CONTROL SWITCH FOR AUTOMATIC TRANSMISSION

CROSS REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority from prior Japanese Patent Application P2012-075469 filed on March 29, 2012; the entire contents of which are incorporated by reference herein.

BACKGROUND OF THE INVENTION

The present invention relates to a control switch for an automatic transmission in an automobile. The control switch generates position signals, which indicate shift positions such as parking, reverse, neutral, drive, second speed and first speed, by switching operations of a shift lever of the automatic transmission concerned.

Heretofore, as disclosed in Japanese Patent Laid-Open Publication No. 2007-155068 (hereinafter, referred to as Patent Literature 1) , a control switch to be described below has been known as a control switch for an automatic transmission. The control switch includes a movable body that rotationally moves in a housing in response to switching operations of a shift lever of the automatic transmission. Then, the control switch provides a movable point of contact on this movable body, and in addition, in the housing, provides a plurality of fixed points of contact, which are to be brought into contact with/opened from the movable point of contact in response to rotational movement positions of the movable body. Then, the control switch outputs position signals, which indicate shift positions of the automatic transmission, the shift positions corresponding to combinations of the fixed point of contact and the movable points of contact, the movable points of contact being brought into contact therewith or opened therefrom.

In this Patent Literature 1, an annular oil seal is housed in a bearing hole of a bearing portion formed in a cover that composes the housing, thereby enhancing sealing performance of the housing in the bearing portion and to enable to maintain air tightness of an inside of the housing.

SUMMARY OF THE INVENTION

However, in the conventional technology described above, the annular oil seal is simply housed in the bearing hole of the bearing portion, thereby enabling to maintain the air tightness of the inside of the housing. Therefore, it has been necessary to form the cover so that the bearing portion can become a perfect circle, and to thereby suppress the sealing performance from being lowered by movement of the housed oil seal, and the like. Thus, the above-described conventional technology has required processing accuracy of the cover, and accordingly, raised such a problem as the control switch for an automatic transmission cannot be manufactured with ease.

In this connection, it is an object of the present invention to obtain a control switch for an automatic transmission, which is easily manufacturable while enhancing the sealing performance of the housing in the bearing portion.

A first feature of the present invention is summarized to be a control switch for an automatic transmission, which has a movable body that rotationally moves in a housing in response to switching operations of a shift lever of the automatic transmission, provides a movable point of contact on the movable body, and in addition, provides, in the housing, a plurality of fixed points of contact, which are to be brought into contact with or opened from the movable point of contact in response to rotational movement positions of the movable body, and outputs position signals indicating shift positions of the automatic transmission, the shift positions corresponding to combinations of the fixed point of contact and the movable points of contact, the movable points of contact being brought into contact with or opened from the fixed point of contact, the control switch including: a housing that has a bearing portion in which a bearing hole is formed, the bearing hole allowing a shaft portion of the movable body to be inserted therethrough and to be freely rotatably pivoted therein; and an oil seal to be attached onto an attachment portion to be formed in a state where the shaft portion of the movable body is inserted through the bearing portion of the housing, wherein a fixing portion that fixes the oil seal is provided in the attachment portion.

A second feature of the present invention is summarized in that the fixing portion is a recessed portion that engages a part of the oil seal.

A third feature of the present invention is summarized in that the fixing portion is a through hole that engages a part of the oil seal.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded perspective view of a control switch for an automatic transmission according to an embodiment of the present invention.

FIG. 2 is a perspective view of the control switch for an automatic transmission according to the embodiment of the present invention.

FIG. 3 is an explanatory view showing operations of movable points of contact and fixed points of contact according to the embodiment of the present invention.

FIG. 4 is a perspective view of a movable body according to the embodiment of the present invention.

FIG. 5 is a perspective view showing an assembled state of the movable body and a shaft according to the embodiment of the present invention.

FIG. 6 is a perspective view showing a cover and an oil seal according to the embodiment of the present invention.

