JPH09191606A - Motor actuator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To utilize the inertial energy of rotor for increasing the starting torque by drive coupling a deceleration means with a motion converting means while pivoting thereto and clamping the deceleration means and the rear end side of a motor rockingly through a resilient member and then starting the motor under no-load and accelerating the rotor up to a maximum speed. SOLUTION: Since a motor 1 is not secured on the rear end side, reaction to the starting torque of a driving means 6 causes the motor 1 to turn about the output shaft 5a of a deceleration means 3 when the motor 1 is started and a vibration absorbing ring 11 is pressed to the left and moved quickly along the rotational direction of rotor by the read end side of motor 1. Since it takes place substantially under no-load state, the motor 1 can be accelerated to a maximum r.p.m. before the vibration absorbing ring 11 is fully shrunk. When the vibration absorbing ring 11 is fully shrunk, the load of a screw shaft 23 is applied instantaneously to a drive means 6 and a large impact force is generated by the inertial force of rotor of the motor 1. Consequently, tight coupling between the screw shaft 23 and a nut 24 can be released instantaneously.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure provided at two points such as a chair having a mechanism for raising and lowering a seat or inclining a back plate at a certain angle, and a raising and lowering mechanism for raising and lowering a floor of a bed. The present invention relates to an electric actuator including a drive mechanism that linearly moves toward or away from one another.

[0002]

2. Description of the Related Art Conventionally, 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 it is used, and the latter air cylinder requires not only air piping but also a large exhaust noise, which may be a source of noise. In order to use two cylinders as a drive source for raising and lowering or tilting a bed used in a medical institution or a chair for dental treatment, etc., consider the installation space, pressure oil leakage and noise problems. Then it was difficult to use.

[0003]

Therefore, in recent years, an electric actuator has been used which converts the rotational movement of the electric motor into a linear reciprocating movement to drive the driving rod in a linear reciprocating manner. Since the drive source of this electric actuator is an electric motor, it can be miniaturized and can be used in a narrow space, which is convenient. Then, as a means for operating the drive rod, for example, a ball nut of a ball screw shaft is fixed to the drive rod in a non-rotatable manner, the drive rod is drivingly coupled to the ball screw shaft, and the ball screw shaft is rotated rightward or leftward by an electric motor. By doing so, the rotational movement of the ball screw shaft is converted into a linear movement, and the drive rod (which is non-rotatably coupled to the operation target at this point) is linearly reciprocated.

However, in the structure of the ball screw shaft, the structure of the ball screw shaft itself is complicated, and high pressure acts due to point contact between the ball screw shaft and the ball, so that good lubrication is always maintained. In particular, it is easy to cause wear and galling of the ball screw part due to poor lubrication, especially in mechanical devices that are difficult to maintain and manage.
There was a problem that impaired reliability.

Further, in place of the ball screw shaft, there is provided a screw shaft drivingly connected to the electric motor through a speed reducer, and a driving rod having a nut fixed to the screw shaft fixed thereto. The driving rod is screwed by the electric motor. Various methods of rotating the shaft and moving it linearly are also used, but in the case of this method,
A large load is applied to the screwing portion of the nut fixed to the drive rod and the screw shaft by the operation target attached to the tip of the drive rod, and when this state is left for a predetermined time, the screwing portion is As a result of being pressed by the load due to the load, the electric motor requires a large starting torque to start the screw shaft, and in order to obtain a predetermined starting torque using this electric motor with a large starting torque, the electric motor itself is large. In addition to modeling, there were various problems such as installation space, weight, cost, etc., and there was a problem in adopting it lightly.

Further, in order to solve the above-mentioned problem, for example, it is conceivable to increase the reduction ratio of the electric motor according to the external load. In this case, it is necessary to prepare gear trains having greatly different gear diameters, The gear train may be provided in multiple stages,
In this case, even if the drive source is downsized by using an electric motor, the reduction gear itself becomes large, resulting in an increase in installation space and weight.

In view of the above-mentioned various problems, the present invention makes the starting torque of the electric motor extremely large or makes the rotation of the screw shaft of the electric actuator a load applied thereto without using a special starting member. It is an object of the present invention to provide an electric actuator having an improved and simple structure, which is adapted to perform well.

