JP2012050204A - Gear and instrument unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gear capable of securing a good light guiding performance and applying a stable load from a brake spring to a rotating shaft, the brake spring and an instrument unit.SOLUTION: An output gear 7 receives application of a load from the lower side toward the upper side by a brake spring 9 used for a movement to rotate a rotating shaft 8. The output gear 7 includes: a gear body in which the rotating shaft 8 having the same axial center as that of a gear shaft is protruded from the upper face and the lower face; and a cylindrical ring part 10 protruded from the lower face of the gear body downwardly so as to store the rotating shaft 8 therein. Any part of a lower face 10B of the ring part 10 comes into contact with a part of an upper face of the brake spring 9 when the output gear 7 receives the application of the load.

Description

  The present invention relates to a gear used for a meter device that rotatably supports a rotating shaft to which a pointer is attached, and a meter unit in a meter device for various uses such as an automotive instrument, a marine instrument, and an aircraft instrument. .

  Conventionally, a meter device used for such an instrument supports a rotating shaft on which a resin gear is fitted to a case so that the rotational force from the step motor is transmitted to a metal pointer shaft. What was done is used a lot. In such a motor, a resin spring is integrally formed on the gear in order to suppress fine shake during rotation of the rotary shaft.

  However, since the resin spring is liable to sag due to changes over time, that is, to be permanently deformed, if it is used for a long period of time, the force for pressing the rotating shaft in the axial direction is weakened, and the swinging of the rotating shaft is increased.

  Thus, a rotating shaft support structure has been proposed that can avoid an increase in the slight shake of the rotating shaft due to the sag over time, and that can reliably suppress the fine shake of the rotating shaft. (For example, refer to Patent Document 1).

  That is, in this rotating shaft support structure, as shown in FIG. 12, a thrust plate spring (hereinafter referred to as a flat plate metal) is formed in a case 101 made of an upper case 101A and a lower case 101B and fixed to a wiring board 106. , Abbreviated as “plate spring”) 102 is placed between the gear 103 and the lower case 101B so as to be bendable. For this reason, the pointer (not shown) and the pointer shaft 105 to which the pointer is attached can be smoothly rotated.

  That is, in this rotary shaft support structure, as shown in FIG. 13, the rotary shaft 104 extending integrally from the pointer shaft 105 is inserted into a hole (not shown) in the center portion of the leaf spring 102. Further, the boss 104A provided on the rotating shaft 104 is pressed against the leaf spring 102, whereby the leaf spring 102 is bent into a curved state, and the reaction force from the leaf spring 102 at that time is used as a load to rotate the rotating shaft. The braking force for 104 is generated.

  The leaf spring 102 is not required to be curved and is incorporated into the case 101 in the form of a flat plate, so that the strength is homogenized throughout and the slight shake of the rotating shaft 104 can be effectively suppressed.

  By the way, in a meter device or the like provided with such a rotating shaft support structure, a structure (rotating shaft support structure with a light guiding function) having a structure in which the rotating shaft also functions as a light guide means for pointer illumination is known. It has been. That is, as a meter device provided with the rotating shaft support structure with the light guiding function, for example, as shown in FIG. 14A, the light source 130 is directly below the lower end surface 111 of the rotating shaft 110 integrated with the gear 120. The one arranged so as to face each other is known.

JP 2005-253272 A

  In the rotating shaft having such a light guiding function, for example, as shown in FIGS. 14A and 14B, the outer diameter of the lower end surface 111 of the rotating shaft 110 is narrow and narrow. In other words, if the diameter of the light receiving portion of the rotating shaft 110 is small, the light receiving efficiency is poor and the light emission luminance of the transmission destination pointer is reduced.

