JP2022042147A - Power converting device - Google Patents

Abstract

To provide a small-sized power converting device using a servo motor.SOLUTION: A power converting device 101 is equipped with a servo motor 10 in which a first direction X is a motor axial direction, a worm 20 in which the first direction X is a gear axial direction, a rack 31 that extends in the first direction X, a rack-and-pinion mechanism 30 that has a pinion 32 engaging with the worm 20 and the rack 31, and converts rotary motion around a gear axis A2 of the worm 20 into a linear motion in the first direction X of the rack 31 through the pinion 32, and a gear mechanism 40 that transmits rotations of the servo motor 10 to the worm 20 by the engagement of gears 41 and 42. The servo motor 10, the worm 20, and the rack 31 are disposed in parallel in a second direction Y orthogonal to the first direction X.SELECTED DRAWING: Figure 1

Description

The present invention relates to a power conversion device.

Conventionally, as an actuator constituting a power conversion device, an air cylinder that converts the energy of compressed air into a linear motion of a moving body is known. Generally, an air cylinder is configured such that a piston rod slides in the cylinder using the energy of compressed air. While such an air cylinder is small and can obtain a high output, it is known that energy utilization efficiency is low because the compressed air introduced into the cylinder is discarded in each stroke.

Therefore, it is preferable to use an electric actuator as described in Patent Document 1 below instead of the air cylinder. This electric actuator is configured to move the moving body in a linear direction by rotating a screw means mechanically connected to the moving body with an electric motor. If an electric motor is used, all but heat loss is converted into mechanical energy, so that higher energy efficiency can be obtained as compared with the case of using an air cylinder.

Japanese Unexamined Patent Publication No. 11-351348

However, when a general-purpose electric motor is used, the electric actuator itself becomes larger than when an air cylinder is used, and as a result, there may be a problem that the power conversion device becomes large. Therefore, a small servomotor can be used to make the electric actuator itself smaller. At this time, it is preferable to reduce the size of the entire power conversion device including the servomotor to the same level as when an air cylinder is used by technically devising the peripheral structure of the servomotor.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a compact power conversion device using a servomotor.

One aspect of the present invention is
Servo motors whose first direction is the motor axis direction,
A worm whose first direction is the gear axis direction,
It has a rack extending in the first direction and a pinion that meshes with the worm and the rack, respectively, and a linear motion of the worm around the gear axis of the worm in the first direction of the rack via the pinion. A rack and pinion mechanism that converts into motion,
A gear mechanism that transmits the rotation of the servo motor to the worm by meshing the gears,
Equipped with
The servomotor, the worm, and the rack are juxtaposed in a second direction orthogonal to the first direction, a power conversion device.
It is in.

In the above power conversion device, when the servomotor rotates around the motor axis, the rotation is transmitted to the worm via the gear mechanism, and the worm rotates around the gear axis. Then, in the rack and pinion mechanism, the rotational motion of the worm around the gear axis is converted into a linear motion in the first direction of the rack via the pinion. As a result, the rack can be slid in the first direction as the servo motor rotates.

Here, since an electric actuator such as a servomotor can convert everything except heat loss into mechanical energy, higher energy efficiency can be obtained as compared with the case of using an actuator such as an air cylinder. Further, the servo motor can be made smaller than a general electric motor, and the actuator itself can be made smaller. In addition, the servomotor, worm, and rack are provided so as to extend parallel to each other and are arranged side by side in the second direction orthogonal to the first direction. As a result, when the direction orthogonal to both the first direction and the second direction is set as the third direction, it is possible to keep both the dimensions of the power conversion device in the second direction and the dimensions in the third direction small.

As described above, according to the above aspect, it is possible to provide a small power conversion device using a servomotor.

The perspective view of the power conversion apparatus of Embodiment 1. FIG. The plan view of FIG. FIG. 2 is a cross-sectional view taken along the line III-III. The system configuration diagram concerning the control of the servomotor in the power conversion apparatus of Embodiment 1. FIG. FIG. 2 is a plan view for explaining the movement of the movable body in FIG. FIG. 3 is a cross-sectional view of the power conversion device of the second embodiment corresponding to FIG. The perspective view corresponding to FIG. 1 about the power conversion apparatus of Embodiment 3. The cross-sectional view corresponding to FIG. 3 about the power conversion apparatus of Embodiment 3.

Preferred embodiments of the above aspects will be described below.

