JP4020022B2 - Crush amount calculation method and crush support structure - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for calculating a crushing amount when a part of a resin fixing member is crushed to temporarily hold a fixing member against a metal fixing member, and a crush support structure using the same.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a component that supports a component by fitting an unevenness is known (for example, Patent Document 1). This is provided with a pair of concave portions 2 facing each other on the fixing member 1 side, and a pair of convex portions 6 that can be fitted to the concave portions 2 on both left and right side surfaces of the fixed member 5. Assembling is performed by inserting the convex portion 6 of the fixed member 5 into the concave portion 2 of the fixing member 1 from the lower side of FIG. Further, in this device, the protrusion 3 is provided on the locking means, that is, the fixing member 1 side, and the stepped portion 7 that can be locked to the protrusion 3 is provided on the fixed member 5. At the same time that the fixed member 5 is assembled to the fixed member 1, the fixed member 5 is locked to the fixed member 1.
[0003]
[Patent Document 1]
JP 11-345653 A
[0004]
[Problems to be solved by the invention]
In the above structure, a certain amount of gap is usually set between the concave portion 2 and the convex portion 6 in order to smoothly assemble, but there is a problem that the fixed member 5 is rattled by the gap after the attachment. is there.
In the above structure, the fixed member 5 is locked to the fixing member 1 simultaneously with the assembling operation. However, when the locking means is configured separately from the fixed member 5 or the fixing member 1, the locking means It is necessary to temporarily hold the fixed member 5 on the fixing member 1 until the main support is performed. In order to meet such a requirement, if the convex part 6 is partially crushed when the concave part 2 is assembled, the rattling can be eliminated and an appropriate holding force can be obtained. However, if the amount of crushing is too large, the insertion force increases, and if the amount of crushing is small, the holding force decreases.
The present invention has been completed based on the above circumstances, and an object of the present invention is to calculate a crush amount that can be assembled with an appropriate insertion force while securing a necessary holding force.
[0005]
[Means for Solving the Problems]
As a means for achieving the above object, the invention according to claim 1 is the process of inserting the support piece provided on the resin fixed member into the groove portion provided on the metal fixing member. The tip portion of the crushing protrusion provided on the abutting and crushing with the inner wall of the groove portion at an angle of θ ° with respect to the insertion direction causes the fixing member to be temporarily held by the fixing member. A method for calculating a crushing amount of a crushing protrusion, wherein F is an insertion force when the support piece is crushed with respect to the groove, and the crushing surface of the crushing protrusion is crushed by the inner wall from the crushing protrusion to the groove. When the reaction force acting on the inner wall is P, the vertical drag of the inner wall of the groove portion on the same crushing surface is N, and the friction coefficient on the same crushing surface is μ, the vertical balance of the forces F, P, N Formula (1) and horizontal direction From the equation (2), which is a balance equation, the equation (3) representing the correlation between the insertion force F and the reaction force P is calculated, while the metal member made of the same material as the fixing member and the fixed member Using a pseudo reaction force measurement model made of a resin material made of the same material, a crush test is performed to press the fixed member against the metal material to crush the resin material, and based on the obtained test data A crushing amount-reaction force correlation characteristic is obtained, and a crushing amount-insertion force correlation characteristic is calculated based on the crushing amount-reaction force correlation characteristic and the above equation (3), and the fixed member is temporarily attached to the fixing member. The magnitude of the holding force of the support piece with respect to the groove required for holding is regarded as the lower limit value of the reaction force, and the crushing amount A corresponding to the lower limit value of the reaction force is the crushing amount-reaction force correlation. And calculating the insertion force F from a predetermined load range. And calculating the crush amount B corresponding to the upper limit value of the insertion force F from the crush amount-insertion force correlation characteristic, and setting the crush amount A and the crush amount B to the lower limit values of the crush amount, respectively. The upper limit value is characterized in that the allowable range of the crushing amount is calculated.
