JP3258168B2 - Linear drive - Google Patents

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 which converts the rotation of a motor into a linear motion of a movable shaft by screwing a screw portion, and linearly moves the movable shaft.

[0002]

2. Description of the Related Art A linear drive of this type is used, for example, for opening and closing a valve of a water supply device. A conventional linear drive device has a structure in which a screw portion is rotated by a motor and a non-rotating movable shaft that is screwed to the screw portion moves linearly, and a fixed screw portion is rotated while the movable shaft is rotated by the motor. There is a structure in which the linear motion is performed by screwing.

[0003]

However, in each of the above linear drive devices, a drive circuit for driving a motor and a rotational position or a moving position of a movable shaft are provided in order to prevent a screw from dropping or screwing. Is provided, and the movable shaft is stopped at the limit position based on the detection signal from the sensor. Therefore, there is a problem that a complicated drive circuit is required and the cost is high.

The present invention has been made in view of the above problems, and has as its object to reduce the cost by reducing the cost of the drive circuit by using a simple structure. It is another object of the present invention to prevent the movable shaft from being bitten by a screw and the occurrence of torque crossing of the movable shaft.

[0005]

Therefore, the invention of claim 1 is provided.
Is the rotor (17) of the motor (5) and the movable shaft (2)
And the rotation of the rotor (17) with the female screw (9)
The movable shaft (2) is straightened by screwing with the male screw (10).
Linear motion that converts the moving axis (2) to linear motion
In the driving device (1), the teeth (15) and
It has a lock portion (15, 23), and is provided by a motor (5).
The rotating missing gear (11) and the missing gear (11)
Has teeth (19a, 19b) that mesh with teeth (15)
And engages with the lock portions (15, 23) of the missing gear (11).
Stopper part (19) for stopping rotation is formed on the outer peripheral surface
Geneva gear (12), and a rotor (17)
With several rotations, the movable shaft (2) moves straight
The locks (15, 23) of the missing gear (11) and Geneva
By stopping engagement of the gear (12) with the stopper (19)
The linear motion range of the movable shaft (2) is regulated.

A second aspect of the present invention is a linear drive device.
In (1), a tooth portion (15) also serving as a lock portion is provided on the outer peripheral surface.
Gear (11) having a rotation by a motor (5)
With the tooth portion (15) also serving as the lock portion of the missing gear (11).
Moving the movable shaft (2) straight along the teeth (19a, 19b)
Geneva gear (1) formed on the outer peripheral surface of the portion corresponding to the range of motion
2), the rotor (17) is rotated a plurality of times to
The shaft (2) is moved linearly, and the Geneva gear is used.
The linear motion of the movable shaft (2) due to the regulation of the rotation range of (12)
We are trying to regulate the area.

Further, the invention according to claim 3 is a linear drive device.
In the arrangement (1), the tooth portion (15) and the tooth
With a lock part (23) that also serves as a tooth part different from the part (15)
A missing gear (11) rotated by a motor (5);
Tooth portion meshing with tooth portion (15) of missing gear (11) on the outer peripheral surface
(19a, 19b), and also serves as the tooth part of the missing gear (11)
Stops rotation by engaging with two surfaces of lock portion (23)
Geneva gear (1) having a stop portion (22) formed on the outer peripheral surface
2), the rotor (17) is rotated a plurality of times to
The shaft (2) is moved linearly, and the Geneva gear is used.
The linear motion of the movable shaft (2) due to the regulation of the rotation range of (12)
We are trying to regulate the area.

According to the present invention, the outer peripheral surface of the partial gear (11)
Lock portions (15, 23) and the outer periphery of the Geneva gear (12)
When the engagement with the stopper (19) of the surface is stopped, the movable shaft
The (2) linear motion range is regulated. others
Between the missing gear (11) and the Geneva gear (12)
Large deceleration does not increase torque on the Geneva gear (12) side
The missing gear (11) and the Geneva gear (12)
Linear motion of movable shaft (2) with small torque between
A stopper mechanism that regulates the area can be configured, a missing gear
(11) and Geneva gear (12)
The embedded space can be used effectively,
Linear motion of the movable shaft (2) near these built-in spaces
The need for a stopper mechanism that regulates the area is eliminated.
The effect is obtained.