  On the other hand, as shown in FIG. 15, in order to increase the light receiving efficiency, if the lower end surface 112 of the rotating shaft 110 and the rotating shaft near the lower end portion have a large diameter (hereinafter referred to as the large diameter portion), The light receiving efficiency at a certain lower end surface 112 is certainly increased. However, the upper portion (upper end portion) of the rotating shaft 110 is usually a structural portion that has a small diameter (hereinafter referred to as a small diameter portion) with a constant diameter due to the press-fitting of the pointer. Accordingly, in the portion where the illumination light guided inside the rotating shaft 110 changes from the large diameter portion to the small diameter portion, the light easily leaks from the rotating shaft 110 to the outside, and the lower end surface and the lower portion, which are light receiving portions, have a large diameter. The effect will be diminished.

  Under such circumstances, it is desired to develop a rotating shaft support structure that does not impair the light guide efficiency of illumination light and that can obtain the necessary braking load from the braking spring on the rotating shaft.

  The present invention has been made in view of the above-described circumstances, and an object of the present invention is to secure a good light guiding performance up to the upper portion of the rotating shaft even when the rotating shaft on the lower side has a large diameter, and a braking spring. It is another object of the present invention to provide a gear and an instrument unit that can apply a stable load to a rotating shaft.

In order to achieve the above-described object, a gear according to the present invention is characterized by the following (1).
(1) A gear that receives an action of a load from below to above by a braking spring used in a movement for rotating a rotating shaft,
A gear body in which the rotating shaft that is coaxial with the gear shaft protrudes from the upper surface and the lower surface;
A cylindrical ring portion projecting downward from the lower surface of the gear body so as to accommodate the lower side of the rotating shaft protruding from the lower surface of the gear body;
With
Any one of the end faces of the ring portion comes into contact with a part of the upper surface of the braking spring when the gear is subjected to a load.
thing.

  According to the gear configured as described in (1) above, the lower side of the rotary shaft integrated with the gear can be formed with the same large diameter as that of the upper side. Even if it exists, while being able to ensure favorable light guide performance to the upper part side of a rotating shaft, the stable load can be made to act on a rotating shaft from a braking spring.

In order to achieve the above-described object, an instrument unit according to the present invention is characterized by the following (2).
(2) a step motor;
The gear according to (1), wherein the rotational force of the step motor is transmitted and rotates,
A braking spring for applying a load to the gear from below to above the gear;
A case that houses the rotating shaft excluding the tip to which the step motor, the braking spring, the gear, and the pointer are assembled; and
Be provided.

  According to the instrument unit configured as described in (2) above, a stable load can be obtained even when a rotating shaft having a large outer diameter is used, and it is favorable to use a rotating shaft having a large outer diameter. Light guiding performance can also be ensured.

  According to the brake spring and the instrument unit of the present invention, it is possible to simultaneously form the lower side of the rotating shaft integral with the gear with a large diameter equivalent to the upper side while suppressing leakage of illumination light. Even if the lower rotary shaft has a large diameter, good light guiding performance can be secured up to the rotary shaft upper side of the rotary shaft, and a stable load can be applied to the rotary shaft from the brake spring.

  The present invention has been briefly described above. Further, details of the present invention will be further clarified by reading through the modes for carrying out the invention described below with reference to the accompanying drawings.