F + P × sin θ = μ × N × cos θ + N × sin θ (1) equation
N × cos θ = μ × N × sin θ + P × cos θ (2)
F = (μ / (cos θ−sin θ)) × P (3)
[0006]
The invention of claim 2 uses the pseudo friction coefficient measurement model made of a metal material made of the same material as the fixed member and a resin material made of the same material as the fixed member, as defined in claim 1, A tensile test was performed in which the resin material was slid by pulling one end side of the resin material on the metal material, and the tensile load at that time was measured while changing the magnitude of the weight M of the resin material. When the measurement load is Y, the force applied from the resin material toward the metal material, and the force acting in the direction almost perpendicular to the moving surface on the metal material to which the resin material moves is R, the equation (6) Based on this, the force-friction coefficient correlation characteristic acting in the orthogonal direction is calculated, and the friction coefficient μp corresponding to the magnitude of the reaction force P is determined by regarding the reaction force P as the force R applied in the orthogonal direction. Orthogonal Force exerted in the direction - is calculated from the friction coefficient correlation characteristics, having the features resulting friction coefficient μp and the reaction force P at which to calculate the insertion force F by substituting respectively the ▲ 3 ▼ expression.
μ = Y / R ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 6 Formula
[0007]
According to a third aspect of the present invention, in the process of inserting the support piece provided on the fixed member made of polybutylene terephthalate into the groove provided on the aluminum fixing member, the tip of the crushing protrusion provided on the support piece A crushing support structure in which the fixed member is temporarily held on the fixing member by abutting and crushing the inner wall of the groove portion at an angle of 1.5 ° with respect to the insertion direction, wherein the crushing protrusion The section has a substantially triangular shape whose cross section tapers at an angle of approximately 60 ° toward the inner wall of the groove, and the crushing protrusion has a crushing height of 0 at the front end in the insertion direction, which is the amount of crushing. . Characteristic in the range of 3 mm to 0.35 mm.
[0008]
[Action and effect of the invention]
<Invention of Claim 1>
According to the invention of claim 1, since the upper limit value of the crushing amount is set so that the insertion force of the support portion falls within a predetermined load, an appropriate insertion force is guaranteed, and the assembly efficiency is not lowered. Since the lower limit of the amount is set so as to ensure the holding force required for temporary holding, the reliability for temporary holding is increased.
[0009]
<Invention of Claim 2>
According to the inventor's knowledge, the friction coefficient on the crushing surface may fluctuate (mainly due to fine irregularities on the crushing surface) depending on the magnitude of the reaction force generated in the crushing protrusion when crushing. If the friction coefficient is calculated as a constant value (constant) when calculating the insertion force by calculation, the calculated insertion force may not match the actual insertion force. However, if the friction coefficient μp for each reaction force P is calculated in advance by performing a pulling experiment, errors due to such a friction coefficient can be eliminated. Therefore, a highly reliable crushing amount-insertion force correlation characteristic can be obtained.
[0010]
<Invention of Claim 3>
According to the invention of claim 3, when the crushing height is 0.35 mm, the magnitude of the insertion force is approximately 30 to 35 (N), so that the assembling ability of the operator is not impaired. When the crushing height is 0.3 mm, the pressing force P is approximately 15 to 20 (N), and a sufficient reaction force (holding force) against the groove is obtained.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described with reference to FIGS.
In FIG. 1, reference numeral 10 denotes a metal (aluminum die-cast) casing (corresponding to the fixing member of the present invention). One side 11 is opened in the front and rear and formed in a box shape as a whole. A circuit board (not shown) can be accommodated. The opening portion of the one side surface 11 is an attachment portion 12 for attaching a standby side connector described below. Hereinafter, the front side in FIG. 1 will be described as the front side.
[0012]
The standby-side connector 20 is made of synthetic resin (made of polybretin terephthalate), and has a first horizontally long rectangular tube-shaped hood 22 on its front surface and a rectangular tube-shaped first hood portion 22 smaller than the first hood portion 22. Two hood portions 23 are formed side by side, and mating connectors (not shown) can be fitted into the hood portions 22 and 23 from the front. A plurality of terminal mounting holes 24 are formed through the front and rear of the rear end surfaces 21 of the hood portions 22 and 23. Each terminal mounting hole 24 is provided in the horizontal direction at a predetermined pitch, and is provided in the first hood part 22 with three stages in the upper and lower stages, and in the second hood part 23 with two stages in the upper and lower parts, and a terminal fitting 30 is press-fitted therein.
