JP4352702B2 - Valve drive structure - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a valve drive structure that reciprocates a valve body in a linear direction using a motor as a drive source.
[0002]
[Prior art]
As this type of valve drive structure, for example, one described in Patent Document 1 below is known.
This valve drive structure has a structure in which a nut that drives a valve stem in a linear direction by screwing a screw and a bearing that receives a thrust force acting on the nut from the valve stem are built in the motor.
[0003]
The valve drive structure configured as described above has an advantage that when a problem occurs in the drive system of the valve stem, it can be easily repaired by replacing the motor.
[0004]
[Patent Document 1]
Japanese Patent Laid-Open No. 8-75024
[Problems to be solved by the invention]
However, in the valve drive structure described above, the bearing and nut can be used regardless of whether a malfunction that has occurred in the drive system of the valve stem is caused by an electrical problem in the motor or a mechanical problem such as a nut. There is a problem that it is extremely uneconomical because the motor has to be replaced because the motor is particularly expensive.
[0006]
This invention is made in view of the said situation, and makes it a subject to provide the valve drive structure which can cope economically, even when a malfunction generate | occur | produces in the drive system of a valve stem.
[0007]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the invention described in claim 1 includes a housing, a nut rotatably held around the axis of the female screw portion, a valve body at one end, and at least the other end. There is a male threaded portion that engages with the female threaded portion on the outer periphery, and a valve stem that extends and contracts the length protruding from one end of the nut as the nut rotates, and the nut attached to the housing is driven to rotate And a thrust bearing that receives a thrust force acting from the valve stem toward the nut and rotatably supports the nut. The thrust bearing is provided at the other end of the nut. and spheres were being placed between the housing and the motor, and a holding plate for receiving the thrust force acting from the sphere, and the Haujin In, provided with a stopper portion for preventing the above nut is moved to one end side thereof, between the stopper portion and the nut, that the nut is provided biasing means for biasing to the holding plate side It is characterized by.
[0009]
According to a second aspect of the present invention, in the first aspect of the invention, the other end portion of the nut is provided with a concave portion that opens to the holding plate side and is formed in a spherical shape so as to fit the spherical body. The recess is formed so that the depth from the opening is larger than the radius of the sphere, and the radius of the opening is formed to a size that allows the sphere to be inserted by elastic deformation. It is a feature.
[0012]
In the invention according to claim 1 or 2 configured as described above, the nut is rotatably held in the housing, and a motor that rotationally drives the nut is provided in the housing, and the thrust force that acts on the nut from the valve stem Is held by a thrust bearing consisting of a sphere provided at the other end of the nut and a holding plate provided between the housing and the motor, so that the drive of the nut, motor, sphere, holding plate, etc. Each system part can be replaced independently. Moreover, since the motor does not have a built-in nut or a bearing that receives a thrust force, and is low in price, even if the motor is replaced, the cost required for the replacement can be suppressed.
[0013]
Therefore, for example, even when it is found that there is a problem with the drive system component at the time of assembly or the drive system component fails as a result of long-term use, the cost required for replacement of the component is reduced. be able to. That is, it is possible to economically cope with a malfunction of the valve stem drive system.
In addition, since the holding plate is disposed between the housing and the motor, when the motor is attached to the housing, the holding plate can be easily installed and the thrust force can be reliably applied to the motor. Can be prevented.
[0014]
In addition, since the urging means for urging the nut toward the holding plate is provided between the stopper portion and the nut, the sphere can be constantly pressed against the holding plate with a predetermined elastic force. Therefore, rattling of the nut and the valve stem screwed to the nut can be prevented, so that the flow rate can be accurately controlled by the valve body, and a difference caused by mechanical vibration of the nut or valve stem can be achieved. Generation of noise or abnormal noise due to fluid vibration can be prevented.
[0015]
In the invention according to claim 2 , since the depth from the opening in the recess is formed larger than the radius of the sphere, and the radius of the opening is formed to a size that allows insertion of the sphere by elastic deformation, The sphere can be easily incorporated into the recess, and the sphere can be securely held in the recess.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to FIGS.
