JP2019045371A - Caliper with sliding spring - Google Patents

Abstract

To provide a caliper capable of realizing smooth slide operation of measurement slide to a main scale as well as preventing looseness, and also capable of maintaining such good sliding characteristics for an extended period from the start of use.SOLUTION: A caliper 1 is configured to comprise a main scale 2 and a measurement slider 3 slidably disposed in a longitudinal direction of the main scale 2. The measurement slider 3 comprises: a pair of holding parts 31A and 31B that hold both end surfaces of the main scale 2 in a direction orthogonal to the longitudinal direction of the main scale 2; and a plate spring 34 that is arranged in a space between either of the holding parts 31A and 31B and the main scale 2, gives energizing force from the holding part 31A to the main scale 2, and forms a frictional sliding part 34A on the main scale 2. The plate spring 34 is formed of carbon fiber reinforced resin (CFRP).SELECTED DRAWING: Figure 1

Description

  The present invention relates to a caliper and to an improvement of its sliding spring.

  Conventionally, in calipers, in order to reduce the frictional resistance of the measurement slider to the main scale to obtain a smooth sliding motion, and also to prevent rattling of the measurement slider relative to the main scale at the time of sliding operation and reading of the measured value. , Metal plate springs are used.

  For example, in the vernier caliper of Patent Document 1, slipways are formed along the longitudinal direction of the vernier at both ends in the short direction orthogonal to the longitudinal direction of the vernier. Further, in the measurement slider, grooves are respectively formed at positions facing the above-mentioned two slideways. Each of the two groove portions is provided with a guide shaft, and the movement of the guide shaft in the longitudinal direction is restricted. In one groove portion of the measurement slider, a metal plate spring is provided which biases a guide shaft provided therein toward a slideway of the main length.

  The biasing force due to the bending of the metal plate spring maintains the guide shaft of the measurement slider in contact with the slideway of this length. Further, the biasing force of the metal plate spring is adjusted by changing the screwing amount of the screw screwed into the measurement slider.

JP-A-8-233503

  However, in general, the spring constant of metal is larger than that of other materials, so in order to obtain the ideal frictional resistance compatible with smooth slide movement of the caliper and prevention of rattling, the amount of deflection of the metal plate spring is strictly determined. It must be managed.

  In addition, when the posture of the metal plate spring in the groove portion of the measurement slider is not stable, that is, when the posture stability of the metal plate spring is poor, the metal plate spring wears out according to the frequency of use of the calipers. It is easy to advance (also called "Hetari"), and the frictional resistance tends to decrease. Even in such a case, in order to maintain the ideal frictional resistance, not only the strict control of the deflection amount, but also the strict adjustment of the biasing force of the plate spring by the screw needs to be performed many times.

  As described above, in order to obtain the ideal frictional resistance that can balance the smooth sliding motion of the caliper and the rattling, and maintain the ideal frictional resistance over a long period of time, the deflection of the metal plate spring is made. It is necessary to perform control and adjustment that strongly requires strictness, such as control of the amount and adjustment of the biasing force by a screw to cope with the wear and tear of the metal plate spring. It is difficult for general workers to carry out such management and adjustment, and this has been the cause of the increase in the cost of maintaining the performance of the calipers and the reduction of the measurement efficiency using the calipers.

  The object of the present invention is to achieve both smooth slide movement of the measurement slide relative to the main scale and prevention of rattle, and to maintain such good sliding characteristics over a long period of time from the start of use. It is to provide vernier calipers. Specifically, it is easy to manage the amount of deflection of an elastic member such as a leaf spring used for vernier calipers, and it is easy to adjust the biasing force by the elastic member even when the frictional resistance of the measurement slide to this measure changes. It is to provide vernier calipers.

In order to solve the above problems, the caliper according to the present invention is
And a measuring slider provided on the main scale in a stationary direction and provided on the measuring slider, and a movable measurement jaw provided on the measuring slider. Both are configured to be able to contact the object to be measured.
The measurement slider is
A pair of sandwiching portions sandwiching both end faces of the main scale in a direction orthogonal to the length of the main scale;
An elastic member for sliding which is disposed in a gap between any one of the holding portions and the main scale to apply an urging force from the one holding portion to the main scale, and which forms a friction sliding portion against the main length. Members,
Equipped with
The sliding elastic member is formed using a fiber reinforced resin.

