JP4937462B2 - Instrument metal pointer shaft and rotating inner unit - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an instrument metal pointer shaft and a rotating inner unit.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, for example, passenger car meters are provided with a turning inner unit for turning a pointer. The rotating inner unit includes an inner unit main body and a metal pointer shaft that extends from the inner unit main body so as to be rotatable and supports the pointer.
[0003]
Here, there is a rotating inner unit in which a step motor and a reduction gear train driven by the step motor are assembled in a casing. The reduction gear train includes a resin output stage gear that coaxially supports the pointer shaft.
[0004]
[Problems to be solved by the invention]
By the way, in the above instrument, the configuration in which the pointer shaft is coaxially supported by the output stage gear is, for example, as shown in FIG. 4, the output stage gear (see FIG. 4 in FIG. 4). The knurled shaft a is preliminarily applied to the fitting shaft portion with the cylindrical boss 2a (see reference numeral 2) to form the knurled shaft portion 1a, and the output gear 2 is integrated with the knurled shaft portion 1a of the pointer shaft 1 by resin. This is done by molding.
[0005]
However, according to such a configuration, the knurled shaft portion 1a is processed even though it is possible to prevent the output stage gear 2 from idling around the pointer shaft 1 and the output stage gear 2 from coming off from the pointer shaft 1 in the axial direction. Since the shape is complicated, there is a problem that the knurling cost of the pointer shaft 1 is high.
[0006]
For this, as shown in FIG. 5, instead of knurling, a processing b for cutting one side axial direction portion of the outer peripheral surface of the fitting shaft portion into a substantially D-shaped section is performed, and a substantially D-shaped section It is also conceivable to form the output stage gear 2 integrally with the shaft portion 1b having a substantially D-shaped cross section of the pointer shaft 1 with the shaft portion 1b. However, according to this, the processing shape of the fitting shaft portion of the pointer shaft 1 is simplified as compared with the case where knurling is performed, but there is a problem that the output stage gear 2 is easily detached from the pointer shaft 1 in the axial direction. . It is also possible to cut the entire outer peripheral surface of the fitting shaft portion of the pointer shaft 1 to have a substantially D-shaped cross section, but this prevents the output stage gear 2 from spinning around the pointer shaft 1. The trouble that it is difficult to occur arises.
[0007]
Therefore, in order to deal with the above, the present invention has been devised in the shape of the fitting shaft portion to ensure the simplification of the processing shape, and the resin gear that is the fitting target cannot be relatively moved. An object of the present invention is to provide an instrument metal pointer shaft and a rotating inner unit that are integrally molded with the instrument.
[0008]
[Means for Solving the Problems]
In solving the above-mentioned problems, the metal pointer shaft for an instrument according to the invention described in claim 1 has a fitting shaft portion (20a) fitted to the cylindrical boss (30b) of the resin gear (30). Then, a gear and insert molding is performed at the fitting shaft portion.
[0009]
In the pointer shaft, the fitting shaft portion is within a range where the cut portion (22) formed by cutting one side axial portion of the outer peripheral surface into a concave shape in the axial direction and the cut portion on the outer peripheral surface is formed. And at least one groove portion (23) formed along the circumferential direction.
[0010]
Since the concave cut portion and the groove portion are formed in the fitting shaft portion of the pointer shaft in this way, the output stage gear is fitted at the boss so that the output shaft gear is fitted to the fitting shaft portion via the cut portion and each groove portion. If it is insert-molded with the mating shaft portion, the portion of the boss that protrudes into the cut-out portion of the fitting shaft portion prevents relative rotation between the fitting shaft portion of the boss and the fitting of the boss. The part which protrudes in the groove part of a shaft part prevents a relative axial direction movement between the fitting shaft parts of a boss | hub. As a result, even if the pointer shaft is rotated, the boss of the output stage gear does not come off from the fitting shaft portion of the pointer shaft in the axial direction or idle around the fitting shaft portion. In addition, since the cut-out portion and the groove portion of the fitting shaft portion can be formed by a very simple process as compared with the knurling process, the above-described effects can be achieved without incurring the high cost of the pointer shaft.
[0011]
Further, the turning inner unit for an instrument according to the invention of claim 2 is:
A metal pointer shaft (20) supported rotatably in the casing (10) and extending from the casing;
The motor (M) supported in the casing, the output stage gear (30) having a cylindrical boss (30b) fitted coaxially to the fitting shaft portion (20a) of the pointer shaft, and the motor coaxially A reduction gear train (G) having a supported input stage gear (60).
[0012]
In the rotating inner machine, the fitting shaft portion is formed with a cut portion (22) formed by cutting one side axial portion of the outer peripheral surface into a concave shape in the axial direction, and the cut portion on the outer peripheral surface . And at least one groove portion (23) formed along the circumferential direction within the range, and the output stage gear is fitted to the fitting shaft portion via the cut portion and each groove portion at the boss. Further, it is characterized by being insert-molded with the fitting shaft portion.
