JP3573828B2 - Inhibitor switch shaft coupling structure - Google Patents

Description

[0001]
[Industrial applications]
The present invention relates to a shaft coupling structure of an inhibitor switch, and more particularly, to a structure in which a shaft holding portion of an inhibitor switch is engaged with a manual shaft or the like to rotate integrally.
[0002]
[Prior art]
The inhibitor switch is a rotary switch attached to the automatic transmission, and outputs an electric signal corresponding to a shift mode set in the automatic transmission by a shift lever. The inhibitor switch includes a shaft holding portion that is rotatably disposed through the switch housing, and a seal device that seals between the periphery of the shaft holding portion and the switch housing.
A rectangular parallelepiped convex portion (key projection) that meshes with the shaft-side key groove is formed in the shaft insertion hole that penetrates the rotation center of the shaft holding portion from end to end of the shaft holding portion.
The sealing device isolates internal electrical circuits and contacts from dust and moist air in the hood. A pair of the sealing devices is arranged on the side where the shaft is inserted and on the opposite side, and overlaps the convex portion of the rectangular parallelepiped back to back at two locations in the axial direction.
An example of such an inhibitor switch is disclosed in JP-A-3-179625. Here, there is shown an inhibitor switch of a type which is directly penetrated through a manual shaft of an automatic transmission having a key groove and is fixed to a housing of the automatic transmission.
[0003]
The shaft holding portion of the inhibitor switch can be manufactured by injection molding using a thermoplastic resin. In this case, if the width of the convex portion of the rectangular parallelepiped is set to be slightly larger than the width of the key groove, and the convex portion of the rectangular parallelepiped is compressed and fitted into the key groove of the shaft, the shaft holding portion is formed on the shaft. Being restrained without rattling, the shaft holding portion of the inhibitor switch follows the shaft well.
[0004]
[Problems to be solved by the invention]
When the shaft holding portion is injection-molded using a thermoplastic resin, a dent is generated on the outer surface of the shaft holding portion along the convex portion of the rectangular parallelepiped, and particularly, the seal is formed in a seal ring groove formed on the outer periphery of the shaft holding portion. When the ring is held, the sealing performance of the sealing device may be impaired by the influence of the bottom of the seal ring groove by the convex portion of the rectangular parallelepiped arranged back to back with the seal ring groove.
In other words, when the high-temperature resin is cooled and solidified in the mold, sink occurs due to shrinkage, but the surface of the member to be solidified first is pulled by the shrinkage inside the convex portion of the rectangular parallelepiped to be solidified later. A depression is formed at the bottom of the seal ring groove. On the depression, the seal ring groove is partially deepened, and there is a possibility that the sealing pressure between the seal ring and the housing is insufficient and the sealing performance is reduced.
[0005]
In addition, a material having little elastic deformation such as a fluororesin does not provide a repulsive force that fills the recess of the seal ring groove, and thus has a problem that the selection range of the material of the seal ring is narrowed.
[0006]
An object of the present invention is to provide a shaft coupling structure of an inhibitor switch in which the sealing performance of the sealing device is not impaired even when exposed to a severe environment, the life of the inhibitor switch is extended, and the reliability is improved.
[0007]
[Means for Solving the Problems]
The invention of claim 1 is disposed rotatably through the switch housing, and extending in the axial direction to mesh with the keyway of the shaft-side shaft insertion hole which is the center axis of the rotating cuboid a shaft holding portion forming a projecting portion which develops the appearance of, are a pair arranged on one end and the other end for inserting the shaft along the central axis direction of the shaft holding portion, the periphery of the shaft holding portion And a seal device that seals between the switch housings, wherein the top of the protrusion has a position overlapping with the seal device when viewed at least from a direction perpendicular to the central axis. A groove extending parallel to the central axis is formed, and the groove has a V-shaped cross section .
