JP3127112B2 - Motor actuator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor actuator that converts the rotation of an electric motor into a linear motion of an output body and outputs the result. More specifically, the present invention relates to a motor actuator suitable for opening / closing a needle valve by reciprocating motion of an output body.

[0002]

2. Description of the Related Art In a needle valve for adjusting a flow rate of a fluid,
The valve element is operated by a motor actuator to open and close the flow path and increase or decrease the flow path area. As this motor actuator, there is a so-called center axis moving type shown as a prior art in JP-A-3-89826. This center axis moving type motor actuator uses a rotor shaft itself that supports a rotor of an electric motor as an output shaft that linearly moves. That is, the rotor shaft is attached to the case so as to be linearly movable in the axial direction thereof, and the rotor shaft is connected to the casing with a screw pair to convert the rotational motion of the rotor into the linear motion of the rotor shaft. The needle valve is opened and closed by the attached valve element.

As another type of motor actuator, there is a pulse motor assembly disclosed in, for example, JP-A-1-288678 or JP-A-3-89826. In this assembly, the rotor shaft of the motor is separated from the output shaft which moves linearly, and the rotation of the pulse motor is transmitted to the output shaft by interposing a reduction gear train between them. The output shaft is connected to an output bearing mounted on the case side with a screw pair. Therefore, the output shaft that has been decelerated and rotated performs linear motion, and reciprocates the valve element of the needle valve.

[0004]

However, in the center axis moving type motor actuator described above, the rotation of the rotor shaft is directly transmitted to the valve body side of the needle valve.
It is not possible to rotate the valve body side with a large rotation torque,
It was difficult to smoothly reciprocate the valve. In addition, since the valve element cannot be rotated at a low speed, the valve element cannot be reciprocated at a low speed, and it is difficult to finely adjust the increase or decrease of the passage area.

On the other hand, in the pulse motor assemblies disclosed in JP-A-1-288678 and JP-A-3-89826 in which the rotation of the pulse motor is transmitted to the output shaft via a speed reduction mechanism, the rotation transmitted to the output shaft is Since the rotation torque is increased by deceleration, smooth movement of the valve body and easy fine adjustment of the position can be achieved, but since the output shaft is offset with respect to the rotation shaft of the pulse motor, The pulse motor assembly becomes large. In addition, since the center of the motor case and the output shaft do not coincide with each other, an eccentric chuck or slicing is required even when the motor case is gripped and the E-ring groove is formed on the bearing, which is expensive.
In the conventional motor actuator structure, the upper and lower cases are closed by curling or by adhesive around the circumference. In addition, performing the water stopping process at the lead wire outlet in the case on the gear box side involves cost and uneasiness of waterproofing. In addition, since the output shaft is thin, it was necessary to stop the steel ball by welding in order to press the needle valve.

SUMMARY OF THE INVENTION An object of the present invention is to provide a motor actuator which can obtain a smooth and highly accurate operation and can be downsized.

[0007]

In order to achieve the above object, according to the first aspect of the present invention, the rotation of the rotor of the electric motor housed in the case is converted into a linear motion, and the output body is reciprocated. In the motor actuator, the base end of the support shaft that rotatably supports the rotor is fixed to the case, and an output body is disposed coaxially with the front end of the support shaft and fitted with a pair of screws, while near the support shaft. A rotation transmitting means for transmitting the rotation of the rotor to the output body while decelerating the rotation is provided, and the rotation of the output body is caused to reciprocate in the axial direction by a pair of screws between the output shaft and the support shaft.

Therefore, in the motor actuator according to the first aspect, when the rotor rotates, the rotation is taken out by the rotation transmitting means around the support shaft and then transmitted again to the output member coaxial with the support shaft. . Since the rotation transmitting means transmits the rotation of the rotor to the output body while reducing the rotation, the output body is slowly rotated with a large torque. Since this output body is fitted to the support shaft with a screw pair,
While rotating at a low speed, it linearly moves slowly and smoothly on the support shaft to obtain an output as an actuator.

According to the second aspect of the present invention, a contact member which comes into contact with a counterpart member which gives a linear motion to the tip of the output body is formed of a metal of high hardness and fitted. Therefore, in the motor actuator according to the second aspect, when the contact member is fitted to the tip of the output member, the contact member is disposed coaxially with the output member. Further, since the contact member is made of a metal of high hardness, the contact pressure is high, and the contact member can withstand a large reaction force received from the operated member operated by the motor actuator, that is, the counterpart member that gives linear motion.

According to a third aspect of the present invention, the rotation transmitting means comprises a reduction gear train, at least one of the pinions and a coaxial gear are formed so as to be separable, and the output member is incorporated into the support shaft. After that, the gear and the pinion are integrated. In this case, in the invention according to claim 4, the splittable pinion and the coaxial gear are gears coaxial with the final-stage pinion that meshes with the output member.

