JP4151502B2 - G sensor manufacturing method - Google Patents

Description

  The present invention relates to a G sensor manufacturing method for attaching a coil spring to a rotatable part, holding the spring in a state of being elastically deformed by twisting and compressing the spring, and assembling the semi-assembly to a housing. It is about.

  For example, in order to operate an airbag device provided in a vehicle at the time of a vehicle collision, a G sensor that detects a large acceleration of a predetermined value or more is used. The G sensor has a rotor provided as a weight rotatable around a shaft, a coil spring that applies a rotational force to the rotor to press the rotor to a non-operating position in a normal state, and a large acceleration greater than a predetermined value. When the rotor rotates around the shaft against the rotational force of the spring, the rotor is made up of a switching element that closes the contact and the like by contact with the rotor, and a housing such as a frame that houses them.

  Not only the G sensor, but generally, after completion, a semi-assembled product in which one end of a coil spring is attached to a component such as a rotor that can rotate around one shaft is twisted and compressed, Inserting into the housing while holding it in an elastically deformed state, and driving the shaft through the hole in the housing so that the rotor and coil spring are inserted, the coil spring is elastic in both the rotational direction and the axial direction in advance. It is very difficult because of the deformation. In order to facilitate this work, in the manufacturing process of the G sensor according to the prior art, one housing is divided into a frame-shaped or open box-shaped main body portion and a lid portion that closes the opening. It is normal to configure it.

  In the assembly process of such a G sensor, the main body part of the divided housing is placed on a special jig having a dummy shaft that can appear and disappear, and the dummy shaft is used for the shaft formed on the main body part. The rotor is mounted in the main body portion and positioned so that it protrudes into the main body portion through the hole and the dummy shaft is inserted into the hole of the rotor. Next, one end of the spring is attached to the rotor, the other end of the spring is rotated on the dummy shaft, the spring is twisted, and the other end is hooked and fixed in a notch groove provided in the main body portion. Further, while the coil spring is compressed in the axial direction of the dummy shaft, the lid portion of the housing is assembled to the main body portion, and the tip of the dummy shaft is inserted into the shaft hole of the lid portion. In this state, the lid portion is joined to the main body portion by a method such as heat caulking to complete the housing. Then, align the rotor hole and coil spring with the shaft hole in the main body and lid of the housing, and press the original shaft to push the dummy shaft into the jig to complete the product. And take it out of the jig.

  However, in the G sensor which takes such a conventional structure and assembly process, a process for assembling and integrally joining the main body portion and the lid portion constituting the housing is necessary. There is a problem that the entire G sensor as a product becomes large and heavy by increasing the size of the housing and the like in order to ensure the strength of the joint.

  The present invention attaches one end of a coil spring to a component that can rotate around a shaft, such as a rotor of a G sensor, and twists the coil spring in the rotational direction and incorporates it in the housing in a state compressed in the axial direction. In view of the problems such as the above-mentioned prior art that occur when the shaft is press-fitted in, the housing is not easily divided into a main body portion and a lid portion, and is constructed as an integrated small and light weight, making it extremely difficult to incorporate. It is an object of the present invention to provide a novel method for manufacturing a G sensor that makes it possible to easily assemble a semi-assembled part of a component and a coil spring into a housing.

  The present invention provides a G sensor manufacturing method according to claim 1 as means for solving the above-mentioned problems.

