JP2022191040A - Clock hand fluctuation reduction structure - Google Patents

Abstract

To provide a clock hand fluctuation reduction structure that can make an arrangement space small, and can prevent or reduce fluctuation of clock hands while reducing load torque acting on an existing wheel train for time display.SOLUTION: A return spring member 10 is a return spring member 10 (a clock hand fluctuation reduction structure) that reduces fluctuation of clock hands for time display, in which a friction spring part 12 (friction part) that comes into contact with a rotational shaft 33 of a third wheel 30 to which the clock hands are fixed with predetermined frictional force, and a return spring part 11 having one end part 11a coupled to the friction spring part 12, another end part 11b whose rotation is restricted by a rotor guide 90 that does not rotate, and a spring part 11c elastically deformed by the rotation of a gear 30 between the one end part 11a and the other end part 11b, are integrally formed.SELECTED DRAWING: Figure 4

Description

TECHNICAL FIELD The present invention relates to a pointer wobble reduction structure that prevents or reduces wobble of a pointer.

Backlash is formed in the gear train in which a plurality of gears for rotating the hands of a timepiece are connected so that the teeth of the gears are smoothly meshed with each other to rotate the gears. Therefore, there is play between the meshed teeth by the amount of backlash, and the gear can move by this amount of play.

Since the hands of a watch are fixed to the gears, they move according to the movement of the gears. If the movement can be visually recognized, the wobble of the needle tends to be conspicuous.

In order to prevent or suppress such movement due to gear play, there are a return gear that is driven in conjunction with the train wheel of the time display, a friction member that is in contact with the return gear and applies a frictional force to the return gear, and a friction member. In addition, there has been proposed a mechanism for reducing variations in stop position of the hands, which includes a return gear and a return spring member that applies torque in a direction opposite to the normal hand movement direction for time display (for example, Patent Document 1).

According to this variation reduction mechanism, it is possible to prevent or suppress the fluctuation of the hands caused by the backlash in the normal movement of the hands for displaying the time.

WO2019/123821

By the way, the variation reduction mechanism described in Patent Literature 1 is configured by combining parts such as a friction member and a return gear, so there is a problem that the cost increases. Another problem is that it is difficult to create a space for arranging the variation reduction mechanism, which is a new component, in the existing gear train mechanism for displaying the time.

Furthermore, for example, a wristwatch for women has a smaller external size than a wristwatch for men, so not only does it require less space for arrangement, but it also requires less driving torque. Therefore, it is necessary to set the slip torque generated between the friction member and the return mechanism of the return gear to be much smaller than in men's wristwatches, and there is also the problem that it is difficult to adjust.

The present invention has been devised in view of the above circumstances, and is capable of reducing the space required for arrangement compared to a variation reduction mechanism configured by a combination of a friction member and a return gear. An object of the present invention is to provide a pointer wobble reduction structure capable of preventing or reducing the wobble of the pointer while reducing the load torque acting on the train wheel.

The present invention is a pointer fluctuation reduction structure for reducing the fluctuation of hands for time display, wherein the pointers are fixed to a rotation shaft of a gear or rotated by another gear connected to the gear. A friction portion that contacts the shaft with a predetermined frictional force, one end coupled with the friction portion, the other end whose rotation is restricted by a non-rotating member, and between the one end and the other end , a spring portion that is elastically deformed by rotation of the gear, and a return spring portion having a return spring portion are integrally formed.

According to the pointer sway reduction structure according to the present invention, it is possible to reduce the space for arrangement compared to a variation reduction mechanism configured by a combination of a friction member and a return gear. It is possible to reduce the fluctuation of the pointer while reducing the load torque acting on the train wheel.

1 is a diagram showing an example of a wheel train mechanism of a hand for displaying time in a timepiece movement incorporating a return spring member, which is an embodiment of a hand wobble reduction structure according to the present invention. FIG. 2 is a perspective view showing a third wheel provided with a return spring member shown in FIG. 1; FIG. FIG. 4 is an exploded perspective view of a third wheel and a return spring member; FIG. 11 is a plan view (part 1) for explaining the action of the return spring member; FIG. 11 is a plan view (part 2) explaining the action of the return spring member; FIG. 11 is a perspective view showing a third wheel provided with a modified return spring member; FIG. 4 is an exploded perspective view of a third wheel and a return spring member; FIG. 5 is a plan view for explaining the action of a return spring member;

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of the wobble reduction structure of the pointer|needle which concerns on this invention is described using drawing.

