Column switch

Abstract: A column switch electrically connects the steering wheel side and the vehicle side by means of a flexible flat cable 5 which is in the form of a spiral and is accommodated in a housing. The housing includes a lower part defined by the base 1 of the column switch 8 and an upper part defined by the rotor 6 having a cancel cam 6e. The housing also has slits 6f formed therein for the steering angle sensor 10. The base 1 has a hollow cylinder 1a formed in the middle thereof through which a steering shaft is inserted. Formed to surround the hollow cylinder 1a is an annular groove 1f which accommodates the flat cable 5 therein. The rotor 6 has resilient fastening straps 6a and an accommodating space 6d that covers the annular groove 1f. The resilient fastening straps 6a rotatably engage a fastening portion 1i formed on the hollow cylinder 1a.

Description: The present invention relates to a column switch with a rotary connector in which the base of a column switch on a steering wheel of an automobile is integral with an on-vehicle rotary connector that makes electrical connection between the steering wheel and the steering column. This type of prior art is disclosed in, for example, Japanese Utility Model Preliminary Publication (KOKAI) No. 3-43053. The prior art includes a rotary connector having a spirally-coiled flat cable that makes electrical connection between a steering wheel of an automobile and a steering column, and a column switch having, for example, an operation lever for a direction indicator. The rotary connector and the column switch are separate items. The rotary connector has a lower housing secured on a base of the column switch and an upper housing secured to an underside of the steering wheel. The aforementioned prior art suffers from a problem that the base of the column switch and the housing of the rotary connector are separate items, requiring a large number of parts and man-hours for assembly. In addition, the construction requires a large mounting space. EP 0 771 693 A1 discloses the features of the preamble of claim 1 describing a combination switch apparatus equipped with a rotary connector. The switch apparatus comprises a flexible flat cable in spiral form accommodated in a space defined between the main body of the switch apparatus and the rotor housing, the flexible cable making electrical connection between the steering wheel side and the vehicle side. The rotary connector is equipped with an attachment which rotatably holds the rotor housing with respect to the base. The attachment includes a cancel cam and a slit board constituting a steering angle sensor. The attachment comprises a resilient plate that is engaged with a pawl formed on the rotor housing. An object of the invention is to provide a structure which serves as both a housing for the rotary connector and a base for the column switch, thereby reducing the number of parts and man hours for assembly and overall cost and allowing miniaturization of overall size of the base and column switch. The present invention according to Claim 1 was made in order to solve the aforementioned drawbacks of the prior art. The present invention of the aforementioned construction offers the following advantages. The invention according to Claim 1 is directed to a column switch having a rotary connector that electrically connects a steering wheel side to a vehicle side by means of a flexible flat cable in a spiral form accommodated in a housing. The housing includes a lower housing defined by a base of the column switch, an upper housing defined by a rotor having a cancel cam, and slits or reflectors for a steering angle sensor. Thus, the base of the column switch serves as a stator side housing of the rotary connector while a rotor side housing includes the cancel cam for the turn signal switch and the slits or reflectors that serve as elements detected by the sensor. The construction implements a multi-function column switch, saving a mounting space as well as achieving miniaturization of column switch. The construction also reduces the number of components man-hours for assembly, thereby reducing overall cost. According to the invention, the base has a hollow cylinder formed in the middle thereof through which a steering shaft is inserted, and an annular groove which is formed to surround the hollow cylinder and accommodates the flat cable therein. The rotor has a resilient fastening strap and an accommodating section that covers the annular groove. The resilient fastening strap rotatably engages a fastening portion formed on the hollow cylinder. According to the invention, the slits are formed in the lower peripheral end portion of the rotor, and the steering angle sensor has a detector disposed on the bottom of the