JPH07305753A - Motor-driven cylinder - Google Patents

Abstract

PURPOSE:To prevent the generation of creak vibration and creak noise through prevention of the occurrence of nonconformity of the axes of male and female screws with each other and to provide an increased life for the male and female screws. CONSTITUTION:A rotating male screw 2 is protruded from a flange 3. One end of a cylindrical thrust rod, 5 is coupled to a thrust bush 4 having a female screw 4a coupled with the male screw 2, and the other end thereof forms a thrust drive end 5a. The thrust rod 5 is surrounded with an outer cylinder and a thrust rod guide 7 is fixed to one end of an outer cylinder 6 the thrust rod 5 is axially guided having the other end to which the flange 3 is fixed, and the thrust rod 5 is axially guided by the thrust rod guide. The thrust rod 5 is brought into an axial movable state and a non-rotatable state by a thrust- driven body. A thrust bush support 11 is located between the thrust bush 4 and one end of the thrust rod 5. Spline coupling 12 wherein a gap is axially provided is arranged between the thrust bush 4 and the thrust bush support 11 and the two ends thereof are locked by a snap ring 13. Annular resilient bodies 14a and 14b are located between the two ends of the thrust bush 4 and the thrust rod 5 side.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention converts the rotational force of an electric motor such as a servomotor, an ordinary induction motor, or an electric gear unit into a linear thrust by a screw pair (including a ball screw in this specification). Regarding electric cylinders.

[0002]

2. Description of the Related Art FIG. 4 is a front view showing a sectional view of a main part of a conventional example. In the figure, a male screw 2 that is rotationally driven by an electric motor 1 projects from a flange 3. One end of a cylindrical thrust rod 5 is connected to a thrust bush 4 having a male screw 2 and a female screw 4a that forms a screw pair, and the other end of the thrust rod 5 forms a thrust driving end 5a. Reference numeral 5a includes a coupling screw 5b which is coupled to a thrust driven body (not shown). A thrust rod guide 7 is fixed to the other end of an outer cylinder 6 that surrounds the thrust rod 5 and has one end fixed to the flange 3, and the thrust rod 5 is guided in the axial direction by the thrust rod guide 7. To fix one end and the other end of the outer cylinder 6 to the flange 3 and the thrust rod guide 7, for example, four stud bolts (not shown) are provided around the outer cylinder 6 to form the flange 3 and the thrust rod guide 7.
Screwed into and. The thrust rod 5 is axially movable and non-rotatable by the thrust driven body. When the thrust driven body does not have such an action, it is easy to provide the thrust rod itself with a mechanism for such action. For example, a key is provided between the thrust rod 5 and the thrust rod guide 7. A dust seal 7a is provided at the end of the thrust rod guide 7.
Is installed.

When the stroke is long and the screw 2 is long, a radial bearing 8 such as a needle bearing is fitted to the tip of the male screw 2, and a collar 9 for holding the radial bearing 8 is provided.
Slides on the thrust rod 5. Washers 9a on both ends of collar 9
Is attached and fixed with a retaining ring 9b. A lubricant is applied to the screw pair, the thrust bush guide 7, the radial bearing 8, the collar 9, and the like.

In this conventional example, in order to connect one end of the cylindrical thrust rod 5 to the thrust bush 4, a bolt seat 91 is fixed to one end of the thrust rod 5 by welding or the like, so that the bolt seat 91 and the thrust bush are joined together. The flange portion 92 of No. 4 is fixed with a bolt 93. Buffer rings 94 are attached to the end faces of the bolt seat 91 and the flange portion 92 in order to buffer the collision at both ends of the stroke.

[0005]

In the above-mentioned conventional example, the non-perpendicularity of the male screw 2 with respect to the flange 3, the male screw 2
Due to a slight meandering of the shaft center of itself, shaft runout of the female screw 4a, etc., the male screw 2 and the female screw 4a do not necessarily have the same shaft center in the entire length of the stroke. Due to the disagreement of the axial centers of the screw pairs, the male screw 2 and the female screw 4a are often partially broken by the lubricant to cause solid friction. Solid friction between the male screw 2 and the female screw 4a causes squeak vibration, which causes squeak noise and causes the entire electric cylinder to resonate. Further, the squeak vibration shortens the life of the male screw 2 and the female screw 4a.