It is a disassembled perspective view of the meter unit which concerns on the 1st Embodiment of this invention. It is a perspective view of the meter unit which concerns on the 1st Embodiment of this invention. It is sectional drawing of the III-III line in FIG. It is a perspective view which shows the contact state with the base side of the motor case inner surface of the braking spring which concerns on the 1st Embodiment of this invention. It is sectional drawing which shows the principal part of the meter unit which concerns on the 1st Embodiment of this invention. It is a perspective view which shows the ring part provided in the lower surface side of the output gear of the meter unit which concerns on the 1st Embodiment of this invention. It is a perspective view which shows the braking spring and output gear of the meter unit which concern on the 1st Embodiment of this invention. It is explanatory drawing which shows the contact state of a brake spring and an output gear of the meter unit which concerns on the 1st Embodiment of this invention. It is a perspective view which shows the inside of the meter unit which concerns on the 1st Embodiment of this invention. It is sectional drawing of the meter unit which concerns on the 2nd Embodiment of this invention. It is a perspective view which shows the braking spring of the meter unit which concerns on the 2nd Embodiment of this invention. It is sectional drawing which shows the conventional rotating shaft support structure. It is explanatory drawing which shows the effect | action of the leaf | plate spring used for the conventional rotating shaft support structure. (A) is sectional drawing which shows the fault in the rotating shaft support structure which provided the small diameter rotating shaft in the lower part side which has the conventional light guide function, (B) is the lower part side structure of the rotating shaft integral with the gear used therefor FIG. 6 is a perspective view showing a state when the gear is turned upside down. (A) is sectional drawing which shows the fault in the rotating shaft support structure which provided the large diameter rotating shaft in the lower part side which has the conventional light guide function, (B) is the lower part side of the rotating shaft integral with the gear used for it It is a perspective view which shows a state when a gear is turned upside down in order to show a structure.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
[First Embodiment]
1 to 3 show an instrument unit 1A according to a first embodiment of the present invention.
The instrument unit 1 </ b> A is such that movement parts such as a step motor 5, a reduction gear train, and a rotating shaft 8 are accommodated in a motor case 4. The meter device to which the instrument unit 1A is mounted includes a light source 3 mounted on the substrate 2 shown in FIG. 3, and an instrument unit 1A attached to a predetermined location on the substrate 2 including the region where the light source 3 is mounted. And a scale plate / character plate (not shown) for displaying necessary information relating to the vehicle itself or the environment around the vehicle, such as numbers, characters, and scales, installed at the top of the instrument unit 1A.

  The meter device to which the meter unit 1A of the present embodiment is applied constitutes a part of a combination meter (not shown), and a facing plate that forms the surface side is fitted over the entire surface. In addition, various types of display windows for installing various instruments including the instrument unit 1A are opened on the facing plate, and are integrated with a combination meter case constituting the side surface and the back surface side. Furthermore, the upper part of the facing plate is covered with a transparent cover glass (not shown) such as black.

  The meter device to which the meter unit 1A of the present embodiment is applied constitutes a speedometer, for example. In this case, based on a sensor signal corresponding to the current speed detected by a sensor (not shown), a later-described pointer is rotated by a predetermined angle to indicate a specific numeral formed on a scale plate / a dial plate (not shown). The current speed is displayed in analog.

  The light source 3 is composed of, for example, an LED (Light Emitting Diode) that emits visible light having a predetermined wavelength (λ), and is in a state facing the lower end surface 8D of the rotating shaft 8 to be described later. It is mounted on the substrate 2 directly below. The LED as the light source 3 has an optical axis set in the Z direction perpendicular to the upper surface of the substrate 2, and most of the main light from this LED (hereinafter referred to as illumination light) is directly above. The light is emitted toward the lower end face 8 </ b> D that forms the light receiving portion of the rotating shaft 8. The illumination light incident from the lower end surface 8D of the rotating shaft 8 is guided to the upper end of the rotating shaft 8 protruding from the upper portion of the motor case 4, and the pointer press-fitted into the upper end of the rotating shaft 8 emits light. It is configured to be.

  The motor case 4 includes a lower case 4A fixed to the substrate 2 and an upper case 4B stacked on the lower case 4A. Inside the motor case 4 is housed a step motor 5, an intermediate gear 6, and a rotary shaft 8 (not including the upper tip) integrally formed with an output gear 7, The brake spring 9 is accommodated in a state where it is assembled between a part of the output gear 7 integral with the rotary shaft 8 and the lower case 4A. This will be described in detail later. Note that the upper end of the rotating shaft 8 protrudes to the outside of the motor case 4 and is fitted to the upper end with a pointer (not shown) being press-fitted.

  The lower case 4A has a substantially box shape with an upper opening. Further, the lower case 4A is provided with cylindrical protrusions P projecting downward (−Z direction) from the lower surface on both left and right side portions, and these are respectively fitted into the respective fixing holes opened in the substrate 2. It is comprised so that.

