JP2000253618A - Motor-driven actuator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make an outputting means easily operable without requiring much time and labor. SOLUTION: A motor-driven actuator is provided with a hollow cylindrical bush 23 put on the outer peripheral surface of a threaded shaft 9 in a state where the bush 23 stretches over both a speed reducing means 3 and a driving force control means 16, a hollow section 25 formed by drilling the base-side end of the supporting section 9b of the shaft 9, a communicative hole 25b which communicates with the inside and outside of the hollow section 25, a control lever 26 slidably inserted into the hollow section 25 through a compression spring 27, and a steel ball 29 which is movably put in the communicative hole 25b and disengageably engaged with an engaging groove 23a formed on the inner peripheral surface of the bush 23 to constitute a clutch mechanism 30. A driving rod 11 which is provided as an outputting means is made easily operable by canceling the connection between the threaded shaft 9 and the speed reducing means 3 and driving force control means 16 attached to the bush 23 in such a way that the steel ball 29 which is positioned on the first swelling section 26b of the control lever 26 and engaged with the engaging groove 23a of the bush 23 is disengaged from the groove 23a by moving the ball 29 toward a recess 26d by pushing the operating lever 26 with the control lever 34 of an operating means 31.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in an electric actuator used as a drive source for moving up and down or up and down a bed or a treatment chair used in a medical institution or the like.

[0002]

2. Description of the Related Art Conventionally, for example, a hydraulic cylinder or an air cylinder has been generally used as a device for linearly reciprocating a drive rod. The former hydraulic cylinder requires a large-scale hydraulic unit when used, and the latter air cylinder requires not only air piping but also a large exhaust noise and may be a source of noise. In order to use the two cylinders as a drive source for raising and lowering or raising and lowering a bed or a treatment chair used in a medical institution or the like, problems such as installation space and pressure oil leakage and noise are required. It was difficult to use when considered.

For this reason, in recent years, electric actuators have been used which convert the rotational motion of a motor into a linear reciprocating motion and linearly reciprocately drive a driving rod connected to an operation target. Since the drive source of the electric actuator is an electric motor, it can be miniaturized and can be used even in a narrow place, which is very convenient. And
The electric actuator includes a driving unit including an electric motor and a deceleration unit, a screw shaft drivably connected to the driving unit, and a driving rod screwed to the screw shaft via a nut, and the deceleration of the driving unit is reduced. By transmitting the rotational motion to the screw shaft and rotating the screw shaft in the right or left direction, the drive rod is linearly reciprocated by using the screw action of the nut, and the operation target (back of the bed or the like) is moved. It is configured to operate.

[0004] Further, the electric actuator is used, for example, in a bed used in a medical institution or the like as a drive source for raising or lowering the back of the bed or raising and lowering the bed itself. Even if the electric actuator cannot be driven due to an accident or the like, if the patient using the bed suffers any seizure, it is manually driven so that the doctor can take prompt action. Retract the rod,
In general, it is configured to be able to perform the operation of tilting the back and the operation of lowering the bed itself.

[0005]

However, when the electric actuator is manually operated in the event of a power failure or the like, the screw shaft connected to the driving means can be rotated by operating the operation handle or the like. However, in order to manually rotate the screw shaft, the electric motor must also be rotated via the speed reduction means constituting the driving means, and as described above, the motor is rotated from the screw shaft side. To do so, the rotation efficiency is very poor, so a great deal of time and labor is required, and it has been difficult to operate quickly and easily.

[0006] When a worm and a worm wheel are used as the deceleration means constituting the driving means, the worm and the worm wheel are characterized in that the worm wheel can be rotated from the worm side, but the worm wheel can be rotated from the worm wheel side. A so-called self-lock phenomenon in which the worm cannot be rotated is known, and as described above, the screw shaft side (worm wheel)
In order to rotate the electric motor (worm) from above, it is necessary to adjust the advance angle of the worm and the worm wheel and the like specially so that the self-lock phenomenon does not occur. As a result, the worm and the worm wheel are specially machined. There was a problem that it had to be used.

The present invention has been made in consideration of the above-described various problems, and has as its object to provide an electric actuator that can be easily operated without requiring much time and labor in the event of a power failure or the like.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a motor comprising a motor for generating a rotational motion and a drive means comprising a speed reducing means for reducing the rotational motion of the motor to a predetermined speed; A motion converting means fitted to the speed reducing means for converting the rotational motion by the driving means into a linear motion; an output means for outputting the linear motion converted by the motion converting means; and a drive provided in the motion converting means. In the electric actuator including the force conversion means, the connection between the movement conversion means, the driving means, and the driving force control means is maintained on a base end side opposite to the output means of the movement conversion means.
The present invention is characterized in that it comprises a clutch mechanism for releasing and an operating means attached to a cover body for accommodating a base end of the motion converting means for operating the clutch mechanism.