[0009]

DETAILED DESCRIPTION OF THE INVENTION Figure 1 to indicate to Linear drive device 1 in FIG. 4, is applied to a structure for linear movement of the movable shaft 2 in a non-rotating state. More specifically, the movable shaft 2 is rotatably supported by a housing 3 connected to a motor 5 via a bearing 4 so as to be able to linearly move, and is prevented from rotating by a D hole 6. A cylindrical portion 8 is coaxially connected to the motor shaft 7, and a female screw portion 9 is formed on the inner peripheral surface of the cylindrical portion 8.
Is formed on the outer peripheral surface of the movable shaft 2.

In this example , as a stop mechanism, a missing gear 11 rotated by a plurality of rotating motors 5, a Geneva gear 12 meshing with the missing gear 11, and a Geneva gear 1
2 and a stopper 14 which engages with the engaging portion 13 to regulate the rotation range of the Geneva gear 12.
And a structure in which the rotation range of the Geneva gear 12 is restricted to regulate the linear motion range of the movable shaft 2.

That is, as shown in FIG.
Is fixedly connected to the motor shaft 7 and has a missing gear 11 formed on the outer peripheral surface of the base of the cylindrical portion 8.
It has one thick tooth portion 15 and thin continuous teeth 11a. FIG.
As shown in FIG. 5, the Geneva gear 12 is rotatably supported by the housing 3, has large and thin teeth 15a and small thick teeth 15b alternately on the outer peripheral surface, and protrudes in a semicircular shape on the end surface. It has an engaging portion 13.

As an example, the stopper portion 14 is obtained by cutting and raising a part of the base plate 16, and the engaging portion 13 abuts on the cut portion so that the rotation range of the Geneva gear 12 becomes approximately 180 degrees according to this embodiment. The moving range of the movable shaft 2 is thereby regulated. In the case of the first embodiment, the missing gear 11
Is formed integrally with the cylindrical portion 8, but may be formed by a separate member.

[0013] to the next, a description will be given of the operation. First, in order to align the origin of the electric system of the drive circuit (not shown) with the origin of the mechanical system, the drive circuit sends a larger number of pulses than the required number of pulses, that is, pulses of the number of oversteps, to the motor 5. When the origin position of the mechanical system is set to, for example, the retreat limit position of the movable shaft 2, the plurality of rotations of the motor shaft 7 of the motor 5 causes the cylinder portion 8 to rotate a plurality of times in the counterclockwise direction in FIG. The missing gear 11 is driven to rotate.

By the rotation of the screw portion 9, the movable shaft 2 in the non-rotational state is screwed into the screw portion 10 and the screw portion 9 as shown in FIG.
Retreats to the left at For each revolution of the missing gear 11,
The Geneva gear 12 intermittently rotates by two teeth and stops. At this stop, the two small thick teeth 15b are in sliding contact with the outer peripheral surface of the thin continuous teeth 11a, so that the Geneva gear 12 is in a detent state.

Eventually, since the Geneva gear 12 has been turned oversteps several times, the end face of the engaging portion 13 hits the stopper portion 14 and the rotation of the Geneva gear 12 is prevented, so that the movable shaft 2 is in the retreat limit position, that is, the mechanical system. Is reliably stopped at the origin. At this point, the origin of the electric system of the drive circuit (not shown) matches the origin of the mechanical system. This origin adjustment ensures the subsequent position control. At this time, since the gap GP2 is formed in the axial direction between the inner bottom surface of the cylindrical portion 8 and the end of the screw portion 10, the screw portion 9 and the screw portion 10 are formed.
There is no bite between them.

Next, when a pulse of a required number of steps is given to the motor 5 by a drive circuit, and the cylinder 8 is rotated clockwise in FIG. 2, the operation of the movable shaft 2 is reversed, and the movable shaft 2 is moved backward. 2 moves forward and stops at the target position.

As described above, since the linear motion of the movable shaft 2 is stopped by stopping the rotation of the Geneva gear 12 by the stopper portion 14, there is no difference between the escape torque and the normal drive torque. The circuit needs only the direction reversing function. Therefore, it is possible to make the drive circuit simple and reduce the cost.