[0008]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides an electric motor as a driving means and a speed reducing means for decelerating the rotational output of the electric motor by, for example, converting it from a horizontal direction to a vertical direction. A motion converting means for converting a rotary motion into a linear motion, and a driving force control means (braking means) built in the motion converting means for controlling the driving force of the motion converting means,
The operation target is linear (horizontal, vertical) or tilted by a drive rod provided in the motion converting means by converting the rotational motion into a linear motion by the motor mounting means for mounting and holding the electric motor swingably. An electric actuator that reciprocates in the direction is configured.

In the electric motor mounting means,
The speed reducing means is drivingly connected to the motion converting means to support the front side of the driving means (the output side of the speed reducing means), and the rear side of the driving means (the rear side of the electric motor) is a ring-shaped vibration absorbing ring (rubber). , An elastic ring made of an elastic member such as a synthetic resin), between the cover and the casing, the electric motor serving as a drive unit having the output shaft of the speed reduction unit as a fulcrum is clamped so as to be swingable at the time of startup. It is configured.

Further, the driving force control means incorporated in the motion converting means releases the braking force when the drive rod is advanced to the side of the operation object, and enables the smooth motion of the motion converting means. When the drive rod retracts due to the load of the operation target, the motion converting means is smoothly driven while applying the braking force, and the drive rod is not retracted by the load (load) when stationary. The one-way clutch that rotates in only one direction is attached to the device.

Further, the motion converting means having the driving force control means built therein is in a state of being floated in the casing of the electric actuator with an anti-vibration member interposed in order to suppress vibration during driving. It is configured to be attached with.

[0012]

In the present invention, when the electric actuator is operated, the motion converting means is provided with the driving force control force means consisting of a one-way clutch that rotates only in one direction. Therefore, for example, the driving rod of the electric actuator is advanced. When pushing the operation target, it is possible to operate by releasing the braking force, while the load of the operation target
When the drive rod is retracted in response to this, the operation target can be operated while applying a predetermined braking force to the motion converting means, so that the electric actuator can be operated safely and reliably.

Further, according to the present invention, the driving means for actuating the motion converting means is sandwiched so that the rear side can be swung by the electric motor mounting means when the front side (output side) is a fulcrum and the rear side is activated. Therefore, when the electric motor is started, it is possible to start the electric motor instantaneously in a no-load state, and as a result, the drive means (the electric motor) causes the rotor of the electric motor to reach the maximum speed in the no-load state. By accelerating, the inertial energy of the rotor can be used for increasing the torque at startup. Therefore, even if the motion converting means is loaded with the entire load of the operation target, by effectively utilizing the torque increase at the time of starting the drive means, the operation target is subjected to a special load from the time of the operation. It can be driven smoothly without applying a load.

Further, according to the present invention, since the electric motor constituting the drive means is operated in a no-load state at the time of starting, that is, the electric motor itself is sandwiched so as to be swingable. Therefore, the vibration accompanying the start of the electric motor tends to be transmitted to the entire electric actuator, but since the vibration absorbing ring at the rear part of the electric motor and the motion converting means are attached to the casing in a state of being levitated via the vibration isolating member, It is possible to satisfactorily absorb and mitigate the vibration at the time of starting the electric motor from propagating to the outside of the electric actuator, and effectively prevent the vibration of the electric actuator from propagating to the operation target and adversely affecting the operation target. It is convenient to avoid.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 shows an electric actuator A of the present invention.
1 is a vertical sectional view of FIG. 1, in which 1 is an electric motor which is a drive source of the electric actuator A, 3 is a front side of the electric motor 1 (the left side of FIG. 1), and the rotational output of the electric motor 1 is As shown in FIG. 4, for example, as shown in FIG. 4, the worm 4 fixed to a rotor shaft (not shown) protruding from the electric motor 1 and the worm 4 meshes with the worm 4 by converting from the horizontal direction to the vertical direction. The worm wheel 5 and the covering member 3a covering the speed reducing means 3 such as the worm wheel 5 in the front part of the electric motor 1 decelerate and rotate the electric motor 1 at a predetermined rotation speed. The electric motor 1 and the speed reducing means 3 drivingly connected to the electric motor 1 constitute a driving means 6 for the electric actuator A.

Reference numeral 7 denotes an electric motor 1 drivably connected to the speed reducing means 3 constituting the driving means 6 of the electric actuator A.
Is an electric motor mounting means for swingably supporting on the casing 8, and the electric motor mounting means 7 is roughly classified as follows.
A ring-shaped casing 8 including a motion converting means 9 which will be described later, a cover 10 covering the casing 8, a rubber fitted to a rear end edge of the electric motor 1, an elastic member such as a synthetic resin having excellent elasticity. It is constituted by the vibration absorbing ring 11.

