JP3829531B2 - Drive device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a drive device.
[0002]
[Prior art]
Conventionally, some gas water heaters and oil water heaters have a valve in which the amount of hot water changes according to the opening, and the hot water temperature is controlled to a predetermined temperature by adjusting the opening of the valve. In order to drive a simple valve, a driving device including a DC motor and a transmission mechanism that reduces the rotation of the DC motor at a predetermined reduction ratio and transmits the rotation to the outside has been used.
[0003]
[Problems to be solved by the invention]
As shown in FIG. 8, the drive device described above includes a brushed DC motor 1 and a speed reduction mechanism (not shown) that reduces the rotation of the DC motor 1 at a predetermined reduction ratio and transmits it to a valve (not shown). In the case. The DC motor 1 is fixed to the lower case 21, and a first gear 10 made of a worm gear is attached to the output shaft 2 of the DC motor 1. Here, the lower case 21 is provided with a rib 24 having a recess 24a into which the tip of the output shaft 2 is inserted, and in the recess 24a and the portion of the output shaft 2 to which the first gear 10 is attached. A washer 30 for receiving the thrust of the first gear 10 is attached to a portion between the tip portion to be inserted.
[0004]
By the way, the reason why the brushed DC motor 1 is used as the motor for the hot water heater is that the brushed DC motor 1 that can be obtained at low cost is selected in order to reduce the cost of the water heater. When the valve is left for a long period of time, the starting torque increases due to the valve body sticking or the like, and therefore there is a reason that the DC motor 1 having a large starting torque is selected. However, the DC motor 1 generally has a rotor as a winding portion and can be obtained at a low cost. However, since the rotor is not balanced, there is a drawback in that vibration noise caused by rotor unbalance increases during rotation. . Further, depending on the mounting state of the DC motor 1, there is a possibility that a resonance phenomenon may occur due to the vibration of the rotor.
[0005]
By the way, in recent years, indoor-installed water heaters are increasing, and demands for reducing noise generated by motors are becoming strict. In addition, for outdoor water heaters, there are users who are concerned about the noise generated by the motor, and there is a demand for further reducing the noise generated by the motor. However, in the conventional driving device described above, since a mechanism for reducing vibration due to the rotation of the DC motor 1 is not provided, depending on a difference in the mounting state of the DC motor 1 with respect to the lower case 12, the mounting state of the driving device, and the like. Since the noise generated by the DC motor 1 changes greatly, there has been only a countermeasure for selecting a DC motor 1 with low noise as a noise countermeasure. Further, although there is a motor provided with a pressing means for pressing the output shaft in one direction, there is a problem that the cost increases because a special motor is used (see, for example, Japanese Patent Laid-Open No. 8-98452). .
[0006]
The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a drive device in which generated noise is reduced.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the invention of claim 1 includes at least a DC motor, a first gear provided on an output shaft of the DC motor, and a second gear meshing with the first gear. A transmission mechanism that transmits the rotation of the DC motor to the outside, and a case that houses the DC motor and the transmission mechanism, and a rib having a recess into which the output shaft of the DC motor is inserted protrudes from the case. Are formed with slit grooves that run in a direction substantially perpendicular to the axial direction of the output shaft. Both ends of the bottom of the slit grooves are higher than the central portion and higher than the height position of the output shaft. Each part is provided, and between both step parts, a wire spring that is elastically contacted with the output shaft and presses the output shaft in a direction substantially orthogonal to the direction in which the first and second gears mesh is bridged. the features, output by pressing the output shaft with the wire spring Vibration suppressing of, can reduce the noise generated by the DC motor, and, since the wire spring are pressed directly output shaft of the DC motor, because there is no member need besides linear springs, the vibration of the DC motor The mechanism that reduces the number of parts can be realized with a small number of parts, and since the number of parts is small, it is inexpensive, has good assemblability, improves reliability, and reduces assembly errors. Moreover, since the wire spring is straight and can be formed simply by cutting the wire, it is extremely easy to process, and since the shape is simple, it can be processed with high accuracy and the mechanism for reducing the noise of the DC motor is extremely inexpensive. Can be realized. Furthermore, since the wire spring that presses the output shaft of the DC motor is provided outside the DC motor, it is not necessary to use a special motor provided with a mechanism for reducing vibration, and is inexpensive and highly reliable. You can use a good DC motor of availability, and, since the wire spring is provided outside of the DC motor, it is possible to visually confirm the assembled state of the wire spring from the outside, exchange of the wire spring Work can be done easily. In addition, since the wire spring presses the output shaft in a direction substantially orthogonal to the direction in which the first and second gears mesh, the meshing of the first and second gears varies due to component variations. However, there is little influence on the meshing of the first and second gears, and when the meshing of the first and second gears is clogged, the first and second gears are substantially in meshing direction. If the direction parallel to the wire spring presses the output shaft meshes joined forces wire spring generated by the clogging, there is a possibility that the wire spring is deformed and the wire spring by the wire spring to stretch Although the life may be shortened, the wire spring presses the output shaft in a direction substantially orthogonal to the direction in which the first and second gears mesh, so that the meshing of the first and second gears is this affected due to the clogged wire spring No.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described with reference to FIGS.
