Connection structure for resistive element

Staking and soldering are eliminated to improve workability in assembly. A connection structure for a resistive element, in which the resistive element having lead wires at both ends is connected to a connection section of a base. A cover is fixably mounted on the base. Further, fixation claws capable of snap-holding the resistive element by elastic force and elastic tongues along lead wires are arranged on the cover. When the cover is fixed to the base, the elastic tongues are in elastic contact with the connection section through the lead wires to press the lead wires to the connection section.

BACKGROUND OF THE INVENTION

The present invention relates to a connection structure to resistive element employed for a lever switch device of an automobile.

The aforementioned connection structure for resistive element as shown inFIGS. 10 and 11has been known.FIG. 10is a sectional view showing a portion of an operation lever of a lever switch including the connection structure for resistive element.FIG. 11is a plan view supplementarily showing a base.

Referring toFIG. 10, the lever switch device with an operation lever101is provided for a combination switch installed in the steering column. The operation lever101includes a base103, first, second and third levers105,107and109, and first and second rotary knobs111and113. The operation lever101is operated to activate a turn signal switch and a headlight selector switch. Then the first rotary knob111is operated to drive the wiper washer switch, and the second rotary knob113is operated to drive the fog lamp switch.

A slide switch for executing a cruise control is provided at a top end (out of view from the left side ofFIG. 10) of the operation lever101. The base103is provided with a terminal116for transmitting an electric signal upon operation of the slide switch. The connection section117of the terminal116is provided with a resistive element119(seeFIG. 11).

The resistive element119is attached to the connection section117through staking and soldering. That is, lead wires121at both ends of the resistive element119are calked and soldered to the connection sections117. This makes it sure to connect the resistive element119to the terminal116.

In the aforementioned connection structure, a large number of steps are required for attaching the resistive element119, thus limiting to improve the workability in assembly. Patent Document 1: Japanese Unexamined Patent Application Publication No. 2002-313191.

SUMMARY OF THE INVENTION

The limit to improve the workability in assembly is intended to be solved.

The present invention is characterized in that a cover which may be fixed to the base is provided with a retaining portion capable of retaining the resistive element and an elastic portion along the lead wire. When the cover is fixed to the base, the elastic portion elastically pushes the lead wire against the connection section.

In the connection structure for resistive element, a cover allowed to be fixed to the base is provided, the cover includes a retaining portion capable of retaining the resistive element and an elastic portion along the lead wires, and the elastic portion serves to elastically push the lead wires against the connection section upon fixing of the cover to the base. The resistive element may be assembled to the base together with the cover. This may omit the staking and soldering as the process for connecting the lead wire to the connection section, thus improving the assembly workability.

In the case where the retaining portion is a fixing claw disposed adjacent to the elastic portion to snap fasten the resistive element with elastic force, and the elastic portion is provided by forming a slit in the cover, when the cover is fixed to the base while snap-holding the resistive element between the fixing claws, the elastic portion receives the abutment force from the connection section via the lead wire. The elastic portion is bent by the abutment force with respect to the cover to apply the elastic force to the lead wire. This makes it sure to perform the connection through pushing the lead wire against the connection section.

In the case where the elastic portion includes a protruding holding portion that protrudes toward the lead wire which abuts the protruding holding portion, the connection section includes a connection groove to which the lead wire is fit, and the protruding holding portion allows the lead wire to be pushed against the connection groove with the elastic force of the elastic portion, the connection groove serves as a wedge between the lead wire and the connection section so as to be connected.

In the case where the base is disposed in a lever switch of an automobile to relay an operation signal of a switch operation unit of the lever switch device, the workability of assembling the lever switch device may be improved.

DETAIL DESCRIPTION OF THE INVENTION

The improvement of the workability in assembly as the object has been realized by the cover with the elastic portion.

FIRST EMBODIMENT

FIGS. 1 to 9show a first embodiment according to the present invention.FIG. 1is a perspective view showing an essential portion where the cover is attached to the base.FIG. 2is a side view showing the essential portion.FIG. 3(a) is a sectional view showing the essential portion.FIG. 3(b) is an enlarged view showing the connection between the connection section and the lead wire.FIG. 4is a perspective view representing the state where the resistive element is attached to the cover.FIG. 5is a plan view of the cover.FIG. 6is a front view of the cover.FIG. 7is a side view of the cover.FIG. 8is a view showing the back surface of the cover.FIG. 9is a sectional view taken along line SA-SA shown inFIG. 8.

Referring toFIGS. 1 to 4, resistive elements3are retained in the cover1which is detachably engaged to be fixed to a base5of an operation lever. The base5is provided for an operation lever of the lever switch device of the automobile and includes a terminal. The terminal is used as a relay to transmit the electric signal through operation of the slide switch functioning as the switch operation portion such that the cruise control unit is activated.