The clutch mechanism has a hollow cylindrical bush fitted on the outer peripheral surface of the motion converting means so as to extend between the speed reducing means and the driving force control means, and is opposite to the output means of the motion converting means. A hollow portion pierced and formed at the base end located on the side, a plurality of communication holes pierced to be communicable with the hollow portion, and an operation rod slidably housed in the hollow portion via a compression spring. And a steel ball movably fitted to the communication hole and detachably engaged with an engagement groove formed in an inner peripheral surface of the bush.

Further, the motion converting means has a plurality of concave grooves formed at a plurality of positions corresponding to the inner peripheral surface of the bush, and a rubber O-ring is fitted into each of the concave grooves. Thus, an auxiliary braking means for generating a predetermined braking force with the bush when the clutch mechanism operates is provided.

A seal bush fitted between the clutch mechanism and the operating means via a seal member on an inner peripheral surface of a cover housing the base end of the motion converting means, and a seal bush of the seal bush. Sealing means constituted by a seal pin slidably fitted on the inner peripheral surface via a seal member and a compression spring for pressing and urging the seal pin in a predetermined direction is interposed.

According to the present invention, a clutch mechanism having a simple structure is provided at the base end side of the motion converting means, and the motion converting means and the driving means are quickly and easily operated by operating the clutch mechanism with the operating means. This is very convenient because the connection with the driving force control means can be released, and only the motion conversion means (screw shaft) can be rotated to retreat the output means (drive rod).

[0013]

FIG. 1 is a block diagram showing an embodiment of the present invention.
This will be described with reference to FIG. FIG. 1 shows a vertical sectional side view of an electric actuator A of the present invention. In FIG.
An electric motor 2 that generates a rotational motion as a driving source; and a deceleration unit 3 that converts the rotational output of the electric motor 2 from, for example, a vertical direction to a horizontal direction and outputs the decelerated output below the electric motor 2 (below FIG. 1). It is comprised including. As shown in FIG. 4, the speed reducing means 3 includes a worm 4 formed at the tip of a rotor shaft 2 a of the electric motor 2 and a worm wheel 5 meshed with the worm 4.
Is reduced to a predetermined speed.

Reference numeral 6 denotes a hollow cylindrical casing in which the speed reduction means 3 and the motion conversion means 7 are arranged and stored linearly in the horizontal direction, and a hollow is provided in the opening 6a (right side in FIG. 1). The base end of the cylindrical fixed cylinder 8 is detachably screwed. An electric motor 2 is mounted upright on an opening end 6b (left side in FIG. 1) located on the opposite side to the opening 6a.

Next, the configuration of the motion converting means 7 will be described. The motion conversion means 7, as shown in FIG.
A screw shaft 9 formed by screwing a trapezoidal screw of the same lead on the distal end side to form a screw portion 9a and forming a support portion 9b smaller in diameter than the screw portion 9a on the base end side; Through a nut 10 that is screwed into the screw portion 9a of the shaft 9,
Hollow cylindrical drive rod 1 drive-coupled to screw shaft 9
1 (output means). When the screw shaft 9 is rotated in a predetermined direction by the driving means 1, the driving rod 11 advances and retreats in a linear direction (the left-right direction in FIG. 1) by the screw action of the nut 10, and is connected to the distal end of the driving rod 11. Operate the operation target.

The supporting portion 9b of the screw shaft 9 has a structure shown in FIGS.
As shown in the figure, on the right end side, a thrust bearing 13 is mounted in a state where a collar 12 is interposed between the screw portion 9a and a radial bearing 14 at almost the center of the thrust bearing 13. Inserted into the fitted bearing housing 15
It is supported in a fixed state, and a driving force control means 16 is arranged between the thrust bearing 13 and the bearing housing 15. In FIG. 1, reference numeral 17 denotes a fixing member such as a retaining ring for preventing the bearing housing 15 from being pulled out of the casing 6. Reference numeral 18 denotes a cover 18 attached to the open end 6b (the left side in FIG. 1) of the casing 6. The support 9b of the screw shaft 9 includes a bearing 18a provided on the cover 18 and a radial bearing 14. And are rotatably supported.

Next, the driving force control means 16 will be described. As shown in FIGS. 1 and 5, the driving force control means 16 includes a holder 19 mounted between the bearing housing 15 and the thrust bearing 13, a one-way clutch 20 press-fitted and fixed to the holder 19, And a metal brake disk 22 attached to the right end of the bearing housing 15 in such a manner that the brake shoe 21 is always in sliding contact with the brake shoe 21. As shown in FIG. 5, the brake disk 22 has an engagement protrusion 22 formed on a part of the outer periphery thereof.
a is engaged with an engaging groove 6c formed at a position corresponding to the engaging protrusion 22a on the inner peripheral surface of the casing 6 so that the casing 6 cannot rotate.

The one-way clutch 20 is
With respect to a rotating object (in this example, the screw shaft 9), it is configured to rotate integrally with the object in one direction and freely rotate the object in the other direction. When the one-way clutch 20 is mounted on the screw shaft 9 shown in FIG. 1, when the screw shaft 9 is to be rotated in the advance direction of the drive rod 11, the screw shaft 9 is freely rotated. 11 is mounted so as to rotate integrally with the screw shaft 9 when rotating in the backward direction.