  In addition, a bearing 42A is formed inside the lower case 4A so as to project in a cylindrical shape from the center of the recess 41 formed on the lower surface toward the upper case 4B. The bearing 42A is provided with a shaft hole 421 (see FIGS. 1 and 3) that rotatably supports the lower side of the rotary shaft 8. Furthermore, on the inner surface of the lower case 4A, as shown in FIG. 1, a bearing 42B and a bearing 42C that protrude slightly in a cylindrical shape toward the upper case 4B are formed at predetermined positions.

  Further, as shown in FIGS. 1 and 3, the lower case 4A has two pedestals 44 on the left and right sides of the bearing 42A at a predetermined position of the inner surface of the lower case 4A that opens toward the upper case 4B. Is protruding. The pedestal 44 serves as a support portion for supporting a part of the lower surface of the brake spring 9, and the surface 44 A (hereinafter referred to as “upper surface” (see FIG. 5)) has a brake spring 9 described later. A protrusion 44B (see FIG. 9 for details) into which the locking groove 93 formed in the hole fits is formed.

  On the other hand, the upper case 4B is provided with a shaft hole 43 at a portion directly above the shaft hole 421 of the bearing 42A provided at the center of the recess 41 (see FIG. 3) of the lower case 4A. The upper side of the rotating shaft 8 passes through the shaft hole 43 in a rotatable state. Further, on the upper case 4B, bearings (not shown) are formed on the inner surface (ceiling surface) of the upper portion corresponding to the bearings 42B and 42C of the lower case 4A.

  The step motor 5 is for rotating the rotating shaft 8 and is a reduction gear train, that is, an intermediate gear 6 and an output gear 7 (in particular, a configuration in which the gear is reduced by a single gear instead of these gear trains). The rotary shaft 8 is rotated while being decelerated via the. Then, by rotating the rotating shaft 8, the pointer integrated therewith is rotated along the surface of the scale plate / dial plate to indicate various necessary information. As shown in FIG. 1, the step motor 5 of the present embodiment includes a stator 51 and a rotor 52 attached to a rotor shaft 52 </ b> A in the central portion where the stator 51 is opened.

  The stator 51 is fixed to the lower case 4A, and a magnetic core serving as a magnetic pole protrudes inside the opening. A coil 51A wound around a bobbin is mounted on the magnetic core.

  The rotor 52 is formed in a substantially cylindrical shape with an appropriate magnetic material, and is rotatably installed in the central portion where the stator 51 is opened. A small-diameter rotor gear 53 having a small number of teeth is concentrically fixed on the upper portion. A plurality of magnets (not shown) are fixed to the outer peripheral surface. As shown in FIG. 2, the rotor shaft 52A to which the rotor 52 is attached is rotatably supported between a bearing 42B provided on the lower case 4A and a bearing (not shown) provided on the upper case 4B.

  The intermediate gear 6 is fixed to a support shaft 6A, and the support shaft 6A is rotatably supported between a bearing 42C provided on the lower case 4A and a bearing (not shown) provided on the upper case 4B. In the intermediate gear 6, large teeth 61 provided on the outer periphery are engaged with a small-tooth rotor gear 53 fixed to the upper portion of the rotor 52, and the rotational speed from the rotor 52 is reduced and transmitted. . Further, on the upper portion of the intermediate gear 6, a small-diameter pinion 62 having a small number of teeth is coaxially fixed integrally with the support shaft 6A.

  The output gear 7 is formed integrally with the rotary shaft 8 in the vicinity of the middle of the rotary shaft 8 in order to transmit the rotational force from the pinion 62 of the intermediate gear 6 to the rotary shaft 8. The output gear 7 of the present embodiment is integrally formed with a rotary shaft 8 having a light guide function, which will be described later, by an appropriate transparent resin material. The case where the output gear 7 and the rotary shaft 8 are integrally formed will be described. However, the output gear 7 and the rotary shaft 8 are formed as separate bodies, and the rotary shaft 8 is mounted so as to pass through and be fixed to the output gear 7. But you can.