Therefore, in the motor actuator according to the third aspect, at the time of assembling, when the output body is screwed into the support shaft in a state where at least one pinion constituting the reduction gear train and a gear coaxial therewith are divided, The rotation of the output body is not transmitted to the motor side, and the work of screwing the output body can be easily performed. In particular, if the pinion and the gear at the last stage of the reduction gear train are divided as in the invention of claim 4, it is possible to screw into the support shaft by rotation of only the output body.

[0012] Further, according to a fifth aspect of the present invention, the case includes:
It is composed of a lower case that houses the rotation transmitting means and the electric motor, and a lid-like upper case that seals the lower case. A block body is inserted between these cases so as to penetrate the lead wire of the electric motor and sandwich it in a liquid-tight manner. Thus, the upper and lower cases are melt-bonded in a liquid-tight manner, while the space between the lead wire and the block body is sealed.

Therefore, in the motor actuator according to the fifth aspect, the upper case is closed and melt-bonded so as to cover the lower case in which most of the case except for the vicinity of the output body is housed, and the space between the upper and lower cases is closed. Sealed. Also, it is necessary to put the electric motor lead wire out of the case,
The space between the lead wire and the block body through which the lead wire passes is also sealed, and the block body is sandwiched in each case in a liquid-tight manner, and the space therebetween is sealed. Therefore, the inside of the case is protected from intrusion of liquid or the like.

Furthermore, the motor actuator of the present invention
The valve body of the needle valve is operated by the output body.
Therefore, in the motor actuator according to claim 6, when the rotor rotates and the output body linearly moves, the valve body of the needle valve also linearly moves with the rotation, and the passage in which the needle valve is installed is opened and closed. The passage area is increased or decreased.

According to a seventh aspect of the present invention, there is provided a motor actuator for converting the rotation of a rotor of an electric motor housed in a case into a linear motion and reciprocating an output body, wherein the support rotatably supports the rotor. While the base end of the shaft is fixed to the case, an output body is arranged coaxially with the support shaft and fitted with a screw pair between the fixed member and a rotation transmission for transmitting the rotation to the output body while reducing the rotation of the rotor. Means are provided so that the output body is reciprocated in the axial direction by a pair of screws between the output body and the fixed member by rotating the output body.

Therefore, when the rotor rotates, the rotation is taken out by the rotation transmitting means and then transmitted again to the output member coaxial with the support shaft. Since the rotation transmitting means transmits the rotation of the rotor to the output body while reducing the rotation, the output body is slowly rotated with a large torque. Since this output body is fitted into the fixed member with a screw pair, the output body performs linear movement slowly and smoothly along the fixed member while rotating at a low speed to obtain an output as an actuator.

Further, in the invention according to claim 8, the screw pair is formed between the output member and a bearing member of the output member. Therefore, the rotation of the output body is converted into a linear motion with the bearing member.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of the present invention will be described below in detail based on an embodiment shown in the drawings.

FIGS. 1 and 2 show an embodiment of a motor actuator to which the present invention is applied. The motor actuator 1 includes a support shaft 2, an output body 3, a rotation transmitting means 4, and the like, and these are housed in a case composed of a lower case 5 and an upper case 6.

The support shaft 2 is disposed substantially at the center of the case interior space 7, and its base end 2 a is fixed to the lower case 5. A rotor 8 constituting an electric motor is rotatably attached to the support shaft 2. A stator 9 constituting an electric motor is arranged so as to surround the rotor 8.

A male screw 10 is fitted near the tip of the support shaft 2. The male screw 10 is tightly fitted to the support shaft 2 and cannot be dropped. The output body 3 is fitted into the male screw 10 with a screw pair. That is, the cylindrical output member 3 is composed of the large diameter portion 3a and the small diameter portion 3b, and the inner peripheral surface of the large diameter portion 3a has
A female screw 3c is formed to be connected to the male screw 10 in a screw-and-even relationship. The small diameter portion 3b is
Is slidably fitted to the front end 2b of the main body. Therefore, when the output body 3 rotates, a linear motion is performed in the axial direction of the support shaft 2.

At the tip of the small diameter portion 3b of the output body 3, a metal contact member of high hardness, for example, a stainless steel ball shaft 19, which is in contact with a counterpart member that gives a linear motion, is fitted. The tip of the ball shaft 19 is formed in a hemispherical shape. The center axis of the ball shaft 19 coincides with the center axis of the output body 3. The ball shaft 19 is a contact member that comes into contact with and operates a valve body 24 described later. This ball axis 1
A washer 20 is inserted between 9 and the output body 3,
The output body 3 is provided so as to receive the force applied to the ball shaft 19 with a large area by the output body 3. The output member 3 is formed by a bearing member 37 fixed to the gear case 16 by caulking.
Thereby, the small diameter portion 3b is rotatably supported.