In the power conversion device, it is preferable that the rack is arranged on a virtual straight line extending in the second direction through the motor axis of the servomotor and the gear axis of the worm.

According to this power conversion device, the servomotor, the worm, and the rack can all be placed side by side in the second direction. This makes it possible to further reduce the dimensions of the power conversion device in the third direction.

The power conversion device includes a movable body mounted on the rack and a guide shaft attached to the movable body and extended in the first direction in order to guide the movement of the movable body in the first direction. It is preferable to prepare.

According to this power conversion device, the movement of the movable body in the first direction can be guided by the guide shaft, so that the straightness of the movable body can be improved. At this time, the rack also serves as a guide function for the movable body, which is similar to the guide shaft. Therefore, it is not necessary to increase the number of guide shafts more than necessary, and the structure for guiding the movable body can be simplified.

In the power conversion device, it is preferable that the servomotor and the worm are interposed between the rack and the guide shaft.

According to this power conversion device, the movable body can be stably supported by separating the rack from the guide shaft, and the guide function of the movable body can be enhanced.

In the power conversion device, it is preferable that the rack and the guide shaft are arranged on a virtual straight line extending in the second direction through the motor axis of the servomotor and the gear axis of the worm.

According to this power conversion device, the servomotor, the worm, the rack, and the guide shaft can all be arranged side by side in the second direction. This makes it possible to further reduce the dimensions of the power conversion device in the third direction.

Hereinafter, specific embodiments of the power conversion device will be described with reference to the drawings.

In the drawings for explaining this embodiment, unless otherwise specified, the first direction in which the rack moves linearly is indicated by an arrow X, and the second direction orthogonal to the first direction is indicated by an arrow Y. It is assumed that the third direction orthogonal to both the first direction and the second direction is indicated by an arrow Z.

(Embodiment 1)
As shown in FIGS. 1 and 2, the power conversion device 101 of the first embodiment includes a base member 1, a servomotor 10, a worm 20, a rack and pinion mechanism 30, a gear mechanism 40, and a movable body 50. And a guide shaft 51.

The base member 1 is provided upright from the bottom plate portion 2 with the third direction Z as the plate thickness direction and the bottom plate portion 2 with the first direction X as the plate thickness direction and separated from the bottom plate portion 2. It has a side plate portion 3 and an upper plate portion 4 provided in parallel with the bottom plate portion 2 extending from the bottom plate portion 2. A case 5 for accommodating all or a part of the components excluding the movable body 50 is attached to the base member 1.

It should be noted that the term "parallel" as used herein means that the comparison targets may be provided substantially in parallel, and in addition to being strictly parallel, there may be slight inclinations or deviations due to tolerances, assembly errors, and the like. Even if it occurs, it shall be included in the category of "parallel" here.

The servomotor 10 is an electric actuator having a motor shaft 11a (see FIG. 2) extending in the first direction X and having the first direction X in the direction of the motor axis along the motor axis A1. The servomotor 10 is fixed so as to be bridged over two side plate portions 3 of the base member 1. The drive unit 11 and the encoder 12 are housed in the motor housing 10a of the servomotor 10.

Since the drive unit 11 is known, the description of the specific structure is omitted, but the drive unit 11 is composed of a plurality of elements such as a stator, a rotor, and a coil. The encoder 12 is configured as a detector that detects information including the rotation angle of the rotor of the drive unit 11.

The type of the servomotor 10 is not particularly limited as long as it is an electric motor. The servo motor 10 may be a DC motor, an AC motor, or a pulse motor. The configuration of the drive unit 11 is appropriately changed according to the type of the servomotor 10.

The worm 20 is configured as a columnar screw gear having the first direction X as the gear axis direction along the gear axis A2. A spiral screw tooth 20a is provided on the peripheral surface of the worm 20. Both ends of the worm 20 in the first direction X are rotatably supported by two side plate portions 3 of the base member 1. The worm 20 is arranged right beside the second direction Y with respect to the servomotor 10.

The rack and pinion mechanism 30 has a rack 31 and a pinion 32.

The rack 31 is a columnar member extending in the first direction X, and is configured to have a smaller diameter than the servomotor 10 and the worm 20. A plurality of rack teeth 31a are provided on the surface of the rack 31 facing the pinion 32 along the first direction X. The rack 31 is slidably supported in the first direction X by being inserted into through holes (not shown) provided in the two side plate portions 3 of the base member 1.

