JP3765248B2 - Leaf spring support structure - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a structure for supporting a leaf spring on which an external force acts.
[0002]
[Prior art]
As shown in FIG. 11, in order to support a rectangular leaf spring 101 to which an external force F acts, for example, one end of the leaf spring 101 is sandwiched between a support member 103 and a plate 105, and this is used as a plurality of screws 107. The support structure fixed with is used.
[0003]
[Problems to be solved by the invention]
However, as shown in FIG. 12, in the longitudinal direction of the leaf spring 101, when an external force F is acting between the adjacent screws 107, the reaction force of the external force F causes the leaf spring 101 between the screws 107. May float up, and there is a problem that desired spring characteristics cannot be obtained.
[0004]
In order to solve this, there are methods of clamping the leaf springs using a strong plate or fixing the leaf springs firmly by increasing the number of screws, but both of them increase the cost. was there.
[0005]
The present invention has been made to solve the above problems, and an object of the present invention is to provide a leaf spring support structure capable of obtaining accurate spring characteristics at low cost.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a support structure for fixing a single leaf spring having both side edges extending in parallel to each other and having an external force acting on a plurality of locations, to the support member, wherein the plurality of fastening members include The fastening member is fastened to the support member in a state of being engaged with a leaf spring, and the fastening portion is positioned on a line that passes through the action point of each external force and extends in parallel to the side edge of the leaf spring, and the plurality of external forces are large. In the region divided in the width direction of the leaf spring according to the magnitude of each external force, the region acts on a straight line that is the center in the width direction of each region and extends perpendicularly to the width direction. The present invention provides a support structure for a leaf spring characterized in that an action point is determined .
[0008]
The front Symbol fastening member is constituted by a screw having a flared head in the radial direction, and the supporting member and the head of the screw, the point of action at the contact edges of the each of the leaf spring It is possible to sandwich the leaf springs by making the closest portions coincide with each other in the leaf spring thickness direction.
[0009]
Here, “the portion closest to the point of action at the contact edge with the leaf spring” means that the leaf spring is folded back in the thickness direction into a U shape or a V shape, and an external force is applied to the folded side. Is the portion with the shortest distance measured along the bent leaf spring.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a first embodiment of a leaf spring support structure according to the present invention will be described with reference to the drawings. 1 is a perspective view of a leaf spring support structure showing a first embodiment of the present invention, and FIG. 2 is a sectional view of FIG.
[0011]
In the following description, the same or similar parts may be denoted by the same reference numerals and description thereof may be omitted.
[0012]
As shown in FIGS. 1 and 2, in the support structure of the present embodiment, one end portion in the longitudinal direction of the leaf spring 1 whose both side edges extend in parallel is fixed to a block-like support member 2. On the other hand, two external forces F act on the other end of the leaf spring 1 on a straight line perpendicular to the width direction. At one end of the leaf spring 1, attachment holes 6 are formed on straight lines L ₁ and L ₂ that pass through the point of action of each external force F and are parallel to both side edges of the leaf spring 1. Then, a screw 4 that is a fastening member is inserted into each mounting hole 6 and is screwed into the support member 2. The screw 4 used at this time has a head portion 4 a that expands in the radial direction, and is fastened with the head portion 4 a engaged with the leaf spring 1.
[0013]
According to the leaf spring support structure thus configured, the point of action of each external force F and the corresponding screw 4 are on the straight lines L ₁ and L ₂ parallel to the side edges of the leaf spring 1. For this reason, the shear stress generated in the two regions sandwiching the straight lines L ₁ and L ₂ is in a substantially equal distribution state. Therefore, it is possible to prevent the leaf spring 1 from being twisted due to shear stress bias.
[0014]
Accordingly, the reaction force of the external force F that attempts to lift one end of the leaf spring 1 from the support member 2 is maximized at the position of each screw 4, and at the position in the width direction of the leaf spring 1 away from the screw 4, The force to lift the spring 1 is reduced. As a result, the leaf spring 1 can be firmly fixed to the support member 2, and desired spring characteristics can be accurately obtained at low cost without using a robust plate.