The rotation transmitting means 4 includes first to fourth gears 11 to 11.
14. The first gear 11 is formed integrally with the tip of the rotor 8. The second gear 12 is rotatably supported between a base plate 15 that partitions the case interior space 7 and a gear case 16. The second gear 12 is a gear unit 1
2a and a pinion 12b, which are integrally formed. The number of teeth of the gear portion 12a is
Many are set compared to the number of teeth. On the other hand, the gear portion 12
a meshes with the first gear 11. The number of teeth of the gear portion 12a is set larger than the number of teeth of the first gear 11,
The rotation of the first gear 11 is transmitted to the second gear 12 while being decelerated.

The third gear 13 includes a main plate 15 and the gear case 1.
6 and rotatably supported. This third gear 1
A gear unit 3 includes a gear 17 and a pinion 18 separate from the gear 17, as shown in FIG. A shaft hole 17a is bored in the center of the gear 17, and four recesses 17b are formed so as to surround the opening of the shaft hole 17a. A shaft hole 18a is also formed in the center of the pinion 18, and projections 18b are formed, for example, at four locations so as to surround the opening of the shaft hole 18a. By inserting each convex portion 18b into each concave portion 17b, the gear 17 and the pinion 18 can be assembled, and by assembling, the gear 17 and the pinion 18 can be integrally rotated.

The gear 17 is a pinion 1 of the second gear 12.
2b, so that the rotation on the rotor 8 side is input. The number of teeth of the gear 17 is set to be larger than the number of teeth of the pinion portion 12, and the rotation of the second gear 12 is transmitted to the third gear 13 while being reduced.

The fourth gear 14 is formed integrally with the large diameter portion 3a of the output body 3. The fourth gear 14 is the third gear 1
The third pinion 18 is engaged. Therefore, the rotation of the pinion 18 is transmitted to the output body 3 side. The number of teeth of the fourth gear 14 is set to be greater than the number of teeth of the pinion 18, and the rotation of the third gear 13 is transmitted to the fourth gear 14 while being decelerated.

A fixed bearing 44 is fixed to the base plate 15. The fixed bearing 44 supports a substantially central portion of the support shaft 2 and improves the mounting rigidity of the support shaft 2. By improving the mounting rigidity of the support shaft 2 and stabilizing it, a load acting on a portion of the output body 3 supported by the bearing member 37 is reduced. Therefore, the diameter of this portion of the output body 3 can be reduced, and the sliding resistance of the output body 3 can be reduced.

The lower case 5 and the upper case 6 are made of, for example, plastic. As shown in FIG. 4, a welding margin 6 a is formed on the outer surface of the upper case 6. And
When the upper case 6 is fitted into the lower case 5 and, for example, ultrasonic welding is performed, the entire space between the cases 5 and 6 is welded and sealed in a liquid-tight manner.

Each lead wire 21 of the electric motor extends through the block 26 to the outside of each of the cases 5 and 6.
The block body 26 is configured by stacking a pair of halves 27, 27 face to face. A plurality of grooves 27a, 27a are formed in the mating surface of each half 27, 27,
The grooves 27a of the respective halves 27 face each other to form a through hole 28. The through-hole 28 is formed for each lead wire 21. Motor actuator 1 of the present embodiment
Has six lead wires 21 so that the block 2
6 have through holes 28 at six locations. The diameter of each through hole 28 corresponds to the thickness of the lead wire 21. Further, the block body 26 is sufficiently long in the length direction of each lead wire 21, and therefore, the contact area between the block body 26 and each lead wire 21 is increased.

In each groove 27a of each half 27, as shown in FIG. 6, a plurality of convex portions 45,..., 45 are formed. Each convex portion 45 is arranged at a predetermined interval in the length direction of each groove 27a, and is formed in a bank shape along the circumferential direction. When the halves 27 are overlapped, the projections 45 are also overlapped with each other to reduce the diameter of the through hole 28. Therefore, each convex portion 45 cuts into the coating of each lead wire 21, thereby improving the sealing property between each half 27 and each lead wire 21 and preventing each lead wire 21 from coming off.

The block body 26 is formed of, for example, an ABS resin (acrylonitrile-butadiene-styrene resin). After the block body 26 is sandwiched between the inner surface of the lower case 5 and the outer surface of the upper case 6,
The space between each lead wire 21 and each of the cases 5 and 6 are adhered with an adhesive, and further sealed in a liquid-tight manner with a sealant 34. Therefore, between each lead wire 21 and the block body 26, and between the block body 26 and each case 5,6.
Is well sealed. Also, as mentioned above,
Since the spaces between the cases 5 and 6 are well sealed, the intrusion of the liquid into the space 7 inside the case is prevented.