annular groove. The detector includes a light-receiving element and a light-emitting element. Thus, the rotor can be provided with both the cancel cam and slits that form the steering angle sensor, reducing the number of parts and man-hours for assembly. Or the reflectors are formed on an outer peripheral surface of the rotor and the steering angle sensor includes a detector disposed on an inner wall of the annular groove. The detector has light-receiving/emitting elements therein. Thus, the invention provides space-saving construction. According to a preferred embodiment of the invention, the rotor has a flange formed at a lower end thereof, the flange having the slits formed therein. The steering angle sensor has a detector disposed on an inner wall of the annular groove, the detector having a light-receiving element and a light-emitting element. Thus, the steering angle sensor can easily be assembled. According to a further preferred embodiment of the invention, the base has a steering angle sensor and is formed with recesses on the left and right sides. The bodies of a turn signal switch and a wiper/washer switch or the like are fitted into the recesses. Each of the bodies has a connector on an underside thereof. The steering angle sensor is provided in a terminal block. The terminal block is secured to the base and has a first connector and a second connector, each of which is fitted into the corresponding connector. Thus, the steering angle sensor and the terminal block can be integrally constructed and connectors of the steering angle sensor so that connectors on the left and right bodies can be located at one place, thereby greatly reducing the number of components and man-hours for assembly. According to a further preferred embodiment of the invention, the terminal block has a third connector incorporating terminals therein which are electrically connected to the connectors, the detector of the steering angle sensor, and the flat cable. The steering angle sensor and connectors on the left and right bodies can be located at one place so that they are connected to a power supply simultaneously, thereby reducing man-hours for assembly. According to a further preferred embodiment of the invention, the bodies have the connector oriented substantially toward the recesses. The terminal block has the first connector and second connector oriented outward so that the first and second connectors are in alignment with the connectors. Upon fixedly mounting the terminal to the base and fitting the left and right bodies into the recesses in the base, the connectors and the first and second connectors of the terminal block can be fitted simultaneously, improving assembly efficiency. According to a further preferred embodiment of the invention, the bodies are formed with the connectors oriented downward. The terminal block has the first connector and the second connector oriented upward so that the first and second connectors are in alignment with the connectors. Upon fitting the left and right bodies into the recesses formed in the base and fixedly mounting the terminal block to the base, the connectors, the first and second connectors of the terminal block can be simultaneously fitted, improving the assembly efficiency. Examples of forms of embodiments of the present invention are explained in greater detail below on the basis of the drawings, in which: Fig. 1 is a perspective view of a first embodiment of the invention; Fig. 2 illustrates the first embodiment of the invention, showing the cancel cam and steering angle sensor; Fig. 3 is an enlarged top view with a partial cross section, illustrating the first embodiment of the invention; Fig. 4 is a cross-sectional view taken along the lines X-X of Fig. 3; Fig. 5 is an enlarged bottom view of the first embodiment of the invention; Fig. 6 is an enlarged cross-sectional view of light-receiving/emitting elements of a second embodiment of the invention; Fig. 7 is an enlarged cross-sectional view of light-receiving/emitting elements of another embodiment of the invention; Fig. 8 is a central enlarged longitudinal cross-sectional view of a third embodiment of the invention; Fig. 9 is an illustrative diagram of the cancel cam and steering angle sensor of the third embodiment of the invention; Fig. 10 is an enlarged bottom view of a fourth embodiment of the invention; and Fig. 11 shows the fourth embodiment of the invention, illustrating the fitting relation between the terminal block and connectors on the bodies. A first embodiment of the invention will be described in detail with reference to Figs. 1, 2, 3, 4, and 5. As shown in Fig. 3 and 5, reference 1 denotes a base of a column switch 8, the base 1 having a hollow cylinder 1a in the middle thereof through which a steering