In the above example, the missing gear 11 is composed of two teeth, but the number of teeth is determined as required. The number of the large thin teeth 15a and the small thick teeth 15b of the Geneva gear 12 also changes accordingly. Further, the origin position of the mechanical system may be the forward limit position as required, instead of the backward limit position. At this time, the gap GP1 is formed in the axial direction, so that there is no difficulty between the screw portion 9 and the screw portion 10. Furthermore, when the movable shaft 2 is stopped at the backward limit or the forward limit, the origin can be adjusted by a method of detecting an increase in the current of the motor 5 or a method of detecting a disturbance in the voltage waveform.
Can also be set.

The linear drive device 1 of the example shown in FIGS. 5 and 6 is applied to a structure in which the movable shaft 2 is caused to move linearly while rotating, and includes a spline mechanism 18 and a motor 5 such as a step motor. In this configuration, the movable shaft 2 is moved linearly while rotating. That is,
The rotor 17 is inserted into the stator 21 of the motor 5, and the movable shaft 2, which is movable in the axial direction as the rotation shaft of the rotor 17, is formed by the bearing 4 and the screw 1 of the motor case 5 b.
0 and is rotatably supported in the axial direction.

The spline mechanism 18 transmits the rotation of the rotor 17 to the movable shaft 2 which can move in the axial direction. The spline mechanism 18 is formed on the outer peripheral surface of the movable shaft 2 and on the inner peripheral surface of the rotor 17. It is composed of a row of grooves. The screw portion 10 formed on the outer peripheral surface of the movable shaft 2 and the screw portion 9 formed on the inner peripheral surface of the cylindrical portion 8 fixed to the stator yoke 20 convert the rotational motion of the rotor 17 into the linear motion of the movable shaft 2. Convert.

As a stop mechanism for stopping the movable shaft 2 at the limit position, a cut-out gear 11 integrally formed with the rotor 17 and a Geneva gear 12 meshing with the cut-out gear 11 are provided inside the motor cases 5a and 5b. , Geneva gear 12
The linear motion range of the movable shaft 2 is restricted by the regulation of the rotation range. The cut-out gear 11 is a thick one that also serves as a lock portion on the outer peripheral surface.
The teeth 15 and the thin continuous teeth 11 on the outer peripheral surface other than the teeth 15
a. The Geneva gear 12 is rotatably supported by the motor case 5b, and the outer peripheral surface of the Geneva gear 12 has a thin tooth portion 19a meshing with the missing gear 11 at a portion corresponding to the linear motion range of the movable shaft 2, and a thick tooth portion. 19b, tooth space 1 between them
9c and a fan-shaped stopper portion 19 are formed.

The stopper mechanism (the missing gear 11, the Geneva gear 12) can be provided outside the motor cases 5a, 5b. Further, the missing gear 11 may be separate from the rotor 17 instead of being integral with the rotor 17.

Next, the operation will be described. In the initial stage of driving, in order to return the movable shaft 2 to the retreat limit, that is, to the origin position of the mechanical system, a pulse of the number of oversteps is sent from the drive circuit (not shown) to the motor 5 to rotate the rotor 17 in reverse. As a result, the movable shaft 2 returns to the retreat limit, that is, returns to the mechanical origin position and stops. At this point, the origin of the electric system of the drive circuit (not shown) matches the origin of the mechanical system. This origin adjustment ensures the position control.

[0024] than then driving circuit (not shown), send the necessary pulses to the motor 5 to send the movable shaft 2 to the target position, when the plurality rotate the rotor 17 in the positive direction, a plurality of rotor 17 by the spline mechanism 18 The rotation is transmitted to the movable shaft 2. The rotational motion of the movable shaft 2 is converted into a linear motion by screwing the screw portion 10 and the screw portion 9 of the cylindrical portion 8. Therefore, the movable shaft 2 moves forward while rotating. And
Finally, one thick tooth portion 15 also serving as a lock portion is a stopper portion.
19, and the Geneva gear 12 stops within one rotation.
Then, the movable shaft 2 stops at the target position. At this time, since the gap GP2 is formed in the axial direction, the screw portion 9 is formed.
And the screw portion 10 are not easily attached.