When mounting the driving means 6, as shown in FIGS. 1 and 6, the upper side of the vibration absorbing ring 11 surrounded by the rear end edge of the electric motor 1 is covered as shown in FIG. Engagement piece 1 with a lower surface vertically extending from the ceiling surface of 10 has an arc shape
The lower side is placed on a mounting piece 13 having a semi-circular upper surface protruding from the lower floor and facing the engaging piece 12 on the upper floor surface of the casing 8. On the other hand, on the front side of the driving means 6, that is, on the speed reducing means 3 side, a seat is fixed to the lower surface of the covering member 3a via a rubber receiving body 14 at the periphery of the opening end of the upper part of the cover body 15 of the motion converting means 9. 16 is mounted. When the cover 8 is capped on the casing 8 in this state, as shown in FIG. 1, the drive means 6 has the speed reducing means 3 on the front side thereof mounted on the motion converting means 9 and the electric motor 1 on the rear side. By sandwiching the rear edge between the engaging piece 12 formed on the cover 10 and the casing 8 and the mounting piece 13 via the vibration absorbing ring 11, the peripheral edge of the electric motor 1 is placed on the floor surface 8a above the casing 8. With a small gap formed between them, they are accommodated and held in a sideways manner.

In this case, as shown in FIG. 6, when the cover 10 is capped on the casing 8, the vibration absorbing ring 11 at the rear edge of the electric motor 1 is elastic by the engaging piece 12 and the engaging piece 13. Is clamped so that it is not pressed so much. In FIG. 1, reference numeral 17 denotes a vibration isolating member made of rubber or sponge interposed between the cover 10 and the upper surface of the front side of the electric motor 1, and the cover 10 includes the vibration absorbing ring 11 and the vibration isolating member 17
It is detachably attached to the casing 8 via a screw member (not shown).

Next, the motion converting means 9 will be described. The motion converting means 9 further decelerates the output from the speed reducing means 3 output via the speed reducing means 3 of the driving means 6, and further converts the output to lateral rotation to output a pair of bevel gears 19, 20 and a trapezoidal screw 22 having the same lead on the tip side, and the bevel gear 20 of the pair of bevel gears 19 and 20 is pivotally attached to the base end and protrudes from the case 21 of the motion converting means 9. Screw shaft 2 in which the trapezoidal screw 22 is screwed only in the part
3 and a drive rod 25 comprising a hollow output means having a base end drivably connected to a nut 24 screwed to the trapezoidal screw 22 of the screw shaft 23.

Of the pair of bevel gears 19 and 20, one bevel gear 19 has a speed reducing means 3 as shown in FIG.
Of the bevel gear 19 is rotatably supported on the upper open end of the cover body 15 via a bearing member.
Engages with the other bevel gear 20 non-rotatably attached to the base end of the screw shaft 23 via a key or the like, converts the output from the speed reducing means 3 to rotate in the horizontal direction, and rotates the screw shaft 23. Rotate. The bevel gear 19 is fitted to the rectangular tube portion at the projecting end of the output shaft 5a and attached to the output shaft 5a so as not to rotate.

On the other hand, the portion of the screw shaft 23 located inside the case 21 is inserted into a bearing housing 27 fitted to the rear end of the bevel gear 20 on the open end side of the case 21.
8 and a bearing member (not shown) attached to the cover body 15 are rotatably supported. The screw shaft 23
Case 2 with a bearing member 28 for rotatably supporting
1 is a bevel gear 1 on its open end (left side in FIG. 1) side.
With the 9 and 20 meshed, the cover body 15 is capped,
From the outside of the cover body 15, as shown in FIG.
By screwing 9 into a screw hole (not shown) of the case 21, a main part of the motion converting means 9 is constructed. Reference numeral 23a shown in FIG. 1 is a collar fixed to the screw shaft 23 on the bottom side of the case 21 by using a locking pin or the like, and 26 is a thrust fixed to the screw shaft 23 by abutting against the collar 23a. It is a bearing.