  In this configuration, the sliding elastic member is molded using fiber reinforced resin (FRP). As a fiber reinforced resin, it is suitable to use carbon fiber reinforced resin (CFRP), for example. When an elastic member made of fiber reinforced resin is used, the spring constant can be reduced and the amount of deflection necessary to obtain the same biasing force becomes larger than that of a metal elastic member. For example, about 2 to 3 times the amount of deflection of a conventional metal leaf spring can be obtained. Therefore, when it is desired to slightly change the biasing force of the sliding elastic member, the adjustment amount of the deflection amount is substantially expanded, so that the biasing force of the sliding elastic member can be easily adjusted.

  Further, since the fiber reinforced resin is more excellent in wear resistance than metal, the wear of the sliding elastic member progresses even when the posture of the sliding elastic member in the gap between the work piece and the measurement slider is not stable. It is difficult to adjust the biasing force of the sliding elastic member significantly.

As described above, the number of adjustment of the biasing force by the sliding elastic member is reduced, and the adjustment itself of the biasing force becomes easy, so that the control of the amount of deflection of the sliding elastic member becomes easy. Moreover, since the fiber reinforced resin has a smaller coefficient of friction than metal, the measurement slider can be moved smoothly only by applying a slight sliding force. At the same time, since the necessary biasing force is secured by the sliding elastic member made of fiber reinforced resin, the sliding characteristics of the measuring slider are significantly improved. Furthermore, since the elastic member for sliding made of fiber reinforced resin is superior to metal in the vibration damping property, it is possible to suppress the vibration at the time of sliding to the minimum level.
In addition, the elastic member for sliding made of fiber reinforced resin is more excellent in fatigue characteristics than metal. When the sliding elastic member is incorporated into the gap between the measuring rod and the measuring slider, the sliding elastic member is incorporated in a state of being slightly elastically deformed from the initial state. In this state, the user slides the measurement slider with respect to the scale, so that each time the slide operation is performed, the force acting on the slide elastic member from the scale and the measurement slider changes, causing a slight elastic deformation. It can be said that the sliding elastic member is exposed to repeated loads. Therefore, by making the sliding elastic member made of fiber reinforced resin with high fatigue strength, damage, cracking and breakage are less likely to occur even under such repeated load, and good sliding characteristics are maintained for a long time Be done.
The simultaneous realization of these effects adds to the feeling of luxury that has never been seen before.

Further, the shape of the sliding elastic member is long in the sliding direction of the measurement slider, and both end portions of the sliding elastic member are curved toward the measurement slider in the gap, and the friction sliding portion is It is preferable that at least an intermediate portion of the sliding elastic member be formed.
According to this configuration, the sliding elastic member is formed, for example, in an arc shape, and a desired amount of deflection can be easily obtained. In addition, since good sliding characteristics of the measurement slider relative to the main length are formed in the middle portion of the long sliding elastic member, the posture stability of the sliding elastic member in the gap between the main length and the measurement slider is Be improved.

Further, it is preferable that the sliding elastic member has a wave shape, and the friction sliding portion is formed at at least two places in an intermediate portion of the sliding elastic member.
According to this configuration, the sliding elastic member is formed in a W shape, for example, and the friction sliding portion is divided into a plurality of locations in the middle portion of the sliding elastic member, thereby generating the friction heat generated in the friction sliding portion. Can reduce the effects of

  If the caliper of the present invention is configured as described above, the sliding elastic member is molded using a fiber reinforced resin, whereby the number of times of adjustment of the biasing force by the sliding elastic member is reduced and the biasing force adjustment itself Also, the control of the amount of deflection of the sliding elastic member is facilitated. As a result, it is possible to achieve both the smooth slide movement of the measurement slide relative to the main scale and the prevention of rattling, and to maintain such good sliding characteristics for a long time from the start of use. It became possible.

(A) is an external appearance front view of a caliper according to an embodiment of the present invention, and (B) is a partial longitudinal sectional view showing an internal structure of a measurement slider. (A) is a front view which shows the leaf spring used for the measurement slider of the said caliper, (B) is a front view which shows the leaf spring which concerns on a modification. It is the graph which showed the characteristic of the amount of load-deflection about the leaf spring of this embodiment in comparison with the case of a metal leaf spring. It is a graph comparing and representing the fatigue strength of some materials including CFRP. It is a graph showing the FFT analysis result of the vibration at the time of sliding of the conventional measurement slider using metal leaf springs.

Hereinafter, embodiments of the present invention will be described based on the drawings.
First Embodiment
The external view which looked at the caliper of this embodiment from the front at FIG. 1 (A) is shown. Further, FIG. 1 (B) shows the internal structure of the measuring slider of this caliper as a partial longitudinal sectional view.