[0008]
According to a second aspect of the present invention, in the configuration of the first aspect, the convex portion continuously extends from a position beyond the seal device on a side of the shaft holding portion where the shaft is inserted, to an end on the other end side. It has been formed.
[0009]
According to a third aspect of the present invention, in the configuration of the first or second aspect, the axially extending groove is located at a position extending from the other end of the shaft holding portion to the sealing device at the other end. It is formed continuously up to.
[0010]
[Action]
In the shaft coupling structure of the inhibitor switch according to the first aspect, the guide performance of the key groove according to the width and height of the convex portion is the same as that of the conventional rectangular parallelepiped convex portion (key projection). However, at least in the axial position where the sealing device is disposed, an axial groove is formed at the top of the convex portion to reduce the wall thickness, and the sink when the material is solidified is reduced in portions other than the convex portion. , So that no serious depression is formed on the back surface of the projection. Thereby, the roundness on the outer peripheral side of the shaft holding portion, which has been damaged in the case of the conventional rectangular parallelepiped convex portion, is secured.
In addition, deformation of the projection itself (a depression on the surface or distortion of the overall shape, etc.) is small, and the amount of reduction in the width dimension due to solidification is small.
Further, since the convex portion has a low elastic coefficient in the width direction due to the deep groove, the frictional force with the key groove is reduced, and the shaft can be smoothly inserted.
[0011]
In the shaft connecting structure of the inhibitor switch according to the second aspect, since there is no convex portion up to a position beyond the sealing device when viewed from the side where the shaft is inserted, the inhibitor switch can be rotated to the manual shaft during the shaft inserting operation using this portion. Can be held.
In addition, on the back side of the seal device on the side where the shaft is inserted, the convex portion itself is eliminated to eliminate the influence of the convex portion on the roundness on the outer peripheral side of the shaft holding portion.
[0012]
In the shaft coupling structure of the inhibitor switch according to the third aspect, the portion from the front of the sealing device on the opposite side as viewed from the side where the shaft is inserted to the opposite end of the shaft holding portion extends in the axial direction to the convex portion. The grooves are formed continuously to ensure roundness of the outer peripheral portion of the shaft holding portion, and the elastic coefficient (spring constant) in the width direction of the convex portion is reduced to enable smooth insertion.
As for the portion before the sealing device on the opposite side as viewed from the side where the shaft is inserted, the convex portion is left thick, and much of the torque transmission for causing the shaft to follow the shaft holding portion is carried by the shaft.
[0013]
【Example】
An inhibitor switch according to an embodiment will be described with reference to FIGS. 1 is an explanatory diagram of the entire inhibitor switch, FIG. 2 is an explanatory diagram of a manual shaft, FIG. 3 is an enlarged view of a shaft holding portion, FIG. 4 is an explanatory diagram of a shape of a key projection, and FIG. 5 is a conceptual diagram of a resin molding process. is there.
In FIG. 1, (a) is an XX sectional view, and (b) is a plan view. 2, (a) is a plan view, (b) is a sectional view, and (c) is a front view. 3A is a plan view of a shaft holding unit, and FIG. 3B is a partial cross-sectional view of an inhibitor switch. 4A is a sectional view in the axial direction, FIG. 4B is a sectional view along AA, and FIG. 4C is a sectional view along BB. 5A shows an example, and FIG. 5B shows a comparative example.
The function of the inhibitor switch of the embodiment and the method of attaching the same to the automatic transmission are basically the same as those disclosed in JP-A-3-179625. In the inhibitor switch of the embodiment, the present invention is applied to a coupling structure of a manual shaft of the automatic transmission and a shaft holding portion of the inhibitor switch, more specifically, a key projection on an inner peripheral surface of the shaft holding portion.
[0014]
1A and 1B, a cover 11 is connected to a switch body 12 to which a wiring connector 14 is fixed, thereby forming a housing of an inhibitor switch. The connection surface between the switch body 12 and the cover 11 is sealed by a seal ring 16.
