JP4864018B2 - Housing fixing structure and housing fixing method - Google Patents

Description

  The present invention relates to a housing fixing structure and a housing fixing method, and more particularly to a housing fixing structure and a housing fixing method suitable for fastening and fixing a resin housing to a fixing structure.

When a resin housing containing various sensors and actuators is fastened and fixed to a fixed structure, a plurality of fastening portions having insertion holes through which fixing members such as screws are inserted are formed in the housing, and the insertion holes of the fastening portions are formed. In general, a screw inserted through the screw is screwed into a screw hole formed in the fixed structure, and the screw is tightened. Such a housing fixing structure is described in Patent Document 1 below, for example.
Japanese Patent Laid-Open No. 11-223508

  However, according to the housing fixing structure described in Patent Document 1, when a screw is tightened, an axial force and a rotational moment act on the fastening portion, and stress is applied to the fastening portion by the action of the rotational moment, and the fastening portion is tightened. In some cases, it may be difficult to securely fix the portion due to deformation or displacement.

  In order to prevent such fastening failure of the fastening part, it is possible to take measures to increase the thickness of the fastening part and increase the strength of the fastening part. However, in this case, the amount of resin used in the fastening portion increases and the cost increases. Moreover, the outer diameter dimension of a fastening part becomes large and the freedom degree of the layout of a housing falls.

  The present invention has been made to solve such a problem, and its purpose is to increase the thickness of the fastening portion when the fixing member is inserted into the fastening portion and the housing is fastened and fixed to the fixing structure. It is an object of the present invention to provide a housing fixing structure and a housing fixing method capable of preventing a fixing failure of a fastening portion associated with tightening and fixing.

In the present invention, when a fixing member inserted through an insertion hole is fastened to a fastening portion having an insertion hole formed around a resin housing and the housing is tightened and fixed to a fixed structure , a metal is inserted into the insertion hole. the tubular member formed in a cylindrical shape is decorated by combining winding a plate, a plurality of protrusions on the end surface in the axial direction bite into the stationary structure of the tubular member is formed, among the plurality of projections At least one is characterized in that it is formed at a position adjacent to the winding surface of the cylindrical member .

According to the present invention, it is possible to prevent the fastening portion from being poorly fixed when the housing is fastened and fixed to the fixed structure without increasing the thickness of the fastening portion.
In addition, even when a rotational moment acts on the winding surface of the cylindrical member when the fixing member is tightened, the protruding portion located adjacent to the winding surface bites into the fixed structure, so that the cylindrical member is wound together. Opening from the surface is prevented. This prevents the cylindrical member opened from the winding surface from being pressed against the housing, and prevents the cylindrical member opened from the winding surface from being pressed against the housing, resulting in poor fixing of the fastening portion. Is done.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a perspective view showing a state in which a housing is fastened and fixed to a fixed structure. FIG. 2 is a plan view illustrating a mechanism housed in the fixed structure. FIG. 3 is a longitudinal side view showing the detection sensor. FIG. 4 is a plan view showing the detection sensor. FIG. 5 is a perspective view showing the housing. FIG. 6 is a perspective view showing a cylindrical member. FIG. 7 is a vertical cross-sectional side view showing a state in which the protruding portion bites into the fixed structure. FIG. 8 is a perspective view for explaining the shape of the protrusion.

  As shown in FIG. 1, for example, a fixed structure 1 fixed to an end portion of a cylinder head (not shown) of an internal combustion engine is provided, and a housing 2 is fastened and fixed to the fixed structure 1.

  In a cylinder head (not shown), an intake valve (not shown), an exhaust valve (not shown), a control shaft 4 that adjusts the lift amount of the intake valve by being rotationally driven around the shaft center, and the like are housed. A motor 3 which is a drive mechanism for rotating the control shaft 4 is provided.

