JP3978887B2 - Shaft reinforcement structure in resin chassis - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a shaft reinforcing structure in a resin chassis, and more particularly to a shaft reinforcing structure in a resin chassis that reinforces a shaft having one end fixed integrally with the resin chassis and the other end being a free end.
[0002]
[Prior art]
For example, in electronic equipment such as a digital audio tape recorder (DAT), the drive mechanism portion is being made of resin in order to reduce weight and reduce costs.
3 and 4 show a speed reduction mechanism 10 provided in the DAT as an example of a drive mechanism using the resin chassis 11. FIG. 3 is a cross-sectional view of the speed reduction mechanism 10, and FIG. 4 is a perspective view in which the speed reduction mechanism 10 is partially cut off.
[0003]
The speed reduction mechanism 10 includes a resin chassis 11, gears 16 to 19, a subchassis 21, reinforcing screws 25 to 27, and a circuit board 28. The resin chassis 11 is formed by, for example, transfer molding a hard resin, and shafts 12 to 15 are integrally formed upright at predetermined positions. Thus, by using the resin chassis 11 as the chassis, the speed reduction mechanism 10 can be reduced in weight and cost can be reduced.
[0004]
On the other hand, the lower parts of the shafts 12 to 15 are fixed to the resin chassis 11 and the upper ends thereof are free ends 12a to 15a. Of the free ends 12a to 15a, screw holes are formed in the free ends 12a, 13a, and 15a as will be described in detail later.
The gears 16 to 19 reduce the rotation transmitted to the input shaft 20 connected to a drive source (for example, a motor). The gears 16 to 19 are rotatably supported by shafts 12 to 15 erected on the resin chassis 11. Further, the gears 16 to 19 are engaged with each other while being supported by the shafts 12 to 15, and the reduction process is performed at a reduction ratio determined by the number of teeth of the gears 16 to 19.
[0005]
By the way, since each shaft 12-15 is formed with resin, if the free end portions 12a-15a are not reinforced, the shafts 12-15 may be bent or in the worst case. This tendency is particularly strong in the shafts 12, 13, and 15 having a long shaft length. For this reason, conventionally, when the shafts 12 to 15 are integrally formed on the resin chassis 11, the free ends 12a to 15a are reinforced.
[0006]
In the speed reduction mechanism 10 shown in FIGS. 3 and 4, the shafts 12, 13 and 15 having a long shaft length are reinforced. As a reinforcing structure of the shafts 12, 13, and 15, a metal sub-chassis 21 is disposed so as to be substantially parallel to the resin chassis 11, and the sub-chassis 21 is used for reinforcement.
A plurality of insertion holes 22 to 24 are formed in the sub chassis 21, and the formation positions of the insertion holes 22 to 24 are set so as to correspond to the standing positions of the shafts 12, 13, and 15. Conventionally, the diameters of the insertion holes 22 to 24 are larger than the diameters of the free ends 12a, 13a, and 15a formed at the tips of the shafts 12, 13, and 15.
[0007]
The sub-chassis 21 configured as described above is disposed on the shafts 12 to 15 after the gears 16 to 19 are disposed on the shafts 12 to 15 of the resin chassis 11.
In this arrangement state, the free ends 12a, 13a, and 15a are positioned inside the insertion holes 22 to 24.
However, since the diameter dimension of the insertion holes 22 to 24 is larger than the diameter dimension of the free ends 12a, 13a, and 15a as described above, the insertion hole can be obtained simply by disposing the sub chassis 21 above the shafts 12 to 15. The free ends 12a, 13a and 15a rattle within 22 to 24, and reliable reinforcement cannot be performed.
[0008]
For this reason, conventionally, the reinforcing screws 25 to 27 are screwed into the screw holes formed in the free ends 12 a, 13 a, and 15 a from the upper part of the subchassis 21, and by the tightening force by the reinforcing screws 25 to 27, The sub-chassis 21 and the shafts 12, 13, and 15 are fixed to thereby reinforce the shafts 12, 13, and 15.
[0009]
On the other hand, a circuit board 28 may be disposed in the sub chassis 21 in the DAT deceleration mechanism. At this time, it is necessary to position and attach the circuit board 28 to the sub-chassis 21. Conventionally, a boss 29 having a positioning projection 30 is provided on the upper part of the sub-chassis 21, and the boss 29 is formed on the circuit board 28. A method has been adopted in which positioning is performed by engaging the positioning holes 31 that are present.
[0010]
[Problems to be solved by the invention]
However, in the reinforcing structure of the shafts 12, 13, and 15 described above, the reinforcing screws 25 to 27 are required in addition to the subchassis 21 in order to reinforce the shafts 12, 13, and 15; There is a problem that the number of parts increases.
[0011]
Further, at the time of assembly, a screwing operation is required for each of the plurality of reinforcing screws 25 to 27, and the assembly process becomes troublesome. Furthermore, it is necessary to form screw holes in the free ends 12a to 15a having a relatively small diameter, and the process of forming these screw holes is troublesome.