A rotator 13 is rotatably disposed through the switch body 12 and the cover 11. The rotor 13 is integrally formed with a shaft holding portion 13B for inserting and holding the manual shaft 10 and an arm 13A on which electric contacts are placed. A large number of electrical contacts arranged on the switch body 12 and electrical contacts of the arm 13A constitute a rotary switch.
The gap between the outer periphery of the shaft holding portion 13B and the switch body 12 is sealed by a seal ring 15B. The gap between the outer periphery of the shaft holding portion 13B and the cover 11 is sealed by a seal ring 15A.
[0015]
2 (a), 2 (b) and 2 (c), the manual shaft 10 inserted through the inhibitor switch has a double-sided portion 26 formed at the tip end protruding from the housing of the automatic transmission. In addition, a pair of front and back key grooves 25 is formed on the housing side with respect to the both side portions 26. A chamfer 25A is formed on the entrance side of the key groove 25 to facilitate guiding of the key projection when the inhibitor switch is inserted. The R-shaped end portion 25B is formed by releasing the blade to the sky when machining the key groove 25.
[0016]
The inhibitor switches shown in FIGS. 3A and 3B are inserted into the manual shaft 10 from the switch body 12 side. The rotor 13 integrally forms the arm portion 13A, the shaft holding portion 13B, the shaft insertion hole 13H, and the key projection 21 by injection molding of a thermoplastic resin. A pair of key projections 21 are formed in the shaft insertion hole 13H penetrating the shaft holding portion 13B. As shown in FIG. 4A, a chamfer 21C in which the width and height of the key projection 21 are changed in a slope is formed at the tip of the key projection 21 on the side where the manual shaft 10 is inserted. The guide of the key groove 25 when the inhibitor switch is inserted into the manual shaft 10 is smooth.
Further, since the key projection 21 is formed from a position beyond the seal ring 15B on the insertion side, even if the inhibitor switch is inserted to a position where the end 25B of the key groove 25 is hidden, the key projection 21 is not moved to the end 25B. Does not interfere with the bottom of the Therefore, it is also possible to apply an inhibitor switch to the stepped portion of the manual shaft 10 shown in FIG.
Further, by using the shaft insertion hole 13H up to the chamfer 21C, when the inhibitor switch is inserted into the manual shaft 10, the posture of the inhibitor switch can be automatically corrected vertically. At this time, with the inhibitor switch inserted into the manual shaft 10 shallowly and held rotatably, the key projection 21 is positioned in the key groove 25, and the inhibitor switch may be inserted further deeper.
[0017]
The intermediate portion 21A of the key projection 21 located between the seal ring 15A and the seal ring 15B is formed in a rectangular parallelepiped shape adapted to the key groove 25 of the manual shaft 10, as shown in FIG. . The entire width of the portion 21 </ b> A is formed to be thick, and most of the torque transmitted from the manual shaft 10 to the rotor 13 via the key protrusion 21 is handled here.
The outlet 21B of the key projection 21 located from a portion overlapping the seal ring 15A in the axial direction to the end on the cover 11 side forms an axial groove 21M in the top portion as shown in FIG. 4B. Thus, the thickness of the key projection 21 is reduced.
[0018]
In the inhibitor switch of the embodiment, as shown in FIG. 5A, the axial groove 21M is formed in the outlet 21B of the key projection 21 located on the back of the seal ring groove 13M of the rotor 13. During injection molding, the material layer is formed as shown by a broken line, and sinkage due to solidification and cooling of the material does not affect the roundness of the bottom surface 13P of the seal ring groove 13M. In addition, the deformation of the key projection 21 itself is reduced, and the decrease in the width dimension due to solidification is reduced.
On the other hand, in the comparative example of FIG. 5B, since the axial groove is not formed in the key protrusion 21E located on the back surface of the seal ring groove 13G, the thickness of the key protrusion 21E and the other portions are reduced. The thickness difference is large, the material layer is formed as shown by the broken line during injection molding, and the sink due to solidification and cooling of the material draws the bottom surface of the seal ring groove 13G toward the center to form a depression 13Q. In addition, the deformation of the key projection 21 itself is large, and the amount of decrease in the width dimension increases.
