JP2004108436A - Gear, molding die and forming method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gear with less backlash without increasing the number of parts. <P>SOLUTION: In a gear speed change mechanism of an actuator for an air conditioner of a vehicle, a gear mesh 17 of a third reduction gear 15 formed of resin is divided into a first gear 17a and a second gear 17b in the teeth widthwise direction and integrally formed. The first teeth 17a and the second teeth 17b have a slipping width in the circumferential direction. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
TECHNICAL FIELD The present invention relates to a gear with low backlash, a molding die for producing the gear, and a method for molding the gear.
[0002]
[Prior art]
Conventionally, as a method of reducing the backlash, there is known a technique in which two gears are coaxially shifted in a circumferential direction, and the two gears are fastened or provided with a function of automatically adjusting a shift amount. I have.
[0003]
For example, Patent Literature 1 discloses a technique for automatically adjusting a circumferential shift amount between two gears (a gear and an auxiliary gear). More specifically, as shown in FIG. 7, a first gear 71 meshing with the input gear 70 and a second gear 73 meshing with the output gear 74 are connected by a gear shaft 72 so as to be integrally rotatable. Further, a first sub gear 75 meshing with the input gear 70 and a second sub gear 77 meshing with the output gear 74 are provided, and a sub gear shaft 76 is provided coaxially with the hollow gear shaft 72. A first auxiliary gear 75, which is integrally rotatably mounted on the auxiliary gear shaft 76, is movably mounted on the auxiliary gear shaft 76 in the axial direction, and meshes with the input gear 70 in a state where the auxiliary gear shaft 76 is torsionally elastically deformed. Automatically adjust the rush.
[0004]
Further, in the case of a resin gear, there is a method of reducing backlash by increasing the tooth thickness using a shift gear.
[0005]
[Patent Document 1]
JP 2000-283266 A
[Problems to be solved by the invention]
However, in the method shown in FIG. 7, the first auxiliary gear 75 and the second auxiliary gear 77 are required, and between the gear shaft 72 and the auxiliary gear shaft 76 to rotatably support the auxiliary gear shaft 76. It was necessary to provide a bearing not shown in FIG.
[0007]
In the method in which the two gears are coaxially shifted in the circumferential direction and fastened, it is necessary to provide an auxiliary gear and a fastening member in addition to the main gear.
That is, these methods have a problem that the number of components is significantly increased.
[0008]
Further, in the case of a structure in which the main gear and the auxiliary gear are fastened, there is a problem that when assembling parts, it is necessary to adjust and assemble each part one by one, which takes time and labor.
[0009]
Also, in the case of a resin gear using a dislocation gear, it is difficult to manufacture a mold because a resin molded part has a dimensional error in addition to the mold accuracy. There is a problem that it is necessary to make the mold once or twice, and it takes a lot of time to manufacture the mold and the cost increases.
[0010]
SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a gear that is easy to assemble and has a small backlash without increasing the number of parts, a molding die thereof, and a molding of the gear. It is to provide a way to do it.
[0011]
[Means for Solving the Problems]
In order to solve the above problem, the invention according to claim 1 is a resin gear, which has a first tooth portion and a second tooth portion whose teeth are divided in a tooth width direction. The gist is that the first and second tooth portions are integrally formed while being shifted in the circumferential direction by a predetermined shift width.
[0012]
The gist of the invention described in claim 2 is to have an output unit integrally formed with the first and second teeth.
The gist of the invention described in claim 3 is that the shift width is determined in accordance with the dimensions of components constituting the gear transmission mechanism.
[0013]
The gist of the invention described in claim 4 is that the invention is used in the last stage of the gear transmission mechanism.
The invention according to claim 5 is a resin gear having a first tooth portion and a second tooth portion formed by dividing a tooth portion in a tooth width direction and shifting the tooth portion by a predetermined shift width in a circumferential direction. A molding die for molding the first tooth portion, and a second molding die for molding the second tooth portion, wherein the second molding die is provided. The gist of the invention is that it is rotatable relative to the first molding die in the circumferential direction.
[0014]
The gist of the invention described in claim 6 is that a mold dividing surface for removing the formed gear is provided between the first molding die and the second molding die.
The gist of the invention described in claim 7 is that the gear has an integrally formed output portion and a third molding die for molding the output portion.