The pinion 32 is configured as a wheel gear that meshes with the worm 20 and the rack 31 with the third direction Z as the rotation axis direction along the rotation axis A3. The pinion 32 is arranged just beside the second direction Y with respect to each of the worm 20 and the rack 31. The pinion 32 is provided with a plurality of engaging teeth 32a on an arc so as to match the worm 20. The pinion 32 is rotatably supported around the rotation axis A3 by the bottom plate portion 2 and the top plate portion 4 of the base member 1.

When the pinion 32 rotates around the rotation axis A3 as the worm 20 rotates around the gear axis A2, the rack 31 is configured to slide in the first direction X. As a result, the rack and pinion mechanism 30 functions to convert the rotational motion of the worm 20 around the gear axis A2 into a linear motion of the rack 31 in the first direction X via the pinion 32.

The worm 20, rack 31 and pinion 32 are designed to increase the size of each tooth (screw tooth 20a, rack tooth 31a, engaging tooth 32a) to increase surface pressure in order to increase thrust and durability. It is preferable to be done.

The pinion 32 constitutes a worm wheel for the worm 20, and a "worm gear" is formed by a mechanism that combines the worm 20 and the pinion 32. As a result, the pinion 32 concurrently serves as an element of the rack and pinion mechanism 30 and an element of the worm gear. Such a configuration is effective in reducing the number of components constituting the load transfer path from the worm 20 to the rack 31 and simplifying the structure of the load transfer path.

The gear mechanism 40 has a gear 41 coaxially provided at one end of the first direction X of the motor shaft 11a, and a gear 42 coaxially provided at one end of the first direction X of the worm 20. .. The two gears 41 and 42 extend parallel to each other in the first direction X. The two gears 41 and 42 are spur gears whose tooth streaks are straight lines parallel to the axis in the first direction X, and are provided so as to mesh with each other.

At this time, the gear 42 is configured to rotate as the gear 41 rotates with the rotation of the motor shaft 11a around the motor axis A1. As a result, the gear mechanism 40 functions to transmit the rotation of the servomotor 10 to the worm 20 by meshing the two gears 41 and 42.

The movable body 50 is a member that moves in the first direction X with the servomotor 10 as a drive source. The shape of the movable body 50 is appropriately set to a plate shape, a block shape, or the like depending on the intended use of the power conversion device 101. The movable body 50 is attached to one end of the rack 31 in the first direction X and one end of the guide shaft 51 in the first direction X, respectively.

The guide shaft 51 extends in the first direction X so as to be parallel to the rack 31. The guide shaft 51 is similar to the rack 31 in that it is made of a columnar member having the same diameter, but is different from the rack 31 in that it is not provided with the rack teeth 31a.

The guide shaft 51 has a function of preventing rotation of the movable body 50 around the first direction X in order to guide the movement of the movable body 50 in the first direction X. The guide shaft 51 is slidably supported in the first direction X by being inserted into through holes (not shown) provided in the two side plate portions 3 of the base member 1.

The guide shaft 51 is provided at a position opposite to the rack 31 with the servomotor 10 and the worm 20 interposed therebetween. Therefore, the servomotor 10 and the worm 20 are interposed between the rack 31 and the guide shaft 51.

As shown in FIGS. 1 and 2, in the power conversion device 101, the servomotor 10, the worm 20, the rack 31, and the guide shaft 51 are provided so as to extend parallel to each other and are orthogonal to the first direction X. It is arranged (parallel) side by side in the second direction Y. In this case, when the power converter 101 is viewed in the second direction Y, the servomotor 10 and the worm 20 overlap each other in whole or in part, and also in whole or in part with respect to the rack 31 and the guide shaft 51. It is arranged like this.

As shown in FIG. 3, when the power conversion device 101 is viewed in the first direction X, the virtual straight line L and the virtual straight line M are configured to be parallel to each other. Here, the virtual straight line L is a virtual straight line extending in the second direction Y through the motor axis A1 of the servomotor 10 and the gear axis A2 of the worm 20. The virtual straight line M is a virtual straight line extending in the second direction Y through the axis of the rack 31 and the axis of the guide shaft 51. In this configuration, in order to reduce the dimension of the power conversion device 101 in the third direction Z, it is preferable to make the distance between the virtual straight line L and the virtual straight line M as small as possible.