Reference numeral 25 in FIG. 1 denotes a nut for attaching the motor actuator 1 to a mating component such as an electronic expansion valve. Reference numeral 35 in the figure denotes an E-ring for preventing the nut 25 attached to the bearing member 37 from coming off, and reference numeral 36 denotes an O-ring for sealing.

Further, in the figure, reference numeral 40 denotes a metal motor case, reference numeral 42 denotes a laminated plate, and reference numeral 43 denotes a bearing. The inside of the motor case 40 is closed by the above-described base plate 15, and a gear case 41 that accommodates the rotation transmitting means 4 is fixed to the base plate 15. The gear case 41 is fixed to the bearing member 37. Therefore, the motor case 4
The motor inside the motor case 0 and the rotation transmitting means 4 inside the gear case 41 are supported by the nut 25 via the bearing member 37 through these cases 40, 41 and the like. For this reason, the lower case 5 and the upper case 6 do not need to have a so-called mechanical function of supporting the load of the motor actuator 1, and only cover the motor actuator 1 from the outside to maintain good airtightness inside. It functions as a sealing member. That is, the lower case 5 and the upper case 6 can be designed so as to obtain the optimum sealing performance.

When manufacturing the motor actuator 1,
It is necessary to screw the output body 3 into the male screw 10. Output body 3
Is screwed into the male screw 10, the gear 17 of the third gear 13 and the pinion 18 are divided, and the pinion 1 is
Leave 8 floating. This eliminates the need to rotate the rotor 8 with the rotation of the fourth gear 14. That is, it is not necessary to screw the output body 3 while rotating the rotor 8, and the assembling work of the output body 3 becomes easy. Then, after the output body 3 is screwed to a predetermined position, the pinion 18 of the third gear 13 is assembled to the gear 17 while sliding the pinion 18 with respect to the fourth gear 14, thereby completing the rotation transmitting means 4.

Next, the operation of the motor actuator 1 will be described.

When the rotor 8 starts rotating around the support shaft 2, the rotation of the rotor 8 is transmitted from the first gear 11 to the pinion 12 a of the second gear 12 while being reduced in speed. Therefore, the gear portion 12b of the second gear 12 also rotates, and this rotation is transmitted to the gear 17 of the third gear 13 while being reduced. Now, since the gear 17 of the third gear 13 and the pinion 18 are integrated, this pinion 18
Also rotates, and this rotation is transmitted to the fourth gear 14 while being decelerated.

Therefore, the output member 3 starts rotating. Since the output body 3 is connected to the male screw 10 fixed to the support shaft 2 by a screw pair, the output body 3 linearly moves in the axial direction of the support shaft 2. The output body 3 projects or sinks in accordance with the rotation direction of the rotor 8.

Now, as shown in FIG. 5, it is assumed that a needle valve using the motor actuator 1 as a drive source is applied to, for example, an electric expansion valve 22 of a refrigerant circuit of an air conditioner. The motor actuator 1 is connected to the electric expansion valve 22
The motor actuator 1 is fixed to the main body side of the electric expansion valve 22 by contacting the motor actuator 1 with a predetermined position on the main body side and tightening the nut 25. Then, when the motor actuator 1 is fixed to the main body side of the electric expansion valve 22, the ball shaft 19 inserted into the output body 3 comes into contact with the rear end face of the valve body 24. Since the center axis of the ball shaft 19 coincides with the center axis of the output body 3, the tip of the ball shaft 19 exactly hits the center recess of the rear end face of the valve body 24.

The electric expansion valve 22 is provided in the middle of the refrigerant passage 23. Therefore, the pressure in the refrigerant passage 23 acts on the ball shaft 19 via the valve element 24. The ball shaft 19 is made of metal and is not damaged by the reaction force. And this reaction force tries to push open the valve body 24. However, the output body 3 and the male screw 10
Are connected with a screw pair, the output shaft 3 does not rotate due to the reaction force. Therefore, the output body 3 does not sink into the respective cases 5 and 6 and the valve body 24
Closes the refrigerant passage 23 against the pressure of the refrigerant.

In this state, when the motor actuator 1 operates and the output body 3 starts to be immersed, the valve body 24 is pushed by the refrigerant to open the refrigerant passage 23 in accordance with the immersion distance. That is, the valve element 24 is pushed and opened by the refrigerant while being pressed against the output element 3. The rotation of the rotor 8 is transmitted to the output body 3 after being sufficiently decelerated by the rotation transmitting means 4, so that the output body 4 is rotated at a low speed with a large torque and slowly linearly moves. Open gradually. Then, the motor actuator 1 moves the output body 4 to a desired position and adjusts the passage area of the refrigerant passage 23. Since the output body 3 of the motor actuator 1 is connected to the support shaft 2 with a screw pair, the refrigerant passage 2
3 does not rotate even if it receives the pressure inside, so that the output shaft 3 does not sink unless the rotor 8 rotates, and the position of the valve body 24 is fixed to keep the passage area of the refrigerant passage 23 constant. keep.