Further, as shown in FIGS. 2, 7 and 8, the cover body 15 capped on the case 21 has a mounting seat 30 having a mounting hole 30a projecting from the lateral side of the outer periphery thereof, and the casing 8 is accommodated therein. The support rod 31a of the support body 31 formed inside the casing 8b and having the support rod 31a projecting from the tip is inserted through a hollow vibration-proof bushing 32 made of an elastic member such as rubber. At the projecting end edge of the receiving casing 33, a receiving projection 33 is provided inside the closing cover 37 that closes the open end side (the left side in FIG. 2) of the housing casing 8b, which is opposed to the support rod 31a. When brought into contact with and held as shown in FIG. 8, the cover body 15 is suspended without being pulled out by the support rod 31a of the support body 31 as shown in FIGS. In the housing 8b of 8 It is housed and held in a state of being floated with the exception of 30 parts. In FIG. 1, 34 is the case 21.
Is a fixing member such as a retaining ring made of a C-shaped ring for preventing the bearing casing 27 fitted to the opening end of the housing from coming off.

Subsequently, in the tubular portion 35 integrally formed with the casing 8 in the casing 8 in the direction in which the drive rod 25 is attached (the right side in FIG. 1), the casing 8b of the casing 8 is formed. A fixed cylinder 36, which is inserted from one end (right side in FIG. 1) and loosely engages the drive rod 25 so as to be able to move forward and backward, is fitted so as not to be removed. As shown in FIG. 1, the drive rod 25 loosely fitted to the fixed cylinder 36 has a nut 24 fixed to the base end thereof by screwing or the like and screwed into the trapezoidal screw 22 of the screw shaft 23. When the screw shaft 23 is rotated in a predetermined direction, the screw action of the nut 24 advances and retreats in a linear direction, so that a member fixed to the tip of the drive rod 25 can be pushed or pulled back. In addition,
The other housing case 8b of the casing 8 into which the fixed cylinder 36 is fitted.
The closing cover 37 is attached to the open end of the.
As shown in FIG. 1, the screw shaft 23 rotates in a horizontal state from the case 21 to the fixed cylinder 36 by a radial bearing 28, a bearing member (not shown) provided on the cover body 15, and the nut 24. It is held freely.

Next, in FIG. 1, 38 is a motion converting means 9.
Is a driving force control means (braking means) for mechanically controlling the rotation of the screw shaft 23 between the bearing housing 27 and the thrust bearing 26, and the driving force control means 38 is constituted by, for example, a one-way clutch 39. There is. 1 and 5 show an example of mounting the one-way clutch 39 and its configuration. In the drawings, a is outer race, c is roller, and d is d.
Is a rolling groove whose depth increases as it goes in the direction of rotation of the screw shaft 23, and e denotes a spring, which is configured to prevent the screw shaft 23 from rotating in the opposite direction. The one-way clutch 39 is fixedly supported by a holder 39 a mounted between the bearing housing 27 and the thrust bearing 26 in a state of being mounted on the screw shaft 23. That is, the outer race a of the one-way clutch 39 is shown in FIG.
The holder 39a is attached by being press-fitted and fixed.

As shown in FIG. 1, the thrust bearing 26 is held between the collar 23a and the thrust bearing 26 at one end of the holder 39a for fixedly supporting the one-way clutch 39. A brake shoe 40 is fixed to the part. Further, a metal brake disk 41 is provided at the end of the bearing casing 27 corresponding to the brake shoe 40.
Are attached, and the brake shoe 40 and the brake disc 41 are always held in sliding contact with each other.

Thus, this one-way clutch 39
When the screw shaft 23 rotates in the positive direction, the screw shaft 23
When you try to rotate the
Since the holder 39a is configured to rotate integrally with the screw shaft 23, in this example, when the one-way clutch 39 is mounted on the screw shaft 23 between the bearing housing 27 and the thrust bearing 26 shown in FIG. , Drive rod 2
This is possible when trying to rotate the screw shaft 23 in the advancing direction of 5, and conversely, when the screw shaft 23 is trying to rotate in the opposite direction, the screw shaft 23 is prevented from rotating. Is installed as. Therefore, the drive rod 25
When the screw shaft 23 is rotated by the drive means 6 in the direction of retreating, the holder 39a for fixedly supporting the one-way clutch 39 is rotated integrally with the screw shaft 23, and the brake shoe 40 fixed to the holder 39a. Bearing housing 2
Since a braking force is generated between the screw shaft 23 and the brake disc 41 attached to the screw disk 7, a large braking force is applied to the screw shaft 23 to suppress its rotation.