Therefore, the surface pressure of the contact surface of the seal ring 15B and the circumference of the cover 11 becomes substantially uniform, and even if the material of the seal ring 15B loses elasticity over a long period of time, the necessary sealing performance can be sufficiently exhibited. Further, even when the margin of the seal ring 15B is set small or the seal ring 15B is formed of a material having a low elasticity but a small friction coefficient to reduce the operation of the inhibitor switch, the necessary sealing performance is ensured. Further, the amount of decrease in the width dimension of the key projection 21 is reduced, so that the variation in the strength of fitting with the key groove 25 can be reduced.
[0019]
In the inhibitor switch of the embodiment, since the key projection 21 itself is not provided on the back side of the seal ring groove 13N, the inhibitor switch can be inserted to a position where the end portion 25B of the key groove 25 of the manual shaft 10 is hidden. Therefore, there is no need to cause the key groove 25 to interfere with the casing of the automatic transmission, and the inhibitor switch can be mounted close to the casing of the automatic transmission. In addition to the functions of the above-described axis alignment and guidance, the sink due to solidification and cooling of the material does not affect the roundness of the bottom surface of the seal ring groove 13N.
Further, since the axial groove 21M formed in the outlet 21B lowers the elastic modulus in the width direction of the key projection 21, the frictional force with the key groove 25 of the manual shaft 10 is reduced, and the key projection 21 is considerably reduced. Even when the rattling between the manual shaft 10 and the rotor 13 is eliminated as a tight compression fit, the inhibitor switch can be smoothly inserted into the manual shaft 10.
[0020]
FIG. 6 is an explanatory diagram of a modification of the embodiment. Here, a special shape is given to the side surface of the key projection 41. As shown in FIG. 6, small protrusions 41 </ b> A that are continuous in the axial direction are formed on the left and right side surfaces of the key protrusion 41 of the shaft holding portion 43. By holding the key projection 41 in the key groove 25 in a manner of elastically crushing the small projection 41A, rattling between the manual shaft 10 and the inhibitor switch is suppressed. Since the contact area between the key groove 25 and the key projection 41 is small, it is easy to insert the inhibitor switch into the manual shaft 10, and the assemblability of the inhibitor switch to the automatic transmission is improved.
[0021]
In the embodiment, the width of the key protrusion 21 is designed to be larger than the width of the key groove 25 by 0 to 3% so that the key protrusion 21 is tightly held in the key groove 25. For example, this intersection is assumed to be ± 1%. Alternatively, the key projections may be held more loosely in the key groove than in the embodiment. This facilitates the insertion of the inhibitor switch into the manual shaft 10.
Further, in the embodiment, the key projection 21 is formed from a position beyond the seal ring groove 13N when viewed from the side where the manual shaft 10 is inserted, but the key projection 21 is formed from one end of the shaft holding portion 13 to the other. The strength of the entire key projection 21 may be further increased.
Further, in the embodiment, the axial groove 21M is not formed in the intermediate portion 21A of the key protrusion 21. However, the axial groove 21M is formed from one end of the key protrusion 21 to the end of the key protrusion 21 to form the key protrusion 21. Ease of doing may be enhanced.
Further, in the embodiment, the key projections 21 are provided at two places 180 degrees apart from each other on the shaft holding portion 13. However, the key projections 21 are arranged at only one place, and the insertion resistance of the inhibitor switch with respect to the manual shaft 10 is reduced. May be halved.
In the embodiment, the shaft holding portion 13 is manufactured by injection molding of a thermoplastic resin, but may be manufactured by another manufacturing method using another material.
[0022]
In the embodiment, when viewed from the side where the manual shaft 10 is inserted, the key protrusion 21 is continuously formed from a position beyond the seal ring groove 13N on the near side to an end on the opposite side. The key projection 21 in the portion where the groove 21M is formed may not be formed.
