JP2011033123A - Stepped reduction gear and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a pinion from being turned to a spur. <P>SOLUTION: This stepped reduction gear 1 includes: a resin-made spur (gear) 2 serving as a first gear whose peripheral surface is geared; and a metal-made pinion 3 having a smaller diameter than the spur 2 and serving as a second gear whose peripheral surface is geared. A hole 4 penetrating the spur 2 in the rotation axis direction of the spur 2 is formed in the rotating central part of the spur 2. A shaft-like press-in part 5 is extended from the rotating central part of the pinion 3. The whole of the press-in part 5 is pressed in the hole 4. Further, part 6 of a geared part in the peripheral surface of the pinion 3 is also forcibly pressed in the hole 4 to be embedded in the spur 2. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a stepped reduction gear and a manufacturing method thereof.

  Conventionally, a stepped reduction gear composed of a resin spar (large gear) and a metal pinion (small gear) is known, and is mainly used in a reduction mechanism such as a motor.

  As a manufacturing method of such a stepped reduction gear, by insert molding in which a metal member serving as a kana is loaded into a mold, a resin is injected, the metal member is wrapped with a molten resin, and a resin serving as a spar is solidified. There is a method or a method of press-fitting a metal kana with a shaft-like press-fitting portion extending into a resin spar having a center hole.

  Patent Document 1 discloses a technique of inserting a pitch tooth portion of a kana in which a part of a gear is processed into a pitch tooth into a center hole of a resin spar having a substantially pitch-shaped center hole.

  The technique described in Patent Document 1 is suitable for obtaining a stepped reduction gear that prevents slipping in the direction of rotation in a trial production stage or when a small amount is manufactured.

JP 2005-66733 A

  In the manufacturing method by insert molding, a mold apparatus for insert molding that includes an apparatus that can continuously supply metal parts for insert into the mold is required. In addition, a dedicated mold is required according to the specifications of the gear (number of teeth, module, shift coefficient). Therefore, the production energy must be larger than the production method by press fitting.

  In the manufacturing method by press-fitting, since the press-fitting part is generally only press-fitted into the center hole of the resin spar, the press-fitting part slips in the center hole when a load torque higher than expected is applied, etc. May cause a malfunction that turns around against the spar.

  In addition, when a load that is not assumed in a normal usage pattern is applied in the direction opposite to the press-fitting direction, there is a possibility that the kana may come out of the spar.

  According to the method described in Patent Document 1, it is particularly effective in preventing slipping in the turning direction. However, the man-hour for pressing the spar with a dedicated processing tool before inserting the kana into the spar. Therefore, it may not be suitable for mass production.

An object of the present invention is to provide a stepped reduction gear excellent in mass productivity that can prevent a small gear from rotating or coming out of a large gear by a manufacturing method with relatively small manufacturing energy. Is to realize.

  (1) The present invention includes a first gear having a hole formed in the rotation center portion, and a second gear having a smaller diameter than the first gear and a press-fit portion extending from the rotation center portion, The press-fitting portion is a stepped reduction gear that is press-fitted into the hole and a part of a portion where the gear of the second gear is formed is embedded in the first gear.

  (2) In this case, the press-fitting portion may be configured such that grooves are continuously formed on the peripheral surface thereof.

  (3) The first gear may be made of phenol resin, and the second gear may be made of metal.

  (4) According to another aspect of the present invention, there is provided a first gear having a hole formed in the rotation center portion, and a second gear having a smaller diameter than the first gear and a press-fitting portion extending from the rotation center portion. A preparatory step of preparing a gear, a first press-fitting step of press-fitting the press-fitting portion into the hole after the pre-preparation step, and a portion where a gear of the second gear is formed after the first press-fitting step. And a second press-fitting step of embedding a portion in the first gear.

  (5) In this case, the preparation step may prepare the second gear in which grooves are continuously formed on the peripheral surface of the press-fitting portion.

  According to the inventions of (1), (3), and (4), it is possible to prevent the second gear from rotating with respect to the first gear.

  According to the inventions of (2), (3), and (5), it is possible to prevent the second gear from coming off from the first gear.