  The fixed structure 1 is formed by, for example, an aluminum alloy by a die casting method, and in this fixed structure, a ball screw shaft connected to a motor shaft 3a of a motor 3 via a connecting member 5 as shown in FIG. 6, a ball nut 7 screwed onto the ball screw shaft 6, a link member 8 having one end pivotably connected to the ball nut 7, and a linkage arm pivotally connected to the other end of the link member 8 9 is stored. The linkage arm 9 is fixed to a mounting flange 4 a provided at the end of the control shaft 4 with a bolt 10. The ball screw shaft 6 is pivotally supported by bearings 11a and 11b at both ends.

  For this reason, when the motor 3 is driven and the ball screw shaft 6 rotates around the axis, the ball nut 7 moves on the ball screw shaft 6 along the axial direction. As the ball nut 7 moves, the link member 8 and the linkage arm 9 rotate. Further, when the linkage arm 9 rotates, the control shaft 4 is driven to rotate within a predetermined rotation angle range between a minimum angle position and a maximum angle position defined by a stopper (not shown) around the axis. Thus, by changing the operating angle of the control shaft 4 with the motor 3, the lift amount and operating angle of an intake valve (not shown) are continuously changed. And this rotation is detected by the detection sensor 12 mentioned later.

  The detection sensor 12 is provided on the front end side of the control shaft 4 and detects, for example, a target rotation angle calculated from an engine operating state such as an accelerator opening degree and a rotation speed of the internal combustion engine accompanying a driver output request. The control device 26 feedback-controls the motor 3 so that the actual rotation angle detected at 12 matches the target rotation angle. Here, since the lift amount and the operating angle of the intake valve can be changed simultaneously by controlling the rotation angle of the control shaft 4, the detection sensor 12 functions as a sensor for detecting the lift amount at the same time as detecting the operating angle of the intake valve. FIG. 9 is a graph showing how the intake valve lift amount (vertical axis direction) and the operating angle (horizontal axis direction) change simultaneously.

  The rotation angle detected by the detection sensor 12 is a value that correlates with the maximum lift amount during the valve opening period of the intake valve or the operation angle of the intake valve. Based on this detected value, the control shaft 4 is It becomes possible to control the rotation to the target rotation angle.

  As shown in FIG. 3, the linkage arm 9 is formed with a protruding portion 9 a that is positioned coaxially with the control shaft 4 and protrudes in the opposite direction to the control shaft 4. And the synthetic resin material holding | maintenance part 13 which is a nonmagnetic material is integrally fixed to the front-end | tip part of the protrusion part 9a by injection molding, for example.

  The holding part 13 is formed in a substantially cylindrical shape having the same diameter as the protruding part 9a, and a holding groove 13a is formed at the tip part. As shown in FIG. 2, the holding groove 13 a is formed such that a part of the opposed inner surface has a substantially parallel straight two-sided width, and a part of the detection sensor 12 that detects the rotational position of the control shaft 4 inside thereof. A plate-like permanent magnet 14 is held and fixed. The holding groove 13 a is set to have a depth dimension larger than the thickness dimension of the permanent magnet 14.

  Therefore, the permanent magnet 14 is positioned and positioned by the peripheral wall 13c of the holding groove 13a by being housed and held in a form embedded in the holding groove 13a.

  Further, the permanent magnet 14 is not limited to be held in the holding groove 13a, and may be attached to the control shaft 4 or the tip of the protruding portion 9a. .

  The housing 2 is provided with a magnetic detection unit 15 that constitutes a part of the detection sensor 12. When the housing 2 is fixed to the fixed structure 1, the magnetic detection unit 15 and the permanent magnet 14 face each other. In addition, the detection sensor 12 is schematically configured.

  The housing 2 is formed with a substantially cylindrical groove 16 into which the permanent magnet 14 and the holding portion 13 enter when the housing 2 is fixed to the fixed structure 1, and the magnetic detection unit 15 includes the cylindrical groove 16. It is formed in a surrounding shape. When the permanent magnet 14 entering and positioned in the groove 16 rotates with the rotation of the control shaft 4, the magnetic detection unit 15 detects the magnetic field from the N pole and the S pole that change due to the rotation of the permanent magnet 14. The detection signal is output to the control device 26 that controls the rotation of the motor 3.