FIG. 1 is a cross-sectional view showing an example of a train wheel mechanism for displaying time in a timepiece movement in which a return spring member 10, which is an embodiment of a pointer fluctuation reduction structure according to the present invention, is incorporated, and FIG. 2 is a return spring member. 3 is an exploded perspective view of the third wheel & pinion 30 and the return spring member 10. FIG. Note that the train wheel shown in FIG. 1 is the train wheel for driving the second hand and the minute hand of the timepiece hands that display the time, and the train wheel for driving the hour hand is omitted.

In this train wheel, the rotor pinion 62 provided coaxially with the rotor 61 of the step motor 60 is meshed with the gear 51 of the fifth wheel 50 , and the fifth wheel 52 coaxial with the gear 51 of the fifth wheel 50 is engaged with the fourth wheel 40 . , the gear 31 of the third wheel 30 meshes with the fourth pinion 42 coaxial with the gear 41 of the fourth wheel 40, and the third pinion 32 coaxial with the gear 31 of the third wheel 30 meshes with the second wheel ( The gear 21 of the center wheel) 20 is meshed.

In FIG. 1, the shaft 43 of the fourth wheel 40 and the hollow shaft 23 of the second wheel 20 are shown separated from each other in order to make the construction easier to see, but in reality both of them are part of the dial of the timepiece. They are arranged coaxially with the central axis C1, and the shaft 43 of the fourth wheel & pinion 40 is arranged on the central axis C1 side of the shaft 23 of the second wheel & pinion 20 .

A second hand is fixed to the shaft 43 of the fourth wheel & pinion 40, and a minute hand is fixed to a hollow cylindrical pinion (not shown) on the shaft 23 in contact with the outer peripheral surface of the shaft 23 of the second wheel & pinion 20. there is

The train wheel of the hour hand (not shown) is arranged outside the minute pinion and is fixed to the hour wheel connected to the minute pinion via the minute wheel (not shown).

<Configuration>
Here, the mechanism for reducing the variation in stop position of the hands of the present embodiment (hereinafter simply referred to as the variation reduction mechanism) is provided in the third wheel & pinion 30 which is decelerated from the fourth wheel & pinion 40 . Specifically, as shown in FIGS. 2 and 3, this variation reduction mechanism is constituted by a return spring member 10 assembled to the third wheel & pinion 30 itself.

The return spring member 10 is made of elastic material. The return spring member 10 is formed by MEMS (Micro Electro Mechanical Systems), for example. However, the return spring member 10 is not limited to being formed by MEMS, and may be manufactured by other manufacturing methods. For example, the return spring member 10 may be made of a material such as silicon or an alloy used for hairsprings.

The return spring member 10 is arranged on the side of the front surface 31a of the gear 31 of the third wheel & pinion 30 opposite to the back surface 31b where the third pinion 32 is arranged.

On the side of the front surface 31a of the gear 31 of the third wheel & pinion 30, a seat 34 is arranged which is fitted to the shaft 33 penetrating the gear 31 from the outside. Since the seat 34 is press-fitted so that the inner peripheral surface 34a is in contact with the shaft 33, it rotates integrally with the shaft 33 around the central axis C2. If the space for arranging the return spring member 10 on the side of the front surface 31a is insufficient due to the positional relationship between the third wheel 30 and other adjacent gears, the return spring member 10 is placed on the back surface together with the seat 34. 31b.

The seat 34 is provided for the purpose of increasing the outer diameter of the shaft 33 in order to bring the friction spring portion 12 (friction portion) of the return spring member 10 into contact with the shaft 33 by frictional force. Therefore, the seat 34 is regarded as the same as the shaft 33, and if the thickness of the shaft 33 is as thick as the outer diameter of the seat 34 and the friction spring portion 12 can be brought into contact with the shaft 33 by frictional force, , seat 34 need not be provided.

The return spring member 10 has a return spring portion 11 and a friction spring portion 12 . The return spring portion 11 and the friction spring portion 12 are formed to have the same thickness in the central axis C2 direction. good too. The return spring portion 11 has a spring portion 11c, one end portion 11a, and the other end portion 11b. The spring portion 11 c has a substantially arc-shaped portion that is slightly inside the outer shape of the gear 31 of the third wheel & pinion 30 and that substantially follows the outer shape of the gear 31 .

The one end portion 11a is formed extending from one end of the spring portion 11c radially inward, which is the center of the arc of the spring portion 11c. The other end portion 11b is formed so as to extend outward in the radial direction of the arc of the spring portion 11c from the other end of the spring portion 11c.