FIG. 7 is a perspective view enlargedly showing a fixing portion of the cover according to the embodiment of the present invention.

FIG. 8 is a cross-sectional view showing a state where the oil seal is attached to an attachment portion according to the embodiment of the present invention, the cross-sectional view being sectioned to include the fixing portion.

FIG. 9 is a cross-sectional view enlargedly showing a portion A in Fig. 8.

FIG. 10 is a cross-sectional view showing the state where the oil seal is attached to the attachment portion according to the embodiment of the present invention, the cross-sectional view being sectioned not to include the fixing portion.

FIG. 11 is a cross-sectional view showing a state where the oil seal is attached to an attachment portion according to a modification example of the embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A description is made below of an embodiment of the present invention in detail while referring to the drawings.

First, a description is made of a schematic configuration of a control switch 1 for an automatic transmission with reference to FIG. 1 to FIG. 3.

As shown in FIG. 1 and FIG. 2, the control switch 1 for an automatic transmission according to this embodiment includes: a housing 10; and a movable body 40 freely rotatably housed inside the housing 10.

The housing 10 includes a body 2 0 and a cover 30, each of which is made of a synthetic resin molded article formed into a substantially fan-like shape.

The movable body 4 0 includes: a main body 41; and a shaft portion 42 provided continuously with the main body 41 concerned. Then, a plurality of movable points of contact 47 elastically urged toward the body 2 0 by coil springs 46 are housed in a recessed portion (not shown) provided on a surface of the main body 41, which is opposite to the body 20. Note that, for the sake of convenience, FIG. 1 illustrates only one of the movable points of contact 47.

The shaft portion 42 includes : a cylinder portion 43 ; and a circular flange portion 44 formed around a center portion of the cylinder portion 43. Then, the cylinder portion 43 is provided continuously with the main body 41 through the flange portion 44. In this embodiment, the flange portion 44 is provided continuously and integrally with a lower portion in a thickness direction (axial direction) of the main body 41. The flange portion 44 is continuously provided in such a manner as described above, whereby a step difference portion 45 having an upper surface 45a, a lower surface 45b and a side surface 45c is formed in the movable body 40.

Moreover, as shown in FIG. 4 and FIG. 5, in the shaft portion 42 of the movable body 40, a press-fitting hole 43b is provided, which penetrates the shaft portion 42 along the axial direction, and has a shaft 7 0 of the automatic transmission press-fitted thereinto through a protection plate (not shown) . The press-fitting hole 43b includes an inner wall surface 43c having substantially the same shape as the cross section of a substantially polygonal shaft 70.

The body 2 0 is formed into a flat and substantially fan-like shapewith one surface thereof (upper surface in FIG. 1) made open. Then, in a portion of the body 20, which is equivalent to a pivot of a fan, a bearing hole 21 though which one end side (lower side of the cylinder portion 43 in FIG. 1) of the shaft portion 42 of the movable body 4 0 is to be inserted is provided so as to penetrate the portion concerned of the body 20 in the thickness direction (axial direction). Moreover, a peripheral edge portion 20f of the bearing hole 21 of the body 2 0 is formed so as to become lower by one step than a peripheral edge portion 2 0a of the body 20. Then, in an event where one end side (lower side of the cylinder portion 43 in FIG. 1) of the shaft portion 42 of the movable body 40 is inserted through the bearing hole 21, one end surface (lower surface in FIG. 1) of the flange portion 44 is supported on the peripheral edge portion 20f of the bearing hole 21 so as to be capable of being brought into sliding contact therewith, and the shaft portion 42 of the movable body 4 0 is rotatably and pivotally supported on the body 2 0.

Moreover, on an inner bottom surface 2 0b of the body 20, a plurality of band plate-like conductors 2 0d, in each of which a fixed point of contact 2 0c is provided on one end portion, are subjected to insert molding. The respective fixed points of contact 2 0c are arranged in a circular arc shape concentric about the bearing hole 21, and are opposed to the movable points of contact 47, which the movable body 4 0 includes, in the housing 10.