[0013]
The terminal fitting 30 is made of an elongated metal rod, and is press-fitted and locked in a state of being penetrated from the rear into the terminal mounting hole 24. One end portion of the terminal fitting 30 that protrudes from the terminal mounting hole 24 into the hood portions 22 and 23 is electrically connected to a female terminal fitting (not shown) included in the mating connector fitted to the hood portions 22 and 23. Connected. Further, as will be described in detail later, a portion of the terminal fitting 30 that extends to the back side of the standby connector 20 is bent at a right angle (L-shaped) at the front end side and is formed on the electric circuit board on the casing 10 side. Connected.
[0014]
A total of five vertical plate-like terminal protection walls 25A, 25B are extended backward on the back surface of the standby connector 20. Each of the terminal protection walls 25A and 25B is provided to be separated from each other at a predetermined interval so as to sandwich each terminal fitting 30 therebetween. Each terminal protection wall 25 </ b> A, 25 </ b> B has a rectangular shape, and its upper end substantially covers the upper side of the terminal fitting 30 sandwiched therebetween, and its rear end projects rearward from the rear end of the terminal fitting 30. That is, most of each terminal fitting 30 is covered with the terminal protection walls 25A and 25B from both the left and right sides, and only the tip portion protrudes above the terminal protection walls 25A and 25B.
[0015]
The pair of terminal protection walls 25A is thicker than the other terminal protection walls 25B, and an attachment protrusion 26 and a screw hole 27 that are fitted into attachment holes (not shown) of the electric circuit board are formed at the upper ends thereof. Has been. The electric circuit board is screwed in a state where the mounting hole is fitted to the mounting protrusion 26 and is fixed to the rear side of the upper surface of the standby connector 20. In this state, the end of the terminal fitting 30 of the standby connector 20 enters the through wheel of the electric circuit board, and the terminal fitting 30 is electrically connected to the circuit on the electric circuit board by soldering. It has come to be. Although not shown in the drawing, a receiving portion (not shown) for supporting the electric circuit board is formed on the inner surface of the casing 10 so as to protrude, and the casing 10 is on the upper surface side in a state where the electric circuit board is accommodated. Is sealed by a lid member (not shown).
[0016]
Next, an attachment structure (temporary holding structure) of the standby connector 20 to the casing 10 will be described.
A pair of rail pieces 13 and 14 extending in the vertical direction are formed on the left and right inner walls of the attachment portion 12. The rail pieces 13 and 14 are formed over the entire height of the mounting portion 12 and open at the upper end side. The portions sandwiched between the opposing wall surfaces 13A, 14A of both the rail pieces 13, 14 form a support groove (corresponding to the groove portion of the present invention) 15, which will be described in detail later. The support piece 42 of the standby connector 20 is inserted from above.
Further, as shown in FIG. 5, both the wall surfaces described above, that is, the wall surface 13A located near the front surface of the casing 10 and the wall surface 14A located on the back side are both inclined, and the distance between the wall surfaces 13A and 14A is lowered. It gradually becomes narrower toward the side (bottom side).
[0017]
On the other hand, a support piece 42 formed so as to be able to be inserted into the support groove 15 is formed to project outward in the center portion in the depth direction of the left and right side surfaces 41 of the standby connector 20. The support piece 42 is formed up and down over the entire height of the standby-side connector 20, and both the support grooves 15 are provided even when the width dimension between the outer edges of both the support pieces 42 (A dimension shown in FIG. 4) is the widest part. It is set so that it may become narrower than the width dimension (B dimension shown in FIG. 1) between back wall 15A. Further, the protruding amount of the support piece 42, that is, the protruding amount from the side surface 41 is formed with a substantially constant width at the upper end portion (rear end in the insertion direction), but from the position closer to the center to the lower end portion (insertion direction). The amount of protrusion gradually decreases toward the tip of The reason for this configuration is that the insertability into the support groove 15 is taken into consideration.
[0018]
Further, the thickness of the support piece 42 is gradually increased from the lower end side (the front end side in the insertion direction with respect to the support groove 15), and the upper end side is formed thicker. The inclination follows the wall surfaces 13A, 14A of the rail pieces 13, 14. Shape. That is, as shown in FIG. 5, among the wall surfaces of the support piece 42, the front temporary holding surface 44 is formed with substantially the same gradient as the wall surface 13A, while the rear temporary holding surface 46 is formed with substantially the same gradient as the wall surface 14A. ing.