shaft 2 is inserted. The base 8 has mounting sections 1b, 1c and 1d fittingly mounted to a steering column, not shown, and is secured to the steering column by a fastening tongue 1e. As shown in Fig. 4, the base 1 has an annular groove 1f defined to surround the hollow cylinder 1a. The annular groove 1f accommodates slide sheets 3 and 4, a flat cable 5, and a rotor 6 inserted therein. The base 1 is formed with recesses 1g and 1h in the left and right sides of the base 1. The recesses 1g and 1h fittingly receive, for example, a body 7a of a turn signal switch 7 and a body 9a of a wiper/washer switch 9, respectively. As shown in Fig. 4, the hollow cylinder 1a has a fastening portion 1i in the form of a stepped portion with which a resilient fastening strap 6a formed on an inner wall of the rotor 6 is engaged. As shown in Fig. 3, the annular groove 1f communicates with the recesses 1g and 1h through cutouts 1j and 1k formed on the left and right sides. A cancel claw 7b of the turn signal switch 7 extends into or retracts from the annular groove 1f through the cutout 1j or 1k. The base 1 has the two cutouts 1j and 1k so that the construction can commonly be applied to both a left-hand-drive vehicle and a right-hand-drive vehicle. For a right-hand-drive vehicle, the turn signal switch 7 is inserted into the recess 1g so that operating the operation lever 7c causes the cancel claw 7b to extend into or retract from the annular groove 1f through the cutout 1j. For a left-hand-drive vehicle, the turn signal switch 7 is inserted into the recess 1h so that operating the operation lever 7c causes the cancel claw 7b to extend into and retract from the annular groove if through the cutout 1k. There is provided a fitting hole, not shown, formed in a bottom surface of the hollow cylinder 1a. The fitting hole receives a terminal 5a attached to an outer end of a flat cable 5. The steering shaft 2 is rotatably inserted into the steering column, extending through the hollow cylinder 1a and shaft hollow cylinder 6b. The steering shaft 2 is fixedly mounted to the steering wheel and rotates together with the rotor 6 whenever the steering shaft 2 is rotated. The slide sheets 3 and 4 are a thin flat ring made of a highly lubricating oleoresin or the like. The slide sheet 3 is placed on the inner bottom of the annular groove 1f as shown in Fig. 4 and under the flat cable 5. The slide 3 is formed with a hole, not shown, in the middle of the slide 3. The hollow cylinder 1a fits into the hole. The slide sheet 4 is disposed over the flat cable 5. The slide sheet 4 is formed with a hole, not shown, in the middle thereof into which the hollow cylinder 1a fits. The slide sheet 4 is also formed with a cutout, not shown, in an outer circumference thereof. The terminal 5b is inserted into the cutout. The flat cable 5 includes flat thin conductors connected to the terminals 5c and 5d. The conductors are insert-molded with a highly lubricating resin into a thin belt-like shape. A terminal 5a is connected to an outer end of the flat cable 5 and a terminal 5b is connected to an inner end of the flat cable 5. The flat cable 5 is wound in a spiral shape and is accommodated in the annular groove 1f with the slide sheet 3 under the flat cable 5 and the slide sheet 4 over the flat cable 5. Then, the rotor 6 is fitted over the flat cable 5, thereby enclosing the flat cable 5 in the annular groove 1b. Upon fittingly mounting the terminal 5a into the connector-inserting hole 1m formed in the bottom of the annular groove 1f, the terminals 5c are placed in position at a lower area of the base 1. The terminal 5b has terminals 5d fitted to a connector housing 6c formed on top of the rotor 6. The rotor 6 is a doughnut-shaped rotary case that rotates with the steering wheel. The rotor 6 has the connector housing 6c which is formed on the rotor 6 and upwardly projects from the rotor 6. The connector housing 6c fits to its mating connector, not shown, provided under the steering wheel, thereby positioning the rotor 6 with respect to the steering wheel. The rotor 6 has an accommodating section 6d that encloses the flat cable 5 from above. The rotor 6 is rotatably inserted into the annular groove 1f. The rotor 6 has a shaft hollow cylinder 6b in the middle thereof and the steering shaft 2 is inserted into the shaft hollow cylinder 6b. The shaft hollow cylinder 6b has a plurality of resilient fastening straps 6a, which are rotatably inserted into the hollow cylinder 1a and rotatably engage the fastening portion 1i formed on the hollow cylinder 1a as shown in Figs. 4 and 5. The rotor 6 has a cancel cam 6e formed on its outer circumference as shown in Figs. 2, 3, and 4, the cancel cam 6e striking the cancel claw 7b of the turn signal switch 7. The cancel cam 6e is not limited