Further, in FIG. 1, reference numeral 42 denotes a bevel gear 20 which is inserted between a retaining shaft 42a fixed to the screw shaft 23 and the bevel gear 20 so that the bevel gear 20 pivotally attached to the screw shaft 23 is constantly thrust bearing 26.
Reference numeral 43 denotes a corrugated washer that is pressed to the side, and 43 is a sealant that also serves as a bearing and that guides the drive rod 25 fitted between the fixed cylinder 36 and the drive rod 25 so that the drive rod 25 can advance and retreat. Further, in the present invention, the casing 8 and the cover 1
0, also at each joint with the closing cover 37, a cover material (not shown) that also serves as a waterproof and dustproof is interposed to cover the cover 1
0 and a closing cover 37 are attached to the casing 8. Reference numeral 44 shown in FIG. 7 denotes a pivot shaft of the electric actuator A which is integrally formed with the cover body 15 and horizontally protrudes from the casing 8b side opening 8c of the casing 8 to the outside of the casing 8. As shown in FIG. 1, a mounting hole 44a such as a screw hole for pivotally supporting the electric actuator A is formed in the.

Next, the operation of the electric actuator A of the present invention will be described. 13 and 14 show application examples in which the electric actuator A can be used. When the electric actuator A is used, its base end, that is, the motion converting means 9 is used.
The pivot shaft 44 of the cover body 15 capped in the case 21 containing the main part of the above is abutted against a support seat 45 provided at a fixed location such as a floor surface, and the support seat 45 pivots the cover body 15 from the support seat 45. A pivot shaft 46 such as a pivot pin is pivotally attached to a mounting hole 44a (see FIG. 1) provided in the support shaft 44 to pivotally support the electric actuator A on the support seat 45. Further, the tip of the drive rod 25, which is the tip of the electric actuator A, is attached to the connecting fitting 47 at the upper end of the pivotal support part f of the operation target (for example, a seat of a treatment chair) B, and the attachment hole 48 ( Figure 1
), And is connected so as to be drivable by inserting the pivot shaft 49.

After the electric actuator A is attached to the operation target B as described above, the operation will be described. First, for example in FIG. 14, drive rod 25
In the case where the operation target B is tilted to raise the operation target B in the vertical direction, the drive means 6 is driven. That is, when the electric motor 1 is started, the output from the electric motor 1 is transmitted to the pair of bevel gears 19 and 20 of the motion converting means 9 via the speed reducing means 3, and the driving shaft 25 advances in the screw shaft 23 (for example, the right direction). Direction).

As shown in FIG. 14, the electric actuator A before actuating the drive means 6 receives the load (load) of the operation object B and is screwed to the base end of the drive rod 25 to be fixed. The nut 24 is screwed into the trapezoidal screw 22 of the screw shaft 23 under the full load of the operation target B as if they were cohesive (tightly coupled). Therefore, the screw shaft 23
When rotating, the drive means having a torque sufficient to repel the load applied to the drive rod 25 is of course required, but the screw part of the nut 24 and the trapezoidal screw 22 of the screw shaft 23 are different from each other. As described above, most of them are in a close-coupled state due to the load applied to the drive rod 25. Therefore, in the drive means only having the torque corresponding to the load of the operation target B, the screw shaft 23 It may be difficult to smoothly rotate.

According to the present invention, when the screw shaft 23 is rotated by the driving of the driving means 6, the electric motor 1 which is a main part of the driving means 6 is swung by the electric motor mounting means 7 at minute intervals. In addition, it is sandwiched between the floor 8 a above the casing 8 and the cover 10. Therefore, the driving means 6
When the motor is started, the electric motor 1 uses the output shaft 5a of the speed reducer 3 as a fulcrum, and the rear end side of the electric motor 1 in the rotation direction (the electric motor
2 is moved clockwise from the position shown in FIG. 2 to the position shown in FIG. 9).

As shown in FIG. 6, the rear edge of the electric motor 1 is sandwiched between the engaging piece 13 on the casing 8 side and the engaging piece 12 on the cover 10 side via the vibration absorbing ring 11. Since only the motor 1 is started, when the motor 1 is started, the motor 1
Since the electric motor 1 itself is not supported by a special fixing means such as a screw, the electric motor 1 is momentarily started in a no-load state. As described above, this is because the rear end of the electric motor 1 is sandwiched between the mounting piece 13 and the engaging piece 12 via the vibration absorbing ring 11, but is not fixed, so that the drive means 6 is started. Electric motor 1 by reaction force of torque
11, the rear end side of the output shaft 5a of the speed reducer 3 is a fulcrum, and the vibration absorbing ring 11 is firmly fixed to the left side of the engaging piece 13 and the engaging piece 12 along the rotational direction of the rotor as shown in FIG. Then, it moves rapidly to the left in FIG.