On the other hand, the rotor 8 of the motor actuator 1
Rotates in the opposite direction, the output body 3 starts to protrude slowly, and gradually pushes back the valve body 24. Although a high-pressure refrigerant flows in the refrigerant passage 23, the output body 3 is rotated with a high torque and smoothly projects. Therefore, the passage area of the refrigerant passage 23 gradually decreases, and the flow rate of the refrigerant decreases. When the output body 3 projects to a predetermined position, the valve body 24 completely closes the refrigerant passage 23 and inhibits the flow of the refrigerant.

The above embodiment is one preferred embodiment of the present invention, but the present invention is not limited to this embodiment, and various modifications can be made without departing from the gist of the present invention.

For example, as in a motor actuator 29 shown in FIGS. 7 and 8, a case 31 manufactured by press working is fixed to a resin case 30 via a packing 32 with screws or the like. Alternatively, a flange-shaped nut receiver 33 manufactured by press working may be caulked. The nut receiver 33 is a nut 2
After fitting 5 into small diameter portion 39 of case 31, it is fixed to the tip of small diameter portion 39 by caulking. An O-ring 38 is interposed between the nut receiver 33 and the nut 25. The nut receiver 33 rotatably supports the small diameter portion 3b of the output body 3. This motor actuator 29
Also, the space 7 in the case is sealed in a liquid-tight manner. The rotation of the rotor 8 is transmitted to the output body 3 while being reduced in speed via the first gear 11, the second gear 12, the gear 17 of the third gear, the pinion 18, and the fourth gear 14. And the output body 3 performs a linear motion, and operates the valve body 24 by the contact member 19 '. Also, the motor actuator 2
In 9, each half 27 ′ of the block body 26 ′ is a rubber packing and is bonded by an adhesive. In addition,
In the motor actuator 29 shown in FIGS. 7 and 8, the same members as those constituting the motor actuator 1 shown in FIGS. 1 and 2 are denoted by the same reference numerals, and description thereof will be omitted.

Furthermore, the case where the motor actuator 1 of this embodiment is applied to the electric expansion valve 22 of the refrigerant circuit of the air conditioner has been described, but this motor actuator 1 is applied as a drive source for other flow control valves and the like. It is possible.

Next, still another example of the motor actuator according to the present invention will be described with reference to FIGS. The motor actuator 51 includes a support shaft (rotor shaft) 52, an output body 53, a rotation transmitting means 54, and the like. These are housed in a case composed of a lower case (mold case) 55 and an upper case 56. Have been.

The support shaft 52 is disposed substantially at the center of the case interior space 57, and its base end 52 a is on the lower case 55 side, specifically, on the laminated plate 92, and the vicinity of the tip is a convex portion 65 a of the base plate 65.
Respectively. A rotor 58 constituting an electric motor is rotatably attached to the support shaft 52. Further, a stator 59 constituting the electric motor is arranged so as to surround the rotor 58.

The upper half of the output body 53 is supported by a bearing member (fixing member) 87. A male screw is formed on the outer peripheral surface of the output body 53, and a female screw is formed on the inner peripheral surface of the bearing member 87. The lower end of the output body 53 is rotatably supported by the support shaft 52. That is, the output body 3 is arranged coaxially with the support shaft 2 and is fitted with the bearing member 87 with a screw pair. Therefore, this output body 5
When 3 rotates, linear motion is performed in the axial direction of the support shaft 52. That is, the motor actuator 51 is
The point that a screw pair is formed between the bearing 3 and the bearing member 87 is different from the point that the motor actuator 1 described above has a screw pair formed between the output body 3 and the male screw 10 (on the support shaft 2 side). Is different.

A hemispherical portion 53a is formed so as to bulge at the center of the distal end surface of the output body 53. The hemispherical portion 53a corresponds to the ball shaft 19 of the motor actuator 1 described above. The bearing member 8
7 is fixed to the gear cover 66 by caulking, and the gear cover 66 is attached inside the upper case 56.

The rotation transmitting means 54 includes first to fourth gears 61.
~ 64. The first gear 61 includes the rotor 5
8 is fixed to the tip. The second gear 62 includes a main plate 65
And a gear cover 66 rotatably supported.
The second gear 62 includes a gear portion 62a and a pinion 62b, which are integrally formed. Gear section 62
The number of teeth a is set larger than the number of teeth of the pinion portion 62b. On the other hand, the gear portion 62a meshes with the first gear 61. The number of teeth of the gear portion 62a is set larger than the number of teeth of the first gear 61, and the rotation of the first gear 61 is transmitted to the second gear 62 while being reduced in speed.