An object of the present invention is to provide an electric cylinder which can prevent the axial center of a male screw and a female screw from being inconsistent with each other, prevent squeak vibration and squeak noise, and prolong the life of the male screw and the female screw. Especially.

[0007]

According to another aspect of the present invention, there is provided an electric cylinder in which a male screw driven to rotate by an electric motor projects from a flange, and a thrust bush having a female screw for mating with the male screw has a cylindrical thrust rod at one end. , The other end of the thrust rod forms the thrust driving end, and the thrust rod guide is fixed to the other end of the outer cylinder that surrounds the thrust rod and one end is fixed to the flange. In an electric cylinder that is guided in a direction and the thrust rod is axially movable by itself or a thrust driven body and is not rotatable, a thrust bush receiver is interposed between the thrust bush and one end of the thrust rod. The thrust bush and the thrust bush receiver are coupled by self-aligning coupling means that is axially immovable and non-rotatable and has a radial gap.

A second aspect of the present invention is the same as the first aspect of the present invention, in which an annular elastic body is interposed between both ends of the thrust bush and the thrust rod side. In the electric cylinder according to the third aspect of the present invention, the male screw driven to rotate by the electric motor protrudes from the flange, and one end of the cylindrical thrust rod is coupled to the thrust bush having the male screw and the female pair of the female screw and the other end of the thrust rod. The end forms the thrust drive end, and the thrust rod guide is fixed to the other end of the outer cylinder that surrounds the thrust rod and one end is fixed to the flange.The thrust rod is guided in the axial direction by the thrust rod guide, and the thrust rod is In an electric cylinder that is axially movable and non-rotatable by itself or by a thrust driven body, a thrust bush and one end of a thrust rod are fixedly coupled via an elastic ring.

In the electric cylinder according to the fourth aspect of the present invention, the male screw driven to rotate by the electric motor projects from the flange, and one end of the cylindrical thrust rod is coupled to the thrust bush having the female screw that makes a pair with the male screw. The other end forms the thrust drive end, and the thrust rod is surrounded by the thrust rod guide, and the thrust rod guides in the axial direction by the thrust rod guide. In an electric cylinder in which the rod is movable in the axial direction by itself or a thrust driven body and is not rotatable, a radial bearing is fitted to the tip of the male screw, and the collar that slides on the thrust rod and the radial bearing An annular elastic body is interposed between them.

In the electric cylinder according to the fifth aspect of the present invention, the male screw driven to rotate by the electric motor projects from the flange, and one end of the cylindrical thrust rod is coupled to the thrust bush having the female screw that makes a thread pair with the male screw. The other end forms the thrust drive end, and the thrust rod is surrounded by the thrust rod guide, and the thrust rod guides in the axial direction by the thrust rod guide. In an electric cylinder in which a rod is axially movable by itself or a thrust driven body and is not rotatable, a thrust transmission piece fixed to a thrust bush cannot move axially to one end of the thrust rod. The elastic members are coupled in a direction through a gap, and an annular elastic body is interposed between the groove on the inner circumference of the thrust transmission piece and the outer circumference of the thrust rod.

A sixth aspect of the present invention is any one of the first, third or fifth aspects, wherein the outer periphery of an annular body axially immovably coupled to one end of the thrust rod is slidably attached to the outer cylinder.

[0012]

According to the first aspect of the invention, the self-aligning connecting means has self-aligning action and absorbs the discrepancy of the axial centers of the male screw and the female screw to prevent squeak vibration and squeak noise. According to the second aspect of the present invention, the annular elastic body interposed between both ends of the thrust bush and the thrust rod side further reliably prevents squeak vibration and squeak noise.

According to the third aspect of the present invention, since the elastic ring connecting the thrust bush and the one end of the thrust rod transmits torque and exerts the self-centering function, squeak vibration and squeak noise are surely suppressed. . According to the invention 4, the annular elastic body interposed between the collar and the radial bearing is
The tip of the male thread prevents squeaking vibration and squeaking noise, which may remain in the case of a long stroke.