[0015]
The invention according to claim 8 is a resin gear having a first tooth portion and a second tooth portion formed by dividing the tooth portion in the tooth width direction and shifting the tooth portion by a predetermined shift width in the circumferential direction. A molding method for molding the first tooth portion with a first molding die for molding the first tooth portion. The molding die is capable of rotating relative to the first molding die in a circumferential direction. And a second molding die for molding the second tooth portion, measuring a deviation width of the first and second tooth portions of the molded gear, and based on the measurement result, (2) The gist is to rotate the molding die in the circumferential direction.
[0016]
(Action)
According to the first aspect of the present invention, the tooth portion of the resin gear is divided into the first tooth portion and the second tooth portion in the tooth width direction, and the first tooth portion and the second tooth portion are divided. By providing the tooth portion with a predetermined shift width in the circumferential direction, backlash between the gear and another gear meshing with the gear can be reduced. In addition, since they are integrally formed, other components for reducing backlash are not required, so that the number of components can be significantly reduced.
[0017]
According to the second aspect of the present invention, the number of components can be reduced by integrally forming the output section.
According to the third aspect of the present invention, the gear is used for a gear transmission mechanism, and a shift width between the first tooth portion and the second tooth portion is determined according to the dimensions of components constituting the gear transmission mechanism. Accordingly, it is possible to determine an appropriate shift width in consideration of the backlash caused by the dimensional tolerance of each component.
[0018]
According to the fourth aspect of the present invention, the gear can be effectively functioned by using the gear in the last stage of the gear transmission. That is, since the dimensional tolerance of each component constituting the gear transmission mechanism is accumulated at the last stage of the gear transmission mechanism, the tolerance can be reduced.
[0019]
According to the fifth aspect of the present invention, the second molding die is rotatable in the circumferential direction of the gear with respect to the first molding die, so that the tooth portion of the gear is divided in the tooth width direction. It is possible to adjust the deviation width in the circumferential direction between the first tooth portion and the second tooth portion. Further, in order to perform accurate backlash adjustment, there is no need to recreate a molding die, and thus costs can be reduced.
[0020]
According to the invention described in claim 6, by providing the mold dividing surface between the first molding die and the second molding die, it is possible to easily take out the gear after molding.
[0021]
According to the seventh aspect of the invention, the output portion of the gear can be formed integrally.
According to the eighth aspect of the present invention, since the rotational position of the second molding die is adjusted based on the deviation width of the first and second tooth portions in the molded gear, gear accuracy can be easily improved. Can be improved.
[0022]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of the present invention will be described below with reference to FIGS.
The actuator 1 used in the vehicle air conditioner according to the present embodiment has a gear transmission mechanism.
[0023]
The vehicle air conditioner includes an air inlet switching door, a temperature adjusting door, an outlet switching door, and the like. The actuator 1 shown in FIG. 1 is provided at each door to open and close each door.
[0024]
The actuator 1 includes a housing 10, a drive motor 11, a first reduction gear 13, a second reduction gear 14, a third reduction gear 15, and a board 18, an IC 19, a plurality of connector terminals 20, and a connector 10a which constitute a gear transmission mechanism. Have.
[0025]
The housing 10 includes a case and a cover, and is formed so as to accommodate the drive motor 11, the first to third reduction gears 13 to 15, and the substrate 18. In the housing 10, bearing holes 10d are formed in a case and a cover, and support shafts 10b and 10c for attaching the first reduction gear 13 and the second reduction gear 14 to the case are formed integrally with the case.
[0026]
A drive motor 11 is housed and fixed in the housing 10, and a worm gear 12 is attached to an output shaft of the drive motor 11 so as to be integrally rotatable. A first reduction gear 13 is rotatably supported on the support shaft 10b so as to mesh with the worm gear 12, and a second reduction gear 14 is rotatably supported on the support shaft 10c so as to mesh with the first reduction gear 13. The third reduction gear 15 is rotatably supported by a bearing hole 10d formed in a case and a cover of the housing 10, and is supported such that an output shaft 16 (see FIG. 3) protrudes from the housing 10. It is in mesh with the gear 14.
