JPH05330795A - Elevator device - Google Patents

Abstract

(57) [Summary] [Purpose] To prevent lateral vibration of the lifting body. [Structure] Left and right ball nuts 12 and 13 having left and right female threads are fixed to two positions of the lifting body 2, and the left and right ball nuts 12 and 13 are respectively left and right. The left and right direction ball screws 10 and 11 having the right and left direction male screws are screwed into the left and right direction ball screws 1.
0 and 11 are suspended and supported on the balance plate body 8, respectively, and the ball screws 10 and 11 in the left and right directions are respectively rotated in opposite directions, so that an evenly shared load is always applied to them. ..

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lifting device for lifting and lowering a transported object, and more particularly to a lifting device which prevents vibration.

[0002]

2. Description of the Related Art A conventional lifting device has a structure in which a lifting and lowering body is penetrated, a ball screw and a ball nut for lifting and lowering are combined in the center, and a guide shaft and a ball bush bearing for guiding are arranged on both sides thereof. Is.

[0003]

In the above-mentioned conventional apparatus, the transfer device mounted on the lifting body is a heavy object, and when the weight of the transferred object is added to this, the transfer apparatus becomes heavier and the transferred object is transferred. During the up-and-down transportation of the object, as the lead of the ball screw becomes larger, a rotating moment is generated in the elevating body to slide down the slope of the lead of the ball screw, and the guide shafts attached to both sides are deflected as the elevating body moves up and down. Since the guide shaft is made of metal, it is an elastic body, and the bending returns to its original state. By repeating this bending and restoring motion, so-called lateral vibration occurs.
When the lateral vibration occurs, there is a problem that the vertical vibration is promoted.

FIG. 4 (A) is a view for clarifying the occurrence of lateral shake of a conventional lifting body. When the weight of the lifting body 2 is WS, the force with which the lifting body 2 slides down the slope 33 formed by the lead of the ball screw can be represented by a vector as shown in FIG. Ignoring the loss when trying to slide down, if the angle between the slope 33 and the horizontal plane is θS1, the sliding force F35 = WS · sin θS2, and if this is further decomposed into horizontal components, the horizontal force F36 = WS · sin θ
This force is represented by S2 × cos θS3, and this force acts on the guide shafts on both sides of the ball screw so as to bend the guide shafts, resulting in lateral vibration as described above. Note that θS1 = θS2 = θS3.

In particular, when the ball screw is rotated in the direction of the rotation arrow 37 and raised as shown by the arrow 38, the static pressure 39
In addition to the direction, a lateral force 40 acts. Therefore, it is self-evident that the vibration increases due to the large force acting on the guide shaft.

When the ball screw is rotated in the direction of the dotted arrow 41 and drops in the direction of the arrow 42, the weight of the lifting body 2 and the weight of the placed object cause the slope 33 to move in the direction of the arrow 43. F35 and F3
6 becomes smaller, and the lateral shake at the time of falling becomes smaller. However, it was difficult to eliminate the phenomenon of lateral shake in the conventional structure.

[0007]

In order to solve the above-mentioned problems, the present invention has ball nuts 12, 13 having two female screws in the left and right directions, which are fixed to the elevating body 2 and control the elevating.
And the left and right ball screws 10 and 11 having the left and right male threads screwed into the left and right ball nuts 12 and 13, respectively, and the left and right ball screws are used. The upper portions of 10 and 11 are suspended and supported by supporting portions 15 having spherical joints provided on both sides of the balance body 8.

[0008]

[Working] In this way, left and right ball screws 10, 1
By rotating 1 in the left and right directions corresponding to the respective left and right male screws, the lateral shake component force generated at the time of the operating force of the lifting body 2 is offset, and the vibration of the lateral shake is eliminated. It can be prevented. Further, the upper portions of the left and right ball screws 10 and 11 are suspended and supported by the supporting portions 15 having spherical joints provided on both sides of the balance body 8 whose center portion is rotatably supported by the upper supporting body 7. Therefore, the weight of the lifting body 2 is
The left and right ball screws 10 and 11 are always evenly shared and received by the balance action of the balance body 8.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a perspective view showing the construction of an embodiment of the device of the present invention. In FIG. 1, reference numerals 4 and 4 denote a pair of guide shafts, through which an elevating / lowering body 2 slidably penetrates via ball bush bearings 3 and the upper end portions of which are attached to an upper support plate 7 by a mechanical lock mechanism 5. , 5 and their lower ends are similarly fastened. Between the pair of guide shafts 4 and 4, the left and right ball nuts 12 and 13 having two left and right female threads are fixed to the lifting body 2, and these left and right ball nuts 12 and 13 are fixed. Thirteen
Left and right ball screws 10 and 11 having left and right male threads are respectively screwed in.

A support shaft 9 is provided so as to penetrate the central portion of the balance plate body 8 so that the balance plate body 8 can rotate, and support bases 51, 51 for supporting the support shaft 9 are fixed on the upper support plate 7. Has been done. The upper portions of the left and right ball screws 10 and 11 penetrate the upper support plate 7 and are suspended, ie, suspended, from the support portions 15 and 15 arranged on both sides of the balance plate body 8.
On the other hand, the lower ends of the left and right ball screws 10 and 11 are ball bearings 14 and 14 provided on the lower support plate 6.
It is held with moderate looseness.