Therefore, when the screw shaft 9 is rotated by the electric motor 2 of the driving means 1 in the direction for retracting the drive rod 11, the holder 19 to which the one-way clutch 20 is fixed is rotated integrally with the screw shaft 9. As a result, the screw shaft 9 is rotated while generating a braking force between the brake shoe 21 and the brake disc 22 fixed to the holder 19.
In this case, since a predetermined braking force is applied to the screw shaft 9, the rotation is greatly suppressed.

Next, in FIG. 5, reference numeral 23 denotes the screw shaft 9
A one-way clutch 20 of the driving force control means 16 with a hollow cylindrical bush made of metal fitted to the supporting portion 9b;
The worm wheel 5, the one-way clutch 20, and the radial bearing 14 are mounted on the supporting portion 9 b of the screw shaft 9 via a bush 23. In addition, on the inner peripheral surface of the left end (the left end in FIG. 5) of the bush 23, as shown in FIG. , For example, at three locations. Reference numeral 24 denotes a set screw for fastening and fixing the worm wheel 5 to the bush 23 at a plurality of locations (only one location is shown in FIG. 5).

In FIGS. 5 and 7, reference numeral 25 denotes a hollow portion formed at a predetermined depth in the base end (the left side in FIG. 5) of the support portion 9b of the screw shaft 9 in the depth direction (FIG. 5). A step 25a is provided in the vicinity of the center of FIG.
reference). A communication hole 25b communicating between the inside and the outside of the hollow portion 25 is provided at an intermediate position between the step 25a of the hollow portion 25 and the front end portion (right end in FIG. 5) as shown in FIG. For example, three holes are formed at angular intervals.

5 and 6, reference numeral 26 denotes the hollow portion 25.
The operating rod is slidably inserted into the inside, and a flange 26a is formed substantially at the center in the length direction. The collar 26
The first and second bulging portions 2 are located on the right side of FIG.
6b, 26c and a concave portion 26d are formed, and the first bulging portion 26b and the concave portion 26d are connected by a slope 26e having a predetermined inclination angle, as shown in FIGS. . 26f is the left side of the flange 26a (FIG. 5).
(In the left direction).

Reference numeral 27 denotes a step 25a provided in the hollow portion 25.
As shown in FIG. 5, a first bulging portion 26 of the operating rod 26 is a compression spring interposed between the operating rod 26 and the flange 26a of the operating rod 26.
The operating rod 26 is always attached to the fixed member 28 such as a snap ring fitted to the open end (the left end in FIG. 5) of the hollow portion 25 in a state where the communication hole 25b of the screw shaft 9 is aligned with the communication hole 25b. Pressing and urging. Reference numeral 29 denotes a steel ball fitted in the communication hole 25b of the screw shaft 9, and an engagement groove 23 formed on the inner peripheral surface of the bush 23.
The screw shaft 9 is connected to the driving means 1 (worm wheel 5) and the driving force control means 16 attached to the bush 23 by engaging with and detachably from the bush 23.

As shown in FIG. 5, the operating rod 26 is inserted through the compression spring 27 into the hollow portion 25, and a steel ball 29 is inserted into a communication hole 25b communicating between the inside and the outside of the hollow portion 25. The screw shaft 9 and the driving means 1 and the driving force control means 16 are engaged with each other by engaging and disengaging the steel ball 29 with an engagement groove 23 a formed on the inner peripheral surface of the bush 23.
And a clutch mechanism 30 for connecting and releasing the connection.

Reference numeral 31 denotes an operating means for operating the clutch mechanism 30. As shown in FIGS. 1, 2 and 5, the cover 1 is fixed to the open end 6b (left end in FIG. 5) of the casing 6.
8 using a fastening member such as a screw.
A fixed support frame 32 and a pivot shaft 3
3 and a pulling wire 35 attached to the lower end of the operating lever 34. The pulling wire 35 is driven by the electric actuator A as a drive source. It is pulled out to a predetermined position of a device (for example, a bed) to be used.

As shown in FIGS. 1 and 5, the operating lever 34 is always in contact with the operating pin 26f of the operating rod 26 constituting the clutch mechanism 30. By operating with the operating lever 34, the clutch mechanism 30 is operated, and the screw shaft 9 can be connected to the driving means 1 and the driving force control means 16 or the connection can be released.

Reference numeral 36 denotes an auxiliary braking means provided at a position corresponding to the inner peripheral surface of the bush 23 of the support portion 9b of the screw shaft 9, and as shown in FIGS. A plurality of grooves 37 (four in FIGS. 5 and 7) are provided on the outer peripheral surface of the corresponding support portion 9b of the screw shaft 9, and rubber O-rings 38 are fitted into the plurality of grooves 37, respectively. When the clutch mechanism 30 is operated and the connection between the driving means 1 and the driving force control means 16 is released and the screw shaft 9 is rotated, the O-ring 38 contacts the inner peripheral surface of the bush 23. By rotating while sliding,
A braking force is applied to the screw shaft 9.