The caliper 1 of FIGS. 1A and 1B includes a scale 2 and a measurement slider 3 provided slidably in the longitudinal direction of the scale 2.
The measuring scale 2 includes a measuring main body 21 which is a longitudinal portion thereof and an outer measuring jaw 22 and an inner measuring jaw 23 provided on one end side of the main body 21 in the longitudinal direction. The outer measurement jaw 22 and the inner measurement jaw 23 respectively project in opposite directions in the lateral direction orthogonal to the longitudinal direction of the main body 21 and both constitute a fixed measurement jaw.
Slideways (rails or grooves) 24 and 25 are provided on the main body 21 toward the other end in the longitudinal direction of the main body 21 with respect to the measurement jaws 22 and 23 for the outside and the inside. .

  In the present specification, in the longitudinal direction of the caliper 1 of FIG. 1, the jaw sides 22 and 23 are called one end side, and the side opposite to the jaw is called the other end side.

  The measurement slider 3 includes a slider body 31, an outer measurement jaw 32 and an inner measurement jaw 33 provided on one end side of the slider body 31, and a main body 21 between the slider body 31 and the main body 21. And a plate spring 34 for biasing the The outer measurement jaw 32 and the inner measurement jaw 33 project in opposite directions in the lateral direction orthogonal to the longitudinal direction of the slider body 31, and both constitute a movable measurement jaw.

  Here, both the outer measurement jaws 22 and 32 of the scale 2 and the measurement slider 3 are configured to be capable of coming into contact with the measurement object from the outside, and each of the measurement scale 2 and the measurement slider 3 The inner measurement jaws 23 and 33 are both configured to be able to abut on the object to be measured from the inside. Then, with the measurement jaws of the scale 2 and the measurement slider 3 in contact with the measurement object, the sliding position of the measurement slider 3 with respect to the measurement 2 is read, and the slider body 31 is used as the length information of the measurement object. The display unit 35 is provided in front of the display unit 35.

  FIG. 1B is a cross-sectional view of the measurement slider 3 along the sliding direction. The slider body 31 is provided with a pair of sandwiching portions 31A and 31B which sandwich the main body 21 from the direction orthogonal to the sliding direction. A gap for housing a plate spring 34 as a sliding elastic member between the main portion 21 and the holding portion 31A is formed in the one holding portion 31A. The gap is a space elongated along the sliding direction, and position regulating pieces 31C and 31D for the plate spring 34 are formed at both ends in the sliding direction.

  The leaf spring 34 is elastically deformed and incorporated in the above-mentioned gap in a state substantially parallel to the sliding direction. That is, the plate spring 34 is formed in advance in a state of being curved in a substantially arc shape by the carbon fiber reinforced resin. Both end portions of the plate spring 34 are warped toward the one holding portion 31A side of the measurement slider in a state of being fitted in the gap. It is incorporated in the gap in a state of being elastically deformed so as to reduce the warpage of the substantially arc shape. The leaf spring 34 applies an urging force from one of the holding portions 31A to the main body 21 and forms a friction sliding portion 34A with respect to the main body 21 at an intermediate portion. The friction sliding portion 34A of the leaf spring 34 directly abuts against the rail 24 of the main body 21 in the leaf spring 34 in a state of being slightly curved at the above-mentioned gap, and the sliding surface in sliding operation. Point to the part that produces friction. The biasing force of the plate spring 34 causes the other sandwiching portion 31B to be in close contact with the main body 21.

The biasing force caused by the plate spring 34 is finely adjusted by the pair of adjustment screws 37 and 38 provided on the measurement slider 3. That is, the adjusting screws 37 and 38 are provided at one end side and the other end side of the clamping portion 31A, and the clamp screw 39 is provided at the middle position thereof, and both are directed from the outside of the measuring slider 3 to the internal length 2 It is screwed together.
The pair of adjustment screws 37 and 38 are located at positions where the screw tips abut on both ends of the plate spring 34, respectively, and the plate spring 34 is always urged toward the main scale 2 side. The amount of deflection of the plate spring 34 changes in accordance with the amount of screwing of the adjusting screws 37 and 38, and the biasing force caused by the plate spring 34 is finely adjusted. The adjusting screws 37, 38 are preferably finely adjusted at the manufacturing stage or at the maintenance stage.
On the other hand, the clamp screw 39 is provided for daily use by the user. During sliding operation of the measurement slider 3, the clamp screw 39 is loosened. Then, when the user wants to temporarily maintain the slide position of the measurement slider 3 or to fix the measurement slider 3 to the scale 2 etc., the clamp screw 39 is tightened, and the plate spring 34 and the scale 2 The sliding position can be fixed to the scale 2 by forcibly increasing the frictional force of