  Further, the output gear 7 has a large tooth 71 provided on the outer periphery thereof and meshed with a pinion 62 provided on the upper portion of the intermediate gear 6, and the rotational speed of the intermediate gear 6 is further reduced and transmitted. Rotate. For this reason, the rotating shaft 8 formed integrally with the output gear 7 rotates integrally at the same angular velocity as the output gear 7 which is greatly decelerated, and the pointer can be rotated with high accuracy.

  The rotating shaft 8 is formed integrally with the output gear 7 from an appropriate light-transmitting (or light-guiding) resin material having excellent light guiding properties. Specifically, the rotating shaft 8 is provided so as to protrude upward and downward from the disk-shaped gear body of the output gear 7, and the upper axis of the rotating shaft extending vertically upward with respect to the gear body, The lower shaft center of the rotation shaft extending vertically downward with respect to the gear body and the gear shaft of the gear body are located on the same straight line. The rotating shaft 8 has a substantially cylindrical shape in order to guide the illumination light from the light source 3 to the pointer.

  The rotating shaft 8 has a larger outer diameter (particularly, the outer diameter W on the lower side (see FIG. 6) is larger) than a rotating shaft that does not have a light guide function in order to secure a required amount of light. Yes. Thus, since the outer diameter dimension of the lower side of the rotating shaft 8 is made larger, the light receiving efficiency with respect to the illumination light from the light source 3 is higher than that of the small diameter dimension. Moreover, the rotating shaft 8 is configured to have a large diameter that is equal to the outer diameter of the lower side as well as the upper side. Accordingly, the illumination light guided inside the rotary shaft 8 on the upper side is different from the structure in which the diameter is reduced from the large diameter to the small diameter, and the illumination light guided inside the rotary shaft 8 is the reduced diameter portion. Since the phenomenon of light leakage can be avoided, the light guide efficiency is also increased.

  Further, as described above, the upper end of the rotary shaft 8 protrudes from the shaft hole 43 of the upper case 4B to the outside of the case 4, and a pointer is assembled to the tip of the rotary shaft 8 that protrudes to the surface of the dial / dial plate. It is attached. Further, the rotating shaft 8 is supported on the shaft hole 43 on the upper case 4B side on the upper side, and rotated on the shaft hole 421 (see FIGS. 3 and 5) of the bearing 42A provided on the lower case 4A on the lower side. It is supported freely.

  As described above, the rotating shaft 8 faces the lower end surface 8D directly above the light source 3. Accordingly, when the illumination light from the light source 3 is incident on the end face 8D, most of the illumination light is repeatedly reflected (for example, total reflection or regular reflection) at the interface with the outer peripheral surface inside the rotary shaft 8. Guided and propagates toward the upper tip.

  The braking spring 9 is made of an appropriate metallic thin plate, and as shown in FIG. 4, has a bilaterally symmetric substantially elliptical ring shape with a hole 91 to be described later at the center, and has a curved thickness. A spring force (elastic force) having a magnitude corresponding to the amount of displacement in the vertical direction is generated. Further, the braking spring 9 has a required region δ on one side (hereinafter referred to as the lower surface 9A) in contact with the upper surface 44A (see FIG. 5) of the pedestal 44 on the inner surface side of the motor case 4 and is opposite to the lower surface 9A. The surface (hereinafter referred to as the upper surface 9B) is accommodated in the case 4 in a state where it contacts the lower end surface 10B of the ring portion 10 on the lower surface side of the output gear 7. As a result, the braking spring 9 applies a load to the output gear 7 from the lower side to the upper side of the output gear 7. By energizing a required spring force against the output gear 7 in this way, a stable rotating operation of the rotating shaft 8 is ensured, and a pointer (not shown) attached to the upper end of the rotating shaft 8 is also provided. The vibration of the is also suppressed. Hereinafter, the structure of the brake spring 9 will be described in detail.