[0009]
The case 20 of the drive device is composed of a substantially box-shaped lower case 21 that is open on one side, and a substantially box-shaped upper case 22 that is attached to the lower case 21 and is open on one side. The attached DC motor 1 and a speed reduction mechanism 3 as a transmission mechanism for reducing the rotation of the DC motor 1 with a predetermined reduction ratio and transmitting the rotation to a valve (not shown) of the water heater are housed. Further, an intermediate plate 23 that partitions the lower case 21 and the upper case 22 is attached to the lower case 21 by using, for example, a fixing screw, and the DC motor 1 is pressed from above by the intermediate plate 23.
[0010]
A first gear (first gear) 10 made of a worm gear is attached to the output shaft 2 of the DC motor 1 by, for example, press fitting. The first gear 10 meshes with a second gear (second gear) 11 that is rotatably supported on the shaft 5, and the second gear 11 is concentric with the second gear 11 from the second gear 11. No. 2 pinion 12 having a smaller number of teeth is integrally formed. 2nd pinion 12, No. 2 many number of teeth than the pinion 12, and then third gear 13 meshes which is rotatably supported by a shaft 6, the third gear 13 third gear 13 is concentric The third pinion 14 having a smaller number of teeth than the third gear 13 is integrally formed. Third pinion 14, many number of teeth than the third pinion 14, meshes with fourth gear 15 which is rotatably supported by a shaft 5, the fourth gear 15 fourth gear 15 is concentric In addition, a fourth pinion 16 having a smaller number of teeth than the fourth gear 15 is integrally formed. Fourth pinion 16 is often the number of teeth than the fourth pinion 16, has fifth gear 17 meshes which is rotatably supported by a shaft 7, the fifth gear 17 Fifth gear 17 is concentric In addition, a fifth pinion 18 having a smaller number of teeth than the fifth gear 17 is integrally formed. Further, the fifth pinion 18 meshes with an output sixth gear 19 having a larger number of teeth than the fifth pinion 18.
[0011]
Thus, the rotation of the DC motor 1 is predetermined by the speed reduction mechanism 3 including the first to sixth gears 10 , 11, 13, 15, 17, 19 and the second to fifth pinions 12, 14, 16, and 18 . Decelerated at a reduction ratio and transmitted to the valve. Both ends of the shafts 5 to 7 are inserted into shaft holes 21 a and 22 a provided in the lower case 21 and the upper case 22, respectively, and are positioned between the lower case 21 and the upper case 22. Further, on the surface of the sixth gear 19 facing the intermediate plate 23, a substantially cylindrical convex portion 19a is provided so as to be coaxial with the gear, and this convex portion 19a is inserted into a shaft hole 23a provided in the intermediate plate 23. ing. Further, the cylindrical portion 19b on the other side of the sixth gear 19 is protruded, is inserted into the opening 22b provided in the upper case 22, 6 toothed wheel 19 and the upper case 22 and the intermediate plate 23 in It is supported rotatably.
[0012]
Here, a printed circuit board 31 is attached to a portion of the intermediate plate 23 facing the sixth gear 19 with an attachment screw 34. Two Hall ICs 32 for detecting the rotation angle of the sixth gear 19 are mounted on the printed circuit board 31, and a permanent magnet 33 is embedded in the sixth gear 19. A sensor for detecting the rotation angle of the sixth gear 19 is constituted by the two Hall ICs 32 and the permanent magnets 33, and a desired detection angle can be obtained by changing the arrangement of the Hall ICs 32. In the present embodiment, two Hall ICs 32 are arranged on the printed circuit board 31. However, the number of Hall ICs 32 is not limited to two, and three or more Hall ICs 32 may be provided. What is necessary is just to change the number and arrangement | positioning of Hall IC32 so that this detection angle may be obtained. Further, reference numeral 35 in FIG. 4 denotes a lead wire for supplying power to the DC motor 1 or outputting a signal from the Hall IC 32.