Further, in positioning the circuit board 28, it is necessary to form the boss 29 on the sub-chassis 21, and there is a problem that the number of parts increases and the product cost increases.
[0012]
The present invention has been made in view of the above points, and an object thereof is to provide a shaft reinforcing structure in a resin chassis that can reduce the number of parts and the cost.
[0013]
[Means for Solving the Problems]
The present invention for solving the above-
The tree fat chassis a shaft reinforcement structure in the resin chassis to reinforce the free end of the shaft which is integrally erected form,
A sub-chassis is arranged in parallel with the resin chassis, and a fitting hole for fitting the free end portion of the shaft is formed in the sub-chassis,
The shaft is supported by the sub-chassis by inserting the free end of the shaft into the insertion hole ,
A circuit board is disposed so as to face the sub chassis and a positioning hole is formed in the circuit board.
In addition, the circuit board is positioned by extending the free end portion of the shaft outward from the sub-chassis and engaging the positioning hole and the free end portion. Is.
[0015]
According to inventions described above, the sub-chassis which is disposed parallel to the resin chassis to form a fitting hole for fitting the free end of the shaft, the free end shaft sub by fitting to the fitting hole With the configuration supported by the chassis, the shaft is directly reinforced to the subchassis.
[0016]
Therefore, a reinforcing screw is not required as in the prior art, and the number of parts can be reduced. In addition, since the shaft can be reinforced by simply inserting the free end portion into the insertion hole of the sub chassis, the assembling work can be facilitated.
Also, to form the positioning holes in the arranged circuit boards so as to face the support Bushashi, a free end portion of the shaft is extended outward from the positioning hole and the sub-chassis of the circuit board by engaging By adopting the configuration for positioning, it is not necessary to separately provide a mechanism for positioning the circuit board in the sub-chassis, and the number of components can be reduced and the assembling work can be facilitated.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings.
1 and 2 show a speed reduction mechanism 40 provided in the DAT as an example of a drive mechanism using a resin chassis 41. FIG. 1 is a cross-sectional view of the speed reduction mechanism 40, and FIG. 1 is a perspective view in which the speed reduction mechanism 40 is partially cut off. The speed reduction mechanism is disposed in an electronic device such as DAT.
[0018]
The speed reduction mechanism 40 includes a resin chassis 41, gears 46 to 49, a sub chassis 41, circuit boards 58 and 59, and the like.
The resin chassis 41 is formed by, for example, transfer molding a hard resin, and shafts 42 to 45 are integrally formed upright at predetermined positions. The lower portions of the shafts 42 to 45 are fixed to the resin chassis 41, and the upper end portions thereof are free end portions 42a to 45a.
[0019]
Thus, by using the resin chassis 41 as the chassis, the speed reduction mechanism 40 can be reduced in weight as compared with a metal chassis (for example, aluminum die cast), and the mass productivity is improved, so the cost is reduced. Can be achieved.
The gears 46 to 49 have a function of decelerating the rotation transmitted from the drive source (for example, a motor) to the input shaft 50. The gears 46 to 49 may be made of metal or resin, but are preferably made of resin in terms of weight reduction.
[0020]
The gears 46 to 49 are rotatably supported by shafts 42 to 45 erected on the resin chassis 41. Further, the gears 46 to 49 are engaged with each other while being supported by the shafts 42 to 45, and the reduction process is performed at a reduction ratio determined by the number of teeth of the gears 46 to 49.
By the way, also in the structure of a present Example, since each shaft 42-45 is formed with resin, unless the free end parts 42a-45a are reinforced similarly to the conventional structure demonstrated using FIG.3 and FIG.4, it is. The shafts 42 to 45 may be bent or be broken in the worst case.
[0021]
For this reason, also in the present embodiment, a shaft reinforcing structure for reinforcing the shafts 42 to 45 is provided. Hereinafter, the shaft reinforcing structure will be described.
Also in this embodiment, the subchassis 51 is used to reinforce the shafts 42 to 45. The sub chassis 51 is disposed so as to be substantially parallel to the resin chassis 41. A plurality of insertion holes 52 to 55 are formed in the sub chassis 51, and the formation positions of the insertion holes 52 to 55 are set to correspond to the standing positions of the shafts 42 to 45.
[0022]
In the present embodiment, the diameters of the insertion holes 52 to 55 are equal to or slightly larger than the diameters of the free ends 42a to 45a formed at the tips of the corresponding shafts 42 to 45. It has been configured. That is, the diameters of the free end portions 42a to 45a and the insertion holes 52 to 55 are set so that the free end portions 42a to 45a can be fitted into the insertion holes 52 to 55 without a gap.
[0023]
The sub-chassis 51 configured as described above is disposed on the shafts 42 to 45 after the gears 46 to 49 are disposed on the shafts 42 to 45 of the resin chassis 41. In this arrangement state, the free ends 42a to 45a are fitted into the fitting holes 52 to 55. Thereby, each shaft 42-45 becomes the structure reinforced by the subchassis 51 directly.