In addition, in a plan view of the movement of the timepiece, the one end portion 11a and the spring portion 11c of the return spring portion 11 are arranged in a range overlapping the gear 31 of the third wheel & pinion 30, but the other end portion 11b is partially is arranged so as to protrude outward from the range overlapping with the gear 31 .

The friction spring portion 12 is formed in a substantially heart shape. The friction spring portion 12 includes two contact portions 12a and 12b and two spring portions 12c and 12c. The contact portion 12 a has a protrusion on the inner surface of the lower corner of the heart shape of the friction spring portion 12 , and this protrusion is in contact with the outer peripheral surface 34 b of the seat 34 .

The contact portion 12 b has a projection on the inner surface of the heart-shaped upper constricted portion of the friction spring portion 12 , and the projection contacts the outer peripheral surface 34 b of the seat 34 . If it is necessary to increase or decrease the amount of friction between the contact portions 12a and 12b and the outer peripheral surface 34b of the seat 34, the contact area of the protrusions, the number of protrusions to be installed, etc. may be increased or decreased, or the protrusions of the contact portions 12a and 12b may be adjusted. It may be eliminated, and the surface may be brought into contact with the seat 34 .

The two contact portions 12a and 12b are formed at positions facing each other across the central axis C2. Since the dimension between the two contact portions 12a and 12b is smaller than the diameter of the outer peripheral surface 34b, the two contact portions 12a and 12b simultaneously contact the outer peripheral surface 34b and sandwich the seat 34. state.

The two spring portions 12c, 12c are substantially C-shaped with the contact portions 12a, 12b as both ends, respectively, and when elastically deformed in the direction of widening the distance between the both ends, the distance between the two ends is narrowed. An elastic force directed toward Therefore, when elastically deformed in the direction of widening the distance between the two end portions, the two contact portions 12a and 12b apply normal force to the outer peripheral surface 34b of the seat 34 due to the elastic force toward the center in the radial direction.

As a result, friction torque is generated between the outer peripheral surface 34b of the seat 34 and the contact portions 12a and 12b in the direction along the outer peripheral surface 34b. This friction torque is proportional to the normal force at the contact portions 12a and 12b due to the elastic force of the spring portions 12c and 12c. Therefore, by adjusting the elastic modulus of the spring portion 12c or by adjusting the distance between the contact portions 12a and 12b when the spring portion 12c is not elastically deformed, the contact with the outer peripheral surface 34b of the seat 34 can be achieved. The magnitude of the friction torque generated between the portions 12a and 12b can be adjusted.

In addition, by adjusting the coefficient of friction between the outer peripheral surface 34b of the seat 34 and the contact portions 12a, 12b, the magnitude of the friction torque between them can also be adjusted.

The coefficient of friction between the outer peripheral surface 34b of the seat 34 and the contact portions 12a, 12b varies depending on the position of the contact portions 12a, 12b with respect to the outer peripheral surface 34b of the seat 34, the contact area, the number of contacting portions, etc. In order to obtain proper friction torque, it is necessary to adjust the elastic force of the spring portion 12c.

The elastic force of the spring portion 12c can be adjusted by adjusting the length of the spring portion 12c. For example, when the coefficient of friction between the outer peripheral surface 34b of the seat 34 and the contact portions 12a, 12b is large, the length of the spring portion 12c is increased in order to reduce the elastic force of the spring portion 12c. The amount of elastic deformation increases and the elastic force decreases.

When the contact portions 12a and 12b contact the seat 34 from above and below as shown in FIG. The elastic force is reduced by lengthening the spring portion 12c as much as possible within the range where it can be visually accommodated within the outer circumference of the gear 31 . As a result, the friction spring portion 12 is formed in a substantially heart shape. In order to further reduce the elastic force, the spring portion 12c may be configured to have a longer length by combining a plurality of curved lines.

On the other hand, when the coefficient of friction between the outer peripheral surface 34b of the seat 34 and the contact portions 12a, 12b is small, there is no need to reduce the elastic force of the spring portion 12c. shorter than

Adjustment of the elastic force of the spring portion 12c can also be realized by reducing the thickness of the spring portion 12c in the direction perpendicular to the central axis C2. By reducing the thickness of the spring portion 12c to the extent that it does not break, the amount of elastic deformation increases and the elastic force can be reduced.

One end portion 11 a of the return spring portion 11 of the return spring member 10 is coupled to the outer surface of one contact portion 12 a of the friction spring portion 12 . One end portion 11a is coupled to the outer surface of one contact portion 12a of the friction spring portion 12, so that the return force generated by the return spring portion 11 is evenly applied to the contact surface or contact point of the contact portion 12a with the seat 34. can be transmitted.