As a result, since the electric motor 1 is close to the no-load state while the electric motor 1 is rapidly moving, the electric motor 1 can be accelerated up to the maximum number of revolutions before the vibration absorbing ring 11 is completely bent. That is, the load of the screw shaft 23 begins to be applied to the drive means 6 at a stroke only when the vibration absorbing ring 11 is completely bent, so that a large impact force (vibration) is generated by the inertial force of the rotor (not shown) of the electric motor 1. The impact force is the trapezoidal screw 22 of the screw shaft 23 of the speed reducing device 3 → motion converting device 9.
The impact force is transmitted to the portion where the screw portion of the nut 24 and the screw portion of the nut 24 are screwed together, and this impact force can momentarily relieve the tightly coupled state of the screw portion of the screw shaft 23 and the nut 24. Becomes This phenomenon is obtained by using the inertial energy of the rotor of the electric motor 1 as a torque increase at the time of starting the electric motor 1, and the electric motor 1 is, as described above,
Due to the impact force generated at the time of starting, it is possible to momentarily relax the close contact state between the screw shaft 23 and the nut 24.

After that, as shown in FIG. 11, the rear end edge of the electric motor 1 presses the vibration absorbing ring 11 and is urged to the left side of the casing 8, and the electric motor 1 continues to be driven. By releasing the no-load state at this point, the full load of the operation target B and the screw shaft 23 and the nut 2 are released.
Since it receives an adhesion force with 4, the rotational speed of the rotor rapidly decreases and the rotational speed of the rotor momentarily drops to near zero. However, due to the impact force generated when the electric motor 1 is started, the tightly coupled state of the screwed portion between the screw shaft 23 and the nut 24 is momentarily released, so that the output from the electric motor 1, that is, the driving means 6 is output. Even if the number of rotations of the rotor drops, the output is reliably transmitted to the screw shaft 23 of the motion converting means 9 in a state of low speed rotation to rotate the same, and the nut 2
4 is moved to the tip side of the screw shaft 23 to gradually push out the drive rod 25 and push the operation target object B clockwise around its pivot point f, and from the tilted state shown in FIG. Raise in a vertical position as shown.

The screw shaft 23, which is rotated by the activation of the electric motor 1, is set so as not to receive the braking force of the driving force control means 38 by the function of the one-way clutch 39 when the driving rod 25 advances. The screw shaft 23 can be smoothly rotated without being braked by the driving force control means 38. When the advance of the drive rod 25 is stopped midway (when the drive means 6 is stopped), the drive rod 25 is pushed by the load of the operation target B, and the brake shoe 40 is firmly pressed by the brake disc 41. The driving force control means 38 is operated by the braking force acting. As a result, the drive rod 25 is braked by the drive force control means 38 and stops without going backward due to the braking force of the brake shoe 40.

Further, during operation of the electric motor of the driving means 6, as shown in FIG. 11, in the state of being pressed against the left side of the casing 8, a slight vibration is generated with the rotation of the rotor (the electric motor 1 is fixed. However, the slight vibration is propagated to the motion converting means 9 through the speed reducing means 3. However, in the case 21 and the cover body 15 having the motion converting means 9 built therein, the mounting seat 30 is on the casing 8 side. Is supported by a support rod 31a of a support body 31 provided in the housing via a vibration-proof bushing 32, and is accommodated in the housing casing 8b of the casing 8 in a floating state. Although it propagates to the cover body 15 of No. 9, it hardly propagates to the casing 8. Therefore, it is possible to favorably suppress the propagation of this minute vibration to the outside.

Further, when the operation target object B is erected by the advance of the drive rod 25, the load (load) of the operation target object B is the drive rod 25 → nut 24 → screw shaft 23 → collar 23.
a → Thrust bearing 26 → Holder 39a → Bearing housing 27, the load is applied to the fixing member 34, so that the load of the operation target B makes the meshing of the pair of bevel gears 19 and 20 unsmooth.
The output from the driving means 6 is not obstructed from being transmitted to the motion converting means 9, and the output of the driving means 6 can be smoothly transmitted. Moreover, the motion conversion means 9
Is a support rod 31 of the casing 8 via a vibration isolation bush 32.
Although supported by a, the motion converting means 9 itself has the pivot shaft 43 of the cover body 15 pivotally supported by the support seat 44, so that the load of the operation target B is not applied to the casing 8. Since it can be received by the support seat 44, the mounting seat 30 of the motion converting means 9 is not damaged by the load of the operation target B at all, so that the vibration-proofing function of the vibration-proof bushing 32 is maintained well. can do.