[0013]
Thus, when electric power is supplied to the DC motor 1 by a signal from an external circuit (not shown), the DC motor 1 rotates, and the rotation of the DC motor 1 is the first to sixth gears 10, 11, The decelerating mechanism 3 composed of 13, 15, 17, 19 and 2-5 pinions 12, 14, 16, 18 is decelerated at a predetermined reduction ratio and transmitted to the valve of the water heater, and the valve opens and closes.
[0014]
In the drive device of the present embodiment, as shown in FIGS. 1 and 2, a rib 24 having a recess 24 a into which the tip of the output shaft 2 of the DC motor 1 is inserted projects from the lower case 21, A washer 30 for receiving the thrust of the first gear 10 is attached to a portion between the portion of the shaft 2 where the first gear 10 is attached and the tip portion inserted into the recess 24a. Here, the rib 24 is formed with slit grooves 24b that run in a direction substantially orthogonal to the axial direction of the output shaft 2, and the stepped portions that are one step higher than the central portion at both ends of the bottom of the slit groove 24b. 24c is provided. A substantially linear wire spring (spring member) 4 having elasticity is arranged in the slit groove 24b so as to be bridged between the two stepped portions 24c. As shown in FIG. Since the height position is higher than the height position of the output shaft 2, the wire spring 4 is bent downward in FIG. 1 by the output shaft 2.
[0015]
Therefore, the output shaft 2 of the DC motor 1 is pressed upward in FIG. 1 by the spring restoring force of the wire spring 4, and the vibration of the output shaft 2 is reduced by pressing the output shaft 2. Here, the wire spring 4 presses the output shaft 2 in a direction substantially orthogonal to the direction in which the first gear 10 and the second gear 11 mesh with each other. Even if the meshing with the number gear 11 varies, the influence on the meshing between the number 1 gear 10 and the number 2 gear 11 is small, and the spring return force of the wire spring 4 causes the number 1 gear 10 and the number 2 gear 11 to Since the preload does not increase, the first gear 10 and the second gear 11 can be smoothly rotated.
[0016]
Further, for example, when the meshing of the first gear 10 and the second gear 11 is clogged due to the eccentricity of the second gear, in a direction substantially parallel to the direction in which the first gear 10 and the second gear 11 are meshed, If the wire spring 4 presses the output shaft 2, the wire spring 4 may be deformed due to the eccentricity of the second gear, and the force applied to the output shaft 2 by the wire spring 4 may change. Although the life of the wire spring 4 may be shortened due to the expansion and contraction of the wire spring 4, in this embodiment, the wire spring 4 outputs in a direction substantially orthogonal to the direction in which the first gear 10 and the second gear 11 are engaged. Since the shaft 2 is pressed, the wire spring 4 is not affected by the eccentricity of the second gear 11 even when the meshing between the first gear 10 and the second gear 11 is blocked.
[0017]
The side wall 24d of the rib 24 and the rib 21b projecting from the lower case 21 restrict the movement of the wire spring 4 in the longitudinal direction.
[0018]
By the way, since the SUS material is generally used for the output shaft 2 of the DC motor 1, it is desirable to use a different material such as phosphor bronze for the material of the wire spring 4. In addition, in order to apply | coat lubricating grease to the contact part of the output shaft 2 and the wire spring 4, even if it uses iron-type material like a piano wire for the material of the wire spring 4, the output shaft 2 and the wire spring 4 Sliding resistance and wear can be reduced, and there is no practical problem.
[0019]
Further, in this embodiment, the output shaft 2 of the DC motor 1 is directly pressed by the linear wire spring 4, there are no necessary members other than the wire spring 4, and there are few parts for reducing the vibration of the DC motor 1. Since the number of parts is small, it is inexpensive, easy to assemble, improves reliability, and reduces assembly errors. Moreover, since the wire spring 4 can be formed simply by cutting the wire, it is extremely easy to process, and since the shape is simple, it can be processed with high precision, and a mechanism for reducing the noise of the DC motor 1 can be realized at a very low cost. Can do. The same effect can be obtained by using a leaf spring instead of the wire spring 4 as a spring member. However, since a mold for forming the leaf spring is required and the manufacturing cost is increased, the wire spring 4 is more preferable. desirable. Moreover, since the wire spring 4 that presses the output shaft 2 of the DC motor 1 is provided outside the DC motor 1, it is not necessary to use a special motor provided with a mechanism for reducing vibrations, and is inexpensive. The DC motor 1 having high reliability and good availability can be used, and the wire spring 4 is provided outside the DC motor 1, so that the assembly state of the wire spring 4 is visually confirmed from the outside. The wire spring 4 can be easily replaced.