When the movable shaft 2 advances , the Geneva gear 12 rotates by the number of two teeth each time the missing gear 11 makes one rotation. After this rotation, the thin continuous teeth 11a are turned into two thick tooth portions. Since the Geneva gear 12 is in a non-rotating state in contact with the 19b, malfunction due to free rotation of the Geneva gear 12 is caused.
Is impossible . Also, the origin position of the mechanical system may be the forward limit position as required, instead of the backward limit position. At this time, the gap GP1 is formed in the axial direction, so that there is no difficulty between the screw portion 9 and the screw portion 10.

The reason why the pulses of the number of oversteps are sent to the motor 5 is to prevent a deviation between the origin of the mechanical system and the origin of the electric system. Even if a power failure occurs during the operation of the motor 5 or a shift occurs in the feed position of the movable shaft 2, the above-described number of oversteps of the feed drive ensures a reliable home position each time. Since the alignment can be performed, no malfunction occurs in the position control.

As described above, since the movable shaft 2 is configured to perform the linear motion while rotating, the conventional D hole portion is not required, and therefore, the movable shaft 2 can be prevented from being bitten or having a torque loss. In addition, since the stopper mechanism is composed of the Geneva gear 12 and the missing gear 11, no biting occurs between the screw portions 9 and 10.
Further, in the drive circuit, it is only necessary to send the pulse of the necessary number of steps in the reverse direction after sending the pulse of the number of oversteps to the motor 5, so that the configuration of the drive circuit can be simplified.

[0028] shown to Example 7 is an improvement of the strike-up mechanism, concave stop portion 22 on the outer peripheral surface of the stopper portion 19
And using the involute flank surfaces at both ends of the thin continuous teeth 11a to lock them together with the locking portions 2 serving as the tooth portions.
It is set to 3. When the missing gear 11 and the Geneva gear 12 are in a locked state, the stop portion 22 and the lock portion 23 come into contact with each other at two locations (a portion and a portion), thereby dispersing the force and reducing partial wear. To prevent. Therefore, at the stop position, the two contact surfaces contact each other from different directions, so that there is no partial loss and the opposing force at the time of stop can be increased.

Instead of the spline mechanism 18, the transmission means may be constituted by a square hole formed in the rotor 17 and a square axis formed in the movable shaft 2. Further, the conversion means of the rotation-linear motion forms a screw hole in the movable shaft 2, and fixes a screw rod to the screw portion 9 of the screw hole and the stator yoke 20.
The threaded portion 10 of the threaded rod may be used.

[0030] Each stop mechanism may also be applied to the movable shaft 2 structure or to linear motion in the non-rotating state, also replaced with any structure for linear motion while rotating the movable shaft 2.

FIG. 8 shows a specific example incorporating Linear drive device 1 to the valve 24. Linear drive 1
Are attached to the mounting surface 26 of the valve body 25 together with the sealing member 28 on the motor case 5b side.
Has been fixed by. The movable shaft 2 penetrates through the holes of the bearing portion 4, the seal cap 29 and the seal member 28, faces the fluid passage 30 inside the valve body 25, and comes into contact with the valve seat 32 by a valve 31 fixed to the tip. ing.

Here, the center holes of the bearing part 4, the seal cap 29 and the seal member 28 are formed slightly larger than the outer diameter of the movable shaft 2. As a result, the movable shaft 2 is supported by the screw portions 9 and 10 at the rear portion, and is supported by the large hole at an intermediate portion so as to be movable in the radial direction. Therefore, when the valve 31 comes into contact with the valve seat 32, the movable shaft 2 is in a state of being supported only at the two positions of the screw portions 9, 10 at the rear end and the valve 31 at the front end.

On the other hand, if the center hole of the intermediate bearing portion 4, the seal cap 29 and the seal member 28 also supports the movable shaft 2, the movable shaft 2 is supported at three points as a whole. When the shaft centers do not coincide with each other, an excessive load is applied, and the movable shaft 2 may be locked.