Gears 16, 16 having the same number of teeth are firmly attached to the upper ends of the left and right ball screws 10, 11, respectively.
And they are meshed in a comfortable state. A servo motor 17 is arranged on the lower surface of the upper support plate 7 at a position that does not hinder the movement of the lifting body 2, and an output shaft 18 of the servo motor 17 is disposed.
The brake shaft 19 of the non-excitation brake 22 is connected in the boss of the gear 20, and the gear 20 is meshed with the gear 16. The non-excitation brake 22 is firmly mounted on the brake base 21, performs braking in the non-excitation state, and fixes the gear 20.
The lifting body 2 is prevented from falling.

In the case of this embodiment, the rotation driving mechanism 1 for transmitting left and right rotations to the left and right ball screws 10 and 11, respectively, includes gears 16, 16 and 20,
Servo motor 17, its output shaft 18, non-excitation brake 2
2 and its brake shaft 19 and the like. 23
Is a mounting portion of the lifting / lowering body 2, and 24 is a transfer device mounted thereon.

FIG. 2 is a side sectional view of the main part of the device of the present invention, showing the details of the support part 15. A counterbore hole 25 is bored at a required position of the balance plate body 8 and a spherical joint combining an outer ring 26 and an inner ring 27 is inserted. The inner ring 27 houses a bearing portion 29 having an angular ball bearing 28 built therein. Has been done. The upper portion of the ball screw 11 in the right direction is inserted into the angular ball bearing 28, and the screw portion 30 is supported by being tightened by a nut 32 via a washer 31 and suspended. The left ball screw 10 is also suspended and supported in the same manner.

FIG. 3 is a view for clarifying the action of preventing the vibration of the lateral shake by the device of the present invention. The weight of the lifting body 2 is W
Then, W / 2 that shares the left and right ball screws 10 and 11 is distributed (the reason will be described later), and the left and right ball screws 10 and 11 are rotated by the output shaft 18 to the gears 20 and 16. When rotated in the directions of the arrows 44 and 45 via the arrows 16 and 16, the lifting body 2 having the weight W moves upward in the direction indicated by the arrow 46 (see FIG. 3A).

From the slopes 47 and 48 formed by the leads of the left and right ball screws 10 and 11, the angles formed by the horizontal planes and the slopes 47 and 48 are θ2 and θ, respectively.
Assuming that 1 (designated θ2 = θ1), the forces that generate the lateral shakes are as shown in FIGS.
Lateral force on the ball screw 10 side to the left F49 = W / 2
× sin θ2 · cos θ2, and lateral force F50 = W / 2 × sin θ1 ·
cos θ1.

As can be seen from Figures (B) and (C), F49
Since F50 and F50 have the same value and the directions in which the forces are applied are opposite directions, the lateral shake acts in the directions in which they cancel each other out, so that the vibration of the lateral shake does not occur.

However, although the above description is a theoretical proof, in reality, the leads generated by the left and right male screws of the left and right ball screws 10 and 11 are accumulated in the manufacturing process. It is difficult to make the lead error the same at the opposite use positions. If the cumulative lead error is different, the left and right ball screws 10, 11 will lose equal distribution of the weight shared by the ball screws 10, 11 and will generate lateral vibration. Cause.

The cumulative lead error of the ball screw currently manufactured is ± 0.05 mm / 300 mm, which is not large, but it is a problem when using the ball screw together, and there is a cumulative lead error. Since the suspension structure of the ball screw for preventing this influence has already been described, its operation will be described below.

As shown in FIG. 2, when the weight including the weight of the lifting body 2 and the transfer device 24 mounted on it is W,
Equal weight W for left and right ball screws 10 and 11
/ 2 will be shared. This is supported by the support bases 51 arranged on both sides of the balance plate body 8 so that the support shaft 9 attached through the central portion of the balance plate body 8 can be rotationally displaced, and the balance plate body 8 is always left. , To act to maintain the balance of the weight shared by the ball screws 10 and 11 in the right direction.

As described above, the cumulative lead error of the ball screw is ± 0.05 mm / 300 mm, and when the length is 2000 mm, it is ± 0.05 mm / 300 × 2000 = ± 0.33 mm, and the difference between the upper and lower cumulative lead errors is +0. It is 0.66mm from 0.33 to -0.33, and ± at the middle 1000mm position.
The difference between the upper and lower sides is 0.05 / 300 × 1000 = ± 0.16, which is 0.32 mm from +0.16 to −0.16. If a difference of 0.32 mm occurs between the left and right ball screws 10 and 11 as described above, the total weight is applied to the higher lead position, and the left and right ball screws 10 and 11 are used together. It has no meaning.