Alternatively, the key projection 21 may be formed intermittently from end to end of the shaft holding portion 13B, avoiding only the back surface portions of the seal ring grooves 13M and 13N.
[0023]
【The invention's effect】
According to the first aspect of the invention, since the axial groove is formed at the top of the convex portion at the position overlapping with the sealing device in the axial direction, sink of the material generated in the molding process is reduced, and the shaft holding portion is formed. The roundness on the outer peripheral side is improved, and the sealing performance and reliability of the sealing device are improved.
Further, the range of choice of materials such as a seal ring used for the sealing device is expanded, and it becomes easy to design a light-weight operation and a small and light inhibitor switch.
Furthermore, since the amount of decrease in the width dimension of the convex portion can be reduced, the variation in the strength of fitting between the convex portion and the key groove can be reduced.
Further, since the convex portion has a low elastic coefficient in the width direction due to the deep groove, the frictional force with the key groove is reduced, and the shaft can be smoothly inserted.
[0024]
According to the second aspect of the present invention, the inhibitor switch is rotatably held by inserting the inhibitor switch into the shaft to such an extent that the projection is not restrained by the key groove, so that the key groove and the linear projection can be aligned. Can be easily and reasonably implemented. Since the position of the inhibitor switch is automatically adjusted vertically with respect to the shaft at the initial stage of insertion, there is no fear that the inhibitor switch is inserted obliquely and the convex portion or the like is damaged.
In addition, since the projection itself does not exist on the back side of the sealing device on the side where the shaft is inserted, the roundness of the outer peripheral side of the shaft holding portion is improved, and the sealing performance and reliability of the sealing device are improved.
[0025]
According to the third aspect of the present invention, since the groove that is continuous in the axial direction is formed in the protrusion, the elastic coefficient (spring constant) in the width direction of the protrusion decreases, and the inhibitor switch is inserted into the manual shaft with low resistance. it can.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of an entire inhibitor switch.
FIG. 2 is an explanatory view of a manual shaft.
FIG. 3 is an enlarged view of a shaft holding unit.
FIG. 4 is an explanatory diagram of a shape of a key projection.
FIG. 5 is a conceptual diagram of a resin molding process.
FIG. 6 is an explanatory diagram of a modification of the embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Manual shaft 11 Cover 12 Switch body 13, 33, 43 Rotor 13A Arm part 13B Shaft holding part 13H Shaft insertion hole 13M, 13N, 13G Seal ring groove 13P Bottom 13Q Recess 14 Connector 15A, 15B Seal ring 21, 31, 41 , 21E Key projection 21A Intermediate part 21B Exit part 21C Chamfer 21M Groove 25 Key groove 25A Chamfer 25B End 26 Double-sided part 41A Projection

Claims (3)

Through the switch housing is arranged rotatably, convex which develops the central axis extending parallel to and cuboid appearance to mesh with the keyway of the shaft-side shaft insertion hole which is the center axis of the pivot A shaft holding portion forming a portion,
A pair of sealing devices that are disposed at one end and the other end of the shaft holding portion along the center axis direction where the shaft is inserted, and seal between the periphery of the shaft holding portion and the switch housing. In an inhibitor switch having a shaft coupling structure,
A groove extending parallel to the central axis at the top, at a position overlapping the sealing device when viewed from at least a direction perpendicular to the central axis, of the convex portion ,
A shaft coupling structure for an inhibitor switch, wherein the groove has a V-shaped cross section . 2. The projection according to claim 1, wherein the protrusion is formed continuously from a position beyond the seal device on a side of the shaft holding portion where the shaft is inserted, to an end on the other end side. 3. Shaft coupling structure of inhibitor switch. The groove extending in the axial direction is formed continuously from an end on the other end side of the shaft holding portion to a position beyond the seal device on the other end side. 3. A shaft coupling structure of the inhibitor switch according to 2.

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