In the case of FIG. 3, there is a deviation between the virtual straight line L and the virtual straight line M, but when the power conversion device 101 is viewed in the second direction Y, the servomotor 10, the worm 20, the rack 31, and the guide shaft 51 are Since all or part of them overlap each other, they are included in the form of "juxtaposed in the second direction Y."

The system configuration relating to the control of the servomotor 10 is not particularly limited, but the one shown in FIG. 4 can be used as an example.

As shown in FIG. 4, in the servomotor 10, the drive unit 11 is electrically connected to the servo driver 13, and the encoder 12 is electrically connected to the control circuit 14. The electric power of the power source B is supplied to the drive unit 11 via the servo driver 13. The detection signal detected by the encoder 12 is transmitted to the control circuit 14 as a feedback signal. The control circuit 14 can accurately determine the rotation speed, rotation position, and the like of the servomotor 10 based on the detection signal from the encoder 12.

The control circuit 14 outputs a control signal for rotation of the servomotor 10 to the servo driver 13 based on the detection signal from the encoder 12 and the command signal from the host ECU 15 such as the controller. As a result, the servomotor 10 is controlled with respect to the rotation direction, rotation speed, rotation start time, rotation stop time, and the like of the motor shaft 11a.

As shown in FIG. 5, the slide position of the movable body 50 in the first direction X is controlled by the control of the servomotor 10. For example, the distance D between the movable body 50 and the base member 1 is adjusted by sliding the movable body 50 between the first position P1 shown by the solid line and the second position P2 shown by the alternate long and short dash line. can do. At this time, by using the servomotor 10, finer grain control is possible as compared with the case of using an actuator such as an air cylinder, and the reliability of control can be improved.

According to the above-mentioned first embodiment, the following effects can be obtained.

In the above power conversion device 101, when the servomotor 10 rotates around the motor axis A1, the rotation is transmitted to the worm 20 via the gear mechanism 40, and the worm 20 rotates around the gear axis A2. Then, in the rack and pinion mechanism 30, the rotational motion of the worm 20 around the gear axis A2 is converted into a linear motion of the rack 31 in the first direction X via the pinion 32. As a result, the rack 31 can be slid in the first direction X as the servomotor 10 rotates.

Here, since an electric actuator such as the servomotor 10 can convert all but heat loss into mechanical energy, higher energy efficiency can be obtained as compared with the case of using an actuator such as an air cylinder. In particular, if a servomotor 10 that performs numerical control based on a feedback signal from the encoder 12 is used, it is possible to further improve energy efficiency.

Further, the servomotor 10 can be made smaller than a general electric motor, and the actuator itself can be made smaller. In addition, the servomotor 10, the worm 20 and the rack 31 are provided so as to extend in parallel with each other, and are arranged side by side in the second direction Y orthogonal to the first direction X. This makes it possible to keep both the dimension of the second direction Y and the dimension of the third direction Z of the power conversion device 101 small. For example, when the second direction Y is the width direction and the third direction Z is the thickness direction, the power conversion device 101 can be miniaturized in both the width direction and the thickness direction.

Therefore, according to the first embodiment, it is possible to provide a small power conversion device 101 using the servomotor 10.

According to the power conversion device 101 described above, the weight can be reduced by simplifying the structure.

According to the power conversion device 101 described above, the movement of the movable body 50 in the first direction X can be guided by the guide shaft 51, so that the straightness of the movable body 50 can be improved. At this time, the rack 31 also serves as a guide function for the movable body 50, which is the same as the guide shaft 51. Therefore, it is not necessary to increase the number of guide shafts 51 more than necessary, and by providing one rack 31 and one guide shaft 51, the structure for guiding the movable body 50 can be simplified.

According to the power conversion device 101 described above, the servomotor 10 and the worm 20 are interposed between the rack 31 and the guide shaft 51, and the rack 31 and the guide shaft 51 are separated from each other to stably support the movable body 50. It is possible to enhance the guide function of the movable body 50.

As a modification particularly related to the power conversion device 101, a structure in which the guide shaft 51 is arranged on the side opposite to the pinion 32 with the rack 31 interposed therebetween can be adopted.

Hereinafter, other embodiments related to the above-described first embodiment will be described with reference to the drawings. In other embodiments, the same elements as those in the first embodiment are designated by the same reference numerals, and the description of the same elements will be omitted.