  As shown in FIG. 3, the housing 2 is formed with a recess 2a that opens upward, and a magnetic detector 15 is formed by mounting electronic components such as a capacitor in the recess 2a. . A cover 2b bulging in a dome shape is attached so as to cover the opening of the recess 2a.

  Further, a connector 2c is provided at one end of the housing 2, and a detection result (voltage) is externally output via the connector 2c and an external connector (not shown) coupled to the connector 2c. It is like that.

  The magnetic detection unit 15 includes a pair of yokes 15 a and 15 b made of a magnetic material provided opposite to each other on the outer periphery of the permanent magnet 14 that rotates in conjunction with the control shaft 4. The yokes 15a and 15b are formed in an arc shape centering on the rotation center M of the permanent magnet 14, and are configured to face each other with the two parallel hall elements 15c and 15d interposed therebetween.

  The range used for angle detection includes the mounting direction (magnetization direction) of the permanent magnet 14 with respect to the control shaft 4 serving as a detection symmetry axis, the arrangement of the yokes 15a and 15b, and the mounting angle of the housing 2 with respect to the fixed structure 1 ( It can be set or adjusted as appropriate by changing the (rotating posture) or the like.

  Further, in order to perform adjustment (particularly fine adjustment) such as the mounting angle (rotation posture) of the housing 2, a pair of fastening portions 17 are formed on the outer peripheral portion of the housing 2 as shown in FIG. The fastening portion 17 has a long hole-shaped insertion hole 18 that follows a circular arc centered on the rotation center M, and has a flange portion 19 formed of a resin material integrally with the housing 2. The bush 20 which is a metal cylindrical member is internally provided by press-fitting.

  The mounting angle of the detection sensor 12 in the present embodiment is a control reference position within a predetermined rotation angle range between the minimum angle position and the maximum angle position specified by the stopper, and is mounted at a specified voltage output position. And

  Further, a long hole-shaped hollow portion 20a is formed inside the bush 20, and a screw 23 described later is inserted into the hollow portion 20a.

  As shown in FIG. 6, the bush 20 is formed in a cylindrical shape by winding a long metal plate, and a portion where two end surfaces of the wound metal plate face each other is a winding surface 21. .

  As shown in FIG. 7, the fixing of the housing 2 to the fixing structure 1 is performed by inserting a screw 23 as a fixing member into the hollow portion 20a of the bush 20 via a washer 22, and this screw 23 is fixed to the fixing structure. 1 is carried out by screwing into the screw hole 24 formed in 1.

  A plurality of protrusions 25 are formed on one end surface of the bush 20 in the axial direction and on the surface facing the fixed structure 1 when the housing 2 is fastened and fixed to the fixed structure 1. Yes. The protrusion 25 is formed in a shape that bites into the fixed structure 1 when the housing 2 is fastened and fixed to the fixed structure 1 by tightening the screw 23. For example, a rectangular parallelepiped shape as shown in FIG. 8A may be used, or a shape in which the inclined surface portion 25a is formed on one side along the circumferential direction of the end face of the bush 20 as shown in FIG. Alternatively, as shown in FIG. 8C, the inclined surface portions 25a may be formed on both sides of the end surface of the bush 20 along the circumferential direction.

  8A, 8 </ b> B, and 8 </ b> C, the area of the protrusion 25 that contacts the fixed structure 1 is the sum of the areas, and the housing 2 is fastened to the fixed structure 1. In the case of attaching and fixing, the protrusion 25 is set to have an area equal to or less than the surface pressure that can bite into the fixing structure 1.

  As shown in FIG. 7, the dimension “a” in the axial direction of the portion of the bush 20 where the protrusion 25 is formed is larger than the dimension “b” in the axial direction of the insertion hole 18. The dimension “b” in the axial direction of the insertion hole 18 is the same as the thickness dimension of the flange portion 19. For this reason, when one end face of the bush 20 in the axial direction and one end face of the flange portion 19 are aligned and positioned, the other end face of the bush 20 in the axial direction is the other end face of the flange portion 19. More prominent.