  According to the invention of (3), the second gear rotates with respect to the first gear, and the second gear is prevented from coming off from the first gear. A stepped reduction gear having excellent reliability can be obtained.

  According to the inventions of (4) and (5), the stepped reduction gear capable of preventing the second gear from turning around or coming off from the first gear can be efficiently manufactured with a small number of work steps.

  Furthermore, according to the inventions of (4) and (5), even when the specifications such as the number of teeth of the first gear or the second gear are changed, the same equipment or without major changes to the equipment, Can respond.

It is a longitudinal cross-sectional view of the stepped reduction gear which is one embodiment of this invention. It is a perspective view of the stepped reduction gear which is one embodiment of the present invention. It is a flowchart explaining the manufacturing process of the stepped reduction gear which is one embodiment of this invention in steps. It is a partial expanded longitudinal cross-sectional view of the state which press-fitted the pressure fitting part of the kana to the hole in the manufacturing process of the stepped reduction gear which is one embodiment of the present invention. It is a partial expanded longitudinal cross-sectional view which shows a deformation | transformation of a spar in steps in the manufacturing process of the stepped reduction gear which is one embodiment of this invention. It is a partial expanded longitudinal cross-sectional view which shows a deformation | transformation of a spar in steps in the manufacturing process of the stepped reduction gear which is one embodiment of this invention. It is a partial expanded longitudinal cross-sectional view which shows a deformation | transformation of a spar in steps in the manufacturing process of the stepped reduction gear which is one embodiment of this invention. It is a longitudinal cross-sectional view including the jig | tool of the state of FIG. 7 in the manufacturing process of the stepped reduction gear which is one embodiment of this invention. It is a longitudinal cross-sectional view including the jig | tool of the state of FIG. 7 which has chamfering in the manufacturing process of the stepped reduction gear which is one embodiment of this invention. It is a longitudinal cross-sectional view of the stepped reduction gear used as a comparative example. It is a flowchart explaining the manufacturing process of the stepped reduction gear used as a comparative example in steps. It is explanatory drawing explaining the effect | action of the stepped reduction gear which is one embodiment of this invention. It is a graph explaining the effect | action of the stepped reduction gear which is one embodiment of this invention. It is a longitudinal cross-sectional view of the stepped reduction gear which is other embodiment of this invention. It is a longitudinal cross-sectional view of the pinion of the stepped reduction gear which is one embodiment of this invention. It is a longitudinal cross-sectional view of the pinion of the stepped reduction gear which is other embodiment of this invention. It is a longitudinal cross-sectional view including the jig | tool of the state of FIG. 14 in the manufacturing process of the stepped reduction gear which is other embodiment of this invention. It is a longitudinal cross-sectional view including the jig | tool of the state of FIG. 14 which has chamfering in the manufacturing process of the stepped reduction gear which is other embodiment of this invention. It is explanatory drawing explaining the effect | action of the stepped reduction gear which is other embodiment of this invention.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  First, the structure of the stepped reduction gear which is one embodiment of the present invention will be described.

  FIG. 1 is a longitudinal sectional view of the stepped reduction gear 1, and FIG. 2 is a perspective view thereof.

  The stepped reduction gear 1 has a smaller diameter than a spar (large gear) 2 made of resin (bakelite) and a spar 2 having a tip diameter of 6 mm on the peripheral surface. And a metal pinion (small gear) 3 serving as a second gear in which is formed. A hole 4 that penetrates the spar 2 in the direction of the rotation axis of the spar 2 is formed at the center of rotation of the spar 2. A shaft-like press-fitting portion 5 extends from the rotation center portion of the kana 3.

  The entire press-fitting portion 5 is press-fitted into the hole 4. Furthermore, a part 6 of a portion where a gear is formed on the peripheral surface of the cane 3 is also strongly pressed into the hole 4. That is, a part 6 of the kana 3 is embedded in the spar 2.

  Next, a method for manufacturing the stepped reduction gear 1 will be described.

  FIG. 3 is a flowchart illustrating the manufacturing process of the stepped reduction gear 1 step by step.