The cover1will be described referring to additional drawings ofFIGS. 5 to 9. Referring toFIGS. 1 to 9, the cover1is entirely formed of plastics to have a rectangular box-like shape, including a top board7and side boards9,11,13and15.

The top board7includes three pairs of fixing claws17and19as retaining portions at the center in the width direction (up-to-down direction inFIG. 5) in parallel, for example. The fixing claws17and19perform one-touch snap-holding of the resistive body3using elastic force. They are integrally formed on the top board7and have latch-like portions21and23at the respective top end portions. Opposite surfaces of the latch-like portions21and23have inclined guide surfaces25and27, respectively.

The top board7includes elastic tongue portions29,31as elastic portions adjacent to the fixing claws17,19, respectively. The elastic tongue portions29,31are defined by U-like shaped slits33and35formed in the top board7of the cover1along lead wires37,39of the resistive element3which has been snap fastened by the fixing claws17,19, respectively.

Protruding holding portions41,43are formed integrally with the elastic tongue portions29,31, which are directed to the lead wires37,39. The protruding holding portions41,43abut on the lead wires37,39, respectively in the state where the resistive element3is snap fastened between the fixing claws17and19.

Hook portions45for engagement/fixation are disposed at two positions on each of the side boards9and11. The hook portion45protrudes from the outer surface of each of the side boards9and11toward the base5and has an engagement window47, respectively.

The base5has fixing protrusions55formed on both side walls51,53at the respective sides of the resistive element attachment surface49. A connection section57of the terminal is formed on the resistive element attachment surface49. Three pairs of the connection sections57are provided, for example. Referring toFIG. 3(b), a connection grooves59of the connection section57has a wedge-like shape, and is elastically brought into tight fit to the lead wires37,39which have been pressed thereagainst.

The resistive element3is preliminarily retained between the fixing claws17and19prior to the connection. The cover1is laid with the inner surface of the top board7up, and in this state, the resistive element3is pushed to be fit between the fixing claws17and19. The resistive element3is thus pushed into abutment on the guide surfaces25and27of the fixing claws17and19. The guide surfaces25and27receive the force from the resistive element3. The resultant force bends the fixing claws17and19to open the space between the guide surfaces25and27such that the resistive element3is snap fastened between the fixing claws17and19through one touch as shown inFIG. 4. In the aforementioned snap fastened state, the latch-like portions21and23engage with the resistive element3so as to be fixed with the top board7between the latch-like portions21and23.

When the resistive element3is retained between the fixing claws17and19, the lead wires37and39at both ends of the resistive element3abut on the protruding holding portions41and43, respectively so as to be slightly bent.

The thus attached resistive element3is retained between the fixing claws17and19.

The cover1is then inverted to allow the resistive element3to face the resistive element attachment surface49of the base5. The cover1is pushed against the resistive element attachment surface49such that each engagement window47of the respective hooks45is engaged with the corresponding fixing protrusion55at the base5.

As the cover1is fixed to the base5, the elastic tongue portions29and31of the cover1elastically abut on the connection section57via the lead wires37and39. That is, the lead wires37,39are fit to the connection groove59of the connection section57such that the protruding holding portions41,43push the lead wires37,39against the connection groove59. The aforementioned pushing operation allows the reaction force to be received by the elastic tongue portions29and31. The elastic tongue portions29and31are slightly bent to generate the elastic force. The resultant elastic force is applied to the lead wires37,39via the protruding holding portions41,43. The lead wires37,39are pushed against the connection groove59, and are tightly fit with the connection groove59through its wedging function, thus making it sure to perform connection.

The process for staking and soldering to connect the lead wires37,39of the resistive element3to the connection section57may be omitted to improve the assembly workability.

When the cover1is fixed to the base5in the state where the resistive element3is snap fastened between the fixing claws17and19, the elastic tongue portions29and31receive the abutment force from the connection section57via the lead wires37and39. The abutment force causes the elastic tongue portions29,31to bend with respect to the cover1, and to apply the elastic force to the lead wires37,39. The thus applied elastic force pushes the lead wires37,39against the connection groove59of the connection section57, making it sure to perform the connection. The wedging function of the connection groove59makes it sure to connect the lead wires37,39to the connection section57.

The base5is provided in the lever switch device for the automobile to improve the assembly workability.

The elastic portion is not limited to the one obtained by forming slits in the cover1, but may be the one to be attached to the cover1as the separate member. The connection groove59of the connection section57is not limited to be formed as the wedge-like shape, but may be formed as the parallel groove.

The elastic tongue portions29and31are disposed opposite the connection section57. However they may be arbitrarily formed so long as they push the lead wires37,39against the connection groove59with the elastic force. The elastic tongue portions29and31may be positionally displaced with respect to the connection section57.

The connection structure for resistive element is applicable to the device other than the lever switch device.