[0019]
Accordingly, the gap between the front temporary holding surface 44 of the support piece 42 and the wall surface 13A of the rail piece 13 and the gap between the rear temporary holding surface 46 of the support piece 42 and the wall surface 14A of the rail piece 14 are supported. In the initial stage when the piece 42 is inserted into the support groove 15, the support piece 42 is secured sufficiently wide so that the insertion operation can be smoothly performed, but the gap gradually becomes narrower as the insertion operation proceeds. . Further, in the attached state (see FIG. 6), the front temporary holding surface 44 of the support piece 42 and the wall surface 13A of the rail piece 13 and the rear temporary holding surface 46 of the support piece 42 and the wall surface 14A of the rail piece 14 Between them, there is a substantially uniform gap over the entire height of the support piece 42.
On the other hand, as will be described in detail below, the support piece 42 is provided with a contact protrusion 47 and a crush protrusion 55. When assembling, both the protrusions 47 and 55 are inserted into the support groove 15 while sliding on the wall surfaces 13A and 14A, and when the assembling is completed, between the front temporary holding surface 44 and the wall surface 13A. The gap and the gap between the rear temporary holding surface 46 and the wall surface 14A are filled.
[0020]
A pair of upper and lower contact protrusions 47 are provided on the rear temporary holding surface 46 of the support piece 42. Both the contact protrusions 47F and 47R have a semicircular cross section (see FIG. 4) and are provided along the insertion direction of the support piece 42. On the other hand, the crushing protrusion 55 is inserted in the direction in which the support piece 42 is inserted in the central portion of the front temporary holding surface 44 on the opposite side of the rear temporary holding surface 46 provided with the abutting protrusion 47. It is provided along. The crushing protrusion 55 is positioned so as to be sandwiched between both contact protrusions 47F and 47R with respect to the insertion direction of the support piece 42, and the protrusions 47 and 55 do not overlap in the insertion direction.
[0021]
The crushing protrusion 55 is formed on a flat plate-like seat 51 and has a substantially triangular cross section that tapers toward the wall surface 13A. As described above, the front temporary holding surface 44 of the support piece 42 is inclined following the wall surface 13A of the rail piece 13, but as shown in FIGS. 6 and 7, the upper surface 51A of the seat 51 and the crushing projection 55 The top edge portion 55A does not follow the inclination of the wall surface 13A and is formed vertically.
[0022]
Further, in the state where the standby connector 20 is assembled with the casing 10, the front end portion (the lower side in FIG. 7) of the top edge portion 55A is set to interfere with the wall surface 13A in the depth direction. Yes. Therefore, when the support piece 42 is inserted into the support groove 15, the front end of the top edge portion 55A comes into contact with the wall surface 13A as the insertion operation proceeds, and in the final stage, the same contact portion comes into contact with the wall surface 13A. It is crushed diagonally along (the hatched portion shown in FIG. 7). In the present embodiment, the angle θ2 formed between the wall surface 13A and the top edge 55A of the crushing protrusion 55 is set to 1.5 °.
[0023]
Thus, when the assembly is completed by press-fitting and crushing the support piece 42 into the support groove 15, the standby-side connector 20 is temporarily held in a state where there is no backlash with respect to the casing 10. In the present embodiment, the temporary holding means that the standby-side connector 20 is prevented from falling off from the casing 10 until the casing 10 is closed by the lid member described above. The holding force is required so that the stand-by connector 20 does not fall off even if it is shaken or the opening side is directed downward.
[0024]
Further, as will be described in detail below, the interference height between the crushing protrusion 55 and the wall surface 13A, that is, the height h (see FIG. 7) at which the crushing protrusion 55 is crushed in the temporary holding state, is relative to the support groove 15. It is calculated in consideration of the insertability of the support piece 42 and the holding force. This crushing height h corresponds to the crushing amount of the present invention.
[0025]
The crushing height h is calculated based on a force balance equation at the time of crushing described below and a test using a pseudo model.
FIG. 9 schematically shows a vertical sectional view in a state in which the crushing protrusion 55 is crushed, where 100 is a crushing protrusion (100A is a shape before crushing), and 110 is a rail The wall surface 13A of the piece 13 and 120 is a crushing surface.