  As shown in FIG. 4, the braking spring 9 of the present embodiment is provided with a hole 91 that is penetrated by the lower side of the rotary shaft 8 in the central portion, and a long side portion 94 (first side) extending on the same plane. The hole 91 is defined by connecting the spring piece) and the projecting portion 92 (second spring piece) curved so as to rise above the plane on which the long side portion 94 is located. Yes.

  The hole 91 has a long hole shape in which at least the opening dimension in the short side (Y) direction is larger than the outer diameter dimension of the rotary shaft 8. Opened in a similar shape to the outer diameter shape.

The protruding portion 92 is provided so as to sandwich the rotating shaft 8 at a position that bisects the length S ₁ (see FIG. 7) in the longitudinal (X) direction of the long side portion 94, and includes two long side portions. 94 and the central axis of the rotating shaft 8 penetrating the hole 91 are located on the same straight line γ (the straight line γ where the two protruding parts 92 and the rotating shaft 8 are located is the center line). Sometimes called). Further, a locking groove 93 that positions and stops the brake spring 9 (prevents being rotated around the rotating shaft 8) is formed in a portion farthest from the center line γ of the long side portion 94. Yes. Such a braking spring 9 has a shape symmetrical with respect to a center line γ and a straight line that is orthogonal to the center line γ and passes through the rotation shaft 8.

  As shown in FIGS. 7 and 8, the protruding portion 92 is provided at the center of the long side portion 94 (on the center line γ) and is curved so as to rise above the plane on which the long side portion 94 is located. It is formed in a shape such as a substantially inverted U-shaped cross section.

  The locking groove 93 is adapted to fit firmly with the protrusion 44B formed on the upper surface 44A of the base 44 on the inner surface side of the lower case 4A described above. For this reason, when the braking spring 9 is disposed in the lower case 4 </ b> A, the lower side 9 </ b> A contacts the upper surface 44 </ b> A of the pedestal 44 and is supported by the pedestal 44. become.

  The locking groove 93 of the brake spring 9 and the projection 44B of the lower case 4A are projections in which the locking groove 93 extends in the same plane as the long side portion 94, contrary to the present embodiment. 44B may be configured as a groove. Regardless of the configuration, the brake spring 9 can be reliably held on the pedestal 44, so that it is possible to prevent the brake spring 9 from causing a swinging operation or the like with the rotation operation of the rotary shaft 8.

The long side portion 94 and the projection 92, along the entire circumference is formed a substantially constant uniform width S ₂ (i.e., the long side portion 94 and the projection 92, the inner end defining the hole 91 And the width of the outer end opposite to the aforementioned inner end defining the hole 91 is substantially the same throughout the entire collection. That is, the long side portion 94 and the projecting portion 92 surrounding the hole 91 have no portion where the width is partially narrowed. In addition, the braking spring 9 has a line-symmetric shape both in the longitudinal (X) direction and in the (Y) direction orthogonal thereto, so that the elastic force generated by the braking spring 9 is uniform and uniform. It is. Therefore, a stable spring load can be obtained by forming the brake spring 9 in such a shape.

  In particular, the output gear 7 of the present invention has a cylindrical ring portion 10 projecting downward from the lower surface of the disc-shaped gear body so as to accommodate the lower side of the rotary shaft 8 therein. . As shown in FIGS. 3 and 6, the ring portion 10 is long from one surface (hereinafter referred to as “lower surface”) of the output gear 7 facing the braking spring 9 to the bottom (−Z direction). The gear body is provided integrally with the gear body so as to hang down by L. The ring portion 10 has a cylindrical shape with an open lower end portion facing the brake spring 9. As shown in FIG. 6, the ring portion 10 has a size D (see FIG. 7) in which the diameter substantially matches the distance between the two protruding portions 92 of the braking spring 9.

  Accordingly, when the rotary shaft 8 is assembled between the upper and lower cases 4A and 4B, a part of the lower end surface 10B of the ring portion 10 that hangs down from the lower surface of the output gear 7 (any region in the phase angle direction) The brake spring 9 mounted on the pedestal 44 of the case 4A is pressed from above while in contact with the top of the protrusion 92. Thereby, as will be described in detail later, the flexible brake spring 9 is elastically deformed and curved in a convex shape downward (in the α direction in FIG. 8).

