JPH07317869A - Linear drive device - Google Patents

Abstract

PURPOSE:To improve wear resistance and to perform continuous use for a long period by a method wherein comparatively simple constitution is provided, precision is improved, manufacture at a comparatively low cost is practicable, rotation of a driven shaft is linearly boosted for conversion, and wear is prevented from being concentrated to a specified driven shaft body. CONSTITUTION:A rotating screw rod-form drive shaft 2 is rotatably and slidably inserted in a cylindrical body case 1. A plurality of rotatable driven shaft bodies 3 brought into pressure contact with the drive shaft 2 and joined in a screwed-in state therewith are pivotally (rotatably) supported to the side plates 4, positioned closer to the both sides, of the body case 1. Each driven shaft body 3 is brought into pressure contact and joined in a screwed-in state with the drive shaft 2 by means of a screw part 5 on an outer periphery or brought into pressure contact and engagement therewith by means of a plurality of annular groove 5a in the outer periphery. This constitution revolves each driven shaft body 3 in a way that each driven shaft body 3 and the body case 1 are brought into pressure contact engagement with each other by means of annular grooves 6 and 7 formed between the former 3 and the latter 1 or a planetary gear part formed at the former 3 is brought into pressure contact engagement with an internal gear part formed at the latter 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a linear drive device for converting a rotary motion into a linear motion, and when a linear motion is obtained from positioning of a robot or the like, feed of a machine tool, or other rotary motion, a drive screw is used. The present invention relates to a device for converting the rotation of a shaft into a linear motion with high accuracy.

[0002]

2. Description of the Related Art The means for converting rotary motion into linear motion is
Although various types have been conventionally devised depending on the use, considerable accuracy is required for positioning of robots and the like, and for feed of machine tools. Conventionally, for example, a feed screw or a ball screw (linear ball unit) has been used as a linear drive device for that purpose. Recently, it has been proposed to use a driven shaft body with a screw without using a nut on the driven side.

A) First, in the feed screw described above, the driven-side nut screwed therein is linearly moved by the rotation of the screw shaft on the driving side. It is used in mobile devices such as. This has a simple structure and can be manufactured relatively easily, and the price is relatively low, and it is possible to obtain a considerable degree of accuracy by precision processing.

B) A ball screw is one in which a ball is interposed between a screw shaft on the drive side and a nut on the driven side to change sliding wear into rolling wear. NC control using a servo motor as a drive source This ball screw is mostly used. This has the advantage that the coefficient of friction is extremely low compared to the feed screw.

C) Further, the driven shaft body with a screw on the driven side is a driven shaft with a plurality of screws rotatably supported by a main body case around a screw rod-shaped drive shaft. Body
It is pressed and screwed together. This is one in which each driven shaft body is rotated by the rotation of the drive shaft, and the main body case supporting the driven shaft body can be linearly driven in the axial direction (see, for example, Japanese Patent Laid-Open No. 5-215196). .

[0006]

However, since the feed screw of a) has a large coefficient of friction and a large frictional resistance as described above, the specific portion of the screw rod and the nut are easily worn.
There is a problem.

Further, the ball screw of the above b) has a complicated structure and is expensive, and since the nut can move only one pitch of the screw thread by one rotation of the screw shaft on the driving side, the linear motion is accelerated. Can not be done.

Further, in the above-mentioned c) in which the driven shaft body with a screw is used on the driven side, the driven shaft body is rotated by the rotation of the screw rod-shaped drive shaft, but the driven shaft body is rotated around the drive shaft. Is not something that revolves around. Therefore, depending on the setting state of the moving block connected to the main body case, the load concentrates on a specific one of the plurality of driven shafts, and only the specific driven shaft wears quickly and lacks durability. There is a problem.

The present invention is intended to solve the problems in the conventional linear drive device. That is, the object of the present invention is a relatively simple structure, excellent in accuracy, can be manufactured at a relatively low cost, the rotation of the driving-side screw shaft can be converted into a linear movement at an increased speed, and a specific follower can be used. It is an object of the present invention to provide a linear drive device in which wear is not concentrated only on a shaft body, wear resistance is improved, and long-term continuous use is possible.

[0010]

[Means for Solving the Problems]

A first linear drive device according to the present invention is configured such that a rotating screw rod-shaped drive shaft 2 is inserted into a cylindrical main body case 1 and a plurality of auto-rotatable members are pressed into the drive shaft 2 and screwed together. Side plates 4 provided with the driven shaft bodies 3 on both sides of the main body case 1
It is rotatably supported by

Each driven shaft body 3 is formed with a threaded portion 5 on its outer periphery to be screwed into pressure contact with the drive shaft 2, and a plurality of annular grooves 6 are formed on the outer periphery of each driven shaft body 3 toward the side. Along with
By forming a plurality of annular grooves 7 on the inner periphery of the main body case 1 toward the side,

By engaging the annular groove 6 of each driven shaft body 3 with the annular groove 7 of the main body case 1 by pressure, each driven shaft body 3 can be revolved.