[0024]
As described above, in the present embodiment, since the shafts 42 to 45 are directly reinforced to the subchassis 51, the reinforcing screws 25 to 27 required in the conventional configuration (see FIGS. 3 and 4) are unnecessary. Therefore, the number of parts can be reduced.
Further, since the shafts 42 to 45 can be reinforced by simply inserting the free end portions 42 a to 45 a into the insertion holes 52 to 55 of the subchassis 51, the assembling work can be facilitated.
[0025]
On the other hand, as described above, a circuit board may be provided in the sub chassis in the DAT deceleration mechanism. In the speed reduction mechanism 40 according to the present embodiment, two circuit boards 58 and 59 are disposed on the sub chassis 51.
Conventionally, as shown in FIGS. 3 and 4, when the circuit board 28 is positioned on the subchassis 21, a boss 29 having positioning protrusions 30 is provided on the subchassis 21, and the positioning protrusions 30 are provided on the circuit board 28. Since the positioning method for engaging with the positioning hole 31 is used, the number of parts is increased and the assembly process is complicated.
[0026]
On the other hand, in the present embodiment, positioning holes 60 to 62 are formed in the circuit boards 58 and 59, and the free ends 42 a to 44 a of the shafts 42 to 44 are extended further upward than the upper surface of the subchassis 21. It has a configuration. The formation positions of the positioning holes 60 to 62 are configured to correspond to the standing positions of the free end portions 42a to 44a.
[0027]
Furthermore, the diameter dimension of the positioning holes 60 to 62 is configured to be equal to or slightly larger than the diameter dimension of the free end portions 42 a to 44 a of the corresponding shafts 42 to 44. That is, the diameters of the free end portions 42a to 44a and the positioning holes 60 to 62 are set so that the free end portions 42a to 44a can be fitted into the positioning holes 60 to 62 without a gap.
[0028]
Therefore, the circuit boards 58 and 59 can be positioned by engaging (fitting) the positioning holes 60 to 62 and the free ends 42a to 44a of the shafts 42 to 44. With this positioning structure, it is not necessary to separately provide a mechanism for positioning the circuit boards 58 and 59 in the sub-chassis 51, and the number of parts can be reduced and the assembling work can be facilitated. Moreover, since each shaft 42-44 is supported also by the circuit boards 58 and 59 in addition to the subchassis 51, reinforcement of each shaft 42-44 can be performed more reliably.
[0029]
In the above-described embodiment, the speed reduction mechanism 40 provided in the DAT is described as an example of the drive mechanism using the resin chassis 41. However, the application of the present invention is limited to the speed reduction mechanism 40 of the DAT. Instead, it can be widely applied to a resin chassis having a shaft.
In this embodiment, the circuit boards 58 and 59 disposed on the subchassis 51 are positioned using the shafts 42 to 44, but other boards other than the circuit board or Even in the case where electronic devices are arranged, it is also possible to position these electronic devices using a shaft.
[0030]
【The invention's effect】
According to the present invention as described above, shea Yafuto is directly to be reinforced in the sub-chassis, it can be a conventionally required by the screw for the reinforcing unnecessary, it is possible to reduce the number of parts.
[0031]
Further, since the shaft can be reinforced by simply inserting the free end portion into the insertion hole of the sub chassis, the assembling work can be facilitated.
Further, it is unnecessary to provide separate mechanisms for positioning the circuit board to support Bushashi, it is possible to facilitate the number of components reduced and assembly work.
[Brief description of the drawings]
FIG. 1 is a sectional view of a resin chassis to which a shaft reinforcing structure according to an embodiment of the present invention is applied.
FIG. 2 is a partially cutaway perspective view of a resin chassis to which a shaft reinforcing structure according to an embodiment of the present invention is applied.
FIG. 3 is a cross-sectional view of a resin chassis to which a shaft reinforcing structure which is a conventional example is applied.
FIG. 4 is a partially cutaway perspective view of a resin chassis to which a shaft reinforcing structure as an example of the prior art is applied.
[Explanation of symbols]
40 Deceleration mechanism 41 Resin chassis 42-45 Shafts 42a-45a Free end 46-49 Gear 51 Sub chassis 52-55 Insertion hole 58, 59 Circuit board 60-62 Positioning hole

Claims (1)

A shaft reinforcement structure in the resin chassis that reinforces the free end of the shaft that is integrally formed upright on the resin chassis,
A sub-chassis is arranged in parallel with the resin chassis, and a fitting hole for fitting the free end portion of the shaft is formed in the sub-chassis,
The shaft is supported by the sub-chassis by inserting the free end of the shaft into the insertion hole ,
A circuit board is disposed so as to face the sub chassis and a positioning hole is formed in the circuit board.
In addition, the circuit board is positioned by extending the free end portion of the shaft outward from the sub-chassis and engaging the positioning hole and the free end portion. Shaft reinforcement structure in resin chassis.

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