Furthermore, on the body 20, a cylindrical connector portion 22 surrounded by a peripheral wall is formed integrally therewith. On an inner bottom surface of the connector portion 22, tip ends of the plurality of conductors 20d are arranged in a plurality of lines so as to protrude therefrom, whereby a connector terminal (not shown) is formed.

As shown in FIG. 3 , when the movable body 4 0 in the housing 10 rotationally moves about the shaft portion 42, the movable point of contact 47 in a contact state with a pair of the fixed points of contact 20c arrayed in parallel to each other slides on a curved surface of one end portion of a rib 2 0e, while compressing the coil spring 46 by elastic deformation, and is opened from the fixed points of contact 20c. Then, coming to other end portion of the rib 2 0e while sliding on an upper surface of the rib 20e, the movable point of contact 47 falls down on another pair of the fixed points of contact 2 0c while sliding on the curved surface by elastic restoration force of the coil spring 46. Thus, the movable point of contact 47 held on the movable body 40 is selectively brought into contact with/opened from the respective fixed points of contact 20c in response to a rotational movement position of the movable body 4 0 relative to the housing 10. In such a way, a position signal corresponding to a shift position of the automatic transmission is taken out through a connectoron the other-side connected to the connector portion 22.

Moreover, as shown in FIG. 1 and FIG. 2, on both sides of such a pivot portion of the fan in the body 20, substantially mount-like collar portions 23 and 23 are formed integrally therewith. In each of the collar portions 23, a cylindrical reinforcement member 23b is subjected to insert molding. The reinforcement member 23b concerned allows penetration of an elliptical bolt insertion hole 23a through which a bolt for attaching the housing 10 to a vehicle body (or the automatic transmission) is to be inserted.

The cover 3 0 is formed into a substantially fan-like shape that covers an opening portion of the body 20. Then, in a portion of the cover 30, which is equivalent to a pivot of a fan, a bearing portion 31 is formed, which allows a bearing hole 31a to be drilled in a thickness direction thereof, the bearing hole 31a having an other end side (upper side of the cylinder portion 43 in FIG. 1) of the shaft portion 42 of the movable body 40 inserted therethrough.

In this embodiment, the bearing portion 31 includes a cylinder portion 32, and this cylinder portion 32 is composed of: a side wall portion 32a,- and a bottom wall portion 32b in which a circular insertion hole 32c is formed in a center portion. Thus, in this embodiment, the bearing hole 31a is formed of: the insertion hole 32c/ and an insertion hole 32d, which is formed inside the side wall portion 32a and is larger in diameter than the insertion hole 32c.

Moreover, with regard to such a fan portion of the cover 30, a center portion thereof becomes an upper step portion 33a higher by one step than a peripheral portion thereof, and a step difference portion 33 is formed of: this upper step portion 33a; and a lower step portion 33b on the periphery of the upper step portion 33a. Then, as shown in FIG. 10, in an inside of the upper step portion 33a, a housing space S is formed, in which the other end side (upper side in FIG. 1) of the main body 41 of the movable body 40 is rotatably housed.

Hence, in an event where the other end side (upper side of the cylinder portion 43 in FIG. 1) of the shaft portion 42 of the movable body 40 is inserted through the bearing hole 31a, an other end surface (upper surface in FIG. 1) of the flange portion 44 is slidably supported on one end surface (lower surface of FIG. 1) of the bottom wall portion 32b, and the shaft portion 42 of the movable body 4 0 is to be rotatably and pivotally supported on the cover 30.

Moreover, in a state where the shaft portion 42 of the movable body 40 is inserted through the bearing portion 31 of the cover 30 (housing 10) , a press-fitting portion (attachment portion) 60 for press-fitting (attaching) the oil seal 50 is to be formed.