B The second linear drive device according to the present invention is
A rotating screw rod-shaped drive shaft 2 in a cylindrical body case 1.
A plurality of driven shaft bodies 3 which are inserted into the drive shaft 2 and are screwed into pressure contact with the drive shaft 2 to rotate about them are rotatably supported by side plates 4 provided on both sides of the main body case 1. ,

Each driven shaft body 3 is formed with a threaded portion 5 on its outer periphery to be screwed into pressure contact with the drive shaft 2, and a planetary gear portion 8 is formed on the outer periphery of each driven shaft body 3 toward the side. , The internal gear portion 9 is formed on the inner periphery of the main body case 1 toward the side,

By engaging the planetary gear portion 8 of each driven shaft body 3 with the inner gear portion 9 of the main body case 1 by pressure contact, each driven shaft body 3 can revolve.

C The third aspect of the linear drive device according to the present invention is
A rotating screw rod-shaped drive shaft 2 in a cylindrical body case 1.
A plurality of driven shaft bodies 3 which are inserted into the drive shaft 2 and are screwed into pressure contact with the drive shaft 2 to rotate about them are rotatably supported by side plates 4 provided on both sides of the main body case 1. ,

Each driven shaft body 3 is formed with a plurality of annular grooves 5a in place of the threaded portion on its outer circumference so that the driven shaft body 3 is screwed into pressure contact with the drive shaft 2, and a plurality of driven shaft bodies 3 are formed on the outer circumference near the side. Forming a plurality of annular grooves 6, and forming a plurality of annular grooves 7 on the inner periphery of the main body case 1 toward the side portion,

By engaging the annular groove 6 of each driven shaft body 3 with the annular groove 7 of the main body case 1 by pressure, each driven shaft body 3 can revolve.

D Fourth of the linear drive device according to the present invention is
A rotating screw rod-shaped drive shaft 2 in a cylindrical body case 1.
A plurality of driven shaft bodies 3 which are inserted into the drive shaft 2 and are screwed into pressure contact with the drive shaft 2 to rotate about them are rotatably supported by side plates 4 provided on both sides of the main body case 1. ,

Each of the driven shafts 3 is formed with a plurality of annular grooves 5a in place of the threaded portion on the outer periphery thereof to be screwed into pressure contact with the drive shaft 2, and the planets are formed on the outer periphery of the driven shafts 3 toward the side. Gear part 8
And the internal gear portion 9 is formed on the inner periphery of the main body case 1 near the side portion,

The driven shaft bodies 3 can be revolved by press-fitting the planetary gear portion 8 of each driven shaft body 3 to the internal gear portion 9 of the main body case 1.

In the above structure, the main body case 1 and the side plates 4 on both sides thereof are relatively rotatable. The press-contact screw engagement / press-contact engagement or press-contact engagement means that the drive shaft 2 and each driven shaft body 3, and each driven shaft body 3 and the main body case 1 are screwed / engaged or engaged with each other with almost no rattling. Means a state.

The drive shaft 2 and each driven shaft body 3 are both 2, 3
May have the same diameter, or one of them may have a large diameter and the other may have a small diameter. The threaded portion of the drive shaft 2 and the threaded portion 5 of each driven shaft body 3 to be screwed into pressure contact therewith may be single-threaded screws, or one or both may be multi-threaded screws.

In the case where an annular groove 5a is formed on the outer periphery of each driven shaft body 3 instead of a screw portion and the drive shaft 2 is screwed into the annular groove 5a by pressure contact, the annular groove 5a has a screw portion of the drive shaft 2. Be prepared for the pitch and lead angle of.

[0025]

The operation state of the linear drive device according to the present invention is as follows. a) As described above, around the drive shaft 2 in the main body case 1, a plurality of driven shaft bodies 3 are press-contacted and screwed with the screw portions 5 on the outer circumference, or with a plurality of annular grooves 5a instead of the screw portions. It is provided in pressure contact engagement. When the drive shaft 2 is rotated by a drive motor (not shown), the plurality of driven shaft bodies 3 which are press-contacted and screwed or engaged with each other rotate (rotate) accordingly.