  FIG. 2A is a front view of a flat spring 34 made of carbon fiber reinforced resin according to the present embodiment, showing a shape in a natural state not subjected to an external force, in which the amount of bending is zero. At least in the direction of orientation of carbon fibers in the surface layer on the main body side (the range in which the friction sliding portion 34A of FIG. 1A is formed), the direction in which the carbon fibers are oriented parallel to the sliding direction It is preferable because it is less likely to be worn than when it is oriented in the direction perpendicular to the moving direction. Alternatively, the carbon fibers may be oriented, for example, in the direction of 45 degrees with respect to the sliding direction in consideration of coexistence of suppression of wear and good sliding characteristics.

  Further, the shape of the plate spring 34 may be long, and the cross section need not be rectangular. For example, the cross section may be circular, or the cross section may be toroidal. By forming the leaf spring 34 of CFRP, the thickness can be thinner than that of a conventional metal leaf spring.

  As an advantage of making the leaf spring 34 into an arc shape, a desired amount of deflection can be easily obtained. Further, since good sliding characteristics of the measurement slider 3 with respect to the scale 2 are formed in the middle portion (frictional sliding portion 34A) of the plate spring 34, the plate spring in the gap between the main body 21 and the sandwiching portion 31A. Attitude stability of 34 is improved.

  FIG. 2B shows a modification of the flat spring made of carbon fiber reinforced resin according to the present embodiment. The leaf spring made of carbon fiber reinforced resin is not limited to the arc shape, and may be a wave shape. In the case of the corrugation, the friction sliding portion is divided into a plurality of locations in the middle portion of the plate spring. For example, as shown in FIG. 2B, a leaf spring 36 formed in a W shape may be used. Since the friction sliding portion 36A is divided into two parts in the middle portion of the plate spring 36, the influence of the friction heat generated in the friction sliding portion 36A is reduced.

  FIG. 3 is a graph showing the relationship between the load P (N) acting on the flat spring made of the carbon fiber reinforced resin of this embodiment and the amount of deflection δ (mm). The load P represents the biasing force in the present embodiment. For comparison, the characteristics of load P-deflection amount δ of a plate spring made of phosphor bronze which is a typical example of a conventional metal plate spring are also described. Assuming that the allowable load range of the vernier caliper is 1 to 2N, the carbon fiber is different from the range of the deflection amount of the phosphor bronze plate spring being approximately 0.2 to 0.45 mm according to each graph of FIG. The range of the amount of deflection of the reinforced resin plate spring was approximately 0.4 to 0.85 mm.

According to such a configuration, the following effects can be achieved.
(1) If a plate spring 34 formed of carbon fiber reinforced resin (CFRP) is used, the spring constant is significantly reduced as compared to a conventional metal plate spring, and it is necessary to obtain the same biasing force P. The amount of deflection δ is increased, and the amount of deflection δ about 2 to 3 times that of the conventional metal plate spring can be obtained. As compared with the case of the phosphor bronze spring considered to be most suitable for the conventional metal plate spring, as shown in FIG. 3, the amount of deflection δ of at least about twice is obtained. Therefore, when it is desired to slightly change the biasing force P by the CFRP leaf spring 34, the adjustment margin of the deflection amount δ is substantially expanded, so that the biasing force P by the leaf spring 34 can be easily adjusted.

(2) Since CFRP is superior in wear resistance to metal, even if the posture of the plate spring 34 in the gap between the main portion 21 and the holding portion 31A is not stable, the CFRP plate spring 34 is Abrasion is difficult to progress, and the adjustment frequency of the biasing force P by the plate spring 34 accompanying the secular change can be greatly reduced. The number of times of adjustment of the biasing force P by the plate spring 34 is reduced, and the adjustment itself of the biasing force P becomes easy, so that the management of the deflection amount δ of the plate spring 34 becomes easy.

(3) Moreover, since CFRP has a smaller coefficient of friction than metal, the measurement slider 3 can be moved smoothly by applying a slight sliding force. At the same time, since the required biasing force P is secured by the CFRP leaf spring 34, the sliding characteristics of the measurement slider 3 are significantly improved. Therefore, the low friction of the measurement slider 3 is realized, and the feeling of sliding and the operation unevenness due to the increase and decrease of the frictional force are reduced. Furthermore, since the CFRP leaf spring 34 is superior to metal in vibration damping characteristics, it is possible to suppress vibration during sliding to a minimum level.