Specifically, the press-fitting portion (attachment portion) 60 is formed of: an inner side surface 32e of the side wall portion 32a; an inner bottom surface (upper surface in FIG. 1) 32f of the bottom wall portion 32b; and an outer surface 43a of the cylinder portion 43. The press-fitting portion (attachment portion) 60 is formed so that the other end thereof (upper end in FIG. 1) can be made open.

Then, the annular oil seal 50 is press-fitted and attached into this press-fitting portion (attachment portion) 60 from the other end side (upper side in FIG. 1), whereby sealing performance of the housing 10 in the bearing portion 31 is enhanced to enable to maintain air tightness of the housing 10.

The control switch 1 for an automatic transmission configured as above, is assembled, for example, in the following manner.

First, the shaft portion 42 of the movable body 40 is inserted through the bearing portion 31 of the cover 3 0 (housing 10) . In such a way, the shaft portion 42 of the movable body 40 is rotatably and pivotally supported on the cover 30, and the other end side (upper side in FIG. 1) of the main body 41 of the movable body 4 0 is housed in the housing space S.

Next, the oil seal 50 is press-fitted (attached) into the press-fitting portion (attachment portion) 60 to be formed in a state where the shaft portion 42 of the movable body 4 0 is inserted through the bearing portion 31 of the cover 3 0 (housing 10) , whereby the sealing performance of the housing 10 in the bearing portion 31 is enhanced.

Then, the movable body 40 attaching the coil spring 46 and the movable point of contact 47 thereto is packaged on the inner bottom surface 20b of the body 20. Then, in this state, the peripheral edge portion 2 0a of the body 2 0 and a peripheral edge portion 3 0a of the cover 3 0 are welded to each other by an ultrasonic wave, whereby the body 2 0 and the cover 3 0 are joined to each other, and the housing 10 is formed. At this time, such a configuration may be adopted, in which a groove is formed on the peripheral edge portion 20a of the body 2 0 or the peripheral edge portion 3 0a of the cover 30, and a packing is arranged in the groove concerned, thereby to further enhance the sealing performance.

Then, the housing 10 is attached to the vehicle body (or the automatic transmission) by press-fitting the shaft 70 (refer to FIG. 5) through the protection plate (not shown) into the press-fitting hole 43b of the movable body 40, and tightening nuts to the bolts inserted through the bolt insertion holes 23a of the reinforcement members 23b.

In such a way, the shaft 70 and the movable body 4 0 rotationally move integrally with each other by a switching operation of a shift lever of the automatic transmission, and it is made possible to take out each position signal in response to the rotational movement position of the movable body 4 0 with respect to the housing 10. At this time, the air tightness of the housing 10 is maintained by the oil seal 50 and the like.

Here, in this embodiment, a fixing portion 61 that fixes the oil seal 50 is provided in the press-fitting portion (attachment portion) 60.

Specifically, a through hole 32g (fixing portion 61) that engages a part of the oil seal 50 is formed on a spot of the cover 30 which composes the press-fitting portion (attachment portion) 60.

In this embodiment, as shown in FIG. 7, the through hole 32g is formed in a spot including a boundary line (line of intersection) L between the inner side surface 32e of the side wall portion 32a and an inner bottom surface (upper surface in FIG. 1) 32f of the bottom wall portion 32b.

Specifically, as shown in FIG. 7 and FIG. 8, on an outer circumference side (boundary line L side) of the inner bottom surface (upper surface in FIG. 1) 32f, the through hole 32g is formed so as to become circular arc-shaped when viewed from the above, and is formed so as to penetrate the inner bottom surface 32f concerned in the axial direction. Moreover, on one end side (lower side in FIG. 1: boundary line L side) of the inner side surface 32e, the through hole 32g is formed so as to become rectangular when viewed from the side, and is formed so as to penetrate the inner side surface 32e concerned in a radial direction. Then, a through hole in the axial direction and a through hole in the radial direction are formed so as to communicate with each other, whereby the one through hole 32g is formed in the press-fitting portion 60. That is to say, the through hole 32g is formed so as to penetrate the region, which includes the boundary line L, in a diagonal direction (direction intersecting the axial direction: on one end side in the axial direction and an outside in the radial direction).