However, in the two-point support as described above, since an excessive load is not applied, a malfunction does not occur due to a dimensional error or a displacement during assembly, and stable operation can be expected. As described above, the movable shaft 2 is supported at two points at the front and rear ends, and allows movement in the radial direction with respect to the center hole of the bearing portion 4 and the seal member 28 at the intermediate portion. The alignment accuracy may be low to some extent, which facilitates manufacture.

The seal member 28 is provided on the valve body 25.
An O-ring 33 is interposed between the
An O-ring 34 is interposed between the linear drive device 1 and the fluid passage 30 to block water intrusion.

The lead wire 36 of the coil 35 of the stator 21 is led out of the motor case 5b while being sandwiched between elastic members 37 such as sponge and rubber sheet.
When the linear drive device 1 is mounted on the mounting surface 26, the elastic member 37 is attached to the mounting surface 26 and the waterproof cover 5c.
The lead wire 36 is elastically pressed into contact with the lead wire 36, so that a reliable waterproof function can be obtained at the lead-out portion of the lead wire 36. In the past, the position of the lead wire was aligned with the high-precision elastic material according to the thickness and number of the lead wires, and the pressure contact was assembled.However, by using such a soft thick sheet material, the waterproof effect can be easily and completely completed. Is obtained. In order to make it safer, another sheet may be added between the waterproof cover 5c and the lead wire 36. The elastic member 37 eliminates direct contact between the lead wire 36 and the circuit board 38 incorporated in the motor case 5a, and also helps prevent a short circuit accident.

[0037]

According to the first aspect of the present invention, the lock portion of the missing gear that is rotated by the plurality of rotating rotors and the missing gear are provided.
The linear motion range of the movable shaft is restricted by stopping the engagement of the Geneva gear that meshes and rotates only within one rotation or less with the stopper portion. Therefore, by stopping the rotation of the Geneva gear, the linear movement of the movable shaft can be stopped. As a result, there is no difference between the escape torque and the normal drive torque, and the drive circuit needs only the direction reversing function. Therefore, it is possible to make the drive circuit simple and reduce the cost.

In particular, there is a large gap between the missing gear and the Geneva gear.
Speed reduction without increasing torque on the Geneva gear side.
You. Due to this large deceleration, less than one rotation of the Geneva gear
Within the range, a sufficient linear motion range of the movable shaft can be secured,
With a small torque between the missing gear and the Geneva gear
A stopper mechanism that regulates the linear motion range of the movable shaft can be configured.
You.

Assembly with small missing gear and Geneva gear
So that their embedded space can be used effectively,
Close to the built-in space, the linear motion range of the movable axis
Eliminating the need for a regulating stopper mechanism
I can get it.

The lock portion on the outer peripheral surface of the missing gear and the Geneva gear
When the engagement with the stopper on the outer peripheral surface is stopped, the
Because the range of motion is regulated,
The built-in space of NEVA gears can be used effectively,
In particular, except for the outer peripheral surface of the missing gear and the outer peripheral surface of the Geneva gear
Position, for example, around the axis of the missing gear or Geneva gear, on the side of the gear
There is no stopper mechanism on the surface that regulates the linear motion range of the movable shaft.
It becomes important.

According to the second aspect of the present invention, the tooth portion of the missing gear is
Since the lock is also used, the gear configuration can be simplified.
You.

According to the third aspect of the invention, the tooth portion of the missing gear also serves as the tooth portion.
Lock part and the stop part of the Geneva gear abut on two sides and become locked, so there is little partial wear,
Also, the opposing force at the time of locking can be increased.

[Brief description of the drawings]

1 is a cross-sectional view showing a Linear drive device. In this figure, with respect to the center line of the movable shaft, the upper part of the movable shaft shows a state in which it is in the forward limit, and the lower part of the movable shaft shows a state in which it is in the backward limit.

FIG. 2 is a front view showing a main part of the linear drive device.

FIG. 3 is a configuration diagram showing a cylindrical portion and a missing gear thereof.

FIG. 4 is a configuration diagram showing a Geneva gear.

5 is a cross-sectional view showing a Linear drive device. In this figure, with respect to the center line of the movable shaft, the upper part of the movable shaft shows a state in which it is in the forward limit, and the lower part of the movable shaft shows a state in which it is in the backward limit.