In FIG. 2, reference numerals 39 and 39 denote pivot shafts of an electric actuator A which is formed integrally with the casing 6 and protrudes in a direction orthogonal to the axial direction of the casing 6, and has a central portion. Mounting holes 40, 40 such as screw holes for pivotally supporting the electric actuator A are formed. In FIG. 1, reference numeral 41 denotes a mounting hole provided at the tip of the drive rod 11.

Next, the operation of the electric actuator A will be described. FIG. 11 shows a usable application example of the electric actuator A. When the electric actuator A is used, the pivot shaft 39 provided on the casing 6 of the electric actuator A comes into contact with a support seat 42 provided at a predetermined fixed place, and the pivot pin 43 is attached to the mounting hole 40 of the pivot shaft 39 from the support seat 42. Is inserted, and the electric actuator A is rotatably supported on the support seat 42. The distal end of the drive rod 11 of the electric actuator A is inserted with the pivot 45 by using the mounting hole 41 at the distal end of the drive rod 11 into the connection fitting 44 of the operation target (for example, the back of the bed) B. To be drivable.

Then, by driving the electric actuator A to move the operation target B, the operation object B is shifted from the lying state (horizontal state) shown by the solid line in FIG.
The case of tilting by a predetermined angle as shown by the two-dot chain line will be described. When the electric motor 2 constituting the driving means 1 of the electric actuator A is started, the worm wheel 5 of the speed reducing means 3 is fitted with the rotation of the electric motor 2 reduced to a predetermined speed by the speed reducing means 3. The drive shaft 11 is transmitted to the screw shaft 9 and turns the screw shaft 9 in a direction in which the drive rod 11 advances.

At this time, the clutch mechanism 30 for connecting the screw shaft 9 with the driving means 1 and the driving force control means 16 is provided by the clutch mechanism 30 shown in FIG.
9A, the communication hole 25b of the screw shaft 9 is provided.
The first bulging portion 26b of the operating rod 26 is present at a position that coincides with the above. The top of the steel ball 29 fitted into the communication hole 25b protrudes from the communication hole 25b and is formed on the inner peripheral surface of the bush 23. Engagement with the engagement groove 23a maintains the connection between the screw shaft 9 and the driving means 1 and the driving force control means 16 attached to the bush 23. 9 and the screw shaft 9 can be rotated.

The nut 10 screwed with the screw shaft 9 by the rotation of the screw shaft 9 is moved to the distal end side of the screw shaft 11 by a screw action as shown in FIG. The drive rod 11 is gradually advanced from the fixed cylinder 8 and the connection fitting 44 of the operation target B connected to the distal end thereof.
11 is tilted leftward in FIG. 11 to tilt the operation target B about the pivot 46 from a lying (horizontal) state shown by a solid line in FIG. 11 to a predetermined angle as shown by a two-dot chain line in FIG. Let it.

When the drive rod 11 is advanced by rotating the screw shaft 9 as described above, the screw shaft 9 is set so as not to receive a braking force by the function of the one-way clutch 20. The screw shaft 9 can be smoothly rotated. Further, when the advancement of the drive rod 11 is stopped halfway (when the drive means 1 is stopped), the drive rod 11 tries to rotate the screw shaft 9 in the opposite direction due to the load applied to the operation target B. Is the driving force control means 1
The brake shoe 21 constituting the brake disc 2
2, a sliding force is generated in a state where the driving rod 11 is pressed by the load, and a braking force is generated. Therefore, the driving rod 11 stops without receiving the braking force without going backward.

Next, a case will be described in which the operation target B is lowered from an inclined state shown by a two-dot chain line in FIG. 11 to a horizontal state as shown by a solid line in FIG. In this case, the electric motor 2 constituting the driving means 1 of the electric actuator A may be started (rotated) in a direction opposite to the previous direction, and the electric motor 2 is started and its rotation is reduced to a predetermined speed by the deceleration means 3. When the screw shaft 9 is rotated in a direction in which the drive rod 11 is retracted by transmitting the screw shaft 9 to the screw shaft 9 in a state where the nut 10 is screwed, the nut 10 screwed to the screw shaft 9 is screwed as shown in FIG. The nut 1 is moved to the proximal end side of the screw shaft 9.
The drive rod 11 attached to the drive object 11 is gradually retracted, and the connection fitting 44 of the operation target B connected to the distal end thereof is pulled rightward in FIG. 11 to move the operation target B about its pivot 46. From the inclined state shown by the two-dot chain line in FIG.
1 is laid down in a horizontal state as shown by the solid line.

