JPH0673504U - Planetary gear - Google Patents

Abstract

(57) [Abstract] [Purpose] To reduce meshing noise in the planetary gear unit. [Structure] Among the gears constituting the planetary gear device 5 that decelerates and rotates the winding drum 4 by the motor 3, with respect to the sun gear 6 on the input side and the internal gears 8 and 10 on the output side,
Only the planetary gear 7 is made of a material having a low elastic modulus, and the other gears are made of a material having a high elastic modulus as usual. Since the hammering sound is reduced by the existence of the planetary gear 7 having a low elastic modulus, the meshing noise is reduced without making the backlash precise or making all the gears a material having a low elastic modulus to increase the size of the planetary gear device.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a planetary gear unit in which each gear is made of resin, and more particularly to a gear unit capable of reducing meshing noise.

[0002]

[Prior art]

 A planetary gear device including an input-side sun gear, an output-side internal gear, and a planetary gear that meshes with these, and a planetary gear device in which each of these gears is made of resin is known.

[0003]

[Problems to be solved by the device]

 It is desired to reduce meshing noise in this type of device, and for this purpose, it is conceivable to reduce the backlash. However, resin gears require high-precision molding, which increases costs and is not realistic.

[0004] Also, it may be considered that the entire gear is made of a material having a low elastic modulus. However, in this case, the tooth surface is increased and the thickness of the gear on the input / output side is increased in order to maintain a predetermined strength. Since it has to be large, there is a limit to the compactness of the entire device, despite the planetary gear mechanism. The present invention solves this problem.

[0005]

[Means for Solving the Problems]

 In order to solve the above problems, the planetary gear device of the present invention includes an input side sun gear, an output side internal gear, and a planetary gear that meshes with these, and a planetary gear device in which each of these gears is made of resin. In the above, the elastic modulus of the material forming the planetary gear is set to be lower than the elastic modulus of the material forming the sun gear and the internal gear.

[0006]

[Action]

 The sun gear on the input side meshes with a planetary gear made of a material with a lower elastic modulus, and the internal gear on the output side with which this planetary gear meshes is made of a material with a higher elastic modulus than the planetary gear, like the sun gear. . Therefore, the hammering noise between the gears is reduced and the meshing noise is reduced. At the same time, the sun gear and the internal gear are materials with a higher elastic modulus, so that they maintain a predetermined strength without being made too thick.

[0007]

【Example】

 An embodiment will be described based on FIGS. 1 to 4. FIG. 2 is a cross-sectional view of the entire telescopic type corner pole device installed in a corner portion of an automobile, in which a pole 1 can be freely extended upward and shortened downward by a drive code 2. The drive cord 2 is wound or unwound by a motor 3 on a winding drum 4 which is driven via a planetary gear device, so that the drive cord 2 can expand and contract.

The planetary gear device 5 is an input side sun gear 6 connected to the motor 3, a planetary gear 7 meshing with the sun gear 6, an output side internal gear 8 with which the planetary gears 7 mesh, and an internal gear of the differential clutch 9. It is composed of 10. The internal gear 8 is formed integrally with the winding drum 4, and the internal gear 10 is formed integrally with a ring member that constitutes a differential clutch 9 that is superposed on the winding drum 4.

A lower portion of a metal pole holder 14 is fitted to a large diameter portion 13 formed upward at one end of a feeder portion 12 extending from a gear case 11 accommodating the motor 3 and the planetary gear device 5, The lower part of the pole 1 is supported therein.

In the planetary gear device 5 shown in FIGS. 1 and 3, the sun gear 6 on the input side and the internal gears 8 and 10 on the output side, to which the output shaft 15 of the motor 3 is connected, have a relatively elastic modulus similar to the conventional one. The planetary gear 7, which is made of a high material and meshes with these, is made of a material having a lower elastic modulus than these gears.

In the present embodiment, all the gears of the planetary gear device 5 are made of polyacetal resin, which is the same material, but have different elastic moduli. The elastic moduli of the respective gears are 25,000 Kg / g for the sun gear 6. cm ² , the planet gear 7 is 10,000 kg / cm ² , and the internal gears 8 and 10 are about the same as the sun gear 6.