[0026]
At this time, considering the balance of forces on the crushing surface 120, first, the insertion force F is applied downward. Next, as a force acting on the inner wall 110 from the crushing protrusion 100, there is a reaction force P of the crushing protrusion 100. This is a force generated when the crushing protrusion 100 is pressed against the wall surface 110 and acts in a direction substantially orthogonal to the crushing surface 120. Further, as a force acting on the crushing protrusion 100 from the wall surface 110, there is a vertical drag N, which also works in a direction orthogonal to the crushing surface 120. Therefore, when the friction coefficient on the crushing surface 120 is μ, the equation (1) is obtained from the vertical balance of the forces F, P, and N, and the equation (2) is obtained from the horizontal balance.
F + P × sin θ = μ × N × cos θ + N × sin θ (1) equation
N × cos θ = μ × N × sin θ + P × cos θ (2)
Then, by substituting one of the formulas (1) and (2) into the formula on the other side, formula (3) representing the correlation between the insertion force F and the reaction force P is obtained.
F = (μ / (cos θ−sin θ)) × P (3)
[0027]
Subsequently, a crush test for obtaining a correlation characteristic between the crush height h and the reaction force P and a tensile test for obtaining a correlation characteristic between the friction coefficient μ and the reaction force P will be described.
The crushing test is performed by a pseudo reaction force measurement model 130 including a metal plate 131 made of aluminum (same material as the casing 10) and a resin piece 135 made of polybutylene terephthalate (same material as the standby connector 20). As shown in FIG. 10, the tip shape (the portion to be crushed) of the resin piece 135 has a pyramid shape.
In addition, about the shape of the pyramid part 136, it is preferable that the vertex angle of one side shall be about 60 degrees. This is because, in this embodiment, the crushing protrusion 55 has a triangular cross-sectional shape, but its apex angle θ1 is approximately 60 °. Therefore, if the apex angle of one side is set to approximately 60 °, the crushing situation approximate to the crushing situation when the crushing protrusion 55 is actually crushed is reproduced in the test.
[0028]
In the test, the resin piece 135 is set on the metal plate 131 with the apex side of the pyramid portion 136 facing down, and the resin piece 135 is lowered along the central axis of the pyramid portion 136 from the state, and the pyramid portion 136 is set. Is contacted and crushed to the metal plate 131, and the crushing area S is measured (see FIG. 11). Thereby, since test data of the pressing load W applied to the resin piece 135 and the corresponding crushing area S are obtained, the correlation characteristics between the crushing area S and the pressing force W can be obtained by processing these experimental data with a computer ( (4) -1 formula) is obtained.
W = −0.388 (S × S) + 9.1 × S (4) -1 formula
[0029]
On the other hand, according to the inventor's knowledge, there is a correspondence relationship between the crushing area S and the magnitude of the reaction force P at that time, and the pressing force W and the magnitude of the crushing area S at that time. The magnitude P1 of the reaction force of the resin piece 135 when the area is S1 can be considered as the pressing force W1 required to crush the resin piece 135 with the area S1. That is, it can be considered that P = W.
Accordingly, by substituting P for W in equation (4) -1, the correlation characteristic between the crushing area S and the reaction force P (equation (4) -2) can be obtained.
P = −0.388 (S × S) + 9.1 × S (4) -2 formula
FIG. 13A shows the correlation between the crushing area S and the reaction force P in a graph.
[0030]
On the other hand, the relationship between the crushing height h of the crushing protrusion 55 and the crushing area S can be calculated by a computer. That is, in the present embodiment, as described above, the apex angle θ1 of the crushing protrusion 55 is 60 °, and the angle θ2 formed by the crushing protrusion 55 and the wall surface 13A of the rail piece 13 is 1.5 degrees. Therefore, if these conditions are determined, the cross-sectional shape of the crushing protrusion 55 and the inclination angle of the crushing surface are specified, so the crushing area S with respect to the crushing height h can be obtained by the equation (5).
S = 22 (h x h) ··················································· 5
Therefore, the crushing height-reaction force correlation characteristic can be obtained by substituting Equation (5) into Equation (4) -2. FIG. 16A is a graph showing the crush height-reaction force correlation characteristic. The crushing height-reaction force correlation characteristic corresponds to the crushing amount-reaction force correlation characteristic in the present invention.