Each driven shaft body 3 has both end portions at the main body case 1.
Since the driven shafts 3 are rotatably supported by the side plates 4 on both sides, the rotational force of the driven shafts 3 becomes an axial driving force to linearly move the main body case 1 in the axial direction. .
Therefore, if a driven block, for example, a mechanical component, is connected to the main body case 1, the component is linearly moved, and the rotary motion of the drive shaft 2 acts as a linear drive device that changes into a linear motion.

In the above description, when the outer diameter of the drive shaft 2 is D1 and the outer diameter of each driven shaft body 3 which is screwed or press-fitted to the drive shaft 2 is D2, when the former 2 is rotated once, the latter 3 is It will rotate (rotate) by "D1 / D2". Therefore, when the outer diameter of the drive shaft 2 is larger than the outer diameter of each driven shaft body 3 (see FIGS. 1 and 2), the former 2 has a large movement distance of the main body case 1 per rotation, so to speak, speed up. You can do it. Conversely, even if the outer diameter of the drive shaft 2 is smaller than the outer diameter of each driven shaft body 3 (not shown), the movement distance of the main body case 1 per rotation of the former 2 becomes smaller, but the former 2 makes one rotation. Since the moving distance of the main body case 1 is added, the speed will be increased, so to speak.

If the threaded portion of the drive shaft 2 or the threaded portion 5 formed on the outer periphery of the driven shaft 3 is formed as a multiple thread, the moving distance of the main body case 1 per one rotation of the drive shaft 2 is Since it is larger than the case of the single-thread screws, the speed is increased in this case as well.

B) On the other side, in the linear drive device according to the present invention, each driven shaft body 3 is not only rotated by pressure contact screwing or pressure contact engagement with the drive shaft 2, but also revolves. That is, the main body case 1 and the plurality of driven shafts 3 are arranged in the annular groove 7 on the inner side of the former 1 and on the outer peripheral side of the latter 3 on the outer side.
Is in pressure contact engagement, or the inner gear portion 9 of the former 1 on the inner side of the side portion is in pressure contact with the planetary gear portion 8 of the latter 3 on the outer side of the side portion.

When the driven shafts 3 rotate by the rotation of the drive shaft 2, the driven shafts 3 frictionally contact the main body case 1 between the annular grooves 6 and 7, or the gear parts 8 and 9 mesh with each other. As a result, the drive shaft 2 is revolved around the inner circumference of the body case 1 together with the side plate 4 which is rotatable relative to the body case 1.

When the outer diameter of the drive shaft 2 is D1 and the outer diameter of each driven shaft body 3 is D2 as described above, the latter 3 becomes "D2 x
It will revolve around π × D1 / D2 ". When each driven shaft body 3 revolves, the load from the driven block connected to the main body case 1 does not concentrate only on one specific driven shaft body, and the plurality of driven shaft bodies 3 are sequentially arranged. Will be received. Therefore, the wear of each driven shaft body 3 becomes uniform, the specific driven shaft body does not wear quickly, and each driven shaft body 3 has improved wear resistance, so long-term continuous use. Is possible.

Among the above, when the driven shaft body 3 and the main body case 1 are in pressure contact with each other by the planetary gear portion 8 and the inner gear portion 9, there is almost no rattling or slippage between the both 3 and 1. Therefore, the revolution of each driven shaft body 3 is performed more reliably.

By forcibly stopping the revolution of each driven shaft body 3, each driven shaft body 3 is less likely to rotate and torque conversion is possible. Therefore, a brake or lock for the linear movement of the main body case 1 is possible. It is also possible to give rise to a function.

[0034]

【Example】

1) FIGS. 1, 3, and 5 show a first embodiment of the linear drive device according to the present invention. Drive motor (not shown)
A plurality of driven shaft bodies 3, here six driven shaft bodies 3, are screwed into pressure contact with the outer periphery of the screw rod-shaped drive shaft 2 that rotates.

That is, side plates 4 are provided on both sides of the cylindrical body case 1 so as to be relatively rotatable, and a drive shaft hole 10 is formed in the central portion of the side plate 4, and the drive shaft hole 10 is driven by the drive shaft. Axis 2
Is rotatably and slidably inserted, and six driven shaft body holes 11 are formed near the outer peripheral portion of the side plate 4,
A side portion of each driven shaft body 3 is rotatably (rotatably) supported by a bearing 12 in each driven shaft body hole 11.

Further, a threaded portion 5 is formed on the outer periphery of each of the six driven shaft bodies 3, and the threaded portion 5 is press-fitted into the threaded portion of the drive shaft 2. Further, a plurality of annular grooves 6 are formed on the outer periphery of each driven shaft 3 toward the side, and a plurality of annular grooves 7 are formed on the inner periphery of the main body case 1 toward the side to form the annular groove of the former 3. The driven shaft bodies 3 can be revolved by engaging 6 with the annular groove 7 of the latter 1 under pressure. When the drive shaft 2 rotates clockwise as in the illustrated example, each driven shaft body 3 also rotates clockwise (see FIG. 5).