[0015]
When external forces of different magnitudes act on the leaf spring 1, the support structure can be configured as follows. As shown in FIG. 3, for example, it is assumed that two external forces F ₁ and F ₂ (F ₁ <F ₂ ) are acting on the leaf spring 1. In this case, the leaf spring 1 is internally divided in the width direction so as to be proportional to the magnitudes of the external forces F ₁ and F ₂ , and the external forces are centered in the width direction of the divided areas E ₁ and E _2. F ₁ and F ₂ are allowed to act. Further, the external forces F ₁ and F ₂ are applied on a straight line in the width direction of the leaf spring 1, and the screw 4 is fastened on the straight lines L ₁ and L ₂ passing through the external forces F ₁ and F ₂ .
[0016]
With such a configuration, each of the regions E ₁ and E ₂ is formed with a width proportional to each of the external forces F ₁ and F ₂ , so that each of the regions E ₁ and E ₂ is against each of the external forces F ₁ and F ₂ . It deform | transforms so that the cross-sectional shape along a longitudinal direction may become the same. Therefore, the shear stress generated in each of the regions E ₁ and E ₂ divided by the internal dividing line is in an equal distribution state. Therefore, the leaf spring 1 can be prevented from being twisted in the width direction due to the shear stress bias, and the spring characteristics faithful to the design values can be obtained in each of the regions E ₁ and E ₂ while being one leaf spring 1. Obtainable.
[0017]
Further, if the screw fastening position is set as follows, more accurate spring characteristics can be obtained. That is, as shown in FIG. 4, the support member 2 and the head 4 a of the screw 4 are the portions closest to the point of application of external force at the contact edge with the leaf spring 1, and in the thickness direction of the leaf spring 1. Configure to match each other. More specifically, a straight line L ₃ extending along the edge on the action point side on the upper surface of the support member 2 and a point P closest to the action point side of the screw head 4 a are indicated in the thickness direction of the leaf spring 1. To match. By doing so, the base end portions of the fixed ends of the springs coincide with each other on the upper surface and the lower surface of the leaf spring 1, so that more accurate spring characteristics can be obtained.
[0018]
The support member 2 is not limited to the block shape as described above, and may be a support member including a plurality of columnar portions 7 as shown in FIG. In this case, each screw 4 is fastened to each column part one by one, and the upper surface of the column part 2 and the head 4 a of the screw 4 are applied with an external force at the contact edge with the leaf spring 1. The portion closest to the point side, that is, the point P and the point Q is configured to coincide with each other in the thickness direction of the leaf spring 1. Even in this case, accurate spring characteristics can be obtained as in the case of using the block-shaped support member 2 described above.
[0019]
In the above embodiment, the support structure of the present invention is applied to a leaf spring on which two external forces are acting. However, the present invention can be applied even when three or more external forces are acting.
[0020]
In the above embodiment, one screw is fastened one by one on a straight line passing through the action point of each external force, but two or more screws may be fastened in the same direction. Furthermore, a screw may be supplementarily fastened to a portion other than a straight line passing through the point of action of each external force to strengthen the support of the leaf spring.
[0021]
In the above embodiment, the attachment hole 6 is drilled in the leaf spring 1 and the screw 4 is fastened. However, the present invention is not limited to this. For example, a slit is formed at the end of the leaf spring, and the slit is formed in the slit. It may be fastened through a screw.
[0022]
Further, the shape of the leaf spring is not limited to the flat plate shape described above, and may be, for example, bent in the thickness direction to be V-shaped or U-shaped. What is necessary is just to support by the support structure made.
[0023]
Next, an example in which the second embodiment of the leaf spring support structure according to the present invention is applied to an operation mechanism of an electronic keyboard instrument will be described with reference to the drawings. 6, 7, and 8 are a plan view, a right side view, and a left side view, respectively, FIG. 9 is a perspective view showing a schematic configuration of an operation mechanism, and FIG. 10 is an enlarged view of FIG. 8. is there. 6 to 8, the player side of the keyboard device is referred to as the front side, and the opposite side is referred to as the rear side.
[0024]
As shown in FIGS. 6 to 8, in this keyboard apparatus, the entire key is supported by the keyboard frame 20, and the keyboard frame 20 is supported by the shelf plate 23. The key 22 is composed of a white key and a black key, and each key 22 is rotated around a rotation center R20 near a contact point with the support portion by a support portion 27 extending in the key arrangement direction behind the keyboard frame 20. Is supported so as to be rotatable in the vertical direction. Under the key 22, the movable member 30 is supported by the keyboard frame 20.