As shown in FIG. 2, assuming that the ideal balanced position is the center balance line 52 of the balance plate body 8 without cumulative lead errors of the left and right ball screws 10 and 11, on the other hand,
When the lead error of the ball screw 10 in the left direction is negative and that of the ball screw 11 in the right direction is positive, a large amount of weight is applied to the ball screw 10 side in the left direction, and the ball screw 11 side in the right direction becomes light. Therefore, the balance plate body 8 is automatically displaced toward the center balance line 53 side and balanced in order to equally divide the weights applied to the left and right ball screws 10 and 11.

If the lead error of the leftward ball screw 10 is positive and that of the rightward ball screw 11 is negative, a large amount of weight is applied to the rightward ball screw 11 side.
The ball screw 10 side to the left becomes lighter. Therefore, the balance plate body 8 is automatically displaced to the side of the center balance line 54 in order to equally divide the weight of the ball screws 10 and 11 in the left and right directions and bear the weight.
The weights of the left and right ball screws 10 and 11 are equally divided.

The balance plate 8 operates to draw an arc 55 around the support shaft 9, but since the rotational displacement is 1 mm or less in the upward and downward directions, the ball screws 10 and 11 in the left and right directions are formed.
The displacement between the suspension positions of is negligible. The structure for suspending the ball screws 10 and 11 in the left and right directions is a support portion 15 as one embodiment as shown in the cross sections of FIGS.

Since the supporting portion 15 uses a spherical joint and smoothly operates with the outer ring 26 and the inner ring 27, a bending force acts on the supporting portions of the left and right ball screws 10 and 11. Instead, it always maintains a natural suspension posture.

The weight of the lift 2 including the transfer device 24 is 5
Since the weight is as heavy as 0 kg to 60 kg and the resistance of the movable and rubbing portions is small, the distribution of the weight to the left and right ball screws 10 and 11 can be made quickly.

Drive transmission to the left and right ball screws 10 and 11 from the output shaft 18 of the servomotor 17 is a combination of gears 20, 16 and 16 as shown in FIG.
The left and right ball screws 10 and 11 are rotated to the left and right, respectively, but this does not hinder the automatic balancing operation of the balance plate body 8 to the left and right ball screws 10 and 11. Lower end shaft 1 of ball screw 11 in the right direction
1'is properly fitted with the ball bearing 14 and is supported so as not to hinder the vertical movement of the ball screw 11 in the right direction. The same applies to the left ball screw 10.

In this embodiment having the above structure, the lifting body 2
Is supported by a pair of left and right ball screws 10 and 11, and the left and right ball screws 10 and 11 are suspended on a balance plate body 8 and the left and right ball screws 10 and 11 are suspended.
In order to operate the lifting / lowering body 2, the left and right ball screws 10 and 11 are respectively rotated in opposite directions to cancel the lateral component forces generated respectively. This has the effect of preventing lateral vibration of the lifting body 2.

[0028]

As described above, according to the present invention, the lifting body 2
The left and right ball nuts 12 and 13 having left and right female threads are fixed to the left and right direction, and the left and right ball nuts 12 and 13 have left and right male threads respectively. Since the ball screws 10 and 11 in the left and right directions are screwed in and the left and right ball screws 10 and 11 are respectively rotated in the left and right directions, the lateral shake generated when the lifting body 2 is operated. It is possible to cancel the component force of and to prevent lateral vibration.

[Brief description of drawings]

FIG. 1 is a perspective view showing the configuration of an embodiment of the device of the present invention.

FIG. 2 is a side sectional view of a main part of the device of the present invention.

FIG. 3A is a development view for explaining the operation of the device of the present invention. (B) is a vector diagram by the load applied to the ball screw in the left direction in the present invention. (C) is a vector diagram by the load applied to the ball screw in the right direction in the present invention.

FIG. 4A is a development view for explaining occurrence of lateral shake in a conventional device. (B) is a vector diagram thereof.

[Explanation of symbols]

 2 Lifting body 4 Guide shaft 6 Lower support (plate) 7 Upper support (plate) 8 Balance (plate) body 9 Support shaft 10 Leftward ball screw 11 Rightward ball screw 12 Leftward ball nut 13 Rightward ball Nut 15 Support 51 Support base

Claims (2)

[Claims] 1. A pair of guide shafts (4, 4) having both end portions firmly attached to upper and lower supports (7, 6), and a pair of guide shafts (4, 4) on which an elevating body (2) is attached. Ball screws are respectively inserted into two ball nuts that slidably penetrate and are fixed to the lifting body (2) between the pair of guide shafts (4, 4), and the upper portions of these ball screws are attached to the upper support body. In an elevating device for penetrating and supporting (7) and rotatably supporting the lower part thereof to a lower support (6), and elevating and lowering an elevating body (2) by rotating each ball screw by a rotary drive mechanism (1). , Fixed to the lifting body (2) 2
Each of the ball nuts is a left and right ball nut (12, 13) having left and right female threads, and each ball screw is a left and right ball screw (10) having left and right male threads. , 11) and imparts left and right rotations to these ball screws (10, 11), respectively. 2. The upper supporting body (7) is provided with supporting portions (15) each having a spherical joint on both sides of a balance body (8) whose central portion is rotatably supported. 1
The lifting device according to claim 1, wherein the upper part of the ball screw (10, 11) in the left and right directions is suspended from and supported by 5).