Moreover, in this embodiment, the through hole 32g is formed so as to communicate with the housing space S, and prevents the press-fitting portion (attachment portion) 60 from communicating with the outside through the through hole 32g itself.

Meanwhile, the oil seal 5 0 is formed of an elastic body, for example, such as rubber, and as shown in FIG. 8, formed into substantially an H shape in cross section thereof. Specifically, the oil seal 50 includes: an annular center support portion 51 formed in a center portion thereof; a cylindrical inner piece 52 provided continuously with an inside (inside in the radial direction) of this center support portion 51; and a cylindrical outer piece 53 provided continuously with an outside (outside in the radial direction) of the center support portion 51.

Then, when this oil seal 50 is press-fitted (attached) into the press-fitting portion (attachment portion) 60, and is moved to the one end side (lower side in FIG. 1) in the axial direction, one end (lower end in FIG. 8) of the outer piece 53 is engaged with the through hole 32g, and a periphery of the bearing portion 31 is sealed by the oil seal 50.

At this time, in the region including the boundary line L, the through hole 32g is formed so as to penetrate the region concerned in the diagonal direction (direction intersecting the axial direction: on the one end side in the axial direction and the outside in the radial direction) . Therefore, when the oil seal 50 is pushed toward the one end side in the axial direction, a component of force, which acts on the outside in the radial direction, is generated on the one end (lower end in FIG. 8) of the outer piece 53 in the vicinity of the through hole 32g. Then, by this component of force, the one end (lower end in FIG. 8) of the outer piece 53 is pushed into the through hole 32g and engaged with the through hole 32g.

Thus, if the through hole 32g is formed so as to penetrate the region, which includes the boundary line L, in the diagonal direction, then it is made possible to engage the one end (lower end in FIG. 8) of the outer piece 53 with the through hole 32g with ease only by pushing the oil seal 5 0 toward the one end side in the axial direction.

Incidentally, in the case where the fixing portion 61 is not provided in the press-fitting portion 60, then owing to a molding error of the cover 3 0 and a draft angle set by molding the cover 3 0 by using a metal mold, it has been apprehended that a dimension of the cover 3 0 may not be stabilized to thereby hold the oil seal 50 non-uniformly, and causing the oil seal 50 to move. In particular, in the case where the bearing portion 31 has a shape, which is shown in FIG. 10, it is apprehended that the oil seal 50 may come off from the press-fitting portion 60 over the whole circumference thereof, resulting in lowering of the sealing performance of the housing 10 in the bearing portion 31.

However, in this embodiment, the fixing portion 61 that fixes the oil seal 50 is provided in the press-fitting portion (attachment portion) 60. Hence, the oil seal 50 press-fitted (attached) into the press-fitting portion (attachment portion) 60 can be suppressed from coming off from the press-fitting portion (attachment portion) 6 0 concerned, and the sealing performance of the housing 10 in the bearing portion 31 can be suppressed from being lowered.

As described above, in this embodiment, the through hole 32g (fixing portion 61) is provided, which fixes the oil seal 50 to the press-fitting portion (attachment portion) 60 formed in the state where the shaft portion 42 of the movable body 4 0 is inserted through the bearing portion 31 of the cover 3 0 (housing 10) . Thus, the oil seal 50 is fixed to the through hole 32g (fixing portion 61) , whereby the oil seal 50 press-fitted (attached) into the press-fitting portion (attachment portion) 60 can be suppressed from moving.