<Action>
FIG. 4 is a plan view (part 1) explaining the action of the return spring member 10, and FIG. 5 is a plan view (part 2) explaining the action of the return spring member.

In the train wheel shown in this embodiment, the rotor pinion 62 of the step motor 60 rotates, for example, in the counterclockwise rotation direction −R for time display. As a result, the fifth wheel & pinion 50 rotates in the clockwise rotation direction R, the fourth wheel & pinion 40 rotates in the counterclockwise rotation direction -R, and the third wheel & pinion 30 rotates in the clockwise rotation direction R.

Here, the other end portion 11b of the return spring portion 11 is arranged in a notch 91 of the rotor guide 90 partitioned by two edges 91a and 91b, as shown in FIG. The rotor guide 90 is a member that does not move in the movement of a timepiece, like the main plate and train wheel bridge.

When the third wheel & pinion 30 rotates in the clockwise rotation direction R, the contact parts 12a and 12b of the friction spring part 12 are caused to friction with the outer peripheral surface 34b of the seat 34 of the third wheel & pinion 30, and the static friction torque causes the third wheel & pinion to rotate. It rotates in the rotation direction R as the vehicle 30 rotates. As a result, the one end portion 11a of the return spring portion 11 coupled to the friction spring portion 12 is pulled so as to rotate in the rotation direction R together with the friction spring portion 12 .

Then, the return spring portion 11 tries to rotate in the rotation direction R together with the one end portion 11a, but the other end portion 11b of the return spring portion 11 arranged in the notch 91 rotates in the rotation direction R, and thus rotates. When it hits the edge 91a on the downstream side (front side) in the direction R, the rotation is restricted.

One end portion 11a of the return spring portion 11 is pulled in the rotational direction as the third wheel & pinion 30 rotates, and the other end portion 11b is restricted in rotation. elastically deformed to change the

As a result, an elastic force is generated in the spring portion 11c to restore the curvature before deformation, and the third wheel & pinion 30 moves in the rotation direction -R to return the one end portion 11a to the position before it was rotated. , a return torque corresponding to the elastic force acts.

Since the 3rd wheel 30 is meshed with the 4th wheel 40, the return torque acting on the 3rd wheel 30 also acts on the 4th wheel 40, and the 4th wheel 40 rotates in the direction of rotation -R for time display. A return torque acts to rotate in the opposite direction R.

As a result, the backlash existing in the train wheel from the rotor pinion 62 to the third wheel 30 of the step motor 60, which rotates for time display, is shifted in the direction of rotation for time display, and the backlash is shifted to one side. It is possible to prevent or suppress the rattling due to the play of the respective pinion wheels 50, 40, 30, which can occur when they are not brought together. Therefore, it is possible to prevent or suppress a pointer such as the second hand fixed to the fourth wheel 40 from wobbling due to rattling.

Here, the static friction torque between the contact portions 12a and 12b of the friction spring portion 12 and the outer peripheral surface 34b of the seat 34 is the rotor of the step motor 60 that rotates the third wheel & pinion 30 in the rotation direction R for time display. It is smaller than the drive torque transmitted from 62.

The return torque increases as the rotation of the third wheel & pinion 30 in the rotational direction R progresses. It slips against surface 34b. After the slip, the return torque reduced by the slip continues to act on the outer peripheral surface 34b of the seat 34 in the direction opposite to the rotational direction R as friction torque.

As described above, according to the return spring member 10 of the present embodiment, by constantly applying friction torque (return torque) to the train wheel that rotates to display the time in the direction opposite to the direction of rotation, the train wheel It is possible to prevent or suppress the fluctuation of the second hand due to the backlash between the gears of the second hand being shifted to one side.

In addition, the pointer wobble reduction structure of this embodiment has a portion (one end portion 11a) attached to the third wheel & pinion 30, which is an existing pointer driving wheel, and the other portion (the other end portion 11b) as a non-moving portion. Since the return spring member 10 is hooked, it is not necessary to newly provide a space occupied in plan view in the movement of the timepiece, compared to using a new gear other than the existing wheel train.

In particular, most of the return spring member 10 of the present embodiment (the entire friction spring portion 12, the spring portion 11c of the return spring portion 11 and the one end portion 11a) other than the other end portion 11b is , it can be arranged only in a range that substantially overlaps with the gear 31 of the existing third wheel 30 in plan view.