[0025]
The movable member 30 extends substantially horizontally in the front-rear direction as a whole, and the tip of the support piece 24 is formed by a support piece 24 standing on the front side of the keyboard frame 20 and a recess 31 for receiving the support piece 24. It rotates as a rotation center R30. In order to maintain the engagement state between the distal end portion of the support piece 24 and the recessed portion 31, a spring engagement comprising one end portion of the S-shaped spring 41 provided on the back side of the recessed portion 31 in the movable member 30 and formed on both side portions. The stop 32 is pressed.
[0026]
The movable member 30 has a front end in contact with the lower end of the hanging piece 21 of the key 22, and rotates in conjunction with the key 22 when the key 22 is depressed. A switch board 42 is supported by the keyboard frame 20 near the lower front end of the movable member 30, and a key switch 43 made of dome-shaped rubber is fixed on the board. On the lower surface of the front portion of the movable member 30, a switch drive unit 33 having a pair of legs extending downward at positions corresponding to the conductive members 42 and 43 is provided. The switch drive unit 33, the switch board 42, and the key switch 43 constitute a key pressing switch that senses the key pressing speed by using the conduction start time difference at the time of key pressing due to the difference in distance between the two contacts in the key switch. Yes.
[0027]
The movable member 30 extends to the rear portion of the keyboard frame 20 and is supported in the vicinity of the rear end portion by a felt stopper member 25 fixed on the keyboard frame 20 in the rest position (non-key-pressed state). When the key 22 is depressed, the movable member 30 moves from the rest position indicated by the solid line in FIG. 7 to the key depression position indicated by the alternate long and short dash line. A stopper member 26 is held immediately behind the key 22 in the keyboard frame 20 and serves to stop the movable member 30 that has reached the key pressing position.
[0028]
The stopper member 26 covers the buffer felt 26a with a protective sheet 26b, and the rear end portion of the movable member 30 presses the buffer felt 26a through the protective sheet 26b. The cushioning felt 26a is usually configured by overlapping felts having different stiffnesses so as to provide a buffering action against the collision of the rear end portion of the movable member 30 and a reliable stop feeling to the player's fingers. The movable member 30 is made of plastic from the front part to the vicinity of the rotation center R30, and is formed so that the metal bar extends from the rear part thereof. Causes resistance.
[0029]
An operation mechanism 50 for so-called after touch control is provided at the rear part of the keyboard frame 20 to control sound generation by detecting a pressing force generated by pressing a key. As shown in FIG. 9, the operation mechanism 50 has a structure in which two tension members 51 and 52 are supported on both sides of the keyboard as a whole. As will be described later, one end portions of the two tension members are supported by a leaf spring 62, and the support structure of the present invention is applied to the attachment of the leaf spring to the keyboard.
[0030]
As shown in the figure, of the two tension members 51, 52, one tension member 51 is for sensing, and is held between the buffer felt 26a and the protective sheet 26b of the stopper member 26 to be a keyboard device. It extends in the key arrangement direction. The other tension member 52 is for compensation provided to eliminate or reduce the influence of disturbance factors on the tension member 51 for detection. The compensation tension member 52 extends in parallel with the detection tension member 51 at a position slightly away from the stopper member 26 so as not to contact the movable member 30.
[0031]
As shown in FIG. 8, an extending portion 60 supported by the keyboard frame 20 is provided on the outer left end of the keyboard row. The tension portion 60 includes a support member 61 fixed to the keyboard frame 20 and an attachment leaf spring 62 attached to the support member 53 with a screw 64. The leaf spring 62 for attachment extends obliquely downward from the support member 61 and then is folded back to form a V-shape, and each end of the detection tension member 51 and the compensation tension member 52 is provided at its free end. Supports to pull.
[0032]
As shown in FIG. 7, a detection unit 70 supported by the keyboard frame 20 is provided outside the right end of the keyboard row. The detection unit 70 has a structure in which a detection leaf spring 72 extends from the detection circuit board 71. The detection leaf spring 72 has a base end portion fixed to the circuit board 71 with a screw 78, and supports the end portion of the detection tension member 51 at the distal end portion. A strain sensor 73 is attached near the base end of the detection leaf spring 72. In this example, the strain sensor 73 is configured using a piezo element. The circuit board 71 is provided with a circuit (not shown) for detecting an output signal from the strain sensor 73 and an adjustment element 74 for fine adjustment thereof. The circuit is further connected to an aftertouch controller (not shown). The end portion of the compensating tension member 52 on the right side of the keyboard row is fixedly supported by an ABS resin fixing portion 75 provided at the rear end portion of the keyboard frame 20.