  The bush 20 is formed of a metal having a higher strength than the aluminum alloy forming the fixed structure 1, for example, an iron material such as a cold rolled steel plate (SPCC).

  Next, when the housing 2 is fastened and fixed to the fixed structure 1, a contact area of the protrusion 25 with the fixed structure 1 necessary for the protrusion 25 to bite into the fixed structure 1 will be described.

  The fixed structure 1 employed in the present embodiment is made of an aluminum alloy formed by an aluminum die casting method and has a limit buckling stress of 200 MPa. The screw 23 used for tightening and fixing is an M6 screw, and the minimum value of the fastening torque is 5 N · m.

When obtaining the axial force acting on the protrusion 25 at the time of fastening and fixing from the fastening torque,
Axial force = fastening torque / (screw constant 0.2 × screw diameter) = 4200N.

Furthermore, from this axial force, the area (S) of the protrusion 25 required for the protrusion 25 to bite into the fixed structure 1 is:
S ≦ 4200 N / 200 MPa = 21 mm ² .

That is, in order to allow the protrusions 25 to bite into the fixed structure 1 when the housing 2 is tightened and fixed, the total area of the plurality of protrusions 25 in contact with the fixed structure 1 may be 21 mm ² or less. I understand.

  The protrusions 25 in the bush 20 need only be formed so that the plurality of protrusions 25 are separated from each other, and the separation distances need not be equal. One of the plurality of protrusions 25 is formed at a position sandwiching the winding surface 21 adjacent to the winding surface 21 of the bush 20 formed by winding metal plates.

  In such a configuration, when the housing 2 is fastened and fixed to the fixed structure 1, the housing 2 is positioned at a fastening fixing position with respect to the fixed structure 1, and the screw 23 is inserted into the hollow portion 20 a of the bush 20. The screw 23 is tightened.

  When the screw 23 is tightened, an axial force and a rotational moment act on the bush 20. Here, since the dimension “a” in the axial direction of the bush 20 is larger than the dimension “b” in the axial direction of the insertion hole 18, when the screw 23 is tightened, the end face of the projection 25 in the bush 20 is the flange 19. It contacts the surface of the fixed structure 1 prior to the end face of. Further, the bush 20 is formed of a metal having a higher strength than the fixed structure 1, and the area of the protruding portion 25 in contact with the fixed structure 1 projects by fixing the housing 2 to the fixed structure 1. Since the portion 25 is set to be equal to or less than an area that is a surface pressure that can bite into the fixed structure 1, the protruding portion 25 of the bush 20 bites into the fixed structure 1 and is fixed by the axial force acting on the bush 20. Since a plurality of protrusions 25 are formed on the bush 20, when these protrusions 25 bite into a plurality of locations on the surface of the fixed structure 1, a resistance against a rotational moment acting on the bush 20 is generated. Even if a rotational moment acts on the bush 20, the bush 20 does not rotate.

  Therefore, when the housing 2 is fastened and fixed, the bush 20 is prevented from moving in the direction in which the rotational moment acts, and the stress acting on the flange portion 19 from the bush 20 is suppressed. For this reason, when the housing 2 is fastened and fixed, a large stress is prevented from acting on the flange portion 19 from the bush 20, and the flange portion 19 is deformed or displaced due to the large stress, and the fastening portion 17. Is prevented from being poorly fixed.

  Thereby, the fixing failure of the fastening portion 17 when the housing 2 is fastened and fixed to the fixed structure 1 can be prevented by a simple structure in which the protrusion 25 is formed on the end surface of the bush 20.

  Moreover, it is not necessary to increase the thickness of the flange portion 19 by increasing the thickness of the flange portion 19 in order to prevent the fastening portion 17 from being poorly fixed, and the amount of resin used to form the flange portion 19 is suppressed. Cost reduction. Further, an increase in the outer diameter dimension of the flange portion 19 can be suppressed, and an increase in the outer diameter dimension of the housing 2 can be suppressed, and the degree of freedom in the layout of the housing 2 can be increased.

