JP2008057754A - Multistage gear - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a multistage gear for highly accurately joining the multistage gear formed by coaxially joining a metallic small diameter gear and a synthetic resin large diameter gear and realize whirl stop of both gears with a simple structure. <P>SOLUTION: This multistage gear 1 is formed by coaxially joining the metallic small diameter gear 2 and the synthetic resin large diameter gear 3, and is joined by fitting the outer periphery 5a of a joining part 5 arranged in the small diameter gear 2 to an inner peripheral hole 4 formed with a uniform inner diameter from the axis of the large diameter gear 3 in a state of locking a bottom part 5b, forming an unevenness 6 in an upper end peripheral part on the opposite side of the bottom part 5b locked on the inner peripheral hole 4 in the small diameter gear 2, forming a projection part 9 having the inclined side 8 on the outer periphery from the upper end on the opposite side of the bottom part of the inner peripheral hole 4 of the large diameter gear 3, and locking the upper end of the small diameter gear 2 and engaging by melting into the unevenness 6 by the projection part 9 weighed down by fusion with heat. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a multi-stage gear formed by coaxially coupling a metal small diameter gear and a synthetic resin large diameter gear.

  For example, in the gear train used in the reducer, resin gears are used for the transmission part of the small torque in order to reduce noise during driving and improve productivity. In the case where the strength is insufficient, a multi-stage gear in which strength distribution is considered is configured by combining a resin gear and a metal gear.

  As a conventional example of such a multi-stage gear, reference is made to Patent Document 1, which includes a combination of a small-diameter metal gear 30 and a large-diameter resin gear 31 as shown in FIG. The gears are described.

The structure is such that a retaining groove 32 is formed on the outer periphery of the lower end of the metal gear 30 and an escape groove 34 is formed on the outer periphery of the lower end of the bearing portion 33 of the resin gear 31, as shown in FIG. When the hole 30a formed at the center of the metal gear 30 is fitted into the bearing portion 33 of the resin gear 31, and then press-fitted while applying ultrasonic waves from the metal gear 30 side, the metal gear 30 is made of resin. A portion in contact with the gear 31 is melted, and the melted resin flows into the retaining groove 32 and the escape groove 34, thereby constituting a gear in which both gears are integrally coupled.
Japanese Utility Model Publication No. 63-44594

  However, in Patent Document 1 described above, when ultrasonic waves are applied to the metal gear 30 as described above, the positions of the metal gear 30 and the resin gear 31 that are in contact with each other due to the influence of the vibration of the ultrasonic waves. There is a possibility that inconvenience may arise in terms of coupling accuracy, such that both are coupled in a state where the accuracy is not good.

  The present invention has been made in view of the above circumstances, and a multi-stage gear formed by coaxially coupling a metal small-diameter gear and a synthetic resin large-diameter gear is coupled with high accuracy and also prevents the rotation of both gears. An object of the present invention is to provide a multi-stage gear that can be realized with a simple structure.

  In order to solve the above problem, a multi-stage gear according to claim 1 of the present invention is a multi-stage gear formed by coaxially coupling a metal small-diameter gear and a synthetic resin large-diameter gear. The outer periphery of the coupling portion provided in the small-diameter gear is fitted in the inner peripheral hole formed with a uniform inner diameter from the shaft center with the bottom portion locked, and the small-diameter gear is fitted with the inner diameter hole. An unevenness is formed in the upper end peripheral portion on the opposite side to the bottom portion locked in the peripheral hole, and the protrusion has an inclined side on the outer periphery from the upper end opposite to the bottom portion of the inner peripheral hole of the large-diameter gear. And the protrusion pushed and bent by heating and melting engages the upper end of the small-diameter gear and melts and engages with the unevenness.

  According to the multi-stage gear of the present invention, a multi-stage gear formed by coaxially coupling a metal small-diameter gear and a synthetic resin large-diameter gear, and a protrusion of the synthetic resin large-diameter gear that is pushed and bent by heating and melting. Since the two gears are connected by engaging the upper end of the metal small-diameter gear and being melted into the irregularities, the molten resin on the large-diameter gear side and the irregularities on the small-diameter gear side mesh with each other. The large-diameter gear and the small-diameter gear are firmly coupled in a state where the large-diameter gear and the small-diameter gear are prevented from rotating.

  Therefore, the present invention does not use ultrasonic waves that generate vibration as in the prior art, and the protrusion is deformed by heating and melting and pressing the protrusion of the large-diameter gear. Both gears are coupled in a state in which the positional accuracy in the fitted state with the small-diameter gear is kept good, and it becomes possible to obtain a good coupling accuracy.

  Embodiments of the present invention will be described below with reference to the drawings.