When the operation object B is caused to fall down as shown by the solid line in FIG. 11 by retreating the drive rod 11, the entire load of the operation object B is applied to the drive rod 11 and the operation object B is rapidly moved. Try to retreat. But,
The load applied to the drive rod 11 is transmitted to the screw shaft 9 via the nut 10, and the screw shaft 9 is pushed leftward in FIG. 1 to strongly press the brake shoe 21 toward the brake disc 22. The one-way clutch 20 attached to the shaft 9 rotates the holder 19 integrally with the screw shaft 9 and generates a braking force between the brake shoe 21 and the brake disk 22 fixed to the holder 19, so that the driving rod Numeral 11 does not retreat rapidly even when the entire load of the operation target B is received, but retreats in a state in which a braking force is applied, so that the operation target B can fall down smoothly and safely.

At this time, a clutch mechanism 30 for connecting the screw shaft 9 to the driving means 1 and the driving force control means 16 is provided.
As shown in FIGS. 5 and 9A, the first bulging portion 2 of the operating rod 26 is located at a position corresponding to the communication hole 25b of the screw shaft 9.
6b, the top of the steel ball 29 fitted in the communication hole 25b protrudes from the communication hole 25b, and engages with the engagement groove 23a formed in the inner peripheral surface of the bush 23, so that the screw shaft 9 and the screw shaft 9 are connected. Since the connection between the driving means 1 and the driving force control means 16 attached to the bush 23 is maintained, the reduced rotation of the driving means 1 is transmitted well to the screw shaft 9 to rotate the screw shaft 9. In addition, the driving force control means 16 also rotates integrally with the screw shaft 9 to generate a braking force, so that the operation target B can safely fall down.

Next, when a power failure or the like occurs, the operation object B is manually tilted at a predetermined angle as shown by a two-dot chain line in FIG. The case of falling down to the state will be described. In this case, by operating the clutch mechanism 30 via the operating means 31, the drive rod 11 can be easily retracted.

That is, in FIG. 5, by pulling the pulling wire 35 of the operating means 31 rightward in the figure, the operating lever 34 is rotated counterclockwise about the pivot shaft 33, and Is pushed to the right in the drawing. As a result, as shown in FIG. 10, the operating rod 26 has its recess 26d formed against the communication hole 25 of the screw shaft 9 against the elastic force of the compression spring 27.
Move to a position that matches b.

As described above, when the operating rod 26 is pushed and the concave portion 26d of the operating rod 26 and the communication hole 25b of the screw shaft 9 match, the steel ball 29 fitted in the communication hole 25b is removed. Then, the operating rod 26 is released from being supported by the first bulging portion 26b, moves to the concave portion 26d, and is disengaged from the engaging groove 23a formed in the bush 23 (FIG. 9B).
And FIG. However, the steel ball 29 fitted into the communication hole 25b drilled on the lower side of the screw shaft 9 can be moved toward the recess 26d due to the height position between the recess 26d and the engaging groove 23a. Engaging with the engaging groove 23a).

As a result, the screw shaft 9 is connected to the bush 23
Is disengaged, that is, the connection between the worm wheel 5 and the driving force control means 16 which generates a braking force when the screw shaft 9 is retracted, which constitutes the deceleration means 3 of the driving means 1 attached to the bush 23. Is released, and the screw shaft 9 is released.
Can be easily rotated.

As described above, when the connection between the screw shaft 9 and the worm wheel 5 and the driving force control means 16 is released,
The screw shaft 9 starts to rotate gradually by the load of the operation target B transmitted from the drive rod 11 to the nut 10 (clockwise in FIG. 9B). At this time, as shown in FIG. 9B, the communication hole 25b on the lower side of the screw shaft 9 is formed.
Although the steel ball 29 is engaged with the engaging groove 23a due to the height position between the recess 26d of the operating rod 26 and the engaging groove 23a formed in the bush 23, the steel ball 29
When the screw shaft 9 starts rotating, the engagement with the engagement groove 23a is released as shown in FIG. 9C. Further, the screw shaft 9 is pressed by the inner peripheral surface of the bush 23 and moves to the concave portion 26d side, so that the screw shaft 9 can be satisfactorily rotated without hindering the rotation of the screw shaft 9 at all.

The screw shaft 9 is connected to the driving force control means 1.
6, the operation object B is released.
When the load is applied to the screw shaft 9, the auxiliary braking means 36 is provided at a portion of the support portion 9b of the screw shaft 9 corresponding to the inner peripheral surface of the bush 23. The rubber O-ring 38 is
By sliding in contact with the inner peripheral surface and generating a frictional force with the bush 23, it is possible to rotate while receiving a predetermined braking force.

When the screw shaft 9 starts rotating, the nut 10 screwed with the screw shaft 9 moves to the base end side of the screw shaft 9 by a screw action, and the drive rod 11 attached to the nut 10 is moved. The operation target B, which is gradually retracted and connected to the distal end portion thereof via the connection fitting 44, is moved horizontally from the inclined state shown by the two-dot chain line in FIG. 11 around the pivot 46 as shown by the solid line in FIG. In a state of rest.