The third gear 63 includes a main plate 65 and a gear cover 6.
6 and rotatably supported. This third gear 6
Reference numeral 3 denotes a gear 63a and a pinion 63b, which are integrally formed. The pinion 63b is formed long in the axial direction. That is, even when a fourth gear 64, which will be described in detail later, moves linearly with the output body 53,
The meshing state with the fourth gear 64 is maintained.

The gear 63a meshes with the pinion portion 62b of the second gear 62, so that the rotation of the rotor 58 is input. The number of teeth of the gear 63a is
The number of teeth is set larger than the number of teeth b, and the rotation of the second gear 62 is transmitted to the third gear 63 while being reduced.

The fourth gear (output gear) 64 includes an output body 53.
And is fixed with an E-ring 67. The fourth gear 64 is a pinion 63 of the third gear 63.
b. Therefore, the rotation of the pinion 63b is transmitted to the output body 53 side. The number of teeth of the fourth gear 64 is set larger than the number of teeth of the pinion 63b,
The rotation of the third gear 63 is transmitted to the fourth gear 64 while being decelerated.

The base plate 65 has a convex portion 65a, and the first gear 61 is arranged below the convex portion 65a. As shown in detail in FIG. 11, the convex portion 65a is formed in a so-called bridge shape and has a closed cross-sectional structure. By forming the convex portion 65a in a bridge shape, rigidity can be improved as compared with a cantilevered open cross-sectional structure, and notches 77, 77 can be formed on both sides of the convex portion 65a. The gear portion 62a of the first gear 61 and the second gear 62 mesh with each other through one notch 77. With such a structure, rotation can be transmitted between the rotor 58 and the second gear 62 disposed with the main plate 65 therebetween.

The convex portion 65a supports the vicinity of the tip of the support shaft 52, and improves the rigidity of the support shaft 52. By improving the mounting rigidity of the support shaft 52 and stabilizing it,
The external force input from the fourth gear 64 to the output body 53 is
2 to prevent the support shaft 52 from rattling, thereby preventing the screw portion between the output member 53 and the bearing member 87 from being worn easily, and the straight line of the output member 53 Make the movement less swaying. If there is no requirement for the life of the threaded portion, the initial characteristics can be maintained without inserting the support shaft 52 into the output body 53.

Further, the convex portion 65a functions as a stopper when the output body 53 is lowered. However, when the hole size of the output body 53 can be accurately determined, the tip of the support shaft 52 may be used as a stopper.

The lower case 55 and the upper case 56 are made of, for example, plastic. As in the case of the motor actuator 1 described above, a welding margin (not shown) is formed on the outer surface of the upper case 56. And the upper case 5
6 is fitted into the lower case 55 and, for example, when ultrasonic welding is performed, the space between the cases 55 and 56 is welded over the entire circumference and is sealed in a liquid-tight manner.

Each lead wire 71 of the electric motor is
6 and extends to the outside of each of the cases 55 and 56.
As shown in FIGS. 12 and 13, the relay plate 76 is used by folding back the center and overlapping. For this reason, the central portion (the portion shown by the one-dot chain line in FIG. 12) is formed to be thin and constitutes a so-called resin hinge 76d.
In the folded state, a pair of upper and lower hooking pieces 76c are hooked on the opposing projecting pieces 76b to prevent the relay plate 76 from spreading. A plurality of grooves 76a,..., 76a are formed on the mating surface of the relay plate 76, and a pair of grooves 76a, 76a facing each other at the time of folding make up a through hole 78. The through-hole 78 is formed for each lead wire 71. Since the motor actuator 51 of the present embodiment has six lead wires 71, the relay plate 76 has through holes 78 at six locations. The diameter of each through hole 78 is
This corresponds to the thickness of the lead wire 71. Also, the relay board 76
Is sufficiently long in the length direction of each lead wire 71,
The contact area between the relay plate 76 and each lead wire 71 increases.
In this example, six lead wires 71 are used, but the number of lead wires 71 is not limited to this, and may be 5
In some cases, a single lead wire is used.

The protrusions 4 of the block body 26 of the motor actuator 1 are provided in each groove 76a of the relay plate 76.
5, a plurality of convex portions 95,..., 95 are formed. And when the relay board 76 is overlapped,
Numeral 5 cuts into the coating of each lead wire 71 to improve the sealing property between the relay plate 76 and each lead wire 71 and also to prevent each lead wire 71 from coming off.