  Further, since the bush 20 is formed in a cylindrical shape by winding metal plates, the manufacturing cost of the bush 20 can be suppressed.

  One of the plurality of protrusions 25 formed on the bush 20 is formed at a position adjacent to the winding surface 21 of the bush 20 and sandwiching the winding surface 21, so that the screw 23 is tightened Even if a rotational moment acts on the portion of the bush 20 that sandwiches the winding surface 21, the protrusions 25 that sandwich the winding surface 21 bite into the fixed structure 1. Opening is prevented. This prevents the bush 20 opened from the location of the winding surface 21 from being pressed against the flange portion 19, and the bush 20 opened from the winding surface 21 is pressed against the flange portion 19, causing the fastening portion 17 to be improperly fixed. Is prevented.

  In the present embodiment, the fastening portion 17 including the flange portion 19 and the bush 20 press-fitted into the insertion hole 18 of the flange portion 19 is described as an example, but the bush is not used. The flange portion having the insertion hole may be used as the fastening portion. In this case, a protrusion is formed on the surface of the flange portion that contacts the fixed structure. In this case, the fixed structure is formed of a resin having a lower strength than the flange portion. When the housing is fastened to the fixed structure, the protrusion formed on the flange portion bites into the fixed structure. Is possible.

  In the present embodiment, the bush 20 formed by winding a metal plate is described as an example of the metal cylindrical member. However, the cylindrical member is formed by winding a metal plate. For example, it may be formed by casting.

It is a perspective view which shows the state which clamped and fixed the housing in one embodiment of this invention to the fixed structure. It is a top view explaining the mechanism accommodated in the fixed structure. It is the sectional view on the AA line in FIG. (A) is a top view which shows a detection sensor, (b) is a vertical side view which shows a detection sensor. It is a perspective view which shows a housing. It is a perspective view which shows a bush. It is a vertical side view which shows the biting state of the projection part to a fixed structure. It is a perspective view explaining the shape of a projection part. It is a graph which shows a mode that the lift amount and operating angle of an intake valve change simultaneously.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Fixed structure 2 ... Housing 17 ... Fastening part 18 ... Insertion hole 20 ... Bush (tubular member)
23 ... Screw (fixing member)
25 ... Protrusions

Claims (5)

In a housing fixing structure in which a fastening portion having an insertion hole is formed around a resin housing, and the housing is clamped and fixed to a fixing structure by fastening a fixing member inserted through the insertion hole.
A cylindrical member formed in a cylindrical shape by winding a metal plate around the insertion hole, and the housing is fastened and fixed to the fixing structure on the end surface in the axial direction of the cylindrical member A plurality of protrusions that bite into the fixed structure are formed ,
At least one of the plurality of protrusions is formed at a position adjacent to a winding surface of the cylindrical member . Housing fixing structure according to claim 1, wherein the dimension in the axial direction, characterized in that largely formed from axial dimension of the insertion hole of the tubular member. The tubular member, housing fixing structure according to claim 1 or 2, wherein in that it is formed by a high strength than the fixed structure metal. Wherein the surface product that Sessu the fixed structure of the protrusions is set to the housing below the area where the protruding portion becomes a surface pressure Kuikomeru to the fixed structure when the fastening fixed to the fixed structure The housing fixing structure according to any one of claims 1 to 3 , wherein the housing fixing structure is provided. A fastening portion having an insertion hole is formed around a resin housing, and a cylindrical member formed into a cylindrical shape by winding a metal plate around the insertion hole is installed, and the fixing is inserted through the cylindrical member. In a housing fixing method for tightening and fixing the housing to a fixed structure by tightening a member,
Wherein when tightening the fixing member, of the plurality of projections formed on the end surface in the axial direction of the tubular member, at least one protrusion that is formed at a position adjacent to the winding mating surface of the tubular member A housing fixing method characterized by causing the fixing structure to bite into the housing.

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