According to the fifth aspect of the invention, the gap between the thrust transmitting piece and the thrust rod absorbs the disagreement of the axial center between the male screw and the female screw to prevent squeaking vibration and squeaking noise, and the annular elastic body to squeak vibration and squeaking. Prevent noise and noise more reliably. Invention 6
According to this, the radial force at the thrust driving end at the other end of the thrust rod is supported at two points, the thrust rod guide and the annular body, and uneven wear of the thrust rod guide is prevented.

[0015]

1 is a front view showing a cross section of a main part of the first embodiment, FIG. 2 is a cross section of a main part of the second embodiment, and FIG. 3 is a front view showing a cross section of the main part of the third embodiment. It is a figure. In the conventional example and in each drawing, those denoted by the same reference numerals have approximately the same function, and duplicate explanation may be omitted.

In FIG. 1, a portion similar to the conventional example will be described first. A male screw 2 that is rotationally driven by the electric motor 1 projects from the flange 3. A cylindrical thrust rod 5 is attached to a thrust bush 4 having a male screw 2 and a female screw 4a that makes a thread pair.
One end is coupled and the other end of the thrust rod 5 forms a thrust driving end 5a. In this case, the thrust driving end 5a includes a coupling screw 5b that is coupled to a thrust driven body (not shown). A thrust rod guide 7 is fixed to the other end of an outer cylinder 6 that surrounds the thrust rod 5 and has one end fixed to the flange 3, and the thrust rod 5 is guided in the axial direction by the thrust rod guide 7. A dust seal 7a is attached to the end of the thrust rod guide 7. One end and the other end of the outer cylinder 6 are connected to the flange 3 and the thrust rod guide 7
To be fixed to the
Book stud bolts are screwed into the flange 3 and the thrust rod guide 7. The thrust rod 5 is axially movable and non-rotatable by the thrust driven body. When the thrust driven body does not have such an action, it is easy to provide the thrust rod itself with a mechanism for such action. For example, a key is provided between the thrust rod 5 and the thrust rod guide 7.

A feature of the first embodiment is that in order to connect one end of the cylindrical thrust rod 5 to the thrust bush 4, a thrust bush receiver 11 is interposed between the thrust bush 4 and one end of the thrust rod 5. Then, the thrust bush 4 and the thrust bush receiver 11 are coupled by the self-aligning coupling means that is axially immovable and non-rotatable and has a radial gap. A specific example of the self-aligning coupling means is a spline coupling 12 that is provided between the thrust bush 4 and the thrust bush receiver 11 and has a gap in the radial direction, and both ends thereof are stopped by snap rings 13. Instead of the spline connection 12, there is a key connection or a prism connection. It is preferable that the annular elastic bodies 14a and 14b are interposed between both ends of the thrust bush 4 and the thrust rod 5 side.
The annular elastic body 14a on one side can contact the flange 3 and buffers the collision at one end of the stroke. A buffer ring 14x is provided on the end surface of the thrust rod guide 7 if necessary.

When the stroke is long and the screw 2 is long, the radial bearing 8 is fitted to the tip of the male screw 2, and the annular elastic body 15 is provided between the radial bearing 8 and the collar 9 sliding on the thrust rod 5. Is installed. Washers 9a are attached to both ends of the collar 9, and are fixed by retaining rings 9b. Example 1
According to the above, the self-centering coupling means such as the spline coupling 12 absorbs the discrepancy of the axial centers of the male screw 2 and the female screw 4a to prevent the squeaking vibration and the squeaking noise. Further, the annular elastic bodies 14a, 14b interposed between the both ends of the thrust bush 4 and the thrust rod 5 side prevent squeak vibration and squeak noise more reliably. The annular elastic body 15 interposed between the collar 9 and the radial bearing 8 prevents the squeaking vibration and the squeaking noise that remain to some extent in the case of a long stroke at the tip of the male screw 2.