The valve drive structure shown in the embodiment of the present invention, as shown in FIG. 1 to FIG. 8, shows an example adopted for driving a valve body in an air flow control valve. The housing 1 has a nut 2 that is rotatably held around the axis of the female screw portion 2a, a valve body 31 at one end, and a male screw portion 3a that is screwed to the female screw portion 2a at the outer periphery of the other end. As the nut 2 rotates, the valve rod 3 that expands and contracts the length protruding from one end of the nut 2, the motor 4 that is attached to the housing 1 and rotates the nut 2, and the valve rod 3 toward the nut 2. A thrust bearing 5 that receives the acting thrust force F and rotatably supports the nut 2 is provided. The thrust bearing 5 is a stainless steel sphere 51 provided at the other end of the nut 2, and is installed between the housing 1 and the motor 4, and is made of stainless steel that receives the thrust force F acting from the sphere 51. Plate 52.
[0019]
As shown in FIGS. 1 to 3, the housing 1 is integrally formed of, for example, a metal such as aluminum or a synthetic resin, and the valve housing 6 is fixed to one end face 1a thereof with a screw S1. The motor 4 is fixed to the other end surface 1b with a screw S2.
[0020]
The housing 1 is formed with a stopper portion 1c for preventing the nut 2 from moving to one end side at the shaft center portion. The stopper portion 1c has a valve stem 3 at the shaft center position. 1d is formed, and a flat guide hole 1e is formed from the one end face 1a side to a predetermined depth position. The flat guide hole 1e has a shape whose interval is narrowed in a direction perpendicular to the axis of the circular hole 1d so as to guide a pin 32 described later.
[0021]
Further, the housing 1 is formed with a circular guide hole 1f for rotatably guiding the circular outer peripheral surface 2b of the nut 2 on the other end surface 1b side of the stopper portion 1c, and further on the other end surface 1b side of the circular guide hole 1f. A recess 1g for accommodating the portion other than the circular outer peripheral surface 2b of the nut 2 and the output gear 41 of the motor 4 is formed.
[0022]
The nut 2 is integrally formed of a synthetic resin such as polyacetal, and the female screw portion 2a and the circular outer peripheral surface 2b are formed at the axial center position. That is, the female screw portion 2a is formed at a predetermined depth from one end side to the other end side, and the circular outer peripheral surface 2b is formed on the outer periphery of the one end portion, and as described above, the circular guide hole 1f. It is designed to fit freely.
[0023]
Further, the nut 2 is formed with a concave portion 2c which is open on the holding plate 52 side and is formed in a spherical shape so as to fit the sphere 51 at the axial center position of the other end. The recess 2c is formed such that the depth from the opening is larger than the radius of the sphere 51, and the radius of the opening is large enough to insert the sphere 51 by elastic deformation.
[0024]
Further, the nut 2 is provided with a communication hole 2d that communicates from the inside of the female screw portion 2a corresponding to the other end portion to the outside of the nut 2. The communication hole 2d opens at two positions on the bottom surface of the hole constituting the female screw portion 2a, and extends in a slit shape toward the other end side so that the diameter position of the concave portion 2c is divided into two equal parts. . For this reason, elastic deformation in the direction of opening the slit is possible, and insertion of the sphere 51 into the recess 2c is facilitated.
A gear portion 2 e is formed on the outer periphery of the other end portion of the nut 2.
[0025]
In the valve rod 3, the valve body 31 is provided at one end of a round bar 3b having a circular cross section, and the male screw portion 3a is formed on the outer periphery of the other end. Further, the valve rod 3 is provided with a pin 32 at a predetermined position in the axial direction thereof. The pin 32 is formed in a rod shape with a circular cross section, and is fixed to the valve stem 3 so as to extend in a direction passing through the axis of the valve stem 3 and perpendicular to the axis.
The pin 32 is inserted into the above-described flat guide hole 1e and guided so as to move in parallel. The pin 32 prevents the valve stem 3 from rotating, and the rotation of the nut 2 causes the valve stem 3 to pivot. It is possible to move in the direction.