[0012] The planetary gear 7 in this embodiment, the difference in elastic modulus with respect to the sun gear 6 and the internal gear 8, 10 is a 15,000 kg / cm ^2, when using the material, 15000 Kg / cm ² of about The above is sufficient.

As is apparent from FIG. 1, the planetary gear 7 is sandwiched between an upper plate 16 made of resin and a lower plate 17 made of a metal ring, and a shaft extending integrally from the upper plate 16 and penetrating the planetary gear 7. The tip of 18 is integrated with the lower plate 17 by heat caulking.

A protrusion 19 is formed in the center of the upper surface of the upper plate 16, and the protrusion 19 is fitted into a recess 21 formed in the center of the rear surface of the lid 20 of the gear case 11 to form the planetary gear device 5. Is positioned.

The ring member of the differential clutch 9 is locked to the gear case 11 side by engaging the corrugated portion 22 formed on the outer peripheral portion with the roller 24 biased by the leaf spring 23.

The winding drum 4 on which the internal gear 8 is formed is provided with an inverted U-shaped winding groove 25 opened downward, and is driven into the winding groove 25 depending on the rotation direction of the winding drum 4. The cord 2 can be wound up. The winding drum 4 is rotatable within an annular groove 27 of the gear case 11 formed on the side of the motor case 26.

Next, the operation of this embodiment will be described. In FIG. 1, the rotation of the motor 3 is transmitted to the sun gear 6 from the output shaft 15 and is decelerated and output from the internal gear 8 via the planetary gear 7, so that the winding drum 4 rotates.

At this time, since only the planetary gear 7 is made of a material having a lower elastic modulus than the sun gear 6 and the internal gears 8, 10 which mesh with each other, the hammering sound is reduced and the planetary gears 7 mesh with each other. Noise is reduced. FIG. 4 is a graph comparing a conventional type in which all gears are made of a material having a high elastic modulus with that of this example, and the backlash is about 20% in both cases.

That is, the graph on the left side of FIG. 4 shows the case where the expansion / contraction speed of the pole 1 is changed, and the graph on the right side shows the case where the rotation of the motor 3 is changed. In any of these cases, the present embodiment shows a significant reduction in meshing noise.

Therefore, even if a gear having a relatively large backlash is used, the meshing noise can be effectively reduced, so that it is not necessary to use an expensive gear, and the cost can be reduced.

In addition, since the input sun gear 6 and the output internal gears 8 and 10 can be made of the same materials having a relatively high elastic modulus as in the conventional case, it is not necessary to increase the thickness. As a result, the required strength can be maintained and the entire apparatus can be made compact.

[0022]

[Effect of device]

 In the present invention, among the gears forming the planetary gear device, only the planetary gear is made of a material having a lower elastic modulus than the sun gear and the internal gear that mesh with each other, so that the hammering noise is reduced and the meshing noise is reduced. be able to. Therefore, even if a relatively large backlash gear is used, the meshing noise can be efficiently reduced, so that it is not necessary to use an expensive gear and the cost can be reduced.

Moreover, since the input sun gear and the output internal gear can be made of a material having a relatively high elastic modulus similar to the conventional material, the wall thickness does not have to be made too thick, and as a result, it is necessary. The strength of the device can be maintained and the entire device can be made compact.

[Brief description of drawings]

FIG. 1 is a partially enlarged cross-sectional view of a main part of an embodiment.

FIG. 2 is an overall sectional view of an example.

FIG. 3 is a partially cutaway plan view of the essential part of the embodiment.

FIG. 4 is a graph showing meshing noise of an example in comparison with a conventional example.

[Explanation of symbols]

1: pole, 2: drive cord, 3: motor, 4: winding drum, 5: planetary gear device, 6: sun gear, 7:
Planetary gear, 8: Internal gear

Claims (1)

[Scope of utility model registration request] 1. A planetary gear device comprising a sun gear on the input side, an internal gear on the output side, and a planetary gear that meshes with these, and in a planetary gear device in which each of these gears is made of resin, the material forming the planetary gear is used. A planetary gear device having an elastic modulus lower than that of a material forming the sun gear and the internal gear.