  As described above, the ring portion 10 is pressed against the brake spring 9 in a state of coming into contact with the brake spring 9 from above. Accordingly, the ring portion 10 is rotated 360 degrees out of an annular (ring-shaped) region which is the shape of the lower end surface 10B of the ring portion 10 shown in FIG. 6 during rotation of the output gear 7 provided integrally therewith. Such a part always slides with the braking spring 9. As a result, it is possible to prevent a slight shake of the rotating shaft 8. As shown in FIG. 3, the gear body of the output gear 7 and the rotating shaft 8 integrally provided with the ring portion 10 are deformed up and down even when the brake spring 9 is rotating. However, there is no contact with the braking spring 9.

Next, the operation of this embodiment will be described.
For example, even if slight vibration occurs in the step motor 5 or rattling occurs between the rotating shaft 8 and the bearing portions of the upper and lower cases 4A and 4B, the rotating shaft 8 is stable even if it tries to generate vibration. The brake spring 9 having a spring load can effectively absorb these vibrations. Accordingly, it is possible to prevent the shake of the rotary shaft 8 and the like.

  Further, for example, when some impact acts on the vehicle body side during driving and the impact also reaches the lower case 4A of the motor case 4 via the substrate 2, the impact force is applied to the base 44 on the inner surface side of the lower case 4A. It propagates to the braking spring 9 via a projection 44B provided on the upper surface 44A of the upper surface 44A and a protrusion 92 in contact therewith.

  Then, the braking spring 9 absorbs and dampens the impact force by elastically deforming in a balanced manner, and the ring portion 10 and the output gear 7 integrated with the ring portion 10, and further the rotation integrated with the output gear 7. Effectively suppressing the impact from propagating to the shaft 8. Thereby, even if the impact from the outside etc. exerts on a vehicle body etc., the shaking of a rotating shaft 8 and the pointer attached to this upper part, a fine shake, etc. can be suppressed reliably.

As described above, according to the present embodiment, since the braking spring 9 has a uniform width over the entire circumference, there is no partial variation in the load, and the left and right sides of the long side portion 94 are left and right. An almost uniform and stable spring load can be obtained. As a result, there is no great change in the amount of spring deflection over the entire length of the long side portion 94. Further, the braking spring 9, since it is provided at a position in contact with the top one point, and its top is the length S ₁ of the longitudinal (X) direction of the long side portion 94 bisects the protrusion 92, The action point is located at the center of the long side portion 94.

  Thereby, since the position of the action point can be fixed regardless of the size of the outer diameter on the lower side and the end face 8D of the rotary shaft 8, as shown in FIG. Since the brake spring 9 is bent in the thickness direction by being pressed down by the ring portion 10, it is easy to stabilize the change amount of the spring load due to the dimensional variation of the individual brake springs and stabilize it. Moreover, since the protruding amount d (see FIGS. 5 and 8) of the protruding portion 92 of the braking spring 9 is proportional to the amount of pushing of the spring, that is, the magnitude of the elastic force of the braking spring 9, the required spring load can be easily set. Can be done. Similarly, since the magnitude of the elastic force of the brake spring 9 is proportional to the magnitude of the droop amount L of the ring portion 10, the required spring load can be easily set by adjusting the droop amount L.

  In addition, according to the present embodiment, the protrusion 92 of the brake spring 9 has a substantially inverted U-shape, so that the lower end surface 10B of the ring portion 10 and the protrusion 92 are dots (or as shown in FIG. 6). Line). As a result, the frictional force can be suppressed to the minimum contact state, in other words, to the minimum. Therefore, even if the ring portion 10 rotates while being in contact with the brake spring 9, the output gear 7 that rotates integrally with the ring portion 10 can be smoothly rotated without hindering the rotation.