(B) FIG. 2, FIG. 4, and FIG. 6 show a second embodiment of the linear drive device according to the present invention, in which the six driven shaft bodies 3 each have a threaded portion formed on the outer periphery thereof. The drive shaft 2 is pressed and screwed at 5. Further, each driven shaft body 3 and body case 1
Means the planetary gear portion 8 formed on the outer periphery of the former 3 near the side portion,
Each driven shaft body 3 is revolvable by being pressed into engagement with an internal gear portion 9 formed on the inner periphery of the main body case 1 toward the side portion. Also in this case, when the drive shaft 2 rotates to the right as in the illustrated example, each driven shaft body 3 also rotates to the right (see FIG. 6). The other parts are the same as those of the first embodiment of the linear drive device according to the present invention, and the description thereof will be omitted.

C) Third of the linear drive device according to the present invention
Since this embodiment looks almost the same as the first embodiment when illustrated, it will be explained with reference to FIG. 1, FIG. 3, and FIG.
A plurality of each of the six driven shaft bodies 3 are press-fitted to the drive shaft 2 by a plurality of annular grooves 5a formed in place of the threaded portion on the outer circumference. Further, each driven shaft body 3 and the main body case 1 are provided with a plurality of annular grooves 6 formed on the outer periphery of the former 3 toward the side.
Are pressed into engagement with a plurality of annular grooves 7 formed on the inner periphery of the main body case 1 toward the side. The other parts are the same as those of the first embodiment of the linear drive device according to the present invention, and the description thereof will be omitted.

D) Fourth linear drive device according to the present invention
Since this embodiment looks almost the same as the second embodiment when illustrated, it will be described with reference to FIGS.
A plurality of each of the six driven shaft bodies 3 are press-fitted to the drive shaft 2 by a plurality of annular grooves 5a formed in place of the threaded portion on the outer circumference. Further, the driven shafts 3 and the main body case 1 are in pressure contact with a planetary gear portion 8 formed on the outer periphery of the former 3 on the side portion side and an internal gear portion 9 formed on the inner periphery of the main body case 1 on the side portion side. I am allowed. The other parts are the same as those of the first embodiment of the linear drive device according to the present invention, and the description thereof will be omitted.

As in the embodiments of the third and fourth linear drive devices, an annular groove 5 is provided on the outer periphery of each driven shaft body 3 instead of the screw portion.
In the case of forming a and screwing it into the drive shaft 2 by pressure in the annular groove 5a, the annular groove 5a is formed so as to correspond to the pitch and the lead angle of the screw portion of the drive shaft 2.

The outer diameter of the drive shaft 2 and the outer diameter of the driven shaft body 3 may be the same, but if the outer diameter of the drive shaft 2 is larger than the outer diameter of the driven shaft body 3 (see FIGS. 1 and 2). In the former case 2, the moving distance of the main body case 1 per one rotation becomes large, and the speed is increased. Conversely, if the outer diameter of the drive shaft 2 is smaller than the outer diameter of the driven shaft body 3 (not shown), the movement distance of the main body case 1 per rotation of the former 2 is small, but the main body 1 is rotated once per rotation of the main body 2. Since the movement distance of case 1 is added, the speed is increased in this case as well.

In each of the first and second b) linear drive units of the above a), the threaded portion 5 of the drive shaft 2 and each driven shaft body 3 press-fitted to the drive shaft 2 may be a single thread. May have multiple threads on one or both, in which case 1
As described above, the linear movement can be accelerated as compared with the case where the threads are threaded.

The side plates 4 in each of the illustrated examples are provided on both outer side portions of the main body case 1, but the side plates 4 may be provided inside the main body case 1. Needless to say, the number of driven shafts 3 is not limited to six in the embodiment.

[0044]

As is apparent from the above, the linear drive device according to the present invention has a relatively simple structure, is excellent in accuracy, can be manufactured at a relatively low cost, and linearly moves the rotation of the driving screw shaft. The speed can be increased and converted to, and the wear is not concentrated only on a specific driven shaft body, and the wear resistance is improved and continuous use can be performed for a long time.

That is, the conventional feed screw has a large frictional resistance and the specific portion of the screw rod and the nut are easily worn, and the ball screw has a complicated structure and is expensive, and it is not possible to increase or reduce the linear motion. Also, with a driven shaft with a screw on the driven side, even if there are multiple driven shafts, the load concentrates on the specific driven shaft at the same location, and only the specific driven shaft wears quickly. Therefore, there was a problem in durability.