[0020]
【The invention's effect】
As described above, the invention of claim 1 includes at least a DC motor, a first gear provided on an output shaft of the DC motor, and a second gear meshing with the first gear. And a case for housing the DC motor and the transmission mechanism, and a rib having a recess into which the output shaft of the DC motor is inserted protrudes from the case, and the output shaft is provided on the rib. A slit groove that runs in a direction substantially orthogonal to the axial direction of the slit groove is formed, and a step portion that is higher than the center portion and higher than the height position of the output shaft is provided at both ends of the bottom of the slit groove. And is characterized in that a wire spring that bridges the output shaft between both step portions and presses the output shaft in a direction substantially orthogonal to the direction in which the first and second gears mesh is bridged . to suppress the vibration of the output shaft by pressing the output shaft with the wire spring It can reduce noise generated in the DC motor, and, since the wire spring are pressed directly output shaft of the DC motor, because there is no member need besides linear springs, less a mechanism for reducing vibration of the DC motor Since it can be realized with parts and the number of parts is small, it is inexpensive, has good assemblability, improves reliability, and reduces assembly errors. Moreover, since the wire spring is straight and can be formed simply by cutting the wire, it is extremely easy to process, and since the shape is simple, it can be processed with high accuracy and the mechanism for reducing the noise of the DC motor is extremely inexpensive. There is an effect that it can be realized. Furthermore, since the wire spring that presses the output shaft of the DC motor is provided outside the DC motor, it is not necessary to use a special motor provided with a mechanism for reducing vibration, and is inexpensive and highly reliable. You can use a good DC motor of availability, and, since the wire spring is provided outside of the DC motor, it is possible to visually confirm the assembled state of the wire spring from the outside, exchange of the wire spring There is an effect that the work can be easily performed. In addition, since the wire spring presses the output shaft in a direction substantially orthogonal to the direction in which the first and second gears mesh, the meshing of the first and second gears varies due to component variations. However, there is little influence on the meshing of the first and second gears, and when the meshing of the first and second gears is clogged, the first and second gears are substantially in meshing direction. If the direction parallel to the wire spring presses the output shaft meshes joined forces wire spring generated by the clogging, there is a possibility that the wire spring is deformed and the wire spring by the wire spring to stretch Although the life may be shortened, the wire spring presses the output shaft in a direction substantially perpendicular to the direction in which the first and second gears mesh, so that the meshing of the first and second gears is this affected due to the clogged wire spring No.
[Brief description of the drawings]
FIG. 1 is an enlarged cross-sectional view of a main part viewed from the side of a drive device according to an embodiment.
FIG. 2 is an enlarged view of a main part when viewed from the upper side of the above drive device.
FIG. 3 is a view from above of a state in which an outer case, a speed reduction mechanism, and an intermediate plate of the drive device are removed.
FIG. 4 is a top view of the above driving device.
FIG. 5 is a cross-sectional view of the above drive device as viewed from the side.
FIG. 6 is a view from above of a state in which the upper case of the drive device is removed.
FIG. 7 is a developed view of the speed reduction mechanism of the above drive device as viewed from the side.
FIG. 8 is an explanatory diagram of a conventional driving device.
[Explanation of symbols]
2 Output shaft 4 Wire spring 21 Lower case 24 Rib 24a Recess 24b Slit groove 24c Stepped portion

Claims (1)

A DC motor, a transmission mechanism having at least a first gear provided on an output shaft of the DC motor and a second gear meshing with the first gear, and transmitting the rotation of the DC motor to the outside; and a DC motor And a case for housing the transmission mechanism, and a rib having a recess into which the output shaft of the DC motor is inserted protrudes from the case, and the rib runs in a direction substantially perpendicular to the axial direction of the output shaft. A slit groove is formed, and both end portions of the bottom of the slit groove are provided with step portions that are higher than the central portion and higher than the height position of the output shaft. And a wire spring that is elastically contacted with the output shaft and presses the output shaft in a direction substantially perpendicular to the direction in which the first and second gears mesh with each other.

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