in number and shape to those of the present embodiment. The rotor 6 may be assembled to the base 1 with a coil spring placed between the rotor 6 and the base 1 so that the rotor 6 presses the underside of the steering wheel at all times. The resilient fastening straps 6a of the rotor 6 and the fastening portion 1i of the base 1 may be reversed with their locations. That is, the fastening portion 1i may be formed on the shaft hollow cylinder 6b and the resilient fastening strap 6a may be formed on the hollow cylinder 1a. As shown in Fig. 2, the rotor 6 is formed with a plurality of slits 6f formed in the lower circumferential surface thereof all around the rotor. The slits 6f pass through the detectors 10a of the steering angle sensor 10 when the rotor 6 is rotated. The steering angle sensor 10 includes the slits 6f, the detector 10a, and a body 10b, and detects the steering angle of the steering wheel. The slits 6f are through-holes formed at predetermined constant intervals in the lower circumferential surface of the rotor 6, which is in the shape of a generally inverted cup. The slits 6f run through the detector 10a when the steering wheel ist rotated. The detector 10a includes the light emitting element and the light-receiving element that detects the light emitted from the light-emitting element, both not shown, disposed to oppose each other with the slit 6f therebetween. The body 10b is accommodated in a case 10c and is in the form of a board 10d having, for example, the light emitting element and light-receiving element mounted thereon. The steering angle sensor 10 detects the slits 6f passing a space between the light-emitting element and light-receiving element when the rotor 6 ist rotated, thereby detecting the steering angle of the steering wheel that rotates together with the slits 6f. The case 10c has a coupler 10f with a terminal 10e accommodated therein, the terminal 10e electrically connecting the board 10d to, for example, the power supply. The column switch 8 includes, for example, the body 7a of the turn signal switch 7 and the body 9a of the wiper/washer switch 9, fitted to the recess 1g and recess 1h on the right and left sides of the base 1, respectively. The column switch 8 may be of the construction where the turn signal switch 7 and wiper/washer switch 9 and others are formed in integral with the base 1. The turn signal switch 7 has the operation lever 7c that is disposed on the body 7a and is pivoted upward and downward and leftward and rightward. Operating the operation lever 7c to a left-turn position or a right-turn position causes the cancel claw 7b to advance into a path in which the cancel cam 6e rotates. Rotating the steering wheel causes the cancel cam 6e to strike the cancel claw 7b. The assembly procedure and operation of the first embodiment of the aforementioned construction will now be described in detail. Switches such as the turn signal switch 7 and wiper/washer switch 9 are fitted into the recesses 1g and 1h of the base 1. The slide sheet 3 is placed on the bottom surface of the annular groove 1f. The terminal 5b connected to one end of the flat cable 5 is inserted into the connector housing 6c, and is fixed to the rotor 6, so that the terminal 5b is fixedly placed in position in the connector housing 6c. The terminal 5a connected to the other end of the flat cable 5 is inserted into the connector-inserting hole 1m, so that the flat cable 5 is fixedly positioned in the annular groove 1f of the base 1. The flat cable 5 is then arranged in a spiral shape in the annular groove 1f to surround the hollow cylinder 1a. The shaft hollow cylinder 6b of the rotor 6 is pushed into the hollow cylinder 1a, so that the resilient fastening strap 6a rotatably engages the fastening portion 1i. A housing that covers the flat cable 5 includes a lower part defined by the base 1 of the column switch 8 and an upper part defined by the rotor 6 on which a cancel cam 6e and in which slits 6f for the steering angle sensor 10 are formed, thereby reducing the number of parts and man-hours for assembly as well as achieving a space-saving construction. The base 1 has the mounting sections 1b, 1c, and 1d fitting to a bracket of the steering column, and is secured to the steering column. The connector housing 6c is fitted to the mating connector on the underside of the steering wheel and the steering wheel is fixed to the steering shaft 2, thereby positioning the rotor 6 in place. When the steering wheel is operated, the steering wheel rotates together with the rotor 6 and the terminal 5b connected to one end of the flat cable 5. If the operation lever 7c has been pivoted to either the left-turn position or the right-turn position, the cancel cam 6e strikes the cancel claw 7b, thereby allowing the operation