(4) In addition, the CFRP leaf spring 34 is superior to metal in fatigue characteristics. The fatigue property refers to the yield strength when a material specimen is repeatedly stressed, and if the number of repetitions until fatigue failure is the same, the larger the stress applied, the better the fatigue characteristics, or the same stress applied. Then, the higher the number of repetitions, the better the fatigue characteristics. As a reference, FIG. 4 shows a graph comparing the fatigue strength of each material of aluminum, steel and CFRP. The fatigue strength of CFRP is about 1.5 times that of aluminum and steel. Phosphor bronze, which is a typical example of a conventional flat spring material, has a fatigue strength close to that of aluminum shown in FIG.

  By adopting CFRP having such excellent fatigue characteristics for the plate spring 34, the following specific effects can be obtained. That is, when incorporating the leaf spring 34 into the gap between the main scale 2 and the measurement slider 3, the leaf spring 34 is incorporated in a state of being elastically deformed slightly from the initial state. Then, each time the slide operation is performed, the force acting on the plate spring 34 from the scale 2 and the measurement slider 3 changes, and a minute elastic deformation of the plate spring 34 occurs. Therefore, by making leaf spring 34 made of CFRP with high fatigue strength, damage, cracking, and breakage do not easily occur in leaf spring 34 even in a state where such repeated load is applied, and good sliding characteristics can be obtained. It can be maintained for a long time.

(5) Since the plate spring 34 is molded using a carbon fiber reinforced resin, the number of times of adjustment of the biasing force P by the plate spring 34 decreases, and adjustment of the biasing force P also becomes easy. Management of the deflection amount δ of the spring 34 is facilitated. As a result, it is possible to achieve both smooth slide motion of the measuring slide 3 with respect to the scale 2 and to prevent rattling, and to maintain such good sliding characteristics for a long time from the start of use. It becomes possible.
The simultaneous realization of these effects adds to the feeling of luxury that has never been seen before with the operation feel of the caliper 1. That is, in the sliding operation, the measurement slider smoothly moves, and the measurement slider stably stops at a desired sliding position by stably obtaining an appropriate frictional force. It is realized with a vernier caliper 1.

<About improvement of operation feeling>
There is data in which the "operation feeling of the measurement slider" is evaluated as follows for a vernier caliper (conventional product) using a metal plate spring. An acceleration sensor was attached to the measurement slider of a conventional vernier caliper, and the measurement slider was slid. FIG. 5 shows the result of FFT analysis of vibration data when the slider slides by the acceleration sensor.

  Such an analysis result can be an indicator of a feeling of roughness during the operation of the slider that the user will realize. For the frequency on the horizontal axis, the vibration in the low frequency region is an index of rough feeling, and the vibration in the high frequency region is an index of rough feeling. Then, the degree of acceleration on the vertical axis is evaluated as the degree of operation feeling of each frequency range.

In the caliper of the present embodiment (implemented product), since an operation feeling superior to that of the conventional product is obtained, as shown in FIG. Be done.
According to the embodiment, in the embodiment, the user hardly feels the operation roughness when sliding the measurement slider. And I can feel that the sense of luxury has never been added to the feel of operation of the calipers.

DESCRIPTION OF SYMBOLS 1 Caliper 2 Bar 3 Measurement slider 22 Fixed side outer diameter measurement jaw 23 Fixed side inner diameter measurement jaws 31A, 31B Pair of holding parts 32 Movable side outer diameter measurement jaw 33 Movable side inner diameter measurement jaw 34, 36 Leaf spring (Sliding elastic member)
34A, 36A Friction sliding part

Claims (3)

And a measuring slider provided on the main scale in a stationary direction and provided on the measuring slider, and a movable measurement jaw provided on the measuring slider. And vernier calipers configured to be able to abut on the object to be measured.
The measurement slider is
A pair of sandwiching portions sandwiching both end faces of the main scale in a direction orthogonal to the length of the main scale;
An elastic member for sliding which is disposed in a gap between any one of the holding portions and the main scale to apply an urging force from the one holding portion to the main scale, and which forms a friction sliding portion against the main length. Members,
Equipped with
The sliding elastic member is molded using a fiber reinforced resin.
The calipers that are characterized. In the caliper according to claim 1,
The shape of the sliding elastic member is long in the sliding direction of the measurement slider,
Both ends of the sliding elastic member are warped toward the measurement slider in the gap,
The friction sliding portion is formed at least at an intermediate portion of the sliding elastic member.
The calipers that are characterized. In the caliper according to claim 2,
The sliding elastic member is corrugated.
The caliper slide according to claim 1, wherein the friction sliding portion is formed at at least two places in an intermediate portion of the sliding elastic member.

Images