[0013]
As described above, the pointer shaft according to claim 1 is employed, and the output shaft gear is inserted into the fitting shaft portion via the cut portion and each groove portion by the boss thereof, and the fitting shaft portion and the insert shaft are inserted. By molding, it is possible to provide a rotating inner unit for an instrument that can achieve the function and effect of the first aspect of the invention.
[0014]
In addition, the code | symbol in the bracket | parenthesis of each said means shows the correspondence with the specific means as described in embodiment mentioned later.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a first embodiment of a passenger car instrument according to the present invention, and this instrument is disposed on an instrument panel (not shown) provided in the passenger compartment of the passenger car.
[0016]
As shown in FIG. 1, the instrument includes a wiring board P and a rotating inner unit D. The rotating inner unit D includes a resin casing 10 attached to the back surface of the wiring board P, a metal pointer shaft 20, and a step motor M and a reduction gear train G assembled in the casing 10. The casing 10 is configured by fitting both casing members 10a and 10b having a U-shaped cross section into each other at their openings.
[0017]
The pointer shaft 20 is rotatably supported at a base end portion 21 in a cylindrical boss 11 a formed on the lower side wall 11 in the casing 10. A cylindrical portion 12a formed on the wall 12 extends coaxially and rotatably from the base end portion 21. Thereby, the pointer shaft 20 is supported by the casing 10 coaxially and rotatably with the boss 11a and the cylindrical portion 12a.
[0018]
The reduction gear train G includes an output stage gear 30, both intermediate gears 40 and 50, and an input stage gear 60. The output stage gear 30 is coaxially supported by the pointer shaft 20 in the casing 10, and this output stage gear 30 is formed by integrally forming a cylindrical boss 30b on a large-diameter spur gear portion 30a. Configured.
[0019]
The intermediate gear 50 is supported by the boss so as to be relatively rotatable coaxially with the rotation shaft 40a, and the intermediate gear 40 is supported coaxially with the boss of the intermediate gear 50 so as not to be relatively rotatable. Yes. Here, the intermediate gear 40 is a pinion gear, and the intermediate gear 50 is a spur gear. The intermediate gear 40 is a gear having a smaller diameter than the spur gear portion 30a and the intermediate gear 50, and meshes with the spur gear portion 30a. The rotation shaft 40a is supported between the upper and lower walls 12 and 11 so as not to rotate on the right side of the pointer shaft 20 in FIG.
[0020]
The input gear 60 is coaxially supported by a cylindrical boss 71 of a magnet rotor 70 (described later) of the step motor M. The input stage gear 60 includes a pinion gear having a smaller diameter than the spur gear portion 30 a and the intermediate gear 50, and meshes with the intermediate gear 50. In the present embodiment, the output stage gear 30, the both intermediate gears 40 and 50, and the input stage gear 60 are formed of a synthetic resin (for example, a soft synthetic resin) that does not generate or at least hardly generates a meshing sound. In FIG. 1, reference numeral 13 denotes a curved spring that biases the output stage gear 30.
[0021]
The step motor M includes a magnet rotor 70 and an annular yoke 80. The magnet rotor 70 is formed by fitting a cylindrical rotor portion 70a made of a non-magnetic material and a large number of magnet portions 70b along the circumferential direction on the outer peripheral surface of the rotor portion 70a. The cylindrical boss 71 is coaxially supported on the rotation shaft 70c so as to be relatively rotatable. The large number of magnet parts 70b are formed by alternately fitting N magnetic pole parts and S magnetic pole parts to the outer peripheral surface of the rotor part 70a. Further, the rotation shaft 70c is supported between the upper and lower walls 12 and 11 so as not to be relatively rotatable on the right side of the rotation shaft 40a in FIG.
[0022]
The yoke 80 is interposed between the openings of the casing members 10a and 10b of the casing 10, and the yoke 80 constitutes a stator of the step motor M together with each field winding (not shown).
[0023]
Next, the configuration of the pointer shaft 20 will be described in detail with respect to the configuration of the output gear 30 with reference to FIGS. The output gear 30 is coaxially fitted to the fitting shaft portion 20a of the pointer shaft 20 by a boss 30b. As shown in FIGS. 1 and 2, the fitting shaft portion 20 a includes a cut portion 22 and three groove portions 23. As shown in FIGS. 2 and 3, the excision portion 22 is formed by excising one axial portion of the outer peripheral surface of the fitting shaft portion 20 a into a substantially D-shaped cross section in the axial direction.
[0024]
Each groove portion 23 is formed on the outer peripheral surface of the fitting shaft portion 20a along the circumferential direction and at intervals in the axial direction. Therefore, the boss 30 b of the output gear 30 is in close contact with the surface of the cut portion 22 and the inner surface of each groove 23 on the inner peripheral surface thereof. For this reason, the part which protrudes in the concave cut part 22 of the fitting shaft part 20a among the bosses 30b prevents relative rotation with the fitting shaft part 20a of the bosses 30b. The part which protrudes in each groove part 23 of the axial part 20a prevents the relative axial direction movement between the fitting axial parts 20a of the boss | hub 30b.