  As shown in FIG. 1 or FIG. 2, the multi-stage gear 1 according to the present invention is a multi-stage gear 1 in which a metal small-diameter gear 2 and a synthetic resin large-diameter gear 3 are coaxially coupled. The outer peripheral surface 5a of the coupling portion 5 provided in the small-diameter gear 2 is fitted in the inner peripheral hole 4 formed with an equal inner diameter from the center while the bottom portion 5b is locked, and the small-diameter gear 2 Is formed with irregularities 6 on the upper peripheral portion on the opposite side to the bottom portion 5b locked to the inner peripheral hole 4, and further on the outer periphery from the upper end on the opposite side to the bottom portion of the inner peripheral hole 4 of the large-diameter gear 3. As shown in FIG. 4, the protrusion 9, which is pushed and bent by heating and melting, locks the upper end of the small-diameter gear 2 and melts and engages with the irregularities 6. . In the present invention, the expression “coupled coaxially”, such as “coaxially coupled the metal small-diameter gear 2 and the synthetic resin large-diameter gear 3”, refers to the small-diameter gear 2 and the large-diameter gear. This means that the axis 3 is the center of rotation.

  The multi-stage gear 1 having such a configuration will be described in detail. FIG. 1A is a perspective view of the metal small-diameter gear 2, and FIG. 3A is a cross-sectional view of the metal small-diameter gear 2. As shown in these drawings, the small-diameter gear 2 made of a metal material has a small-diameter gear portion 2b formed coaxially on the side surface of the coupling portion 5 having a disk shape, and a bottom portion 5b ( A circumferential stepped portion 7 having irregularities 6 formed on the upper peripheral portion on the opposite side (the gear portion 2b side) to the opposite side of FIG. 3A is provided, and the shaft center between the gear portion 2b and the coupling portion 5 is provided at the axial center. The shaft hole 2a is formed in a penetrating manner.

  FIG. 1B is a perspective view of the synthetic resin large-diameter gear 3, and FIG. 3B is a cross-sectional view of the synthetic resin large-diameter gear 3. As shown in these figures, the outer periphery 5a of the coupling portion 5 of the small-diameter gear 2 has a uniform inner diameter from the axial center of the large-diameter gear 3 formed of a synthetic resin such as polyacetal (POM). An inner peripheral hole 4 is formed. A ring-shaped locking piece 10 is formed inwardly on the bottom inner periphery of the inner peripheral hole 4, and the small-diameter gear fitted in the inner peripheral hole 4 of the large-diameter gear 3 as shown in FIG. The peripheral part of the bottom part 5 b of the second part is locked by the locking piece 10 of the inner peripheral hole 4.

  Further, the synthetic resin large-diameter gear 3 is formed with a protrusion 9 having an inclined side 8 on the outer periphery from the upper end opposite to the bottom of the inner peripheral hole 4. The protrusion 9 has an inclined side 8 formed on the outer peripheral side of the inner peripheral hole 4 and an inclined groove 8a that is depressed toward the outer periphery, and the tip of the protrusion 9 is the end surface 3a of the large-diameter gear 3. It is formed so as to protrude upward.

  In order to couple the metal small-diameter gear 2 and the synthetic resin large-diameter gear 3 configured as described above, the coupling portion 5 of the small-diameter gear 2 is inserted into the inner peripheral hole 4 of the large-diameter gear 3 and fitted. Then, the bottom 5b of the small-diameter gear 2 is locked by the locking piece 10 on the inner periphery of the bottom of the inner peripheral hole 4, and the projection 9 is pushed and bent by heating and melting (a portion to be crushed also occurs), thereby generating a small-diameter gear. 2 is engaged with the circumferential stepped portion 7 in a state of being melted into the concavo-convex portion 6 (in FIG. 5, the pushed and bent projection portion is indicated by 9a), and the small diameter gear 2 and the large diameter gear 3 are connected. It is assumed to be an integrated connection.

  The process of pushing and bending the protrusion 9 of the large-diameter gear 3 by heating and melting as described above uses a positioning jig 11 and a heating horn 12 as shown in FIG. This positioning jig 11 is a jig for positioning the heating horn 12 and the base 14. The positioning jig 11 positions the outer periphery of the body 12 d of the heating horn 12 and the base 14 for placing the large-diameter gear 3. The mutual positioning is performed by fitting the inner periphery 13a of the cylindrical member 13 of the tool 11. The cylindrical member 13 is removed after the heating horn 12 and the base 14 are positioned.

  In order to place the large-diameter gear 3 on the base 14, the core pin 15 protrudes upward and is inserted into the center hole 14 a of the base 14, and the small-diameter gear 2 is fitted in the inner peripheral hole 4 of the large-diameter gear 3. Thus, the shaft hole 2 a of the small-diameter gear 2 is fitted to the core pin 15.