[0031]
Subsequently, a tensile test for obtaining a correlation characteristic between the friction coefficient μ and the reaction force P will be described. Note that the friction coefficient is generally specific to the substance. For example, when considering the movement of the movable part on the upper surface (sliding surface) of the fixed part, the friction coefficient is specified by the material of both members. If there is no change, the force acting from the movable part side to the fixed part side on the sliding surface, that is, the magnitude of the reaction force P in this embodiment is not affected. However, if there are fine irregularities on the sliding surface, the friction coefficient μ may vary depending on the magnitude of the reaction force.
[0032]
The tensile test is performed by a pseudo friction coefficient measurement model 140 including a metal base 141 made of aluminum (same material as the casing 10) and a resin piece 143 made of polybutylene terephthalate (same material as the standby connector 20). As the resin piece 143, a flat plate is used as shown in FIG. 14. In the test, one end side of the metal piece 143 is pulled while a weight 145 having a mass M is placed on the resin piece 143. This is performed by changing the weight M of the weight, and the tensile load at each weight M is measured.
When the measured tensile load is Y and the force acting perpendicularly from the resin piece 143 side to the metal base 141 side is R, the friction coefficient μ is calculated by the following equation (6).
μ = Y / R ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 6 Formula
By processing this with a computer, a force-friction coefficient correlation characteristic (equation (7)) applied in the orthogonal direction is obtained.
μ = 0.0001 (R × R) + 0.082 × R + 0.171... (7) -1 formula
[0033]
On the other hand, as described above, the force R is a force that works perpendicularly from the resin piece 143 side to the metal base 141 side, and the reaction force P is also a force that works perpendicularly from the crushing protrusion 55 to the wall surface 13A. That is, the above-mentioned force R and reaction force P both act from the movable side to the fixed side when considering the action of the force on the crushing surface (sliding surface on which the resin material moves), and both directions are also on the movable side. It is perpendicular to the direction of movement. Therefore, the correlation characteristic between the force R acting perpendicularly and the friction coefficient μ can be considered as the correlation characteristic of the reaction force and the friction coefficient (Expression (7) -2).
μ = 0.0001 (P × P) + 0.082 × P + 0.171...
Incidentally, the friction coefficient μ corresponding to the magnitude of each reaction force P calculated by the equation (7) -2 corresponds to μp of the present invention. FIG. 15 is a graph showing the correlation characteristics between the reaction force P and the friction coefficient μ.
[0034]
Subsequently, based on the above formula (3), crushing height-reaction force correlation characteristics (4 formula-2, formula 5) and reaction force-friction coefficient correlation characteristics (7 formula-2). The crush height-insertion force correlation characteristic is calculated. For example, in order to calculate the insertion force Fo in the case of the crushing height ho, first, the reaction force Po and the friction coefficient μo are calculated.
To calculate the reaction force Po, So is calculated by substituting ho into the equation (5). Subsequently, the obtained So is substituted into equation (4) -2. Thereby, the reaction force Po is calculated.
Next, in order to calculate the friction coefficient μo, Po obtained in equation (7) -2 may be substituted. Thus, when μo and Po are calculated, if these values are substituted into the equation (3), the insertion force Fo corresponding to the crushing height ho is calculated.
[0035]
On the other hand, in the present embodiment, since a pair of support pieces 42 are provided on the left and right sides of the standby connector 20, the insertion force Fo of the standby connector 20 with respect to the casing 10 needs to be doubled.
The insertion force Fo described above is calculated based on the correlation characteristics obtained from the test data. These correlation characteristics are all derived based on the average value of the test data. Therefore, the average value of the insertion force Fo obtained is also calculated. However, since the insertion force actually fluctuates due to variations in component accuracy and the like, when considering the insertion force G of the standby connector 20 with respect to the casing 10, it is necessary to calculate the maximum value instead of the average value. . Therefore, in this embodiment, the insertion force F is divided by 0.71 in order to perform such an average value-maximum value conversion (correction). From the above, the insertion force G of the standby connector 20 with respect to the casing 10 can be obtained from the following equation (8).
G = 2 x F / 0.71 ... Formula (8)
Thus, since the magnitude of the insertion force G corresponding to each crushing height h is calculated, a crushing height-insertion force correlation characteristic is obtained (see FIG. 16B). This crushing height-insertion force correlation characteristic corresponds to the crushing amount-insertion force correlation characteristic of the present invention.