[0025]
In the present embodiment, the fitting shaft portion 20a of the pointer shaft 20 is maintained in an insert molding die with the fitting shaft portion 20a of the output gear 30, and the synthetic resin is placed in the insert molding die. By supplying, the output stage gear 30 is insert-molded with the fitting shaft portion 20a, thereby supporting the output stage gear 30 coaxially and integrally with the pointer shaft 20 as described above.
[0026]
In the present embodiment configured as described above, when the step motor M rotates, the input stage gear 60 rotates in the reduction gear train G. Accordingly, the output stage gear 60 is decelerated and rotated by the input stage gear 60 via the intermediate gears 50 and 40 to rotate the pointer shaft 20.
[0027]
Here, in the fitting shaft portion 20a of the pointer shaft 20, as described above, the cut portion 22 is formed in a substantially D-shaped cross section in the axial direction, and each groove portion 23 is formed in the outer peripheral direction. And the fitting shaft part 20a of such a structure is insert-molded with the output stage gear 30 and the synthetic resin as described above.
[0028]
Therefore, as described above, the portion of the boss 30b that protrudes in the cutout portion 22 of the fitting shaft portion 20a prevents relative rotation between the boss 30b and the fitting shaft portion 20a, and thus the boss 30b. Of these, the protruding portions in the respective groove portions 23 of the fitting shaft portion 20a prevent relative axial movement between the boss 30b and the fitting shaft portion 20a.
[0029]
As a result, even if the pointer shaft 20 is decelerated and rotated by the reduction gear train G by the step motor M as described above, the boss 30b of the output stage gear 30 may come off from the fitting shaft portion 20a of the pointer shaft 20 in the axial direction. Alternatively, the output stage gear 30 can reliably maintain the coaxial support with the pointer shaft 20 without idling around the fitting shaft portion 20a. In addition, since the formation of the cut portion 22 and each groove portion 23 of the fitting shaft portion 20a is very simple processing compared to the knurling processing, the above-described effects can be achieved without incurring a high cost of the pointer shaft. Can be achieved.
[0030]
In carrying out the present invention, the cut shape of the concave cut portion 22 with respect to the fitting shaft portion 20a is not particularly limited as long as it is concave in the axial direction. Further, the number of the groove portions 23 is not necessarily limited to three as described in the above embodiment, and may be changed as appropriate, for example, one, two, or four.
[0031]
In implementing the present invention, various electric motors may be used in place of the step motor M.
[0032]
Moreover, in carrying out the present invention, the present invention may be generally applied to automobiles and other vehicles, marine instruments, and other various instruments without being limited to passenger car instruments.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of an essential part showing an embodiment of the present invention.
2 is a cross-sectional view showing a relationship between a pointer shaft and an output stage gear in FIG. 1;
3A is a cross-sectional view taken along line 3a-3a in FIG. 2, and FIG. 3B is a cross-sectional view taken along line 3b-3b in FIG.
FIG. 4 is a cross-sectional view showing a structural relationship between a conventional pointer shaft and an output stage gear.
FIG. 5 is a cross-sectional view showing another structural relationship between a conventional pointer shaft and an output gear.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Casing, 20 ... Pointer shaft, 20a ... Fitting shaft part, 22 ... Resection part,
23 ... groove, 30 ... output gear, 30b ... boss, 60 ... input gear,
G: Reduction gear train, M: Step motor.

Claims (2)

In a metal pointer shaft for an instrument having a fitting shaft portion (20a) fitted to a cylindrical boss (30b) of a resin gear (30) and insert-molded with the gear at the fitting shaft portion. ,
The fitting shaft portion includes a cutout portion (22) formed by cutting a side axial portion of the outer peripheral surface into a concave shape in the axial direction, and a periphery thereof within a range where the cutout portion is formed on the outer peripheral surface . An instrument metal pointer shaft having at least one groove (23) formed along the direction. A metal pointer shaft (20) supported rotatably in the casing (10) and extending from the casing;
An electric motor (M) supported in the casing;
An output step gear (30) having a cylindrical boss (30b) fitted coaxially to the fitting shaft portion (20a) of the pointer shaft, and an input step gear (60) supported coaxially by the electric motor; A rotation internal unit for an instrument comprising a reduction gear train (G) having
The fitting shaft portion includes a cutout portion (22) formed by cutting a side axial portion of the outer peripheral surface into a concave shape in the axial direction, and a periphery thereof within a range where the cutout portion is formed on the outer peripheral surface . And at least one groove (23) formed along the direction,
The output stage gear is insert-molded with the fitting shaft portion so as to be fitted to the fitting shaft portion via the cut portion and each groove portion at a boss thereof. Internal machine.

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