Inhibitor switch

Details Inhibitor switch Inhibitor switch

2002-04-17

2004-02-17

Luebke, Renee (Department: 2833)

Electricity: circuit makers and breakers

Special application

Actuated concurrently with operation or use of art device

Reexamination Certificate

active

06693249

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to an inhibitor switch.
2. Description of the Related Art
Conventional inhibitor switches are shown, for example, in FIG. 7 of Japanese Patent Laid-Open No. 293228/1996.
FIG. 7
shows a perspective view of an inhibitor switch.
As shown in
FIG. 7
, an inhibitor switch
101
is provided with a terminal block
103
, a casing
105
and a moving block
107
. The terminal block
103
is provided with a plurality of fixed contacts
109
.
The moving block
107
is provided with moving contacts
111
. The moving block
107
is supported to be rotatable relative to the terminal block
103
and a casing
105
. The moving block
107
is provided with a fitting hole
119
, which is fitted onto a manual shaft of an automatic transmission.
A body
121
of the moving block
107
is formed of a resin, and the moving contacts
111
are positioned on and heat clamped on the body
121
to be fixedly joined thereto. An example of such positioning and fixed joining is shown in FIG.
8
.
As shown in
FIG. 8
, the body
121
of the moving block
107
, which is generally formed of a resin, is provided with positioning projections
123
for positioning and caulking projections
125
for heat caulking. In
FIG. 8
, the caulking projections
125
have heads after heat caulking but are in the form of straight projections prior to heat caulking. The moving contacts
111
are provided with positioning holes
127
for positioning and caulking holes
129
for heat caulking. The positioning holes
127
of the moving contacts
111
are fitted onto the positioning projections
123
of the body
121
to be positioned on the body
121
, in which state the caulking projections
125
being fitted into the caulking holes
129
of the moving contacts
111
are heat clamped as shown in
FIG. 8
such that the moving contacts
111
are fixedly joined to the body
121
.
Accordingly, when the terminal block
103
is fixed on a housing of the automatic transmission and the manual shaft is fitted into the fitting hole
119
of the moving block
107
for use, the moving block
107
rotates together with rotation of the manual shaft. Rotation of the moving block
107
causes the moving contacts
111
to slide relative to the fixed contacts
109
so that the moving contacts
111
put the fixed contacts
109
in selective conducting condition at predetermined speed change positions. Accordingly, speed change positions of the automatic transmission can be electrically detected based on the relative rotation positional relationship of the fixed contacts
109
and the moving contacts
111
, conformed to rotation of the manual shaft.
Hereupon, the inhibitor switch
101
is mounted inside or outside the housing of the automatic transmission to be under severe conditions exposed to high temperatures. Accordingly, when the body
121
of the moving block
107
is generally formed of a resin, it undergoes some slight deformation or camber at the time of high temperature, which causes rotation of the moving contacts
111
to be behind rotation of the manual shaft, that is, angular hysteresis leading to a limit on enhancement of detection accuracy of speed change positions.
In contrast, it is possible to suppress deformation or camber at the time of high temperature with the use of a resin having an excellent heat resistance, but there has been caused a problem that a product is increased in cost as a whole because such resin is expensive.
Also, since positioning of the moving contacts
111
relative to the body
121
of the moving block
107
is performed by fitting the positioning holes
127
of the metallic fixed contacts
111
onto the positioning projections
123
of a resin provided on the body
121
as shown in
FIG. 8
, there has been caused a limit in enhancement of accuracy in positioning the moving contacts
111
on the body
121
. Further, since fixation of the moving contacts
111
to the body
121
is performed by heat caulking of the caulking projections
125
formed from a resin, not only is it difficult to manage the enhancement of the strength, but a large space is also needed for enhancing the strength in such fixation. In this regard, there is a limitation in ensuring a space in the inhibitor switch
101
which has little spatial margin. Accordingly, enhancement of accuracy in speed change positions has been limited in view of the above-mentioned problems.
SUMMARY OF THE INVENTION
The invention has its object to provide an inhibitor switch, of which positional accuracy is further enhanced.
In a first aspect, the invention provides an inhibitor switch comprising a terminal block with fixed contacts, and a moving block which is mounted and fitted onto a manual shaft of an automatic transmission, has moving contacts, and is rotatable relative to the terminal block, and for electrically detecting a speed change position of the automatic transmission on the basis of a relative rotating positional relationship of the fixed contacts and the moving contacts in accordance with rotation of the manual shaft, the moving block having a boss portion formed of a resin and being mounted on the manual shaft, and an arm-shaped contact support portion mounting thereon the moving contacts, the contact support portion being formed of metal and at least a part of the moving contacts being joined to the contact support portion by caulking.
In a second aspect, the invention provides an inhibitor switch according to the first aspect, wherein a positioning projection for positioning is formed on the contact support portion by means of a press, a positioning hole for positioning is formed on at least a part of the moving contacts, and the positioning hole is fitted onto the positioning projection to position at least a part of the moving contacts relative to the contact support portion.
In a third aspect, the invention provides an inhibitor switch according to the second aspect, wherein a caulking projection for caulking is formed on the contact support portion by means of a press, a caulking hole for the caulking is formed on at least a part of the moving contacts, and the caulking hole is fitted onto the caulking projection to effect the caulking.
In a fourth aspect, the invention provides an inhibitor switch according to any one of the first to third aspects, wherein the contact support portion has a joining hole, which is joined to the boss portion circumferentially.
In a fifth aspect, the invention provides an inhibitor switch according to any one of the first to fourth aspects, wherein a part of the moving contacts comprises a signaling contact formed of a leaf spring and the other part of the moving contacts comprises large capacity current-carrying contacts having a larger conductor cross sectional area than that of the signaling contact, the signaling contact is joined to an intermediate portion of the contact support portion by caulking, and a contact receiving portion formed of a resin is provided on a tip end side of the contact support portion farther than a position of the signaling contact and the large capacity current-carrying contacts are received in the contact receiving portion with biasing members therebetween to elastically bias the large capacity current-carrying contacts toward the fixed points.
The invention according to the first aspect comprises a switch housing having a terminal block with fixed contacts and a cover, and a moving block which is mounted and fitted onto a manual shaft of an automatic transmission, has moving contacts, and is rotatable relative to the switch housing, and can electrically detect a speed change position of the automatic transmission on the basis of a relative rotating positional relationship of the fixed contacts and the moving contacts in accordance with rotation of the manual shaft.
The moving block also has a boss portion formed of a resin and mounted on the manual shaft, and an arm-shaped contact support portion mounting thereon the moving contacts. The contact support portion is formed of metal and at least

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