Furthermore, according to the present embodiment, since the outer diameter of the lower end surface 8D of the rotating shaft 8 is made larger, the light receiving efficiency for the illumination light from the light source 3 is higher than that of the conventional small diameter. In addition, according to the present embodiment, the rotating shaft 8 does not constitute a means for receiving the elastic force of the braking spring 9. In other words, the member that receives the elastic force is left to the ring portion 10 described later of the output gear 7. Thus, since the elastic force transmission site is separated, not only the upper side of the rotary shaft 8 has a large diameter but also the outer diameter of the lower side can be configured to have a large diameter of the same size.
Therefore, the rotating shaft 8 is prevented from forming a reduced diameter portion having a step between the outer diameter on the lower side of the rotating shaft 8 and the outer diameter on the upper side. It is also possible to suppress the light leakage phenomenon at the boundary between the portion and the reduced diameter portion.

[Second Embodiment]
Next, an instrument unit 1B according to a second embodiment of the present invention will be described with reference to FIGS. In the present embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals, and redundant description is avoided.

  The meter unit 1B of this embodiment is different from the meter unit 1A of the first embodiment in that the brake spring 20 is different from the brake spring 9 of the first embodiment (projects from the lower surface side of the output gear 7). ) A spring piece 22 extending on the same plane having a hole 21 through which the lower side of the rotary shaft 8 passes. In other words, the brake spring 20 is not formed with a curved second spring piece. The spring piece 22 has a rectangular shape that is substantially line-symmetric with respect to the center line γ that passes through the hole 21.

  In the braking spring 20 having such a configuration, when a load is applied to the output gear 7, the portion farthest from the center line γ of the spring piece 22 is located on the pedestal 44 on the inner surface of the lower case 4A that houses the movement. An arcuate portion 22A on the upper surface that is supported by the lower surface in contact and surrounds the hole 21 near the center of the spring piece 22 serves as a point of action on the ring portion 10 of the output gear 7.

  Therefore, the brake spring 20 of the present embodiment has a simpler configuration than the brake spring 9 of the first embodiment, but can exhibit the same effects as the brake spring 9.

  The present invention is not limited to the embodiment described above, and can be implemented in various forms without departing from the gist of the present invention.

  In addition, the instrument unit of the present invention can be applied to various instruments such as a fuel meter section, a tachometer section, a speedometer section, and a water temperature gauge.

1A, 1B Instrument unit 2 Substrate 3 Light source 4 Motor case 4A Lower case 4B Upper case 41 Recess 42A Bearing 421, 43 Shaft hole 44 Base 44A (Front surface) Upper surface 44B Projection 5 Step motor 51 Stator 52 Rotor 6 Intermediate gear 7 Output gear ( (Gear body)
8 Rotating shaft 8D End face (light receiving part)
9 Braking spring 9A Lower surface 9B Upper surface 91, 21 hole 92 Projection (second spring piece)
93 Locking groove 94 Long side (first spring piece)
DESCRIPTION OF SYMBOLS 10 Ring part 10B Lower end surface 20 Braking spring 22 Spring piece 22A Arc-shaped part L Drooping amount of ring part S ₁ Length in longitudinal direction S ₂ Width of long side part

Claims (2)

A gear which receives an action of a load from below to above by a braking spring used in a movement for rotating a rotating shaft,
A gear body in which the rotating shaft that is coaxial with the gear shaft protrudes from the upper surface and the lower surface;
A cylindrical ring portion projecting downward from the lower surface of the gear body so as to accommodate the lower side of the rotating shaft protruding from the lower surface of the gear body;
With
Any one of the end faces of the ring portion comes into contact with a part of the upper surface of the braking spring when the gear is subjected to a load.
Gear characterized by that. A step motor,
The gear according to claim 1, wherein a rotational force of the step motor is transmitted to rotate.
A braking spring for applying a load to the gear from below to above the gear;
A case that houses the rotating shaft excluding the tip to which the step motor, the braking spring, the gear, and the pointer are assembled; and
An instrument unit comprising:

Images