In the second embodiment shown in FIG. 2, the thrust bushing 4 and one end of the thrust rod 5 are fixedly connected by the elastic ring 21. Specifically, the bolt seat 22 is fixed to one end of the thrust rod 5 by welding or the like, and the thrust bush coupling body 24 and the thrust bush 4 fixed by the bolt seat 22 and the bolt 23 are fixed via the elastic ring 21. Then combined. Instead of using the bolt seat 22 and the thrust bush coupling body 24, the thrust bush 4 and one end of the thrust rod 5 may be directly fixed and coupled to each other via the elastic ring 21.

According to the second embodiment, since the elastic ring 21 connects the thrust bush 4 and the thrust bush coupling body 24 and exhibits the self-centering function, the squeaking vibration and the squeaking noise are suppressed more reliably. . Example 3 shown in FIG.
In, motor 1, male thread 2, flange 3, female thread 4
a, thrust bush 4, thrust rod 5, thrust drive end 5a,
The connecting screw 5b, the outer cylinder 6, the thrust rod guide 7, and the like are the same as in the first embodiment.

A feature of the third embodiment is that the thrust transmission piece 32 fixed to the thrust bush 4 with a screw 31 cannot move in the axial direction at one end of the thrust rod 5 by means of the retaining rings 33a, 33b, and has a radial gap. Connect via C. An annular elastic body 34 is interposed between the groove on the inner circumference of the thrust transmission piece 32 and the outer circumference of the thrust rod 5. Further, the outer periphery of the annular body 35, which is coupled to one end of the thrust rod 5 by the retaining rings 33b, 33c and the like so as to be immovable in the axial direction, is slidably attached to the outer cylinder 6.

According to the third embodiment, the gap C between the thrust transmission piece 3 and the thrust rod 5 absorbs the discrepancy of the axial center between the male screw and the female screw to prevent squeak vibration and squeak noise, and the annular elastic body 34 is used. Scratch vibration and squeak noise are prevented more reliably. Further, the radial force of the thrust driving end 5a at the other end of the thrust rod 5 is supported by the thrust rod guide 7 and the annular body 35 at two points and opposes the bending force, and uneven wear of the thrust rod guide 7 is caused. To be prevented.

In this embodiment, the thrust rod 5 is axially movable by the thrust driven body and cannot be expected to be unrotatable. Therefore, the thrust rod 5 itself is axially movable and non-rotatable. Therefore, the hole 37 of the thrust transmission piece 32 penetrates through the detent rod 36 provided between the flange 3 and the thrust rod guide 7. Hole 3 in ring 35
8 is provided. Buffer rings 14x and 14y may be provided on the flange 3 and the thrust rod guide 7.

[0024]

According to the electric cylinder of the first aspect of the invention, the self-aligning connecting means has the effect of absorbing the discrepancy in the axial center between the male screw and the female screw to prevent squeaking vibration and squeaking noise. According to the second aspect of the invention, the annular elastic body interposed between the both ends of the thrust bush and the thrust rod side has an effect of further reliably preventing squeaking vibration and squeaking noise.

According to the electric cylinder of the third aspect of the invention, since the elastic ring connecting the thrust bush and the one end of the thrust rod exerts a self-aligning action, squeak vibration and squeak noise are reliably suppressed. . According to the electric cylinder of the invention 4, the annular elastic body interposed between the collar and the radial bearing prevents the squeaking vibration and the squeaking noise that remain to some extent in the case of a long stroke at the tip of the male screw. effective.

According to the electric cylinder of the invention 5, the gap between the thrust transmitting piece and the thrust rod absorbs the discrepancy of the axial center between the male screw and the female screw to prevent squeak vibration and squeak noise, and the annular elastic body squeaks. There is an effect of further reliably preventing vibration and stain noise. According to the sixth aspect of the invention, the radial force of the thrust driving end at the other end of the thrust rod is supported by the thrust rod guide and the annular body at two points, so that uneven wear of the thrust rod guide is prevented.

[Brief description of drawings]

FIG. 1 is a front view in which a main part of a first embodiment is shown in section.

FIG. 2 is a cross-sectional view of the essential parts of Embodiment 2

FIG. 3 is a front view showing a cross-sectional view of a main part of the third embodiment.