FIG. 6 is an enlarged front view of the missing gear and the Geneva gear.

FIG. 7 is an enlarged front view of the missing gear and the Geneva gear.

8 is a cross-sectional view of an example incorporating a Linear drive device to the valve.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Linear drive device 2 Movable shaft 3 Housing 4 Bearing part 5 Motor 5a Motor case 5b Motor case 5c Waterproof cover 6 D hole part 7 Motor shaft 8 Cylindrical part 9 Screw part 10 Screw part 11 Partial gear 11a Thin continuous tooth 12 Geneva gear 13 Engaging part 14 Stopper part 15 Tooth part 15a Large thin tooth part 15b Small thick tooth part 16 Base plate 17 Rotor 18 Spline mechanism 19 Stopper part 19a Thin tooth part 19b Thick tooth part 19c Tooth groove 20 Stator yoke 21 Stator 22 Stop part 23 Lock Part 24 Valve 25 Valve body 26 Mounting surface 27 Mounting screw 28 Seal member 30 Fluid passage 31 Valve 32 Valve seat 33 O-ring 34 O-ring 35 Coil 36 Lead wire 37 Elastic material 38 Circuit board GP1, GP2 Gap

Claims (3)

(57) [Claims] The rotor (17) of the motor (5) and the rotor (17)
Has a shaft (2), the translatory movement of the rotor female threaded portion rotation (17) (9) and screwed into by Rika shaft of the male threaded section (10) (2) In the linear drive device (1) that converts and moves the movable shaft (2) linearly , the tooth portion (15) and the lock portions (15, 23) are provided on the outer peripheral surface.
Missing gear (11) having and rotating by a motor (5)
If, teeth meshing with the teeth (15) of the partial teeth (11) on the outer peripheral surface has a (19a, 19b), lock of the partial teeth (11)
Stop that engages with the locks (15, 23) to stop rotation.
Includes path portion and a Geneva gear (12) formed on the outer peripheral surface (19) and the rotor (17) is more rotated, the movable shaft
(2) is made to move linearly, and
(15, 23) and Geneva gear (12) stopper
A linear drive device (1) characterized in that a linear motion range of a movable shaft (2) is regulated by stopping engagement with a portion (19 ). 2. The rotor (17) of the motor (5) and a rotor (17).
Has a shaft (2), the translatory movement of the rotor female threaded portion rotation (17) (9) and screwed into by Rika shaft of the male threaded section (10) (2) A linear drive device (1) for converting and moving the movable shaft (2) in a straight line , having a tooth portion (15) also serving as a lock portion on the outer peripheral surface, and a missing gear (11) rotated by a motor (5); Missing gear (1
The tooth portion (1) meshing with the tooth portion (15) also serving as the lock portion of (1).
9a, 19b) on the outer peripheral surface of a portion corresponding to the linear motion range of the movable shaft (2), and a Geneva gear (12).
The movable shaft (2) is moved linearly by rotating the rotor (17) a plurality of times, and the linear movement region of the movable shaft (2) is regulated by regulating the rotation region of the Geneva gear (12). Linear drive (1). 3. The rotor (17) of the motor (5) and the rotor (17)
Has a shaft (2), the translatory movement of the rotor female threaded portion rotation (17) (9) and screwed into by Rika shaft of the male threaded section (10) (2) In the linear drive device (1) for converting and moving the movable shaft (2) linearly , a tooth portion (15) on the outer peripheral surface and different from this tooth portion (15)
A missing gear (11) having a lock portion (23) serving also as a tooth portion and rotated by a motor (5), and a missing gear (1 ) on an outer peripheral surface.
Teeth (19a, 19b) meshing with the tooth (15) of 1)
And a lock portion (23) serving also as a tooth portion of the missing gear (11).
Stop part (22) that stops rotation by engaging with two surfaces of
And a Geneva gear (12) formed on the outer peripheral surface. The rotor (17) is rotated a plurality of times to cause the movable shaft (2) to move linearly, and the movable shaft is regulated by regulating the rotation range of the Geneva gear (12). (2) The linear drive device (1), wherein the linear motion range is regulated.