As described above, according to the present invention, even when the electric actuator A cannot be driven due to a power failure or the like, the clutch mechanism 30 of the electric actuator A can be operated via the operating means 31. By doing so, the connection between the screw shaft 9 and the driving means 1 and the driving force control means 16 can be easily released, and the screw shaft 9 can be rotated. As a result, the load applied to the operation target B is reduced. The drive rod 11 is retracted by rotating the screw shaft 9 using the same, and the operation target B is lowered from a state in which the operation object B is inclined by a predetermined angle indicated by a two-dot chain line in FIG. 11 to a horizontal state as indicated by a solid line. be able to.

Further, when the screw shaft 9 is rotated and the drive rod 11 is retracted in a state where the connection between the screw shaft 9 and the driving means 1 and the driving force control means 16 is released, the screw shaft 9 is rapidly moved. Since the drive rod 11 can be rotated backward while receiving a predetermined braking force by the auxiliary braking means 36 without being rotated, the operation object B connected to the distal end thereof can be safely moved down. be able to.

Next, when the connection between the screw shaft 9 and the driving means 1 and the driving force control means 16 is to be restored, the pulling of the pulling wire 35 is released in FIG. 26 operation pins 26f
Is released.

Thus, the operating rod 26 is connected to the compression spring 2
The elastic member 7 is pressed and urged leftward in FIG. 10 to return to the original position. At this time, the concave portion 26d of the operating rod 26
Is easily moved onto the first bulging portion 26b by using the slope 26e connecting the concave portion 26d and the first bulging portion 26b, and the communication ball 2
5b, and engages with an engaging groove 23a formed in the bush 23, as shown in FIG. 5, to connect the screw shaft 9 with the driving means 1 and the driving force control means 16 mounted on the bush 23.

As described above, when the operating rod 26 returns to the original position, the steel ball 29 existing in the concave portion 26d has the inclined surface 2 connecting the concave portion 26d and the first bulging portion 26b.
By using 6e, it is possible to smoothly move on the first bulging portion 26b and protrude from the communication hole 25b without being affected by the step between the recessed portion 26d and the first bulging portion 26b, Can be engaged with the engagement groove 23a on the inner peripheral surface of the bush 23.

When the connection between the screw shaft 9 and the driving means 1 and the driving force control means 16 is restored, the communication hole 25b of the screw shaft 9 and the engaging groove 23a on the inner peripheral surface of the bush 23 match. If not, the operating lever 26 by the operating lever 34
In a state where the pressing is released, the electric motor 2 of the driving means 1 is started to rotate the bush 23 to which the speed reducing means 3 is attached, so that the engaging groove 23a on the inner peripheral surface of the bush 23 and the communication hole 25b are connected. As a result, the steel ball 29 fitted in the communication hole 25b protrudes from the communication hole 25b and engages with the engagement groove 23a on the inner peripheral surface of the bush 23,
The connection between the screw shaft 9 and the driving means 1 and the driving force control means 16 is restored.

Next, a second embodiment of the present invention will be described with reference to FIG. In the second embodiment shown in FIG. 12, the same members as those in the first embodiment shown in FIGS. The difference between the first embodiment and the second embodiment is that a sealing means 50 is interposed between the operating means 31 and the clutch mechanism 30.

In FIG. 12, reference numeral 51 denotes the sealing means 5.
The seal bush constituting one of the first and second casings 6 is provided in the tubular portion 18b of the cover body 18 attached to the open end 6b (the left side in FIG. 12) of the casing 6 and between the inner peripheral surface of the tubular portion 18b. It is fitted with a seal member 52 made of an O-ring or the like inserted. The seal bush 51 is provided with a support portion 9 for the screw shaft 9 projecting into the cylindrical portion 18b of the cover body 18.
b, a housing portion 51a for housing the base end, and a fitting portion 51b into which a seal pin 53 described later fits.

Reference numeral 53 denotes a seal pin constituting the other of the sealing means 50, and a fitting portion 51b of the seal bush 51.
Is slidably fitted to the inner peripheral surface of the fitting portion 51b with a sealing member 54 made of an O-ring or the like interposed therebetween. At one end (the left end in FIG. 12) of the seal pin 53, a pressing pin 53a which comes into contact with the operating lever 34 of the operating means 31 is provided so as to protrude therefrom.
A pressing portion 53b that presses the operation pin 26f of the operation rod 26 protrudes from the right side of FIG.

Reference numeral 55 denotes a fitting portion 51b of the seal bush 51.
And a compression spring inserted between the other end of the seal pin 53 and a concave portion 53c formed on the other end of the seal pin 53. The seal pin 53 fits a part thereof (the left side in FIG. 12) by the elastic force of the compression spring 55. In the state of being fitted to the joint portion 51b, the cover body 18
12 is pressed and urged via a washer 57 to a fixing member 56 side formed of a retaining ring or the like fixed to the opening end side (the left side in FIG. 12) of the cylindrical portion 18b.