[0027]
The rotation of the worm gear 12 driven by the drive motor 11 is first transmitted to the first reduction gear 13, and the rotation of the first reduction gear 13 is transmitted to the second reduction gear 14. Similarly, the rotation of the second reduction gear 14 is transmitted to the third reduction gear 15 and output by the output shaft 16 provided on the third reduction gear 15.
[0028]
A board 18 is disposed on the bottom of the housing 10, and an IC 19 is mounted on the board 18. Further, the connector terminals 20 are mounted on the board 18 in a line, and the ends of the connector terminals 20 are provided on the connector 10 a formed on the housing 10. The connector terminal 20 is provided for inputting electric power, a signal, and the like for driving the actuator 1.
[0029]
FIG. 2 shows a state in which the second reduction gear 14 and the third reduction gear 15 are engaged. FIG. 3 is an enlarged perspective view showing only the third reduction gear 15 taken out. Further, FIG. 4 (a) is a view as viewed in the direction of arrow A in FIG. 3, and FIG. 4 (b) is a view as viewed in the direction of arrow B in FIG. 4 (a).
[0030]
As shown in FIG. 3, the third reduction gear 15 includes a tooth portion 17 and an output shaft 16. The tooth portion 17 is divided into two in the axial direction (tooth width direction), and is formed by a first tooth portion 17a and a second tooth portion 17b. The tooth widths of the first tooth portion 17a and the second tooth portion 17b are substantially the same, and the first tooth portion 17a and the second tooth portion 17b are integrally formed so as to have a shift width d in the circumferential direction. (See FIGS. 3, 4 (a) and 4 (b)). Therefore, the tooth part 17 has the total value of the tooth thickness of the first tooth part 17a (second tooth part 17b) and the deviation width d as the tooth thickness.
[0031]
The output shaft 16 has a D-shaped output portion 16a having a flat surface in the radial direction at a tip end thereof, and is formed so as to prevent idling when the rotation of the output shaft 16 is output to the outside. Have been.
[0032]
As shown in FIG. 2, the output side gear 14 a of the second reduction gear 14 is configured to mesh with both the first teeth 17 a and the second teeth 17 b of the third reduction gear 15. More specifically, when the second reduction gear 14 rotates forward (clockwise in FIG. 2), the output gear 14a meshes with the first tooth portion 17a. Further, when the rotation is reversed, the output side gear 14a meshes with the second tooth portion 17b. As will be described later, the backlash between the second reduction gear 14 and the third reduction gear 15 is reduced by adjusting the shift width d when the third reduction gear 15 is formed.
[0033]
Here, the worm gear 12, the first reduction gear 13, the second reduction gear 14, the third reduction gear 15, and the housing 10 are made of resin as described above. When each part is molded with resin, the accuracy of each part is substantially determined by the resin molding die. Also, the finished dimensions of each part have tolerances. Therefore, in general, when designing a gear transmission mechanism, in consideration of the linear expansion coefficient, the water absorption expansion, etc., in terms of design, the space between the shafts is wide, the clearance between the shaft and the bearing is large, and the pitch circle diameter of the gear is small. Set it up. Therefore, backlash naturally increases when components are combined. In the last stage of the gear transmission, the dimensional tolerances of the components (first to third reduction gears 13 to 15) constituting the gear transmission are stacked.
[0034]
The third reduction gear 15 of the present embodiment is a gear provided at the last stage of the gear transmission mechanism, and is provided at a portion where the dimensional tolerance of each component is stacked as described above. Therefore, the third reduction gear 15 is manufactured while adjusting the shift width d in consideration of the dimensional tolerance of each part based on the dimensions of each part after molding, and the optimum shift width d is determined.
[0035]
Next, a molding die for molding the third reduction gear 15 will be described.
FIG. 5 is a schematic view illustrating a cross section of a molding die 50 for molding the third reduction gear 15.
[0036]
The molding die 50 includes a first molding die 51 for molding the first tooth portion 17a side of the third reduction gear 15, a second molding die 52 for molding the second tooth portion 17b, and an output. And a third molding die 53 for molding the portion 16a side. A mold dividing surface for taking out the molded third reduction gear 15 is provided between the first molding die 51 and the second molding die 52. That is, the molding die 50 is divided into a first molding die 51 and second and third molding dies 52 and 53.