FIG. 4 is a front view showing a cross-sectional view of a main part of a conventional example.

[Explanation of symbols]

1 Electric Motor 2 Male Thread 3 Flange 4 Thrust Bushing 4a Female Thread 5 Thrust Rod 5a Thrust Drive End 5b Coupling Screw 6 Outer Cylinder 7 Thrust Rod Guide 8 Radial Bearing 9 Collar 9a Washer 9b Retaining Ring 11 Thrust Bushing 12 Retaining Ring 14a Annular elastic body 14b Annular elastic body 14x Buffer ring 21 Elastic ring 22 Bolt seat 23 Bolt 24 Thrust bush coupling body 32 Thrust transmission piece 34 Annular elastic body 35 Annular body 36 Whirl-stop rod 37 Hole 38 Hole C Gap

Claims (6)

[Claims] 1. A male screw driven to rotate by an electric motor projects from a flange, one end of a cylindrical thrust rod is connected to a thrust bush having a female screw and a male screw and a male screw, and the other end of the thrust rod is thrust. A thrust rod guide is fixed to the other end of the outer cylinder that forms the drive end and surrounds the thrust rod and one end of which is fixed to the flange.The thrust rod is guided in the axial direction by the thrust rod guide, and the thrust rod itself or In an electric cylinder that is axially movable and non-rotatable by a thrust driven body, a thrust bush receiver is interposed between the thrust bush and one end of the thrust rod, and the thrust bush and the thrust bush receiver are An electric cylinder that is axially immovable and non-rotatable, and is coupled by self-aligning coupling means having a gap in the radial direction. 2. The electric cylinder according to claim 1, wherein an annular elastic body is interposed between both ends of the thrust bush and the thrust rod side. 3. A male screw driven to rotate by an electric motor projects from a flange, one end of a cylindrical thrust rod is coupled to a thrust bush having a female screw and a male screw and a male screw, and the other end of the thrust rod is thrust. A thrust rod guide is fixed to the other end of the outer cylinder that forms the drive end and surrounds the thrust rod and one end of which is fixed to the flange.The thrust rod is guided in the axial direction by the thrust rod guide, and the thrust rod itself or In an electric cylinder that is axially movable and non-rotatable by a thrust driven body, an electric cylinder characterized in that a thrust bush and one end of a thrust rod are fixedly coupled via an elastic ring. . 4. A male screw driven to rotate by an electric motor projects from a flange, one end of a cylindrical thrust rod is coupled to a thrust bush having a male screw and a female screw forming a screw pair, and the other end of the thrust rod is thrust. A thrust rod guide is fixed to the other end of the outer cylinder that forms the drive end and surrounds the thrust rod and one end of which is fixed to the flange.The thrust rod is guided in the axial direction by the thrust rod guide, and the thrust rod itself or In an electric cylinder that is axially movable and non-rotatable by a thrust driven body, a radial bearing is fitted to the end of the male screw, and a ring-shaped elastic member is provided between the thrust rod sliding collar and the radial bearing. An electric cylinder characterized in that the body is interposed. 5. A male screw driven to rotate by an electric motor protrudes from a flange, one end of a cylindrical thrust rod is coupled to a thrust bush having a female screw and a male screw and the other end of the thrust rod is thrust. A thrust rod guide is fixed to the other end of the outer cylinder that forms the drive end and surrounds the thrust rod and one end of which is fixed to the flange.The thrust rod is guided in the axial direction by the thrust rod guide, and the thrust rod itself or In an electric cylinder that is axially movable and non-rotatable by a thrust driven body, a thrust transmission piece fixed to a thrust bush is not axially movable to one end of a thrust rod and a radial gap exists. The electric cylinder is characterized in that an annular elastic body is interposed between the groove on the inner circumference of the thrust transmission piece and the outer circumference of the thrust rod. 6. The electric cylinder according to claim 1, 3 or 5, wherein an outer circumference of an annular body axially immovably coupled to one end of the thrust rod is slidably attached to the outer cylinder. A characteristic electric cylinder.