  The heating horn 12 has a through hole 12b into which the gear portion 2a of the small diameter gear 2 can be inserted, and the inner periphery of the cylindrical horn lower end portion 12a is slightly smaller in diameter than the inner peripheral hole 4 of the large diameter gear 3. It is desirable to become. Moreover, the heating horn 12 heats so that the horn lower end part 12a may become about 200 degreeC. By doing this, the temperature of the horn lower end 12a is lowered by lowering the heating horn 12 and keeping the horn lower end 12a in contact with the projection 9 of the large-diameter gear 3 for a predetermined time (for example, about 5 seconds). It is transmitted to the protrusion 9 and the protrusion 9 is in a molten state. It should be noted that the melted state of the protrusions may be a softened state in which the protrusions 9 are bent and deformed and are engaged with the irregularities 6 of the small-diameter gear 2 instead of being melted.

  Further, when the heating horn 12 is lowered, the horn lower end portion 12a presses the softened projection 9 downward to deform the projection 9 so that it is pushed inward, and then the inner circumference of the horn lower end 12a. When the end portion 12 c hits the inclined side 8 and presses the entire projection portion 9, the projection portion 9 engages with the upper end of the small-diameter gear 2 while being melted and engaged with the unevenness 6.

  As described above, the projections 9 of the synthetic resin large-diameter gear 3 are melted and engaged with the projections and recesses 6 of the metal small-diameter gear 2 so that the two gears 2 and 3 are coupled to each other. The melted resin and the unevenness 6 on the small-diameter gear 2 side mesh with each other, so that the two gears are firmly coupled in a state where they are prevented from rotating.

  Further, the protruding portion 9 of the large-diameter gear 3 is engaged by the concave and convex portions 6 of the small-diameter gear 2 by being pressed and bent by the above-mentioned pressing and heating and melting, and the resin melted in this state is surrounded by the surroundings. Since it is accommodated in the stepped portion 7 and the inclined groove 8 a, the pushed and bent protruding portion 9 is accommodated without protruding outward from the end face of the large-diameter gear 3.

  In addition, although the structure of the small diameter gear 2 of said Example is set as the structure by which the gear part 2b was provided in the side facing the same direction as the inclined side 8 of the large diameter gear 3, this invention is limited to this. Alternatively, the gear portion 2b may be provided in a direction in which the gear portion 2b is pulled downward from the locking piece 10 of the large-diameter gear 3. In any case, the bottom portion 5b of the small-diameter gear 2 is provided with the locking piece 10 of the large-diameter gear 3. The concave and convex portions 6 are formed in the upper peripheral portion on the opposite side of the bottom portion 5b of the small-diameter gear 2.

  The multi-stage gear according to the present invention is capable of coupling a multi-stage gear formed by coaxially coupling a metal small-diameter gear and a synthetic resin large-diameter gear with high accuracy, and realizing a detent of both gears with a simple structure. It can be used as a multi-stage gear.

(a) is a perspective view which shows the small diameter gear of the multistage gear by this invention, (b) is a perspective view which shows a large diameter gear. It is a perspective view of the multistage gear by this invention, and shows the state which fitted the small diameter gear in the internal peripheral hole of the large diameter gear. (a) is sectional drawing which shows the small diameter gear of the multistage gear by this invention, (b) is sectional drawing which shows a large diameter gear. It is sectional drawing which shows the state which fitted the small diameter gear in the internal peripheral hole of the large diameter gear in the multistage gear by this invention. It is sectional drawing which shows the state which engaged the protrusion part of the large diameter gear in the multistage gear by this invention with the unevenness | corrugation of the outer peripheral step part of a small diameter gear. It is sectional drawing which shows the process which pushes and bends the projection part of the large diameter gear which concerns on this invention by heat melting. (a) And (b) is sectional drawing which shows the state before the coupling | bonding in the gear of patent document 1, and sectional drawing which shows the state after coupling | bonding.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Multi-stage gear 2 Small diameter gear 2a Shaft hole 2b Small diameter gear part 3 Large diameter gear 3a End surface 4 Inner peripheral hole 5 Outer part 5a Outer part 5b Bottom part 6 Concavity and convexity 7 Peripheral step part 8 Inclined side 8a Inclined groove 9 Protruding part 9a Push bending Protruding portion 10 Locking piece 11 Positioning jig 12 Heating horn 12a Horn lower end portion 12b Through hole 12c Inner peripheral end portion 12d Body portion 13 Cylindrical member 13a Inner periphery 14 Base 14a Center hole 15 Core pin

Claims (1)

In a multi-stage gear formed by coaxially coupling a metal small-diameter gear and a synthetic resin large-diameter gear, the small-diameter gear is provided in an inner peripheral hole formed with an equal inner diameter from the axial center of the large-diameter gear. The outer periphery of the coupled portion is fitted with the bottom portion locked, and the small-diameter gear has an unevenness at the upper peripheral portion on the opposite side to the bottom portion locked in the inner peripheral hole. Further, a protrusion having an inclined side is formed on the outer periphery from the upper end opposite to the bottom of the inner peripheral hole of the large-diameter gear, and the protrusion that is pushed and bent by heating and melting engages the upper end of the small-diameter gear. A multi-stage gear that is stopped and melted into and engaged with the unevenness.