The manufacturing method of this G sensor is as follows:
A rotor that protrudes in a flange shape from a cylindrical boss portion having a through hole and has a locking hole on the outer periphery;
A coil spring having one end engaged with the locking hole and the other end protruding outward;
A bottom wall, a pair of first side walls disposed opposite to each other on the bottom wall, bearing holes formed in each of the pair of first side walls, and a pair of first side walls facing each other A housing having a second side wall provided on one side edge side, wherein a notch groove is formed at an upper end of the second side wall, and a switching element is provided at a position facing the second side wall. When,
A shaft inserted into the through hole of the boss part and the bearing hole of the housing;
Prepare
A substrate,
A first base fixed to the substrate, and a first claw provided so as to protrude from the first base substantially perpendicular to the substrate;
A first rail and a second rail provided extending from the first base along the substrate in the X direction and the Y direction perpendicular to each other;
A second base movably guided by a first actuator along the first rail;
A second claw projecting from the second base parallel to the first claw;
A third base movably guided by a second actuator along the second rail;
A third claw projecting from the third base parallel to the first claw;
A third rail provided extending from the second base parallel to the second rail;
A fourth rail provided extending from a third base in parallel to the first rail;
A fourth base guided movably along a third rail by a third actuator and movably guided along a fourth rail by a fourth actuator;
A fourth claw projecting from the fourth base in parallel to the first claw;
With
A holder in which the first to fourth claws are adapted to translate along two axes orthogonal to each other,
A first notch is formed on the first nail side of the second nail, a second notch is formed on the third nail side of the fourth nail, and the third nail has the above-mentioned Preparing a holder in which a groove opening on the fourth and first claw side is formed;
By loosely inserting the coil spring into the boss portion of the rotor, locking one end of the coil spring in the locking hole, compressing the coil spring, and rotating the other end of the coil spring around the axis of the coil spring, A coil spring is wound up at a predetermined angle to form a semi-assembled product,
In this state, the coil in which the first notch of the holder is engaged with the boss portion of the rotor and is gripped by the first and second claws, and the second notch is loosely inserted into the boss portion. Engage the spring with the third claw and the fourth claw, engage the other end of the coil spring wound by a predetermined angle in the groove, and hold the half assembly by the holder,
The half-attachment held by the holder is lowered from above the housing, the through holes of the bosses of the half-attachment are aligned with the bearing holes formed in the pair of first side walls, and the shaft is Insert into the bearing hole and through hole, open the first to fourth pawls of the holder to release the semi-assembly, and release the other end of the coil spring locked in the groove The other end is locked in the notch groove of the second side wall.

  This G sensor manufacturing method uses a holder that can hold a semi-assembly made up of a component and a coil spring that is assembled to the part in a lump. As the distance between the plurality of claws expands and contracts by moving in parallel with each other, the coil spring of the semi-assembled object maintains a state where it is elastically deformed in the axial direction and the rotational direction around the axis. However, the semi-assembly can be grabbed and released freely. Therefore, the semi-assembled product can be positioned at the target position while holding the elastically deformed state of the coil spring by holding the semi-assembled product and moving it to any desired position.

  Therefore, in the G sensor manufacturing method of the present invention, the coil spring that constitutes a part of the semi-assembled product is twisted in the rotational direction and the part that constitutes the other part is maintained while being compressed in the axial direction. At the same time, it can be held together, moved to any desired position, and assembled at that position. Therefore, if there is a small opening through which the plurality of claws holding the semi-attachment can pass at the target position to be assembled, the semi-assembly can be easily inserted through the opening. There is no need to form a large opening. For this reason, it is not necessary to increase the strength of the housing in accordance with the large opening, so that the housing can be made thin, light and small.

  Prior to detailed description of the embodiments of the present invention, the above-described prior art and problems thereof will be described in more detail with reference to FIGS. In the following description of the drawings, the same reference numerals are assigned to portions common to the conventional technology and the embodiments of the present invention, and the detailed description thereof is omitted. .

  As shown in FIGS. 9A and 9B, in the conventional G sensor 1, the housing 2 is composed of two parts, that is, a main body part 3 and a cover part 4 made of synthetic resin that are molded separately. Has been. The main body portion 3 is provided with a plurality of protrusions 5, and the lid portion 4 is previously formed with a plurality of holes 6 that match the protrusions 5. Further, in order to receive the shaft 7 that is press-fitted in the final process, a hole 8 is formed in the lid portion 4 and a hole 9 is formed in the main body portion 3 so as to be aligned therewith.

  In the completed G sensor 1, a rotor 10 incorporated in the housing 2 is attached so as to be rotatable with respect to the shaft 7. Since the rotor 10 is a rotatable inertial weight, the rotor 10 is manufactured from a metal such as iron. In the illustrated example, the outer shape is elliptical. However, the shape of the rotor 10 is not limited to an ellipse, and may take other shapes. A hole 11 for fitting with the shaft 7 is formed at a position deviated from the center of gravity of the rotor 10. In addition, cylindrical boss portions 12 and 13 are integrally provided on both sides of the rotor 10 at the position of the hole 11 in order to reinforce and axially position and hold a coil spring described later.