[0026]
Therefore, the flat guide hole 1e has a stroke so that the pin 32 can be sufficiently guided when the valve stem 3 is stroked to change a valve port 6c described later from a fully closed state to a fully open state. Direction dimensions are set. Also, the axial length of the female screw portion 2a and the male screw portion 3a that are screwed together is set so as to enable the stroke of the valve stem 3.
In this embodiment, the pin 32 is fixed to a through hole formed at the position of the round bar 3b near the male screw portion 3a by press fitting, brazing, or the like.
[0027]
As shown in FIG. 3, the motor 4 includes an output gear 41 that meshes with the gear portion 2e of the nut 2 at a position translated from a rotor shaft (not shown) located on the center line C via a reduction gear mechanism. .
The center line C of the motor 4 is arranged at a position on the same straight line as the axis of the nut 2 and the center of the sphere 51 arranged at the axial center of the housing 1.
[0028]
Further, a disc spring (biasing means) 7 that biases the nut 2 toward the holding plate 52 is provided between the stopper portion 1 c and one end of the nut 2.
[0029]
On the other hand, the valve housing 6 is provided with flow paths 6a and 6b that are bent in an L shape, and the bent portion is provided when the valve stem 3 moves in a direction protruding from one end side of the nut 2. A valve port 6c that is closed by the valve body 31 is formed.
4 and 5, 52a is a through hole for inserting the screw portion of the screw S2.
[0030]
In the valve drive structure configured as described above, the nut 2 is rotatably held in the housing 1, and the motor 4 that rotationally drives the nut 2 is provided in the housing 1, and the thrust acting on the nut 2 from the valve stem 3 is provided. The force F is held by a thrust bearing 5 including a sphere 51 provided at the other end of the nut 2 and a holding plate 52 provided between the housing 1 and the motor 4. Drive system components such as the motor 4, the sphere 51, and the holding plate 52 can be replaced independently. In addition, since the motor 4 does not include the nut 2 or the bearing that receives the thrust force F, it is a low-priced one. Therefore, even when the motor 4 is replaced, the cost required for the replacement is minimized. Can be suppressed.
[0031]
Therefore, for example, even if a failure is found in the drive system parts during assembly, or if a failure occurs in the drive system parts as a result of long-term use, measures such as replacement of these parts should be taken. Can be done economically.
Further, since the holding plate 52 is disposed between the housing 1 and the motor 4, when the motor 4 is attached to the housing 1, the holding plate 52 can be easily installed, and the thrust force F is applied to the motor. 4 can be reliably prevented.
[0032]
And since the disc spring 7 which urges | biases the nut 2 to the holding plate 52 side is provided between the stopper part 1c and the nut 2, the spherical body 51 can be always closely_contact | adhered to the holding plate 52 with a predetermined elastic force. it can. Therefore, rattling of the nut 2 and the valve stem 3 screwed to the nut 2 can be prevented, so that the flow rate can be accurately controlled by the valve body 31 and the valve port 6c, and the nut 2 and the valve can be controlled. Generation of abnormal noise due to mechanical vibration of the rod 3 or the like, or abnormal noise due to vibration of air flowing through the valve port 6c can be prevented.
[0033]
Further, since the depth of the recess 2c is formed larger than the radius of the sphere 51, and the radius of the opening is formed so as to allow the sphere 51 to be inserted by elastic deformation, the sphere 51 can be easily incorporated into the recess 2c. be able to. Further, since the communication hole 2d functions as a slit that bisects the other end portion of the nut 2 at the diameter position of the recess 2c, it is possible to more easily incorporate the sphere 51 by the elastic deformation.
[0034]
Further, since the communication hole 2d communicating from the inside of the female screw portion 2a of the nut 2 to the outside of the nut 2 is provided, a closed space is formed in the female screw portion 2a by the valve rod 3 screwed into the female screw portion 2a. Can be prevented. Therefore, there is no problem in moving the valve stem 3 in the axial direction.
[0035]
Further, since the axis of the nut 2, the center of the sphere 51, and the center line C of the motor 4 are arranged on the same axis, each component can be arranged compactly with respect to the housing 1. Therefore, the overall size can be reduced.
[0036]
In the above-described embodiment, the example in which the valve drive structure is adopted for the air flow control valve has been shown, but it is adopted for driving the valve bodies of various valves using other fluids such as water and hydraulic pressure. It is also possible to do.