Next, the operation of the second embodiment will be described. In the state shown in FIG.
5 is pulled rightward in the figure, and the operation lever 34 is pivoted to the pivot shaft 33.
, The seal pin 53 in contact with the operation lever 34 via the pressing pin 53a moves rightward in the figure against the elastic force of the compression spring 55.

By the movement of the seal pin 53, the pressing portion 53 b protruding from the other end of the seal pin 53 makes the operating rod 2 protruding into the fitting portion 51 b of the seal bush 51.
6 is pressed against the operating pin 26f, and the operating rod 26 is moved rightward in FIG. 12A against the elastic force of the compression spring 27.

Then, as shown in FIG. 12 (b), the operating rod 26 is connected to the communication hole 2 between the recess 26d and the screw shaft 9.
5b is moved to a position where it coincides with the communication hole 25.
The steel ball 29 fitted to b moves to the concave portion 26d, and the engagement with the engagement groove 23a formed in the bush 23 is released. As a result, the screw shaft 9 is disconnected from the driving means 1 and the driving force control means 16 attached to the bush 23, and can be freely rotated. Devices using the electric actuator A as a drive source can be easily operated.

When the connection between the screw shaft 9 and the driving means 1 and the driving force control means 16 is to be restored, FIG.
In (b), by releasing the pulling of the pulling wire 35, the pressing of the seal pin 53 by the operation lever 34 is released.

Thus, the seal pin 53 is pressed and urged leftward in FIG. 12B by the elastic force of the compression spring 55 and returns to the original position. Accordingly, the operating rod 26 is also moved leftward in FIG. 12B by the elastic force of the compression spring 27. At this time, the concave portion 26d of the operating rod 26
Is easily moved onto the first bulging portion 26b by using the slope 26e connecting the concave portion 26d and the first bulging portion 26b, and the communication ball 2
5b, and as shown in FIG. 12 (a), engages with an engaging groove 23a formed in the bush 23, and connects the screw shaft 9 with the driving means 1 and the driving force control means 16 mounted on the bush 23. connect.

As described above, in the second embodiment, the seal bush 51 and the seal pin 53 are provided in the cylindrical portion 18b of the cover 18 from which the base end of the support portion 9b of the screw shaft 9 projects.
By operating the operating rod 26 via the seal pin 53 with the operating lever 34 and operating the operating rod 26 with the operating lever 34, the airtightness inside the cylindrical portion 18 b of the cover body 18 is maintained, and the Shaft 9 and drive means 1
In addition, the connection with the driving force control means 16 can be released and restored.

Further, the inside of the cylindrical portion 18b of the cover body 18 can be kept airtight by the sealing means 50. As a result, for example, equipment such as a bed provided with the electric actuator A can be used. Even in the case of washing, the electric actuator A can be washed without removing the electric actuator A from a bed or the like while preventing the intrusion of moisture into the casing 6, and also the intrusion of dust and the like can be prevented. it can.

The electric actuator A of the present invention
The operation object B is tilted at a predetermined angle from a horizontal state or is returned from the tilted state to a horizontal state. However, the present invention is not limited to this example. Needless to say, it can also be used when the object B is moved up and down. Further, in the present invention, the electric motor 2 constituting the driving means 1 has been described as an example in which the electric motor 2 is mounted upright on the open end 6b of the casing 6, but the present invention is not limited to this. On the upper side, arranged in parallel with the casing, the rotation of the electric motor is transmitted to a screw shaft via a reduction gear comprising a worm and a worm wheel, and a pair of bevel gears and the like provided on the output side of the reduction gear,
The screw shaft may be rotated.

Further, a locking means for maintaining the pulling operation of the pulling wire 35 is provided in the middle of the pulling wire 35 constituting the operating means 31, and once the pulling operation is performed, the hand is pulled from the pulling wire 35. Even when the screw shaft 9 is released, the disconnected state between the screw shaft 9 and the driving means 1 and the driving force control means 16 may be maintained.

[0063]

As described above, the present invention maintains and releases the connection between the screw shaft and the driving means and the driving force control means on the base end side of the screw shaft constituting the motion converting means. Since the clutch mechanism and the operating means for operating the clutch mechanism are provided, the clutch mechanism and the operating means can be provided by effectively utilizing the dead space of the electric actuator, and as a result, the electric actuator is increased in size. It can be configured without doing.

The clutch mechanism includes a bush fitted on the outer peripheral surface of the screw shaft so as to straddle between the speed reduction means and the driving force control means, and a hollow portion formed by drilling and forming the base end of the screw shaft. An operating rod slidably fitted in the hollow portion, a communication hole communicating between the inside and the outside of the hollow portion, a movable hole fitted in the communication hole, and an inner peripheral surface of the bush. The operation lever is operated by a pull wire attached to the operation lever of the operation means, and the operation lever is operated by simply operating the operation lever by a pulling wire attached to the operation lever of the operation means. The engagement between the steel ball fitted into the communication hole and the engagement groove on the inner peripheral surface of the bush can be released, and the connection between the screw shaft and the driving means and the driving force control means attached to the bush can be released. Requires a lot of time and effort as before Without easily the screw shaft can retract the drive rod is rotated.