Moreover, the other end portion 11b of the return spring member 10, which does not overlap the area of the gear 31 of the third wheel & pinion 30 in plan view, is also arranged in the notch 91 formed in the existing rotor guide 90. As shown in FIG. Therefore, there is no area in plan view that is newly required for arranging the return spring member 10 .

The return spring member 10 is arranged on the front surface 31a side of the gear 31 of the third wheel & pinion 30, but the return spring portion 11 and the friction spring portion 12 are arranged in the space on the front surface 31a side of the gear 31. It can be arranged in the existing dead space by forming it in a shape corresponding to (an area where there are no other parts).

The other end portion 11b of the return spring portion 11 in the return spring member 10 of the present embodiment is formed so as to protrude outward from a range that overlaps with the gear 31 in plan view. They may be formed so as to be within an overlapping range in plan view. In this way, the entire return spring member 10 is arranged within a range overlapping the gear 31 in plan view, so that the pointer fluctuation reduction structure of the present embodiment occupies a smaller space in the movement of the timepiece in plan view. can do.

Since the return spring member 10 of the present embodiment can adjust the friction torque between the friction spring portion 12 and the outer peripheral surface 34b, the return torque (load torque) acting on the existing train wheel for displaying the time is reduced. It is possible to

Since the friction spring portion 12 in the return spring member 10 of the present embodiment is heart-shaped and substantially line-symmetrical, the two contact portions 12 a and 12 b are in contact with the outer peripheral surface 34 b of the seat 34 . , a good balance can be maintained on both sides of the line of symmetry, and a stable friction torque can be obtained.

Further, since the return spring member 10 of the present embodiment is not constructed by combining two or more parts, but is constructed by a single member, the return spring member 10, it is constructed by combining a plurality of parts. The manufacturing cost can be reduced compared to the conventional one.

In addition, the return spring member 10 of the present embodiment is in contact with the outer peripheral surface 34b of the seat 34 by means of the projections of the two contact portions 12a and 12b. In the case of a configuration in which the surfaces contact each other, the friction torque can be made more stable than in the case of the point contact.

As shown in FIG. 1, the outer peripheral surface 34b of the seat 34 has a taper in which the radius from the central axis C2 decreases as it approaches the front surface 31a of the gear 31 in the axial direction of the central axis C2. doing.

As a result, the contact portions 12a, 12b contacting the outer peripheral surface 34b are biased toward the front surface 31a of the gear 31 in the axial direction of the central axis C2. As a result, the contact portions 12a and 12b are less likely to move away from the front surface 31a of the gear 31 in the axial direction of the central axis C2. It is possible to prevent or suppress the contact portions 12a and 12b from coming off the seat 34 by moving away from the .

Further, as described above, as the third wheel & pinion 30 rotates in the rotational direction R, the contact portions 12a and 12b in contact with the seat 34 rotate, and the return spring portion 11 also rotates. The end portion 11b abuts against the edge 91a on the downstream side (front side) in the rotational direction R, and its rotation is restricted. Therefore, the position of the other end portion 11b serves as a load point, and the return spring portion 11 elastically deforms and bends so that the arc-shaped spring portion 11c changes the curvature of the arc.

In this state, the load at the load point is obtained based on the friction torque generated by the friction between the contact portions 12a and 12b and the seat 34 and the distance from the center of the third wheel to the load point (load point distance). can be done. This load causes the spring portion 11c to bend, and a return torque is generated to return the spring portion 11c to its original state. You can suppress the fluctuation of the second hand.

Therefore, it is necessary to adjust the return torque of the spring portion 11c according to the amount of backlash and the frictional torque between the contact portions 12a and 12b and the seat 34. In particular, it is necessary to adjust the return torque according to the load point distance. There is a need to. Specifically, the longer the load point distance, the lower the return torque, and the longer the length of the spring portion 11c, the lower the return torque.

As a method for reducing the return torque, the thickness of the spring portion 11c in the direction perpendicular to the central axis C2 may be reduced within a range that does not cause breakage, thereby increasing the amount of elastic deformation and reducing the return torque. For example, the return torque of the spring portion 11c is reduced by reducing the thickness of the spring portion 11c in the direction perpendicular to the central axis C2, the thickness in the direction of the central axis C2, or both. In this case, since the spring portion 11c does not have to be elongated, the spring portion 11c may be formed in a linear shape instead of a substantially arc shape.

<Modification>
FIG. 6 is a perspective view showing a third wheel & pinion 30 provided with a modified return spring member 110, FIG. 7 is an exploded perspective view of the third wheel & pinion 30 and the return spring member 110, and FIG. 4 is a plan view for explaining the action of a spring member 110; FIG.

