even if the feed screw is long or requires high speed rotation.

The critical speed can be kept high, and the feed device can be configured with a small diameter feed screw.

[Brief explanation of the drawing]

Fig. 1 shows a feeding device using a bearing device according to the present invention, and a feeding device using a bearing device according to the present invention.
The figure is a sectional view taken along the line AA in FIG. 1, FIG. 3 is a sectional view taken along the line BB in FIG. 1, FIG. 4 is a feeding device using the bearing device according to the present invention, and FIG. , 6th
The figure is a sectional view taken along the line CC in FIG. 1...Feed screw 2...Driven body 4...
Bearing device 6... Frame 7... Rack
8a, 8b, 8c...Gear 9...Transmission 13...Motor agent Patent attorney Nori Chika Ken Yudo Mitsumata Hirofumi>

Claims (1)

[Scope of Claims] A feed screw rotatably supported by a frame at both ends and a first nut fitted in the middle portion, a rack and a pair of guide rails provided parallel to the feed screw between the frames. , a bearing device for supporting a feed screw of a moving device comprising a driven body driven by rotation of the feed screw, with the first nut passing through an intermediate portion of the feed screw, the mount of the feed screw; and a frame body provided at a central portion between the driven body and through which a second nut and the feed screw rotatably pass through the central portion; and a frame body through which the feed screw passes through and is fixed to one side of the second nut. a gear attached to the frame and provided between the rack and the gear to rotate the gear by 1/2 of the rotation angle of the feed screw and mesh with the rack by a pinion to move the frame to the feed screw; A bearing device consisting of a transmission that moves by 1/2 of the feed amount.