  First, a jig for placing the spar 2 flat is set (step S1), and the spar 2 is placed flat on the jig (step S2). And kana 3 is set on it (step S3).

  Next, the press-fitting portion 5 of the kana 3 is press-fitted until it abuts against the hole 4 (step S4). FIG. 4 is a partially enlarged vertical sectional view showing a state where the press-fitting portion 5 of the kana 3 is pressed into the hole 4 up to the abutting portion 7. Kana 3 and Spur 2 are hitting each other.

  Thereafter, part 6 of the portion where the gear is formed on the peripheral surface of the cane 3 is also strongly pressed into the hole 4 (step S5). 5 to 7 are partially enlarged longitudinal sectional views showing the deformation of the spar 2 at this time in stages.

  When a part 6 of the portion where the gear is formed on the peripheral surface of the can 3 is strongly pressed into the hole 4, the teeth of the can 3 bite into the hole 4 and the spar 2 is elastically deformed (state shown in FIG. 5). Further press-fitting causes the spar 2 to undergo elastic deformation and plastic deformation, and the teeth of the kana 3 bite into the resin-ruptured portion of the spar 2 (state of FIG. 6). Thereafter, when the strong pressure input is released, the kana 3 is pushed back a little by the action of the elastically deformed portion (state of FIG. 7).

  Since the bakelite, a phenolic resin with excellent mechanical properties, is used as the material of the spar 2, it is possible to generate elastic deformation, resin rupture, and plastic deformation of the spar 2 in an optimal manner. Is partially embedded in the spar 2.

  FIG. 8 is a longitudinal sectional view including the jig in the state of FIG.

  The jig 11 is an instrument in which the upper surface 12 is a flat surface and a hole 13 matching the size and shape of the hole 4 is opened. Since it has such a shape, by receiving the spar 2 as a whole, the elastic deformation of the spar 2 can be suppressed, and as a result, the spar 2 can be plastically deformed and the spar 2 can be prevented from deforming.

  On the other hand, as shown in FIG. 9, it is not preferable that the jig 11 has the chamfer 14 in the hole 13 portion of the upper surface 12, because the spar 2 is deformed.

  FIG. 10 is a longitudinal sectional view of a stepped reduction gear 101 as a comparative example.

  10, members having the same reference numerals as those in FIGS. 1 and 2 are the same as those of the stepped reduction gear 1 described above, and detailed description thereof is omitted. The stepped reduction gear 101 is different from the configuration of the stepped reduction gear 1 in that a part of a portion where the gear is formed on the peripheral surface of the pinion 3 is not strongly pressed into the hole 4.

  FIG. 11 is a flowchart for explaining the manufacturing process of the stepped reduction gear 101 step by step.

  In FIG. 11, the same steps as those in FIG. 3 are the same as those in the manufacturing process of the stepped reduction gear 1 described above, and detailed description thereof is omitted. In the stepped reduction gear 101, the step of strongly press-fitting a part of the peripheral surface of the pinion 3 into which the gear is formed (step S5) is not performed. Different from the process.

FIG. 12 is an explanatory diagram for explaining the operation of the stepped reduction gear 1, and shows a strong press-fitting depth when a part 6 of the portion where the gear is formed on the peripheral surface of the pinion 3 is press-fitted into the hole 4. The relationship between the strength of the kana 3 relative to the spar 2 is shown.
At this time, the tip circle diameter φ6 mm of the spar 2 and the tip circle diameter φ2.3 mm of the kana 3 are set.

  The turning strength (gf · cm) when the strong press-fitting depth is 0 (mm) is the turning strength in the case of the stepped reduction gear 101. Based on this, the strong press-fitting depth is 0.1 (mm), 0. It shows the magnitude (gf · cm) of the surrounding strength and the increase ratio when it is 2 (mm).

  When the press-fit depth is 0.1 (mm), the strength (gf · cm) of the surrounding strength is increased 2.4 times compared to when the press-fit depth is 0 (mm), and the press-fit depth is 0. It can be seen that the magnitude of the surrounding strength (gf · cm) is increased 4.3 times in the case of .2 (mm) compared to the case of the deep press-fit depth of 0 (mm).