The relay plate 76 is formed of, for example, an ABS resin (acrylonitrile-butadiene-styrene resin). After the relay plate 76 is sandwiched between the inner surface of the lower case 55 and the outer surface of the upper case 56, the relay plate 76 is bonded to each of the lead wires 71 and to each of the cases 55 and 56 with an adhesive. , A liquid-tight seal with an ultraviolet curable resin 84. Therefore, each lead wire 71
Between the relay plate 76 and the relay plate 76, and between the relay plate 76 and each case 55,
56 is well sealed. Further, as described above, the space between each of the cases 55 and 56 is well sealed, so that the intrusion of the liquid into the space 57 inside the case is prevented.

Reference numeral 75 in FIG. 9 denotes a nut for attaching the motor actuator 51 to a counterpart component, for example, an electronic expansion valve. Reference numeral 86 denotes an O-ring for sealing. Reference numeral 90 denotes a metal motor case. Further, reference numeral 91 is a spring washer for pressing the rotor 58 upward.

When assembling the motor actuator 51, when the gear cover 66 fixed to the upper case 56 and the upper case 56 are positioned and inserted into the lower case 55, the fourth gear 64 attached to the output body 53 becomes The third gear 63 meshes with the pinion 18 projecting from the second gear 65. Positioning of the lower case 55 with the gear cover 66 and the upper case 56 is performed by positioning each guide groove 55a provided on the inner peripheral surface of the lower case 55 with each protrusion 66a (FIG. 11) provided on the outer periphery of the gear cover 66. This can be easily performed by inserting the projections 56a (FIG. 10) provided on the outer periphery of the upper case 56. Each guide groove 55a and each protrusion 56a, 66a are provided, for example, at three locations.

Next, the operation of the motor actuator 51 will be described.

When the rotor 58 starts to rotate around the support shaft 52, the rotation of the rotor 58 is transmitted from the first gear 61 to the pinion 62a of the second gear 62. Therefore, the gear portion 62b of the second gear 62 also rotates, and this rotation is transmitted to the gear 63a of the third gear 63, and further transmitted to the fourth gear 64 from the pinion 63b.

Therefore, the output member 53 starts to rotate.
Since the output body 53 is connected to the bearing member 87 with a screw pair, the output body 53 performs a linear motion in the axial direction of the support shaft 52. The output body 53 is provided in accordance with the rotation direction of the rotor 58.
It protrudes or sinks, and operates, for example, the electric expansion valve 22 of the refrigerant circuit of the air conditioner in the same manner as the motor actuator 1 described above.

In this motor actuator 51, the fourth case is achieved only by fitting the upper case 56 to the lower case 55.
The gear 64 meshes with the third gear 63, thereby completing the rotation transmitting means 54, so that the assembly is easy.

[0066]

As described above, in the motor actuator according to the first aspect, the base end of the support shaft for rotatably supporting the rotor is fixed to the case, and the output body is coaxially formed at the distal end of the support shaft. While being arranged and fitted with a pair of screws, a rotation transmitting means for transmitting rotation to the output body while decelerating the rotation of the rotor is provided in the vicinity of the support shaft, and by rotating the output body, the axis line is formed by the pair of screws between the support shaft. Since the reciprocating motion is performed in the direction, the output body is decelerated on the same axis as the motor shaft, and smoothly performs linear motion with a large torque. For this reason, it is easy to finely adjust the moving distance of the output body, and it is possible to improve the accuracy of the output control of the motor actuator.
In addition, since the output body is arranged coaxially with the rotor, the size of the motor actuator can be reduced, and the directivity at the time of mounting is eliminated. In addition, even when trying to machine a groove of the E-ring where the axis of the output body and the rotor axis (center axis of the case) match, it is easy to perform ordinary processing such as turning without using an eccentric chuck. And the processing cost can be reduced.

Further, in the motor actuator according to the second aspect, since the contact member made of a high-hardness metal is fitted to the tip of the output member, the center axis of the contact member can easily coincide with the center axis of the output member. And manufacturing can be facilitated. In addition, since the contact member is made of a high-hardness metal, the contact pressure can be increased, and a large reaction force received from the operated member operated by the motor actuator can be counteracted. Improvement can be achieved.

Further, in the motor actuator according to the third aspect, the rotation transmitting means is constituted by a reduction gear train, and at least one of the pinions and a coaxial gear therewith are formed so as to be separable, and the output member is formed. Since the gear and pinion are integrated after being incorporated into the support shaft,
When the output body is screwed into the support shaft, the output body does not need to be rotated to the motor side, which facilitates assembly. In particular, in the case of the invention according to claim 4, wherein the pinion and the gear at the last stage are divided,
The screwing of the output body is completed only by rotating the output body.

According to the motor actuator of the present invention, in a state where the motor and the rotation transmitting means are housed in the case, the block body having the lead wire of the electric motor penetrated between the upper and lower cases is sandwiched between the case and the case. Because of the fusion bonding, the intrusion of the liquid into the case can be prevented, and the sealing performance can be improved.