[0036]
By the way, generally, when an operator performs assembly work on a production line or the like, if there is a work process that requires a force of 40 [N] or more, it is difficult to perform the work in that process continuously for several hours. Work efficiency decreases. Therefore, in this embodiment, the upper limit value of the insertion force of the standby connector 20 is set to 40 [N].
Therefore, the upper limit value of the crush height h is calculated based on the crush height-insertion force correlation characteristic shown in FIG. That is, the crushing height h needs to be 0.4 [mm] or less in order for the insertion force to be 40 [N] or less.
[0037]
On the other hand, the lower limit value of the crushing height h is calculated based on the holding force of the standby connector 20 with respect to the casing 10 in the temporary holding state. With respect to this holding force, if the reaction force P is increased, the standby connector 20 is strongly held with respect to the casing 10 and accordingly, the reaction force P can be regarded as the holding force. On the other hand, in the present embodiment, the size of the standby-side connector 20 is only required to be temporarily held with respect to the casing 10 until the lid member is assembled. Therefore, when the reaction force P of the crushing protrusion 55 with respect to the wall surface 13A is set to 10 N or more per location, for example, the crushing height is based on the crushing height-reaction force correlation characteristic shown in FIG. The lower limit of h can be calculated. That is, in order for the reaction force P to be 10 N or more, the crushing height h needs to be 0.25 or more.
Therefore, the allowable range of the crushing height h may be 0.25 [mm] to 0.4 [mm], but if it is set in the range of 0.3 [mm] to 0.35 [mm] Some allowance for insertion force G and retention force is desirable.
[0038]
Conventionally, in many cases, such a setting of the crushing height h has been determined by the designer empirically. However, when actually verifying with a prototype, both the insertion force G and the holding force are set. It is difficult to satisfy the requirements at the same time, and even if the insertion force G falls within the set range, the required holding force cannot be obtained, or the holding force can be obtained but the insertion force G may increase. In such a case, the design is re-performed. According to the present embodiment, such an allowable range of the crushing height h is calculated according to a force balance equation and a correlation characteristic based on an experiment. As a result, the above-described design redo is prevented in advance.
Further, since the friction coefficient μ for each reaction force P is calculated by conducting a pulling experiment in advance, the error of the insertion force due to the fluctuation of the friction coefficient due to the fine unevenness of the wall surface 13A is eliminated. I can do it.
[0039]
In addition, in this embodiment, the angle θ1 of the crushing protrusion 55 is calculated as 60 °, and the angle θ2 formed by the crushing protrusion 55 and the wall surface 13A is 1.5 °. However, these angles θ1 and θ2 are assumed to be calculated. When calculating the crushing height h when changed, if the correlation characteristic (corresponding to equation (5)) between the crushing height h and the crushing area S at the changed angle is newly calculated, The permissible range of the crush height h can be calculated using the correlation characteristics obtained from the force balance equation, the crush test, and the tensile test as described above.
[0040]
<Other embodiments>
The present invention is not limited to the embodiments described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention, and further, within the scope not departing from the gist of the invention other than the following. Various modifications can be made.
[0041]
(1) In the present embodiment, the friction coefficient μ is calculated for each reaction force P, and the insertion force is calculated using the calculated friction coefficient μ. The insertion force may be calculated.
[Brief description of the drawings]
FIG. 1 is a perspective view of a standby connector and a casing according to an embodiment of the present invention.
[Fig. 2] Front view of standby connector
FIG. 3 is a side view of the standby connector.
FIG. 4 is a rear view of the standby connector.
FIG. 5 is a sectional view showing a state before the standby connector is attached to the casing.
FIG. 6 is a cross-sectional view showing a state in which the standby connector is attached to the casing.
FIG. 7 is an enlarged view showing a state in which the crushing protrusion is crushed.
FIG. 8 is a horizontal sectional view showing a state in which the crushing protrusion is crushed.
FIG. 9 is a schematic diagram showing a balance of forces on the crush surface.
FIG. 10 is a perspective view of a pseudo reaction force measurement model.
FIG. 11 is a perspective view showing a crushing area and a crushing height.
FIG. 12 is also a diagram showing the crushing area and crushing height.
FIG. 13 is a graph showing a crush area-reaction force correlation characteristic and a crush height-crush area correlation characteristic.
FIG. 14 is a side view of a pseudo friction force measurement model.