  The rotor 10 that operates as an inertia weight inside the housing 2 can rotate within a small angle range around the shaft 7. However, since the rotor 10 is urged to rotate in one direction by the rotational force generated by the coil spring 14 mounted around the shaft 7, the inner surface of one wall 15 of the housing 2 is usually urged. Further rotation is prevented by being pressed against. In order to apply the rotational force generated by the spring 14 to the rotor 10, one end 16 of the spring 14 is inserted into a hole 17 provided in the rotor 10, while the other end 18 of the spring 14 is attached to the axis of the shaft 7 when assembled. Is applied to the notch groove 19 of the housing 2 after a twisting force (rotational force) is applied.

  Reference numeral 20 denotes a switching element mounted in the housing 2. For example, a small limit switch can be used as the switching element 20. Normally, the rotor 10 is stopped by being pressed against the inner surface of the one wall 15 of the housing 2 by the biasing force of the spring 14. Then, it rotates around the shaft 7 and contacts the switching element 20. As a result, the switching element 20 is electrically turned on to operate the airbag device. Although not directly related to the present invention, as the switching element 20, a magnetic switch or a semiconductor switch that closes the circuit when the rotor 10 approaches is used in addition to the element that operates by contact of the rotor 10. In some cases.

  In the conventional G sensor 1 shown in FIG. 9, the housing 2 is mounted in order to mount a semi-assembly made of a rotor 10 and a coil spring 14 that is twisted in the rotational direction and compressed in the axial direction into the housing 2. The main body part 3 and the lid part 4 are divided into two parts. The assembly in this case is performed using a special jig 21 shown in FIG. The jig 21 includes a substrate 25 having a recess 22 for placing and positioning the main body part 3 of the housing, a dummy shaft 23 that can protrude into the main body part 3 through a hole 9 formed in the main body part 3, and A coil spring 24 that can be pushed into the main body 3 and a long hole 26 that accommodates the coil spring 24 and guides it when the dummy shaft 23 is retracted are provided.

    In the assembly process of the G sensor 1 having the divided housing 2, the positioning is performed by fitting the main body portion 3 of the housing into the recess 22 on the substrate 25 of the jig 21. Thereby, the dummy shaft 23 of the jig 21 is aligned with the shaft hole 9 of the main body portion 3 and protrudes into the main body portion 3. The hole 11 of the rotor 10 is fitted to the dummy shaft 23 and the rotor 10 is positioned in the main body portion. Next, the coil spring 14 is loosely inserted into the dummy shaft 23 and the boss portion 12 of the rotor 10, and one end 16 of the spring 14 is inserted into the hole 17 of the rotor 10, and the other end 18 of the spring 14 is placed on the dummy shaft 23. By rotating, the spring 14 is twisted, and the other end 18 is hooked and fixed in a notch groove 19 provided in the main body portion 3.

  Further, the lid portion 4 of the housing is aligned so that the hole 8 is fitted to the tip of the dummy shaft 23, and the lid portion 4 is pushed down to compress the coil spring 14 in the axial direction of the dummy shaft 23. Is assembled to the main body 3. As a result, the plurality of protrusions 5 formed on the main body portion 3 are fitted into the holes 6 of the lid portion 4, so that the tips of the protrusions 5 are melted by heating and welded to the holes 6. In this way, the divided main body portion 3 and lid portion 4 are integrated to form the housing 2. Finally, the shaft 7 is press-fitted from the hole 8 of the lid portion 4, and the dummy shaft 23 is pushed back into the hole 26 of the jig 21 against the coil spring 24, and the shaft 7 is connected to the center of the coil spring 14 and the rotor 10. Since the G sensor 1 as a product is completed by passing through the hole 11 and inserting it into the hole 9 of the main body portion 3, the G sensor 1 is taken out from the recess 22 of the jig 21.