Next, a case where the operation target B is retracted from the vertical state shown in FIG. 13 to the electric actuator A side as shown in FIG. 14 will be described. in this case,
It suffices to rotate the drive means 6 of the electric actuator A in the opposite direction to the above. In this case as well, in the same manner as when the drive rod 25 is advanced, the load (load) of the operation target object B on the drive rod 25. Therefore, the nut 24 of the drive rod 25 and the screw shaft 23 are tightly coupled and screwed together.

In this state, when the electric motor 1 of the driving means 6 is started, the rear end side of the electric motor 1 is sandwiched by the electric motor mounting means 7, and the front side of the electric motor 1 supports the output shaft 5a of the speed reducing means 3 as a fulcrum. Since it is pivotally supported by the cover body 15 of the motion converting means 9, the electric motor 1 is momentarily operated in a no-load state only at the time of starting, as when the drive rod 25 advances. As a result, the rotor (not shown) of the electric motor 1 is accelerated by the no-load operation, and the reaction of the electric motor 1 at the time of high speed rotation causes the rear end edge side of the electric motor 1 to rotate with the output shaft 5a of the speed reduction means 3 as a fulcrum. As shown in FIGS. 10 and 12, along the direction, the vibration absorbing ring 11 is rotated counterclockwise.
12, the vibration absorbing ring 11 is pressed firmly to the right side of the mounting piece 13 and the engaging piece 12 and rapidly moves to the right side of FIG. 12, as shown in FIG.

When the electric motor 1 itself rapidly moves in that direction by the activation of the electric motor 1, a large impact force is generated due to the rapid movement, and the impact force is transmitted to the screw shaft 23 of the speed reducing means 3 → motion converting means 9. , At the portion where the trapezoidal screw 22 of the screw shaft 23 and the screw portion of the nut 24 are screwed together,
When the impact force is transmitted, the tightly coupled state of the screwed portion can be alleviated almost instantaneously. As a result,
As shown in FIG. 12, the rear end side of the electric motor 1 continues to be driven in a state in which the vibration absorbing ring 11 is pressed and pressed to the right side of the casing 8, but the rotor of the electric motor 1 is in an unloaded state at this point. Is released, and the full load and adhesion of the operation target B are received, so that the rotation speed thereof rapidly decreases.

Even if the rotation speed of the electric motor 1 rapidly decreases, the nut 24 and the screw shaft 23 attached to the drive rod 25 are attached.
Since the tight coupling with the trapezoidal screw 22 is instantaneously relieved by the impact force generated when the electric motor 1 is started, even if the rotation speed of the electric motor 1 is reduced, the output of the electric motor 1 is output from the driving means 6. It is transmitted to the screw shaft 23 of the motion converting means 9 in a state of low speed rotation and is rotated, and the drive rod 25 is moved to the position shown in FIG.
As shown by 4, retract the electric actuator A side,
The operation target B is pulled back counterclockwise around its pivot point f and tilted from the vertical state shown in FIG. 13 as shown in FIG.

When the operation target B is tilted and retracted as shown in FIG. 14, the drive rod 25 receives the full load of the operation target B and tries to rapidly retract it. However, when a large load is applied to the drive rod 25 as described above, the load force is applied via the nut 24 to the screw shaft 23.
1 is pushed to the left in FIG. 1 to firmly push the brake shoe 40 to the brake disc 41 side, and the one-way clutch 39 attached to the screw shaft 23 makes the holder 39a integral with the screw shaft 23. Since the large braking force is generated between the brake shoe 40 and the brake disc 41, which are fastened to the holder 39a, the drive rod 25 is rapidly retracted even when the operation target B is fully loaded. Instead, the braking force is favorably applied and the vehicle can retreat.

That is, when the operation target B is moved backward by the electric actuator A and tilted as shown in FIG. 14, a one-way clutch 39 is provided in the motion converting means 9.
Since the drive force control means 38 including the brake shoe 40 and the brake disc 41 formed between the one-way clutch 39 and the bearing housing 27 is built in, the drive rod 25 effectively uses the load of the operation target object B. Therefore, it is possible to move backward smoothly and safely.