[0033]
As shown in FIG. 9, large diameter portions 57 and 58 larger than the diameter of the tension members 51 and 52 are provided at both ends of the tension members 51 and 52, and the above-described attachment leaf spring 62 and detection leaf spring are provided. 72 and the large-diameter portions 57 and 58 of the tension members 51 and 52 are engaged with T-shaped small grooves 63, 76 and 79 formed in the fixing portion 75.
[0034]
In the operation mechanism 50, the following settings are further made. The attachment leaf spring 62 is stronger in spring force than the detection leaf spring 72, and the compensation tension member 52 is higher in tensile rigidity than the detection tension member 51. In other words, the compensation tension member 52 is fixedly supported at the right end by the fixing portion 75 of the keyboard frame 20 and pulled at the left end by the mounting plate spring 62 to be in a predetermined extended state. On the other hand, the detection tension member 51 is held at the left end together with the compensation tension member 52 with the mounting plate spring 62 as a common holding portion, and the right end is held at its free end by bending the detection plate spring 72. . Therefore, in order to stabilize the position of the left end in a state in which the compensation tension member 52 is pulled, the spring force of the attachment leaf spring 62 is increased so that the detection leaf spring 72 does not bend greatly. The tensile rigidity of is increased.
[0035]
Thus, since the tension acting on the compensating tension member 52 is larger than the tension acting on the detection tension member 51, two external forces having different sizes act on the attachment leaf spring 62. The attachment leaf spring 62 is attached to the support member 61 as follows.
[0036]
Assuming that the tension acting on the compensation tension member 52 and the detection tension member 51 is F ₁ and F ₂ (F ₁ > F ₂ ), the tension members 52 and 51 are attached as shown in FIG. The plate springs 62 are attached to the first region 62a and the second region 62b, respectively, which are divided in the width direction into F ₁ : F ₂ . The end portions of the tension members 52 and 51 are positioned on the straight line extending in the width direction at the center in the width direction of each region.
[0037]
As shown in FIG. 10B, one end of the attachment leaf spring 62 is sandwiched between the support member 61 and the screw 64, and the leaf spring 62 extends in the direction in which the leaf spring 62 extends from the support member 61. The edge S of the support member 61 and the edge T of the head portion 64a of the screw 64 coincide with each other in the thickness direction of the leaf spring 62. Further, as shown in FIG. 10A, the screw 64 that fixes the attachment leaf spring 62 passes through the attachment positions of the tension members 52 and 51, and is straight lines L ₁ and L ₂ parallel to the edge of the leaf spring 62. Two are provided on the top.
[0038]
Next, the operation of this keyboard apparatus will be described. FIG. 8 shows a pause state before key depression. When the key is pressed from this state, the key 22 rotates downward about the rotation center R20, and the hanging piece 21 pushes down the movable member 30. As a result, the movable member 30 rotates about the rotation center R <b> 30, and the switch drive unit 33 moves downward toward the key switch 43. The switch drive unit 33 of the key 22 is in contact with the key switch 43, turns on the key depression switch, operates the sound generation mechanism, and generates sound. During this time, the movable member 30 raises the rear part from the rotation center R30. Immediately after the switch drive unit 33 comes into contact with the key switch 43, the rear end portion of the movable member 30 comes into contact with the stopper member 26, thereby stopping the rotation of the movable member 30 and the key 22.
[0039]
The operation mechanism 50 operates as follows. When the key pressing force is increased or decreased in the key pressing state, the rear end portion of the movable member 30 changes the amount of bending of the stopper member 26, particularly the buffer felt 26a. The detecting tension member 51 is held between the buffer felt 26a of the stopper member 26 and the protective sheet 26b. Therefore, when the amount of bending of the buffer felt 26a changes, the amount of meandering of the detection tension member 51 accompanying the bending also changes. When the amount of meandering increases, the distance between the ends of the detection tension member 51 decreases, and accordingly, the deflection of the detection leaf spring 72 increases. Therefore, the output of the strain sensor 73 increases. By picking up this output change, it is possible to detect a change in the pressing force applied to the key after the key is pressed, and after touch control can be performed if the volume, sound quality, etc. are changed accordingly.