The return spring member 10 of the embodiment shown in FIGS. is not limited to a single arc), but the shape of the return spring portion is not limited to a single arc.

FIGS. 6-8 show a return spring member 110 having a return spring portion 111 and a friction spring portion 112 formed in a single non-arcuate shape, such as an S-shape. This return spring member 110 is another embodiment of the pointer wobble reduction structure according to the present invention, and is a modification of the return spring member 10 shown in FIGS.

As shown in FIGS. 6 and 7, the return spring member 110, like the return spring member 10, is the front surface of the gear 31 of the third wheel 30 opposite to the back surface 31b on which the third pinion 32 is arranged. 31a side.

The return spring member 110 includes a return spring portion 111 and a friction spring portion 112 . The return spring portion 111 has a spring portion 111c, one end portion 111a, and the other end portion 111b. The spring portion 111c is formed in a substantially S shape. The S shape of the spring portion 111c is formed across the central axis C2.

In other words, the S shape of the spring portion 111c is not formed within a radial range on one side of the central axis C2, but is formed over a radial range on both sides of the central axis C2. Therefore, the S-shape of the spring portion 111c can be made larger than the S-shape formed within the range of radius on one side with respect to the central axis C2, and the length of the spring portion 111c can be increased. can be done. In addition, the S shape of the spring portion 111c may be formed within the radius of one side with respect to the central axis C2.

The one end portion 111a is formed at one end of the spring portion 111c and coupled to the friction spring portion 112, which will be described later. The other end portion 111b is formed at the other end of the spring portion 111c. A cylindrical pin 113 is fixed to the other end portion 111b and protrudes in the direction opposite to the gear 31 in the direction of the central axis C2.

The pin 113 provided at the other end portion 111b protrudes in the direction of the central axis C2, and a hole formed in an existing non-moving member (for example, the rotor guide 90 may be used) arranged in the protruding direction. 95 is fitted. Accordingly, the other end portion 111b of the return spring portion 111 does not move in the same manner as the other end portion 11b of the return spring portion 111 does.

As the third wheel & pinion 30 rotates in the rotational direction R, the contact portions 112a and 112b in contact with the seat 34 rotate, and the return spring portion 111 also rotates. Rotation is restricted. As a result, the position of the other end portion 111b becomes a load point, and the arc-shaped spring portion 111c is elastically deformed and bent.

Here, the load at the load point can be obtained based on the friction torque generated by the friction between the contact portions 112a and 112b and the seat 34 and the distance from the center of the third wheel to the load point (load point distance). . This load causes the spring portion 111c to bend, and a return torque is generated to try to return the third wheel.

Therefore, it is necessary to adjust the return torque of the spring portion 111c according to the amount of backlash and the frictional torque between the contact portions 112a and 112b and the seat 34. In particular, the return torque should be adjusted according to the load point distance. There is a need. Since the load point distance of the return spring portion 111 in the modified examples of FIGS. 6 to 8 is shorter than the load point distance of the return spring portion 11 in FIGS. It may be larger than the portion 11, and the length of the spring portion 111c is shorter than that of the spring portion 11c.

A certain amount of length is required for the spring portion 111c in order to generate an elastic force that restores the curvature before deformation. In the modification, the spring portion 111c is formed in an S shape so that the area occupied by the spring portion 111c is narrowed. As a result, the return spring member 110 is less likely to interfere with gears other than the third wheel and timepiece parts, and the degree of freedom in their arrangement can be improved.

As a method for adjusting the return torque, it is also possible to adjust the return torque generated by elastic deformation by adjusting the thickness of the spring portion 111c in the direction perpendicular to the central axis C2 so as not to break.

As shown in FIGS. 6 and 7, the friction spring portion 112 is formed in a shape in which portions of two substantially C-shaped spring portions 112c, 112c facing each other are joined together. These two substantially C-shaped spring portions 112c, 112c are formed substantially symmetrically with respect to the central axis C2.

The friction spring portion 112 has a contact portion 112a formed on the inner peripheral surface of the joined portion. Further, the friction spring portion 112 has contact portions 112b, 112b formed on the inner peripheral surfaces of the other ends on the side where the spring portions 112c, 112c are not coupled. These three contact portions 112a, 112b, and 112b are arranged to surround the central axis C2 from the outside, and are portions that are in point contact with the outer peripheral surface 34b of the seat 34, respectively.