lever 7c to return to the neutral position. Operating the steering wheel also causes the slits 6f to run, so that the passage of light emitted from the light-emitting element to the light-receiving element is alternately allowed and blocked. Thus, the steering angle sensor 10 detects the steering angle of the steering wheel in terms of the slits 6f running through the sensor 10. A second embodiment will be described in detail with reference to Figs. 6 and 7. The same elements as those of the first embodiment have been given the same numerals and references and the description thereof is omitted. The second embodiment of the present invention is directed to a steering angle sensor which includes reflectors 12a and a detector 10a. The reflectors 12 are provided in place of the slits 6f formed in the rotor 6 of the first embodiment. The detector 10a is a light-receiving/emitting element 13 as shown in Fig. 6, having a light-emitting element 13a and light-receiving element 13b. The light-receiving/emitting element 13 shown in Fig. 6 is a light-receiving/emitting element for a so-called absolute steering angle detection. The light-receiving/emitting element 13 is a reflection type photosensor accommodated in a housing in which mounting holes 13c and 13d are formed. The light-emitting element 13a and light-receiving element 13b are mounted to the mounting holes 13c and 13d and are oriented toward the middle of the reflectors 12a formed on the rotor 12. Alternatively, the light-receiving/emitting element 13 may be of a mini reflection type photosensor as shown in Fig. 7. The light-receiving/emitting element 14 shown in Fig. 7 is of the construction where the reflectors are provided at the locations of slits formed in a flange of, for example, a rotor 15 of a later described third embodiment. The reflectors are arranged at locations where the slits 15b of Fig. 9 are formed in the flange 15a. Disposed under the reflectors to oppose the reflectors are a desired number of light-receiving/emitting elements 14. The light-receiving/emitting element 14 includes a package 14a, a light-emitting element 14d, a light-receiving element 14e, a lead 14f connected to the light-emitting element 14d, and a lead 14g connected to the light-receiving element 14e. The package 14a has two spaces 14b and 14c. The light-emitting element 14d and light-receiving element 14e are sealed in the spaces 14b and 14c, respectively, with a encapsulating material 14h such as an epoxy resin that blocks visible light. The light-receiving/emitting elements 13 and 14 are disposed to oppose the reflectors 12a provided on, for example, the outer circumferential surface of the rotor 12. A third embodiment of the present invention will be described in detail with reference to Figs. 8 and 9. The third embodiment of the invention is directed to a steering angle sensor 16 where a rotor 15 has a flange 15a formed at its lower end, slits 15b are formed in the flange 15a, and the light-emitting element and light-receiving element are vertically disposed with the slits 15b therebetween. The light-emitting element and light-receiving element are in the form of, for example, a photo-interrupter that serves as a detector 16a. The rotor 15 has a cancel cam 15c formed in one-piece construction with the rotor 15 on the circumferential surface of the rotor 15. The cancel cam 15c has an outer circumferential surface to which a cancel claw 7b abuts. The detector 16a is disposed on the inner wall surface of the annular groove 1f near the bottom of the annular groove 1f. The operation of the third embodiment is the same as that of the first embodiment. A fourth embodiment will be described in detail with reference to Figs. 10 and 11. The fourth embodiment of the present invention provides a structure where the body 10b of the steering angle sensor 10 is in one piece construction with the terminal that electrically connects the body 7a of the turn signal switch 7 according to the first embodiment of the present invention to the body 9a of the wiper/washer switch 9, and the terminal block 17 is mounted to the underside of the base 1 by, for example, screws. The terminal block 17 has a curved surface 17a formed in its middle, the curved surface being configured to the cylindrical shape of the hollow cylinder 1a. Formed on both sides of the curved surface 17a are a first connector 17b and a second connector 17c in one piece construction with the terminal block. The first and second connectors fit into connectors 7d and 9d disposed under the body 7a and 9d for electrical connection. The first and second connectors 17b and 17c can be of any shape and orientation as long as the turn signal switch 7 and wiper/washer switch 9 are electrically connected to each other. For example, as