Further, although the male screw portion 3 a is configured to be formed on the outer periphery of the other end portion of the valve stem 3, the male screw portion 3 a may be formed on the entire outer peripheral surface of the valve stem 3.
[0037]
【The invention's effect】
As described above, according to the invention described in claim 1 or 2 , the nut is rotatably held by the housing, the motor for rotating the nut is provided in the housing, and the thrust force acting on the nut from the valve stem is applied. Is held by a thrust bearing consisting of a sphere provided at the other end of the nut and a holding plate provided between the housing and the motor, so that the drive of the nut, motor, sphere, holding plate, etc. Each system part can be replaced independently. Moreover, since the motor does not have a built-in nut or a bearing that receives a thrust force, and is inexpensive, even when the motor is replaced, the cost required for the replacement can be suppressed.
[0038]
Therefore, for example, even if it is found that there is a problem with the drive system component at the time of assembly or the drive system component fails as a result of long-term use, the replacement of the component can be performed at low cost. it can. That is, it is possible to economically cope with a malfunction that has occurred in the drive system of the valve stem.
In addition, since the holding plate is disposed between the housing and the motor, when the motor is attached to the housing, the holding plate can be easily installed and the thrust force can be reliably applied to the motor. Can be prevented.
[0039]
In addition, since an urging means for urging the nut toward the holding plate is provided between the stopper portion and the nut, the sphere can be constantly pressed against the holding plate with a predetermined elastic force. Therefore, rattling of the nut and the valve stem screwed to the nut can be prevented, so that the flow rate can be accurately controlled by the valve body, and a difference caused by mechanical vibration of the nut or valve stem can be achieved. Generation of noise or abnormal noise due to fluid vibration can be prevented.
[0040]
According to the second aspect of the present invention, the depth from the opening in the recess is formed larger than the radius of the sphere, and the radius of the opening is formed to a size that allows the sphere to be inserted by elastic deformation. The sphere can be easily incorporated into the recess, and the sphere can be securely held in the recess.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a valve drive structure shown as an embodiment of the present invention.
FIG. 2 is a plan view of the valve drive structure as viewed from one end surface side of the housing.
3 is a view showing the valve drive structure, and is a cross-sectional view taken along the line III-III in FIG. 2;
FIG. 4 is a plan view showing a holding plate of the valve drive structure.
FIG. 5 is a sectional view showing a holding plate of the valve drive structure.
FIG. 6 is a plan view showing a nut of the valve drive structure.
7 is a view showing a nut of the valve drive structure, and is a cross-sectional view taken along line VII-VII in FIG.
FIG. 8 is a bottom view showing a nut of the valve drive structure.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Housing 1c Stopper part 2 Nut 2a Female thread part 2c Recessed part 2d Communication hole 2e Gear part 3 Valve rod 3a Male thread part 4 Motor 5 Thrust bearing 7 Disc spring (biasing means)
31 Valve body 41 Output gear 51 Sphere 52 Holding plate C Center line F Thrust force

Claims (2)

A housing, a nut held rotatably around the axis of the female screw portion in the housing, a valve body at one end, and a male screw portion that is screwed into the female screw portion at least at the outer periphery of the other end; A valve stem that expands and contracts the length protruding from one end of the nut as the nut rotates, a motor that is attached to the housing and that drives the nut to rotate, and a thrust that acts from the valve stem toward the nut A thrust bearing that receives the force and rotatably supports the nut,
The thrust bearing includes a sphere provided at the other end of the nut, and a holding plate that is installed between the housing and the motor and receives the thrust force acting from the sphere .
In addition, the housing is provided with a stopper portion for preventing the nut from moving to one end thereof, and biasing means for biasing the nut toward the holding plate is provided between the stopper portion and the nut. A valve drive structure characterized by being provided . The other end of the nut is provided with a concave portion that is open to the holding plate side and is spherically shaped to fit the sphere.
The concave portion is formed such that a depth from the opening is larger than a radius of the sphere, and a radius of the opening is formed to a size capable of inserting the sphere by elastic deformation. Item 2. The valve drive structure according to Item 1.

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