  However, in order to manufacture such a G sensor 1, in the case of taking a conventional divided structure of the housing 2 and an assembly process using the jig 21 having the dummy shaft 23, the main body of the housing 2 is used. A part for assembling the part 3 and the lid part 4 and joining them together by a method such as heat caulking, and a part such as the protrusion 5 of the main body part 3 and the hole 6 of the lid part 4 As described above, when the housing 2 is enlarged in order to sufficiently secure the strength of the joint portion made of the above, the G sensor 1 as a product becomes large and heavy as a whole.

  In order to solve this problem, it is necessary to form the main body portion 3 and the lid portion 4 from the beginning without dividing the housing 2, but in this case, the rotor 10 and the rotational direction and the axial direction are formed. In the prior art, it is difficult to press-fit the shaft 7 while inserting a semi-assembled object including a coil spring 14 given elastic deformation into the housing and maintaining the elastic deformation state of the spring 14. This is apparent from the reason that the housing 2 is divided into the main body portion 3 and the lid portion 4. However, this difficulty in the assembly process can be eliminated by using a holder 27 as shown in FIG. 5 which is an embodiment of the present invention described below.

  The details of the holder 27 will be described later. Here, the structure of the G sensor 29 having an integral housing 28 that needs to be assembled using the holder 27 and the procedure of the entire assembly process will be described. In this case, since the main body portion and the lid portion of the housing 28 are formed as a single body, the housing 28 can be manufactured as a small, light and thin wall. Accordingly, the housing 28 can be used by selecting various methods such as molding at once by injection molding of a synthetic resin material, manufacturing by press molding from a thin metal plate, or manufacturing by light metal die casting. it can.

  The procedure of the entire assembly process is shown in FIG. A single rotor 10 is placed on a temporary assembly jig 32 as shown in FIG. 2 in advance, and the hole 11 of the rotor 10 is fitted into a fixed dummy shaft 33 provided in the jig 32. Yes. In step A of FIG. 1, the coil spring 14 is loosely inserted into the boss portion 12 of the rotor 10 as shown in FIG. 2, and at the same time, one end 16 of the spring 14 is inserted into the hole 17 of the rotor 10. The half assembly 30 in this state is shown in step B in FIG. The process A in which the rotor 10 is placed on the temporary assembly jig 32 or the spring 14 is assembled thereto can be mechanically performed by means such as a robot hand.

  In step C, the other end 18 of the coil spring 14 has a claw 34 engaged therewith, and a winding head 31 as shown in FIG. 3 is lowered onto the jig 32 to fit the hole 35 into the dummy shaft 33. By being rotated in the state, it is wound up by a predetermined rotation angle. The other end 18 of the wound spring 14 is held by an F-shaped arm 36 attached to the jig 32. This state is shown in FIG. The arm 36 proceeds further to hold the entire spring 14. Note that the F-shaped arm 36 is mechanically operated by an automatic control device via a pneumatic or electromagnetic actuator (not shown) provided inside the jig 32.

  Since the spring 14 of the semi-attachment 30 that has undergone the process C is held in an elastically deformed state by the F-shaped arm 36 on the temporary assembly jig 32, this is referred to as an integral housing 28 in the process D. To attach to the holder, a holder 27 as shown in FIG. 5 is required. The semi-assembly 30 is held by the holder 27 while maintaining its posture, and is inserted into the housing 28 as in steps D to E shown in FIG.

  FIG. 5 shows the structure of the holder 27 that can be inserted into the housing 28 while holding the semi-assembly 30 while maintaining its posture. The holder 27 in the illustrated embodiment has four claws 37, 38, 39, and 40. The claw 37 may be fixed, but the other three claws 38 to 40 are movable. In this case, the movable claw 38 can move in parallel with the fixed claw 37 only on the axis named the X axis. On the other hand, the movable claw 39 can move in parallel with the fixed claw 37 only on the Y axis orthogonal to the X axis. The other movable claw 40 includes a movable claw 38 and includes a virtual plane that is orthogonal to the X axis and parallel to the Y axis, and includes a movable claw 39 that is orthogonal to the Y axis and parallel to the X axis. It can move parallel to the claws 37, 38, and 39 so that it lies on a straight line formed by orthogonal to the plane.