The electric actuator A of the present invention is
Although the embodiment has been described in which the operation target B is tilted at a certain angle or is vertically erected, the present invention is not limited to this, and the operation target B can be used for raising and lowering or moving in the horizontal direction. Of course. Further, the driving force control means 38 has been described as an example in which the one-way clutch 39 is used, but the invention is not limited to this, and braking means such as an electromagnetic brake may be used. Further, according to the present invention, the rotation of the electric motor 1 is reduced by the speed reducer 3 including the worm 4 and the worm wheel 5.
Once converted to the vertical direction by, then a pair of bevel gears 1
Although the example of performing the lateral conversion again at 9 and 20 has been described, the invention is not limited to this, and the electric motor 1, the speed reduction means 3, and the motion conversion means 9
And may be connected linearly.

[0045]

Since the present invention is configured as described above, it has the following effects. (1) According to the present invention, the drive means momentarily swings at the time of its activation, and the impact force generated by the swing is transmitted to the threaded portion between the motion converting means and the output means, and the tightness of this threaded portion is transmitted. Since the coupling is satisfactorily alleviated and the electric actuator is activated, the electric actuator does not require a driving means for outputting a large torque, and therefore a small-sized and economical manufacturing is possible.

(2) Further, in the constitution in which the driving means is rocked, the front side of the driving means is drivably supported by the movement converting means for converting the rotational movement into the linear movement, and the rear end side is made of the elastic member. Since it has a simple structure in which it is sandwiched by means of, it is convenient because the drive means can be easily supported without using special fixing means.

(3) Further, since the motion converting means is provided with a driving force control means such as a one-way clutch which prevents the output means from moving backward, the output means is required. Therefore, even if the vehicle is retracted under a heavy load, it is safe and reliable and convenient.

(4) In addition, since the motion converting means is installed in a state in which the motion converting means is substantially floated on the casing through the vibration isolating member, the impact force generated when the driving means is started is transmitted to the casing. It is possible to satisfactorily prevent the electric actuator from moving, and there is an advantage that the electric actuator can be used by suppressing vibration and noise.

[Brief description of the drawings]

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

FIG. 2 is a plan view showing the inside of the electric actuator of the present invention with the casing cover removed.

FIG. 3 is a vertical cross-sectional 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 showing a notch of a main part of a speed reducer.

FIG. 5 is a cross-sectional view showing a main part of a one-way clutch.

FIG. 6 is a cross-sectional view showing a supported state of an electric motor which is a main part of driving means.

FIG. 7 is a cross-sectional view showing a mounted state of a main part of the motion converting means.

FIG. 8 is a sectional view of an essential part showing a vibration isolation structure of a motion converting means.

FIG. 9 is an explanatory diagram for explaining the operation of the drive means when the drive rod advances.

FIG. 10 is an explanatory diagram for explaining the operation of the drive means when the drive rod is retracted.

FIG. 11 is an explanatory diagram illustrating a state in which the drive means is swung by the advance of the drive rod.

FIG. 12 is an explanatory view for explaining a state in which the drive means is swung by the retreat of the drive rod.

FIG. 13 is an explanatory diagram showing an application example of the electric actuator.

FIG. 14 is an explanatory diagram showing another application example of the same electric actuator.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electric motor 3 Reduction means 6 Driving means 7 Electric motor mounting means 9 Motion conversion means 11 Vibration absorbing ring 22 Trapezoidal screw 23 Screw shaft 25 Drive rod 34 Fixing member 38 Driving force control means 39 One-way clutch A Electric actuator

Claims (4)

[Claims] 1. A drive means for producing a rotary motion, a motion converting means for converting the rotary motion into a linear motion, and an output means for outputting the linear motion converted by the motion converting means, wherein the drive means is a motion. An electric actuator characterized in that a driving force control means for controlling a driving force of the output means is provided between the movement conversion means and the output means so as to be swingably connected to the conversion means. 2. The drive means comprises an electric motor and a speed reducer having a speed reducer built therein. The speed reducer is pivotally supported by the motion converting means for drive connection, and the speed reducer and the electric motor are on the rear edge side. 2. The electric actuator according to claim 1, wherein the electric actuator is configured to be swingably held by an elastic member. 3. The driving force control means provided between the motion converting means and the output means has a one-way clutch mounted on the screw shaft of the motion converting means drivingly connected to the driving means, and the output means is provided for the screw shaft. 2. The electric actuator according to claim 1, wherein the electric actuator is configured to rotate only in a direction of advancing. 4. The motion converting means is configured to be accommodated in a casing for accommodating the motion converting means in a floating state except for a portion where the vibration isolating member is located. 1. The electric actuator according to 1.