  The relationship between such a strong press-fit depth and the amount of bite is shown in the graph of FIG.

  As can be seen from the above results, the stepped reduction gear 1 has a greater turning strength with respect to the hole 4 of the press-fit portion 5 than the stepped reduction gear 101, and prevents the problem that the kana 3 turns around the spar 2. I understand that I can do it.

  Next, another configuration example of the present embodiment will be described.

  FIG. 14 is a longitudinal sectional view of a stepped reduction gear 21 according to another configuration example.

  In FIG. 14, members having the same reference numerals as those in FIGS. 1 and 2 are the same as those in the case of the stepped reduction gear 1 described above, and thus detailed description thereof is omitted.

  15 is a longitudinal sectional view of the pinion 3 of the stepped reduction gear 1, and FIG. 16 is a vertical sectional view of the pinion 3 of the stepped reduction gear 21.

  The stepped reduction gear 21 is different from the stepped reduction gear 1 in that grooves 22 are continuously formed in the circumferential direction on the peripheral surface of the press-fit portion 5.

  The manufacturing process of the stepped reduction gear 21 is the same as the process described above with reference to FIG. 3 except that the groove 3 shown in FIG.

  FIG. 17 is a longitudinal sectional view showing a state in which the strong press-fitting process (step S5) is performed on the jig 11, and here, as shown in FIG. 18, the jig 11 is chamfered in the hole 13 portion of the upper surface 12. 14 is not preferable because shape deformation occurs in the spar 2.

  FIG. 19 shows the removal force (N) of the pin 3 with respect to the spar 2 with the pin 3 (stepped reduction gear 21) in which the groove 22 is formed and the pin 3 (stepped reduction gear 1) in which the groove 22 is not formed. It is explanatory drawing of the result of having compared.

  The removal force (N) of the pinion 3 in which the groove 22 of the stepped reduction gear 21 is formed is increased 2.5 times that of the pinion 3 in which the groove 22 of the stepped reduction gear 1 is not formed. I understand.

  Although the embodiments have been described above, the present invention is not limited to the above-described embodiments, and various modifications may be made within the scope of the present invention with respect to the materials, external dimensions, number of teeth, etc. of the spar and kana depending on the application. Can be appropriately selected.

  Specifically, for example, bakelite was used as the material for the resin spar in this example. However, Duracon, which is a typical acetal resin, nylon resin as an engineering plastic, and various other resins can be used depending on the application. Can be selected.

The stepped reduction gear of the present invention can be used for various reduction mechanisms, and is particularly suitable for use in the unit portion of the first stage gear in the reduction mechanism of a small geared motor having an outer diameter of 30 mm or less.

DESCRIPTION OF SYMBOLS 1,101 Stepped reduction gear 2 Spar 3 Kana 4 Hole 5 Press-in part 6 Kana part 7 Abutting part 11 Jig 12 (Jig) upper surface part 13 (Jig) hole 14 (Jig) Chamfered part 21 Stepped reduction gear 22 Groove

Claims (5)

A first gear having a hole formed in the center of rotation;
A second gear having a smaller diameter than the first gear and a press-fit portion extending from the center of rotation;
With
The press-fitting portion is press-fitted into the hole, and a part of a portion where the gear of the second gear is formed is embedded in the first gear.
Stepped reduction gear.   The stepped reduction gear according to claim 1, wherein a groove is continuously formed on a peripheral surface of the press-fitting portion.   The stepped reduction gear according to claim 1 or 2, wherein the first gear is made of phenol resin, and the second gear is made of metal. Preparing a first gear having a hole formed in the rotation center portion, and a second gear having a smaller diameter than the first gear and a press-fit portion extending from the rotation center portion;
A first press-fitting step of press-fitting the press-fitting portion into the hole after the preparation step;
A second press-fitting step of embedding a part of the portion where the gear of the second gear is formed after the first press-fitting step into the first gear;
The manufacturing method of the stepped reduction gear which comprises this.   The manufacturing method of the stepped reduction gear of Claim 4 which prepares the said 2nd gearwheel in which the groove | channel is continuously formed in the surrounding surface of the said press-fit part in the said preparation process.

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