FIG. 15 is a graph showing a coefficient of friction-reaction force correlation characteristic;
FIG. 16 is a graph showing a crush height-reaction force correlation characteristic and a crush height-insertion force correlation characteristic.
FIG. 17 is a perspective view of a conventional example.
[Explanation of symbols]
10. Casing (fixing member)
13A ... Wall surface
14A ... Wall surface
15 ... Support groove (groove)
20 ... Standby connector
42 ... support piece (support part)
55 ... Crushing protrusion
130 ... Pseudo reaction force measurement model
140 ... Pseudo friction coefficient measurement model

Claims (3)

In the process of inserting the support piece provided on the resin fixed member into the groove provided on the metal fixing member, the tip portion of the crushing protrusion provided on the support piece is θ relative to the insertion direction. A method for calculating a crushing amount of the crushing protrusion when the fixed member is temporarily held on the fixing member by being abutted and crushed on the inner wall of the groove with an angle of °,
The insertion force when the support piece is crushed with respect to the groove is F, and the reaction force acting on the inner wall of the groove from the crushing protrusion on the crushing surface of the crushing protrusion crushed by the inner wall is P. When the vertical drag of the inner wall of the groove portion is N and the friction coefficient at the crushing surface is μ, the vertical balance formulas of the forces F, P, N are the formula (1) and the horizontal balance. From the formula (2), which calculates the formula (3) representing the correlation between the insertion force F and the reaction force P,
F + P × sin θ = μ × N × cos θ + N × sin θ (1) Formula N × cos θ = μ × N × sin θ + P × cos θ (2) Formula F = (μ / (cos θ− sin θ)) × P (3) Equation (3) A pseudo reaction force measurement model made of a metal material made of the same material as the fixing member and a resin material made of the same material as the fixed member. Using the crush test to crush the resin material by pressing the fixed member against the metal material, and obtaining a crush amount-reaction force correlation characteristic based on the obtained test data, and this crush amount -Calculate the crushing amount-insertion force correlation characteristic based on the reaction force correlation characteristic and the above equation (3),
The magnitude of the holding force of the support piece against the groove, which is required when the fixed member is temporarily held by the fixing member, is regarded as the lower limit value of the reaction force, and the collapse corresponding to the lower limit value of the reaction force is performed. While calculating the amount A from the crushing amount-reaction force correlation characteristics,
When the insertion force F is set within a predetermined load range, a crush amount B corresponding to the upper limit value of the insertion force F is calculated from the crush amount-insertion force correlation characteristic, and the crush amount A, crush amount A crushing amount calculation method, wherein an allowable range of the crushing amount is calculated by setting B as a lower limit value and an upper limit value of the crushing amount, respectively. The resin material is pulled by pulling one end side of the resin material on the metal material using a pseudo friction coefficient measurement model made of a metal material made of the same material as the fixing member and a resin material made of the same material as the fixed member. A tensile test by sliding the material is performed, and the tensile load at that time is measured by changing the magnitude of the weight M of the resin material in various ways. The obtained measurement load is Y, and the resin material is directed toward the metal material. When the force acting in the direction almost perpendicular to the moving surface on the metal material on which the resin material moves is R, the force-friction coefficient correlation characteristic acting in the perpendicular direction is expressed based on the equation (6). As well as calculating
μ = Y / R ····································································································· By calculating the friction coefficient μp corresponding to the magnitude of P from the force-friction coefficient correlation characteristic applied in the orthogonal direction, and substituting the obtained friction coefficient μp and the reaction force P into the equation (3), respectively. The crushing amount calculation method according to claim 1, wherein the insertion force F is calculated. In the process of inserting the support piece provided on the fixed member made of polybutylene terephthalate into the groove provided on the aluminum fixing member, the tip of the crushing protrusion provided on the support piece is in the insertion direction. A crush support structure that temporarily holds the fixed member on the fixing member by being abutted and crushed on the inner wall of the groove portion at an angle of 1.5 °,
The crushing protrusion has a substantially triangular shape whose cross section tapers at an angle of approximately 60 ° toward the inner wall of the groove, and the crushing protrusion has a crushing height at the front end in the insertion direction that is the amount of crushing. A crush support structure, wherein the thickness is in the range of 0.3 mm to 0.35 mm.

Images