Therefore, it becomes unnecessary to enhance a degree of roundness of the bearing portion 31 for the purpose of suppressing the sealing performance of the housing 10 in the bearing portion 31 from being lowered. That is to say, it becomes unnecessary to enhance processing accuracy of the cover 30. As a result, the control switch 1 for an automatic transmission can be obtained, which can be manufactured with ease while enhancing the sealing performance of the housing 10 in the bearing portion 31.

Moreover, in this embodiment, on the spot of the cover 30, which composes the press-fitting portion (attachment portion) 60, the through hole 32g is formed as the fixing portion 61 that engages a part of the oil seal 50. Therefore, a press-fitted state of the oil seal 50 and an engaged state thereof with the through hole 32g can be visually recognized from a back side (housing space S side) thereof. This enables the oil seal 50 to be press-fitted more reliably and to engage with the through hole 32g.

Note that, while FIG. 8 shows a state where the main body 41 of the movable body 4 0 is located at the spot where the through hole 32g is formed, the main body 41 is rotatably housed in the housing space S. Hence, if the main body 41 is rotationally moved, and the through hole 32g and the main body 41 (side surface 45c of the step difference portion 45) are prevented from overlapping each other in the radial direction, then the press-fitted state of the oil seal 50 and the engaged state thereof with the through hole 32g can be visually recognized from the back side (housing space S side) thereof. That is to say, it is preferable that the through hole 32g be formed so that the through hole 32g concerned and the main body 41 can establish a positional relationship, in which both thereof do not overlap each other in the radial direction at any position, in an event where the main body 41 is rotationally moved within a rotatable range thereof in the housing space S.

The description has been made above of the preferred embodiment of the present invention; however, the present invention is not limited to the above-described embodiment, and is modifiable in various ways.

For example, in the above-described embodiment, the fixing portion 61 is illustrated to be the through hole 32g; however, as shown in FIG. 11, the fixing portion 61 may be a recessed portion 32gA. Even if such a configuration is adopted, substantially similar functions and effects to those of the above-described embodiment can be exerted.

Also, in the above-described embodiment, the control switch is illustrated, in which the peripheral edge portion of the body and that of the cover are joined to each other by the ultrasonic welding. However, both of the peripheral edge portions may be joined to each other by using an adhesive.

In addition, the fixing portion (through hole or recessed portion) may be formed at two spots or more. In this case, only either one of the through hole and the recessed portion may be formed at the plurality of spots, or alternatively, at least one of each of the through hole and the recessed portion may be formed.

Moreover, the fixing portion may be formed on the shaft portion of the movable body.

Furthermore, it is also possible to appropriately change specifications (shapes, sizes, layout and the like) of the body, the cover, the press-fitting hole of the movable body, and other details.

What is claimed is:

[Claim 1]

A control switch for an automatic transmission, which includes a movable body that rotationally moves in a housing in response to switching operations of a shift lever of the automatic transmission, provides a movable point of contact on the movable body, and in addition, provides, in the housing, a plurality of fixed points of contact, which are to be brought into contact with or opened from the movable point of contact in response to rotational movement positions of the movable body, and outputs position signals indicating shift positions of the automatic transmission, the shift positions corresponding to combinations of the fixed point of contact and the movable points of contact, the movable points of contact being brought into contact with or opened from the fixed point of contact, the control switch comprising:

a housing that includes a bearing portion in which a bearing hole is formed, the bearing hole allowing a shaft portion of the movable body to be inserted therethrough and to be freely rotatably pivoted therein; and

an oil seal to be attached onto an attachment portion to be formed in a state where the shaft portion of the movable body is inserted through the bearing portion of the housing,

wherein a fixing portion that fixes the oil seal is provided in the attachment portion.

[Claim 2]

The control switch for an automatic transmission according to claim 1, wherein the fixing portion is a recessed portion that engages a part of the oil seal.

[Claim 3]

The control switch for an automatic transmission according to claim 1, wherein the fixing portion is a through hole that engages a part of the oil seal.