[0037]
The second molding die 52 is attached to the third molding die 53 so as to be rotatable in the circumferential direction of the teeth 17 of the third reduction gear 15. The second molding die 52 is rotated in the circumferential direction to determine a deviation width d between the first tooth portion 17a and the second tooth portion 17b. With such a configuration, the shift width d in the circumferential direction between the first tooth portion 17a and the second tooth portion 17b can be adjusted.
[0038]
Next, a method of forming the third reduction gear 15 will be described.
First, the molding die 50 is provided with a second molding die so as to have a predetermined circumferential width d between the first tooth portion 17a and the second tooth portion 17b of the third reduction gear 15 to be molded. The mold 52 is pivotally disposed with respect to the third molding die 53.
[0039]
After the resin is injected into such a molding die 50 and solidified, the molded third reduction gear 15 is separated from the mold dividing surface provided between the first molding die 51 and the second molding die 52. Taken out.
[0040]
The formed third reduction gear 15 measures the width d in the circumferential direction of the first tooth portion 17a and the second tooth portion 17b and is actually incorporated into the actuator 1.
[0041]
At this time, it is determined whether or not the backlash is appropriate. If the backlash is large, the second molding die 52 is rotationally adjusted so as to increase the deviation width d, and the third reduction gear 15 Is molded.
[0042]
By doing so, the third reduction gear 15 with high gear accuracy is manufactured. Moreover, in this case, the molding die 50 itself does not need to be remade, so that it can be easily handled.
[0043]
FIG. 6 is a schematic diagram showing a cross section of a molding die for molding a conventional gear attached to the same place as the third reduction gear 15. The molding die 60 is divided into a first molding die 61 for molding the tooth portion side of the gear and a second molding die 62 for forming the output portion side, and a mold for taking out the molded gear. The division surface is provided between the first molding die 61 and the second molding die 62. In the molding die 60 having this configuration, it is necessary to re-create the first molding die 51 in order to adjust the backlash of the tooth portion of the gear, and it cannot be easily coped with. In this respect, the molding die 50 of the present embodiment is excellent.
[0044]
As described above, the present embodiment has the following effects.
(1) The tooth portion 17 of the third reduction gear 15 is divided into a first tooth portion 17a and a second tooth portion 17b in the tooth width direction, and the first tooth portion 17a and the second tooth portion 17b are circumferentially separated. Has a shift width d. As a result, the second reduction gear 14 and the third reduction gear 15 are substantially meshed with each other in the forward and reverse rotation, and the backlash in the third reduction gear 15 can be reduced.
[0045]
(2) Since other components for reducing backlash are not required, the number of components can be significantly reduced.
(3) When the actuator 1 is assembled, only the third reduction gear 15 is assembled, so that the operation for adjusting the backlash is not required, and the assembly can be easily performed.
[0046]
(4) The third reduction gear 15 is a gear provided at the last stage of the gear transmission mechanism in the actuator 1, and is provided at a portion where the dimensional tolerance of each component is accumulated. Therefore, by manufacturing the third reduction gear 15 while adjusting the deviation width d in consideration of the dimensional tolerance of each part based on the dimensions of each part after molding, the dimensional variation of each part is absorbed, and Backlash between the second reduction gear 14 and the third reduction gear 15 can be reduced.
[0047]
(5) The molding die 50 of the third reduction gear 15 is composed of a first molding die 51, a second molding die 52, and a third molding die 53, and the second molding die 52 is a third reduction gear. 15 can be rotated in the circumferential direction. Thereby, the shift width d in the circumferential direction can be easily adjusted.
[0048]
(6) It is not necessary to rebuild the molding die 50 for performing accurate backlash adjustment, and the production of the molding die can be facilitated.
(7) Since the rotational position of the second molding die 52 is adjusted based on the deviation width d of the first and second tooth portions 17a and 17b in the molded third reduction gear 15, the third reduction gear is used. The gear accuracy of No. 15 can be easily improved.
[0049]
(8) The deviation width d of the first and second teeth 17a and 17b is adjusted when the third reduction gear 15 is formed. Therefore, the third reduction gear 15 is not provided with a mechanism for adjusting the shift width d. Therefore, the size of the actuator 1 can be reduced as compared with the conventional example shown in FIG.
[0050]
Note that the embodiment of the present invention may be modified as follows.