  Thereby, the fixed claw 37 and the movable claw 38 always form one plane including the X axis, and the fixed claw 37 and the movable claw 39 always form one plane including the Y axis. The movable claw 38 and the movable claw 40 always form a plane that translates perpendicularly to the X axis, and the movable claw 39 and the movable claw 40 always translates perpendicularly to the Y axis. Form.

  First, the base 41 of the fixed claw 37 is fixed to the substrate 45 which is the main body portion of the holder 27 so that the four claws 37, 38, 39, 40 always maintain such a relative positional relationship. ing. The base 42 of the movable claw 38 is configured to be able to slide along guide means such as a rail 46 fixed to the substrate 45 on the X axis. Similarly, the base 43 of the movable claw 39 is configured to be able to slide along guide means such as a rail 47 fixed to the substrate 45 on the Y axis. Further, the base 43 of the movable claw 39 and the base 44 of the movable claw 40 are configured so that they can always slide along guide means such as a movable rail 48 parallel to the X axis. . Furthermore, the base 42 of the movable claw 38 and the base 44 of the movable claw 40 are configured so that they can always slide along a guide means such as a movable rail 48 parallel to the Y axis. .

  In addition to those using such fixed rails 46 and 47 and movable rails 48 and 49, the parallel movement mechanism itself that can realize parallel movement based on two axes of the X axis and the Y axis orthogonal to each other is used. Various things have been known so far, and in the semi-assembled fixture of the present invention, it is possible to freely select and use the optimum one among them according to specific design conditions. In addition, since the present invention does not have a feature in the translation mechanism itself, the detailed structure of the translation mechanism itself is omitted here in order to avoid complicated explanation.

  The movable claw bases 42 to 44 are moved to positions instructed by an automatic control device (not shown) by a pneumatic actuator (not shown) that operates in the X-axis direction and the Y-axis direction. Thereby, the four claws 37 to 40 can hold the semi-assembly 30 when closed as shown in FIG. At this time, the triangular cutouts 50 formed in the movable claws 38 and 40 engage with the boss portions 12 and 13 at both ends of the rotor 10 as shown in FIG. Retained. At that time, the movable claws 39 and 40 approach the fixed claws 37 and the movable claws 38, so that the coil spring 14 is compressed in the axial direction as shown in FIG. Further, the other end 18 of the spring 14 held by the F-shaped arm 36 of the temporary assembling jig 32 maintains a state in which the spring 14 is twisted, and the movable claw as shown in FIG. It is held in the groove 51 formed in 39.

  In this manner, the semi-assembly 30 on the temporary assembly jig 32 is sandwiched and held between the claws 37 to 40 of the holder 27 while maintaining the posture. 45 is moved by means such as a robot hand (not shown), and the semi-assembly 30 is removed from the dummy shaft 33 of the jig 32 and inserted into the housing 28 as it is in the process D shown in FIG. Can be positioned. When the positioning is completed, the semi-assembly 30 is in a state as shown in step E, and the shaft 7 is press-fitted into the hole 52 of the housing 28 in the next step F. Since the assembly of the semi-assembly 30 is finished, the four claws 37 to 40 of the holder 27 are opened to release the semi-assembly 30 and, when the claws are extracted from the housing 28, the movable assembly 30 is movable. The other end 18 of the spring 14 held by the groove 51 of the claw 39 moves away from the groove 51 to a notch groove 19 formed in a part of the housing 28 and is locked thereby.

  Step G in FIG. 1 shows the completed G sensor 29, which particularly shows the operating state in which the rotor 10 contacts the switching element 20 by rotating around the shaft 7 under a large acceleration. ing.

  The semi-assembly holder of the present invention is not only used for assembling the G sensor 29 as in the illustrated embodiment, but generally has a similar structure and rotates on the shaft 7. The rotary component such as the rotor 10 that can be used and the spring such as the coil spring 14 that is assembled to the rotary component can be used when assembled into a housing or the like as a semi-assembly.