Since the dimension between the contact portions 112a and 112b of the spring portions 112c and 112c is formed to be smaller than the diameter of the outer peripheral surface 34b, the contact portions 112a and 112b simultaneously contact the outer peripheral surface 34b, sandwiched between. As a result, friction torque is generated between the outer peripheral surface 34b of the seat 34 and the contact portions 112a and 112b in the direction along the outer peripheral surface 34b.

This friction torque is proportional to the normal force at the contact portions 112a and 112b due to the elastic force of the spring portions 112c and 112c. Therefore, the return spring member 110 can be adjusted by adjusting the elastic modulus of the spring portion 112c or by adjusting the distance between the contact portions 112a and 112b when the spring portion 112c is not elastically deformed. It is possible to adjust the magnitude of the friction torque generated between the outer peripheral surface 34b and the contact portions 112a and 112b.

The return spring member 110 can also adjust the magnitude of the friction torque between the outer peripheral surface 34b of the seat 34 and the contact portions 112a, 112b by adjusting the coefficient of friction between them.

6 to 8, the friction spring portion 112 is in contact with the seat 34 at three points, that is, the contact portion 112a and the contact portions 112b, 112b, and the contact portion 112b is substantially C-shaped. Therefore, the coefficient of friction between the seat 34 and the contact portions 112a and 112b is smaller than that of the friction spring portion 12 having the structure in which the seat 34 is sandwiched between the contact portions 12a and 12b shown in FIGS.

Therefore, in the return spring member 110, the elastic force of the spring portion 112c needs to be higher than the elastic force of the spring portion 12c to ensure the friction torque. Therefore, the return spring member 110 reduces the amount of elastic deformation and increases the elastic force by shortening the length of the spring portion 112c compared to the spring portion 12c.

As a method of adjusting the elastic force of the spring portion 112c, a method of increasing the elastic force by increasing the thickness of the spring portion 112c in the direction perpendicular to the central axis C2 to reduce the amount of elastic deformation can be applied. .

In the return spring member 110, one end 111a of the return spring portion 111 is connected to the outer surface of the portion of the friction spring portion 112 where the two spring portions 112c, 112c are connected.

<Action>
In the return spring member 110 of the modified example configured as described above, similarly to the return spring member 10 of the embodiment, when the third wheel & pinion 30 rotates in the clockwise rotation direction R, the contact portion 112a of the friction spring portion 112 is disengaged. , 112b, 112b rotate in the rotational direction R together with the rotation of the third wheel & pinion 30 due to static friction torque generated by friction with the outer peripheral surface 34b of the seat 34 of the third wheel & pinion 30. As shown in FIG.

The return spring portion 111 tries to rotate in the rotational direction R together with the one end portion 111a, but since the pin 113 is hooked in the hole 95 of the rotor guide 90, for example, the other end portion 111b of the return spring portion 111 does not rotate. Therefore, the return spring portion 111 is elastically deformed and bent so that the shape of the S-shaped spring portion 111c changes.

As a result, an elastic force is generated in the spring portion 11c to restore the shape before deformation, and the third wheel & pinion 30 moves in the rotation direction -R to return the one end portion 111a to the position before it was rotated. , a return torque corresponding to the elastic force acts.

As a result, the backlash existing in the train wheel from the rotor pinion 62 to the third wheel 30 of the step motor 60, which rotates for time display, is shifted in the direction of rotation for time display, and the backlash is shifted to one side. It is possible to prevent or suppress the rattling due to the play of the respective pinion wheels 50, 40, 30, which can occur when they are not brought together. Therefore, it is possible to prevent or suppress a pointer such as the second hand fixed to the fourth wheel 40 from wobbling due to rattling.

In addition, the pointer wobble reduction structure of the modified example is such that a portion (one end portion 111a) is attached to the third wheel & pinion 30, which is an existing pointer driving wheel, and the other portion (the other end portion 111b) is hooked to a stationary portion. Since the return spring member 110 is used, it is not necessary to newly provide a space occupied in a plan view in the movement of the timepiece, as compared with a case in which a new gear other than the existing train wheel is used.

Since the return spring member 110 of the modified example is formed so that the entirety including the pin 113 is within the range of the gear 31 in plan view, part of the other end portion 11b is outside the gear 31 in plan view. Compared to the projecting return spring member 10, the area occupied in plan view can be further reduced.