Further, in the motor actuator according to the sixth aspect, since the output member operates the valve member of the needle valve, it is possible to provide a motor actuator suitable as a drive source of the needle valve.

According to a seventh aspect of the present invention, a base end of a support shaft for rotatably supporting a rotor is fixed to a case, and an output member is disposed coaxially with the support shaft to provide a space between the output shaft and a fixed member. In the meanwhile, a rotation transmitting means for transmitting the rotation of the rotor to the output body while decelerating the rotation is provided, and the rotation of the output body is caused to reciprocate in the axial direction by the screw pair between the fixed member by rotating the output body. As in the case described above, the output body can be smoothly and linearly moved with a large torque.

In this case, since the screw pair is formed between the output member and the bearing member of the output member, a linear motion is given to the output member using the bearing member. be able to.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of a motor actuator to which the present invention is applied.

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

FIG. 3 is a sectional view showing a state where a third gear of the motor actuator of FIG. 1 is divided.

FIG. 4 is an enlarged sectional view showing a welded portion between a lower case and an upper case of the motor actuator of FIG. 1 in detail;

FIG. 5 is a schematic configuration diagram showing an example in which the motor actuator of FIG. 1 is used for an electric expansion valve of a refrigerant circuit of an air conditioner.

6A and 6B show a half constituting a block body of the motor actuator of FIG. 1; FIG. 6A is a front view thereof, FIG. 6B is a partially enlarged view of a cross section taken along the arrow BB of FIG. (C) is a partially enlarged view of a cross section along the arrow CC of (A).

FIG. 7 is a sectional view showing another embodiment of the motor actuator to which the present invention is applied.

FIG. 8 is a plan view of the motor actuator of FIG. 7;

FIG. 9 is a sectional view showing still another embodiment of the motor actuator to which the present invention is applied.

FIG. 10 is a plan view of the motor actuator of FIG. 9;

11 is a plan view of the motor actuator of FIG. 9 in a state where an upper case is removed.

FIG. 12 is a front view showing a relay plate of the motor actuator of FIG. 9 in an unfolded state.

FIG. 13 is a side view of the relay board of FIG.

[Explanation of symbols]

 1,29,51 Motor actuator 2,52 Support shaft 3,53 Output body 4,54 Rotation transmitting means 5,55 Lower case 6,56 Upper case 8,58 Rotor 9,59 Stator 11-14,61-64 1st to 4th gear 17 gear 18 pinion 19 ball shaft (contact member) 21, 21 lead wire 22 electric expansion valve (needle valve) 24 valve body 26, 26 'block body 28 through hole

Claims (8)

(57) [Claims] 1. A motor actuator for converting rotation of a rotor of an electric motor housed in a case into linear motion and reciprocating an output body, wherein a base end of a support shaft rotatably supporting the rotor is connected to the case. Rotation transmitting means for transmitting the output body to the output body while reducing the rotation of the rotor near the support shaft while the output body is arranged coaxially with the tip of the support shaft and fitted with a pair of screws. A motor actuator characterized in that the output body is rotated and reciprocated in the axial direction by the screw pair between the output body and the support shaft. 2. The motor actuator according to claim 1, wherein a contact member that contacts a counterpart member that gives a linear motion to the tip of the output body is formed of a metal having high hardness and fitted therein. 3. The rotation transmission means comprises a reduction gear train, at least one of which is formed with a pinion and a coaxial gear so as to be separable, and after the output body is incorporated into the support shaft, the rotation transmission means is connected to the gear. 3. The motor actuator according to claim 1, wherein the motor actuator is integrated with a pinion. 4. The motor actuator according to claim 3, wherein the splittable pinion and the coaxial gear are gears coaxial with the last-stage pinion that meshes with the output member. 5. The case comprises a lower case for accommodating the rotation transmitting means and the electric motor, and a lid-like upper case for hermetically sealing the lower case. A lead wire of the electric motor is passed between these cases. The upper and lower cases are liquid-tightly melt-bonded with a liquid-tightly sandwiched block interposed therebetween, and a seal is provided between the lead wire and the block. The described motor actuator. 6. The motor actuator according to claim 1, wherein the valve body of the needle valve is operated by the output body. 7. A motor actuator for converting rotation of a rotor of an electric motor housed in a case into linear motion and reciprocating an output body, wherein a base end of a support shaft rotatably supporting the rotor is connected to the case. And a rotation transmission means for transmitting the output body to the output body while decelerating the rotation of the rotor, while disposing the output body on the same axis as the support shaft and fitting the output body with a fixing member with a screw pair. A motor actuator characterized in that the output body is reciprocated in the axial direction by a pair of screws between the output body and the fixed member by rotating the output body. 8. The motor actuator according to claim 7, wherein the screw pair is formed between the output body and a bearing member of the output body.