Further, since the first bulging portion and the concave portion of the operating rod are connected by a slope having a predetermined inclination angle, the connection between the screw shaft and the driving means and the driving force control means is restored. In the case, when the operating rod returns to the original position by the elastic force of the compression spring, it is fitted into the communication hole of the screw shaft,
In addition, the steel ball at the position of the concave portion can be smoothly used by the first inflation without being affected by the step between the first bulging portion and the concave portion of the operating rod by using the slope. It is possible to move over the protruding portion to protrude from the communication hole and engage with the engagement groove formed on the inner peripheral surface of the bush,
As a result, the screw shaft and the driving means and the driving force control means can be connected smoothly and reliably.

In addition, at a portion corresponding to the inner peripheral surface of the bush of the screw shaft, an auxiliary braking means comprising a concave groove and an O-ring fitted into the concave groove is provided.
When the drive rod is retracted in a state in which the connection between the screw shaft and the driving means and the driving force control means is released, even if the drive rod attempts to retreat rapidly due to a load applied to the operation target connected to the distal end thereof, The screw shaft can be rotated in a state where a predetermined braking force is generated by sliding the O-ring and the bush, so that the operation target having the driving rod connected to the distal end thereof can be operated safely. It becomes possible.

Further, between the clutch mechanism and the operating means,
By interposing the sealing means, it is possible to reliably prevent dust from entering the casing, and for example, even when cleaning a device such as a bed provided with an electric actuator as a drive source, the electric actuator This is convenient because the washing can be performed in a state in which water is prevented from infiltrating into the casing without removing the casing from the bed or the like. Moreover, the clutch mechanism is
By operating the operating means, it is possible to operate satisfactorily while maintaining airtightness via the seal pin of the sealing means.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional side view showing a state in which a drive rod is retracted in an electric actuator of the present invention.

FIG. 2 is a plan view of the electric actuator.

FIG. 3 is a longitudinal sectional side view showing a state where a drive rod is advanced in the electric actuator of the present invention.

FIG. 4 is a cross-sectional view of a driving unit with a main part cut away.

FIG. 5 is a cross-sectional view showing a clutch mechanism with a main part cut away.

FIG. 6 is a perspective view of an operating rod.

FIG. 7 is a perspective view showing a main part of the screw shaft in a cutaway manner.

FIG. 8 is a perspective view of a bush.

FIG. 9 is a fragmentary sectional view for explaining the operation of the clutch mechanism.

FIG. 10 is a fragmentary sectional view showing a state where the clutch mechanism is operated.

FIG. 11 is an explanatory diagram showing an application example of an electric actuator.

FIG. 12 is a cutaway sectional view of a main part showing a second embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1 driving means 9 screw shaft 11 driving rod 16 driving force control means 30 clutch mechanism 31 operating means 36 auxiliary braking means 50 sealing means A electric actuator

Claims (4)

[Claims] An electric motor for generating a rotational motion, a driving means comprising a deceleration means for decelerating the rotational motion of the electric motor to a predetermined speed, and a rotational motion fitted to the deceleration means and converting the rotational motion by the driving means into a linear motion. An electric actuator comprising: a motion conversion unit that performs the linear motion converted by the motion conversion unit; and a driving force conversion unit that is provided in the middle of the motion conversion unit. A clutch mechanism for maintaining / releasing the connection between the motion converting means and the driving means and the driving force control means, and a cover body for accommodating the base end of the motion converting means on the base end side opposite to the means; And an operating means for operating the clutch mechanism. 2. The clutch mechanism according to claim 1, wherein said clutch mechanism has a hollow cylindrical bush fitted on the outer peripheral surface of said motion converting means so as to extend between said speed reducing means and said driving force control means, and is opposed to said output means of said motion converting means. A hollow portion pierced and formed at the base end located on the side, a plurality of communication holes pierced to be communicable with the hollow portion, and an operation rod slidably housed in the hollow portion via a compression spring. , Movably fitted to the communication hole, and
The electric actuator according to claim 1, further comprising a steel ball removably engaged with an engagement groove formed on an inner peripheral surface of the bush. 3. The motion conversion means, wherein a plurality of concave grooves are formed in a portion corresponding to the inner peripheral surface of the bush, and a rubber O-ring is fitted into each of the concave grooves. 3. The electric actuator according to claim 2, further comprising an auxiliary braking unit for generating a predetermined braking force between the bush and the bush when the clutch mechanism operates. 4. A seal bush fitted between the clutch mechanism and the operating means via a seal member on an inner peripheral surface of a cover body for accommodating a base end of the motion converting means, and a seal bush of the seal bush. 2. A seal means comprising a seal pin slidably fitted on an inner peripheral surface of the seal pin via a seal member and a compression spring for pressing and urging the seal pin in a predetermined direction. The electric actuator according to any one of the preceding claims.