Since the return spring portion 111 and the friction spring portion 112 are formed to have the same thickness in the central axis C2 direction, the thickness of the return spring member 110 as a whole can be suppressed. The return spring member 110 is arranged on the front surface 31a side of the gear 31 of the third wheel & pinion 30, but the return spring portion 111 and the friction spring portion 112 are arranged in the space on the front surface 31a side of the gear 31. It can be arranged in the existing dead space by forming it in a shape corresponding to (an area where there are no other parts).

According to the return spring member 110 of the present embodiment, the friction torque between the friction spring portion 112 and the outer peripheral surface 34b can be adjusted. can be reduced.

In the return spring member 110 of the present embodiment, the return spring portion 111 is formed in an S shape, and compared to the C shape of the return spring portion 11 of the return spring member 10, the elastic force with respect to the amount of deflection is stronger. Therefore, when compared with the same deflection amount, the return torque generated by the friction spring portion 112 is larger than the return torque generated by the friction spring portion 12 .

Therefore, the structure in which the friction spring portion 112 and the outer peripheral surface 34b are in surface contact with each other, such as the contact portions 12a and 12b between the friction spring portion 12 and the outer peripheral surface 34b, does not reduce the return torque acting on the outer peripheral surface 34b. increases, the loss of power for driving the train wheel for displaying the time may increase.

On the other hand, the return spring member 110 of the modified example has a configuration in which the friction spring portion 112 and the outer peripheral surface 34b are in point contact with each other like the contact portions 112a, 112b, and 112b. The return torque acting on the wheel can be reduced as compared with the structure in the form of surface contact, and the loss of power for driving the train wheel for displaying the time can be reduced.

In the return spring member 10 of the embodiment, the return spring portion 11 is formed in a greatly deformed circular arc shape that follows the outer shape of the gear 31. Therefore, the return spring portion 111 of the return spring member 110 of the modified example has In comparison, there is an advantage that the return torque can be gradually increased with respect to the amount of deflection of the return spring portion 11 .

Further, like the return spring member 10, the return spring member 110 of the modified example is not configured by combining two or more parts, but is configured by a single member. Manufacturing costs can be reduced compared to what is used.

In the return spring member 10 of the embodiment and the return spring member 110 of the modification described above, the portions where the one ends 11a and 111a of the return spring portions 11 and 111 are connected are the friction spring portions 12 and 112 having the spring portions 12c and 112c. However, in the pointer wobble reduction structure according to the present invention, the portion where the one ends 11a and 111a of the return spring portions 11 and 111 are connected may be a friction portion that generates a friction force by coming into contact with the shaft 33 or the seat 34. However, it may be one that does not have the spring portions 12c and 112c.

In the return spring member 10 of the embodiment and the return spring member 110 of the modified example described above, the other end portions 11b and 111b of the return spring portions 11 and 111 are hooked on a non-rotating member (for example, the rotor guide 90). Although it is designed not to move, it is not limited to the hooked mode as long as it fixes the other ends 11b and 111b so as not to move.

The return spring member 10 of the embodiment and the return spring member 110 of the modified example described above are examples provided for the gear 31 of the third wheel & pinion 30. It may be provided on the gear 41 of the fourth wheel 40, the gear 51 of the fifth wheel 50, etc.).

10 Return spring member (pointer fluctuation reduction structure)
11 return spring portion 11a one end portion 11b other end portion 11c spring portion 12 friction spring portion (friction portion)
30 third wheel 31 gear 33 rotating shaft

Claims (6)

A pointer wobble reduction structure for reducing wobble of a time display pointer,
a friction portion that contacts the rotating shaft of the gear to which the pointer is fixed or the rotating shaft of another gear that operates in connection with the gear with a predetermined frictional force;
one end coupled with the friction portion, the other end whose rotation is restricted by a non-rotating member, and a spring portion elastically deformed by the rotation of the gear between the one end and the other end. and a return spring portion. 2. The pointer wobble reduction structure according to claim 1, wherein the friction portion is a friction spring portion that sandwiches the rotating shaft with an elastic force. 3. The pointer fluctuation reduction structure according to claim 2, wherein the friction spring portion has two spring portions that are formed substantially symmetrically with respect to the axis of the gear. The pointer according to any one of claims 1 to 3, wherein the return spring portion is formed in a range in which at least the one end portion of the return spring portion and the spring portion overlap the gear in a plan view. wobble reduction structure. 5. The spring portion of the return spring portion has a substantially arcuate portion slightly inside the outer shape of the gear and substantially along the outer shape of the gear. Wobbling reduction structure of the indicated guideline. The pointer fluctuation reduction structure according to any one of claims 1 to 5, wherein the return spring portion and the friction portion have the same thickness in the axial direction.

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