In the above embodiment, the output shaft 16 of the third reduction gear 15 has the output portion 16a, and the rotation is output from the output portion 16a. However, another gear is provided on the output portion 16a side of the output shaft 16. May be formed. With such a configuration, in the gear transmission mechanism, a gear having a tooth portion divided into two, such as the third reduction gear 15, can be used even in a portion other than the last stage of the gear transmission mechanism. Note that, in this case, due to the structure of the molding die, the gear configured on the output portion side is formed smaller than the gear whose tooth portion is divided into two.
[0051]
In the above-described embodiment, the third reduction gear 15 is used in the actuator 1 as a gear having a tooth portion divided into two. However, this gear is not limited to the actuator 1 and may have a resin gear transmission mechanism. Anything can be used.
[0052]
-In the above-mentioned embodiment, although the 1st tooth part 17a and the 2nd tooth part 17b were constituted so that the tooth width was almost the same, it is not limited to this.
In the above-described embodiment, the teeth 17 of the third reduction gear 15 and the output shaft 16 are integrally formed. However, the teeth 17 and the output shaft 16 that are separately formed are integrated by fitting or bonding. You may.
[0053]
In the above embodiment, the tooth portion 17 of the third reduction gear 15 is constituted by the first and second tooth portions 17a and 17b divided into two in the axial direction (tooth width direction), but is divided into three or more. May be formed.
[0054]
【The invention's effect】
Advantageous Effects of Invention According to the present invention, it is possible to provide a gear with less backlash, a molding die for the gear, and a method for molding the gear without increasing the number of parts.
[Brief description of the drawings]
FIG. 1 is a schematic view showing an actuator using a gear according to an embodiment.
FIG. 2 is an explanatory diagram showing meshing between a second reduction gear and a third reduction gear.
FIG. 3 is a perspective view of a third reduction gear.
4 (a) is a view as viewed from an arrow A in FIG. 3, and FIG. 4 (b) is a view as viewed from an arrow B in FIG. 3 (a).
FIG. 5 is a schematic view showing a cross section of a molding die for molding a third reduction gear.
FIG. 6 is a schematic view showing a cross section of a molding die for molding a conventional gear.
FIG. 7 is a schematic perspective view showing a conventional gear transmission mechanism.
[Explanation of symbols]
15: third reduction gear, 16: output shaft, 16a: output portion, 17: tooth portion, 17a: first tooth portion, 17b: second tooth portion, 50: molding die, 51: first molding die, 52: second molding die, 53: third molding die, d: deviation width.

Claims (8)

A resin gear,
The tooth portion has a first tooth portion and a second tooth portion divided in the tooth width direction, and the first and second tooth portions are integrally formed so as to be shifted in a circumferential direction by a predetermined shift width. A gear characterized by the above. The gear according to claim 1, further comprising an output unit integrally formed with the first and second tooth units. 2. The gear according to claim 1, wherein the shift width is determined according to dimensions of components used in the gear transmission mechanism, and constituting the gear transmission mechanism. 3. 3. The gear according to claim 2, wherein the shift width is determined according to the size of a component used in a final stage of the gear transmission mechanism and constituting the gear transmission mechanism. 4. A molding die for molding a resin gear having a first tooth portion and a second tooth portion formed by dividing the tooth portion in the tooth width direction and shifting in the circumferential direction by a predetermined shift width. So,
A first molding die for molding the first tooth portion;
A second molding die for molding the second tooth portion;
With
The molding die according to claim 1, wherein the second molding die is rotatable in a circumferential direction with respect to the first molding die. The molding die according to claim 5, wherein a mold dividing surface for removing the molded gear is provided between the first molding die and the second molding die. The gear includes an output unit integrally formed,
The molding die according to claim 5, further comprising a third molding die for molding the output portion. A molding method for molding a resin gear having a first tooth portion and a second tooth portion formed by dividing a tooth portion in a tooth width direction and shifting the tooth portion by a predetermined shift width in a circumferential direction using a molding die. And
The molding die,
A first molding die for molding the first tooth portion;
A second molding die that is provided so as to be relatively rotatable in the circumferential direction with respect to the first molding die and that forms the second tooth portion;
Has,
A method of forming a gear, comprising: measuring a shift width of first and second tooth portions of the formed gear; and rotating the second forming die in a circumferential direction based on the measurement result.

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