It is process drawing which shows the whole assembly process over time in order to demonstrate one Example of this invention. It is a perspective view which shows the jig | tool for temporary assembly | attachment. It is a side view which shows the winding process of a coil spring. It is a perspective view which shows the process of hold | maintaining the edge part of the coiled-up coil spring. It is a perspective view which illustrates the holder of the half assembly thing of the present invention. It is a perspective view which shows the holding state by a holder. It is a front view which shows the holding state by a holder. It is a side view which shows the holding state by a holder. The G sensor assembled | attached by a prior art is shown in the middle process, (A) is a perspective view which shows the state before attaching the cover part of a housing, (B) is an exploded perspective view of the part except the main-body part of the housing. It is. It is a perspective view which shows the jig | tool for temporary assembly used in a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Conventional G sensor 3 ... Divided housing body part 4 ... Divided housing lid part 7 ... Shaft 10 ... Rotor 14 ... Coil spring 16 ... One end 18 of spring ... Other end 19 of spring ... Notch groove DESCRIPTION OF SYMBOLS 20 ... Switching element 21 ... Conventional jig 23 ... Destroyed dummy shaft 27 ... Holder 28 of this invention ... Monolithic housing 29 ... Example G sensor 30 ... Semi-attachment 31 ... Winding head 32 ... Temporary assembly Jig 33 ... dummy shaft 36 ... F-shaped arm 37 ... fixed claw 38-40 ... movable claw 46-49 ... rail 50 ... triangular notch 51 ... groove for holding the end of the spring

Claims (1)

A rotor that protrudes in a flange shape from a cylindrical boss portion having a through hole and has a locking hole on the outer periphery;
A coil spring having one end engaged with the locking hole and the other end protruding outward;
A bottom wall, a pair of first side walls disposed opposite to each other on the bottom wall, a bearing hole formed in each of the pair of first side walls, and the pair of first side walls facing each other A second side wall provided on one side edge of the second side wall, wherein a notch groove is formed at an upper end of the second side wall, and a switching element is provided at a position facing the second side wall. A molded housing;
A shaft inserted into the through hole of the boss portion and the bearing hole of the housing;
Prepare
A substrate,
A first base fixed to the substrate, and a first claw provided so as to protrude from the first base substantially perpendicular to the substrate;
A first rail and a second rail provided extending from the first base in the X direction and the Y direction perpendicular to each other along the substrate;
A second base movably guided by a first actuator along the first rail;
A second claw projecting from the second base parallel to the first claw;
A third base guided movably by a second actuator along the second rail;
A third claw provided so as to protrude from the third base parallel to the first claw;
A third rail provided extending from the second base in parallel to the second rail;
A fourth rail provided extending from the third base in parallel to the first rail;
A fourth base guided movably along a third rail by a third actuator and movably guided along a fourth rail by a fourth actuator;
A fourth claw provided so as to protrude from the fourth base portion in parallel to the first claw;
With
The first to fourth claws are configured to translate along two axes orthogonal to each other,
A first cutout is formed on the first claw side of the second claw, a second cutout is formed on the third claw side of the fourth claw, and the third claw is formed. A holder having grooves formed on the fourth and first claw sides is prepared,
The coil spring is loosely inserted into the boss portion of the rotor, one end of the coil spring is locked in the locking hole, the coil spring is compressed, and the other end of the coil spring is connected to the axis of the coil spring. By rotating around, the coil spring is wound up by a predetermined angle to constitute a semi-attachment,
In this state, the first notch of the holder is engaged with the boss portion of the rotor and is gripped by the first claw and the second claw, and the second notch is held by the boss portion. The coil spring that is loosely inserted into the groove is held by the third claw and the fourth claw, and the other end of the coil spring wound up by a predetermined angle is engaged with the groove to hold the holding. Holding the semi-attachment with a tool,
The semi-attached product held by the holder is lowered from above the housing, and the through hole of the boss portion of the semi-assembled product coincides with the bearing hole formed in the pair of first side walls. The shaft was inserted into the pair of bearing holes and the through hole, and the first to fourth claws of the holder were opened to release the semi-attached product and locked in the groove. A method of manufacturing a G sensor, comprising: disengaging the other end of the coil spring and engaging the other end with a notch groove in the second side wall.

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