(Embodiment 2)
The power conversion device 201 of the second embodiment shown in FIG. 6 is different from that of the power conversion device 101 of the first embodiment in the relative arrangement of the servomotor 10, the worm 20, the rack 31, and the guide shaft 51. There is.

In the power conversion device 201, the rack 31 and the guide shaft 51 are both arranged on a virtual straight line L extending in the second direction Y through the motor axis A1 of the servomotor 10 and the gear axis A2 of the worm 20. That is, this embodiment corresponds to a mode in which the deviation between the virtual straight line L and the virtual straight line M is eliminated in FIG.

Other configurations are the same as those in the first embodiment.

According to the power conversion device 201 of the second embodiment, the dimensions of the power conversion device 201 in the third direction Z are implemented by arranging all of the servomotor, the worm, the rack, and the guide shaft side by side in the second direction Y. It is possible to keep the size even smaller than that of the first embodiment.

Other than that, it has the same effect as that of the first embodiment.

(Embodiment 3)
The power conversion device 301 of the third embodiment shown in FIGS. 7 and 8 does not include the movable body 50 and the guide shaft 51, and the servomotor 10, the worm 20, the rack 31, and the guide shaft 51 are relative to each other. The arrangement is different from that of the power conversion device 101 of the first embodiment.

In the power conversion device 301, the rack 31 itself functions as a movable body. Further, as shown in FIG. 8, the rack 31 is arranged on a virtual straight line L extending in the second direction Y through the motor axis A1 of the servomotor 10 and the gear axis A2 of the worm 20.

Other configurations are the same as those in the first embodiment.

According to the power conversion device 301 of the third embodiment, by omitting the movable body 50 and the guide shaft 51, the number of parts can be reduced and the structure can be simplified as compared with the case of the first embodiment. Further, by arranging all of the servomotor 10, the worm 20, and the rack 31 side by side in the second direction Y, the dimensions of the power conversion device 301 in the third direction can be further reduced as compared with the case of the first embodiment. Will be possible.

Other than that, it has the same effect as that of the first embodiment.

As an example of modification particularly related to the above power conversion device 301, when the rack 31 hardly rotates around the first direction X, a structure in which only the guide shaft 51 of the movable body 50 and the guide shaft 51 is omitted is adopted. You can also.

The present invention is not limited to the above-described embodiment, and various applications and modifications can be considered as long as the object of the present invention is not deviated. For example, the following embodiments to which the above-described embodiments are applied can also be implemented.

In the above-described first and second embodiments, the case where only one guide shaft 51 for guiding the movable body 50 is provided has been illustrated, but instead, two or more guide shafts 51 may be provided. ..

In the above-described first to third embodiments, the case where the number of gears constituting the gear mechanism 40 is two has been illustrated, but instead, three or more gears may be provided. For example, one or more different gears may be provided between the two gears 41, 42 so that the different gears mesh with each of the two gears 41, 42.

10 Servo motor 20 Warm 30 Rack and pinion mechanism 31 Rack 32 Pinion 40 Gear mechanism 41,42 Gear 50 Movable body 51 Guide shaft 101,201,301 Power converter A1 Motor axis A2 Gear axis L Virtual straight line X 1st direction Y 1st Two directions

Claims (5)

Servo motors whose first direction is the motor axis direction,
A worm whose first direction is the gear axis direction,
It has a rack extending in the first direction and a pinion that meshes with the worm and the rack, respectively, and a linear motion of the worm around the gear axis of the worm in the first direction of the rack via the pinion. A rack and pinion mechanism that converts into motion,
A gear mechanism that transmits the rotation of the servo motor to the worm by meshing the gears,
Equipped with
A power conversion device in which the servomotor, the worm, and the rack are juxtaposed in a second direction orthogonal to the first direction. The power conversion device according to claim 1, wherein the rack is arranged on a virtual straight line extending in the second direction through the motor axis of the servomotor and the gear axis of the worm. 1 or 2 comprising a movable body attached to the rack and a guide shaft attached to the movable body and extending in the first direction to guide the movement of the movable body in the first direction. The power conversion device described in. The power conversion device according to claim 3, wherein the servomotor and the worm are interposed between the rack and the guide shaft. The power conversion device according to claim 3 or 4, wherein the rack and the guide shaft are arranged on a virtual straight line extending in the second direction through the motor axis of the servomotor and the gear axis of the worm.

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