On the other hand, the linear drive device according to the present invention is
The ball screw has a simple structure as compared with the conventional ball screw, can be manufactured at a relatively low cost, and can increase the speed when converting the rotation of the drive shaft into the linear movement. In addition to being superior in accuracy to conventional feed screws, it is also superior in durability.

Further, in the linear drive device according to the present invention, the plurality of driven shafts not only rotate but also revolve as compared with the conventional one using a driven shaft with a screw on the driven side. Since each driven shaft receives a load in sequence and the load is not concentrated only on a specific driven shaft, durability can be improved and continuous use over a long period of time can be achieved, which is a useful effect. .

[Brief description of drawings]

FIG. 1 is a partially cutaway vertical front view showing an embodiment of a linear drive device according to the present invention.

FIG. 2 is a partially cutaway vertical front view showing another embodiment of the linear drive device according to the present invention.

FIG. 3 is an enlarged vertical sectional front view of a main part of what is shown in FIG.

FIG. 4 is an enlarged vertical sectional front view of a main part of what is shown in FIG.

FIG. 5 is a partially cutaway side view of what is shown in FIG.

FIG. 6 is a partially cutaway side view of what is shown in FIG.

[Explanation of symbols]

 1-Main Body Case 2-Drive Shaft 3-Driven Shaft 4-Side Plate 5-Screw Part 5a-Ring 5a-Ring 6-Ring 7-Ring 8-Planet Gear 9-Internal Gear 10-Drive Shaft 11- Hole for driven shaft 12-Bearing

Claims (4)

[Claims] 1. A plurality of driven shaft bodies 3 are inserted into a cylindrical main body case 1 and are rotated by screw rod-shaped drive shafts 2. Body case 1
Of the driven shaft body 3 is rotatably supported by side plates 4 provided on both sides of the driven shaft body 3. A plurality of annular grooves 6 are formed on the outer periphery of the shaft body 3 toward the side.
And a plurality of annular grooves 7 are formed on the inner periphery of the main body case 1 toward the side, and the annular grooves 6 of each driven shaft body 3 are pressed into engagement with the annular groove 7 of the main body case 1. The linear drive device is characterized in that each driven shaft body 3 can revolve. 2. A plurality of driven shaft bodies 3 are inserted into a cylindrical main body case 1 and are rotated by screw rod-shaped drive shafts 2. Body case 1
Of the driven shaft body 3 is rotatably supported by side plates 4 provided on both sides of the driven shaft body 3. The planetary gear portion 8 is formed on the outer periphery of the shaft body 3 toward the side portion, and the inner gear portion 9 is formed on the inner periphery of the body case 1 on the side portion side, so that the planetary gear portion 8 of each driven shaft body 3 is formed in the main body case. A linear drive device characterized in that each driven shaft body 3 can revolve by being brought into pressure contact with the inner gear portion 9 of 1. 3. A plurality of driven shaft bodies 3 are inserted into a cylindrical body case 1 and are rotated by screw rod-shaped drive shafts 2. Body case 1
Is rotatably supported by side plates 4 provided on both sides of the drive shaft 3. Each driven shaft body 3 has a plurality of annular grooves 5a formed on its outer periphery instead of a screw portion, and is screwed into the drive shaft 2 by pressure. And a plurality of annular grooves 6 on the outer periphery of each driven shaft body 3 toward the side.
And a plurality of annular grooves 7 are formed on the inner periphery of the main body case 1 toward the side, and the annular grooves 6 of each driven shaft body 3 are pressed into engagement with the annular groove 7 of the main body case 1. The linear drive device is characterized in that each driven shaft body 3 can revolve. 4. A plurality of driven shaft bodies 3 are inserted into a cylindrical main body case 1 and are rotated by a screw rod, and are driven to rotate by being screwed into pressure contact with the drive shaft 2. Body case 1
Is rotatably supported by side plates 4 provided on both sides of the drive shaft 3. Each driven shaft body 3 has a plurality of annular grooves 5a formed on its outer periphery instead of a screw portion, and is screwed into the drive shaft 2 by pressure. And the planetary gear portion 8 is formed on the outer periphery of each driven shaft body 3 toward the side portion thereof, and the internal gear portion 9 is formed on the inner periphery of the main body case 1 toward the side portion of each of the driven shaft bodies 3. A linear drive device in which each of the driven shafts 3 can revolve by press-fitting the planetary gear unit 8 with the inner gear unit 9 of the main body case 1.