[0040]
According to such a configuration, since the screw 64 is fastened on the straight lines L ₁ and L ₂ passing through the points of action of the external forces F ₁ and F _{2 in} the attachment leaf spring 62, the reaction of the external forces F ₁ and F ₂ is reversed. The leaf spring 1 can be prevented from floating between the screws adjacent in the width direction by force. For this reason, the fixing of the attachment leaf spring 62 to the support member 2 becomes strong, and accurate spring characteristics can be obtained. Furthermore, since a plate for pressing the attachment leaf spring 62 is not required, the cost can be reduced.
[0041]
Further, the two regions 62a to mounting leaf spring 62 corresponding to the magnitude of the external force F _1, F _2, is internally divided in 62b, the external force F _1, F ₂ are configured to act on the center in the width direction Therefore, the spring characteristic faithful to the design value can be generated in each of the regions 62a and 62b even though the leaf spring is one sheet.
[0042]
Further, the structure of the support member 61, the number of the screws 64, and the like are not limited to those described above, and various types shown in the first embodiment can be applied.
[0043]
【The invention's effect】
As is apparent from the above description, according to the support structure of the present invention, the following effects can be obtained. That is, since the point of action of each external force in the leaf spring and the corresponding fastening member are on a line parallel to the side edge of the leaf spring, the shear stress generated in the region sandwiching each wire is approximately equal to the distribution state. Become. Therefore, it is possible to prevent the leaf spring from being twisted in the width direction due to the uneven distribution of the shear stress, and to prevent the leaf spring from being lifted between the adjacent fastening members due to the reaction force of the external force acting on the leaf spring. Can do. As a result, the leaf spring can be firmly fixed to the support member, and desired spring characteristics can be accurately obtained at low cost without using a robust plate.
[0044]
When a plurality of external forces of different magnitudes act on the leaf springs, the leaf springs are internally divided into regions corresponding to the magnitudes of the external forces, on the straight line extending in the width direction center and in the width direction. What is necessary is just to comprise so that each external force may act. By doing so, since the shear stress generated in each region is almost equal to the distribution state, it is possible to generate a spring characteristic faithful to the design value in each region, although it is a single leaf spring.
[0045]
Furthermore, a screw having a radially extending head is used, and the portion where the support member and the screw head are closest to the point of action of the external force at the contact edge with the leaf spring is located in the thickness direction of the leaf spring. By making them coincide with each other, an accurate spring characteristic can be obtained. As a result, no plate is required, and the cost can be reduced.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a leaf spring support structure according to the present invention.
FIG. 2 is a cross-sectional view of FIG.
FIG. 3 is a perspective view showing another example of a leaf spring support structure according to the present invention.
FIG. 4 is a view showing still another example of a leaf spring support structure according to the present invention.
FIG. 5 is a perspective view showing still another example of a leaf spring support structure according to the present invention.
FIG. 6 is a plan view showing an example in which the leaf spring support structure according to the present invention is applied to a keyboard device portion of an electronic piano.
7 is a right side view of the keyboard device portion of FIG. 6;
FIG. 8 is a left side view of the keyboard device portion of FIG. 6;
9 is a perspective view schematically showing an operation mechanism in the keyboard device of FIG. 6. FIG.
FIG. 10 is an enlarged view of an example of a support structure applied to a keyboard device of an electronic piano.
FIG. 11 is a perspective view showing a conventional support structure for a leaf spring.
12 is a cross-sectional view of FIG.
[Explanation of symbols]
1 leaf spring 2 support member 4 screw (fastening member)
4a head 61 support member 63 leaf springs 63a, 63b for mounting region 64 screw (fastening member)
E _1, E ₂ regions F, F _1, F ₂ external force L _1, L ₂ straight (linear)

Claims (2)

A support structure for fixing a single leaf spring having both side edges extending in parallel to each other and having an external force acting on a plurality of locations to a support member,
A plurality of fastening members are fastened to the support member in a state of being engaged with a leaf spring, and the fastening portion is positioned on a line that passes through the action point of each external force and extends parallel to the side edge of the leaf spring,
The plurality of external forces are different in magnitude, and extend in the width direction center of each region and perpendicular to the width direction in the region divided in the width direction of the leaf spring according to the magnitude of each external force. A support structure for a leaf spring, wherein an action point is determined so as to act on a straight line. The fastening member is constituted by a screw having a radially extending head, and the support member and the head of the screw are portions closest to the action point at the contact edge between each of them and the leaf spring. The leaf spring support structure according to claim 1, wherein the leaf springs are sandwiched by causing the leaf springs to coincide with each other in the leaf spring thickness direction.

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