shown in Fig. 10, the terminal block 17 is first secured to the base 1 and then the bodies 7a and 9a are fitted into the recesses 1g and 1h. Thereafter, the connectors 7d and 9d are fitted into the first connector 17b and second connector 17c. The first and second connectors 17b and 17c have terminals 17d and 17e, respectively, outwardly extending in directions in which the connectors 7d and 9d are inserted. The terminals 17d and 17e of the first and second connectors 17b and 17c and the terminals 7e of the connectors 7d and 9d can be of any shape as long as they fit to each other. If the bodies 7a and 9a are to be first fitted to the base 1 and then the terminal block 17 is mounted to the base 1, the terminal block 17 should be designed with the connectors 7d and 9d oriented downward and the connectors 17b and 17c of the terminal block 17 oriented upward to oppose the connectors 7d and 9d, thereby allowing the terminal block 17 to be mounted to the base 1 while at the same time as the first and second connectors 17b and 17c are fitted to the connectors 7d and 9d. The terminals 17d and 17e provided in the first and second connectors 17b and 17c can also be of any shape. The terminal block 17 incorporates the steering angle sensor 18 therein and has a third connector 17g formed on the underside thereof in one piece construction therewith. The third connector 17g has terminals 17f electrically continuous to the terminals 17d and 17e. The terminals 17d, 17e, and 17f are insert-molded with the terminal block 17. The third connector 17g is used for gathering electrical wires from the turn signal switch, wiper/washer switch 9, and steering angle sensor 18 at one place so as to connect the wires to, for example, a power supply. The terminal block 17 may be fastened to the base 1 by, for example, a resilient fastening means or any other means.

Claims: A column switch (8) having a rotary connector with a flexible flat cable (5) in a spiral form accommodated in an annular groove (1f) of a housing, the flexible cable making electrical connection between a steering wheel side and a vehicle side, the housing comprising: a lower part defined by a base (1) of the column switch (8); an upper part defined by a rotor (6, 12, 15) having a cancel cam (6e, 15c); and slits (6f, 15b) or reflectors (12a), for a steering angle sensor (10, 16); the base (1) comprising a hollow cylinder (1a) formed in the middle of the base through which a steering shaft (2) is inserted, the annular groove (1f) surrounding the hollow cylinder (1a); characterized in that the rotor (6, 12, 15) comprises a resilient fastening strap (6a) which rotatably engages a fastening portion (1i) formed on the hollow cylinder of the base; and said slits (6f) are formed in a lower, peripheral end portion of the rotor (6) or said reflectors (12a) are formed on an outer peripheral surface of the rotor (12); and the steering angle sensor (10, 16) has a detector (10a, 16a) disposed on a bottom and an inner wall of the annular groove (1f) respectively, the detector having a light-receiving element (13) and a light-emitting element (14). The column switch according to Claim 1, wherein the rotor (15) has a flange (15a) formed at a lower end thereof, the flange having the slits (15b) formed therein; and the steering angle sensor (16) has a detector (10a) disposed on an inner wall of the annular groove (1f), the detector having a light-receiving element and a light-emitting element. The column switch according to Claim 1, wherein said base (1) has a steering angle sensor (18) and is formed with recesses (1g, 1h) on a left side and a right side thereof into which bodies (7a, 9a) of a left/right turn signal switch (7) and a wiper/washer switch (9) or the like are fitted, each of the bodies (7a, 9a) having a connector (7d, 9d) on an underside thereof, the steering angle sensor (18) being provided in a terminal block (17), the terminal block (17) being secured to the base (1) and having a first connector (17b) and a second connector (17c) each of which fits into the connector (7d, 9d). The column switch according to Claim 3, wherein said terminal block (17) has a third connector (17g) incorporating terminals (17f) therein which are electrically connected to the connectors (7d, 9d), the detector (10a) of the steering angle sensor (10), and the flat cable. The column switch according to claim 3, wherein the bodies (7a, 9a) have the connectors (7d, 9d) oriented substantially toward the recesses (1g, 1h), and the terminal block (17) has the first connector (17b) and second connector (17c) oriented outward so that the first and second connectors are in alignment with the connectors (7d, 9d). The column switch according to claim 3, wherein the bodies (7a, 9a) are formed with the connectors (7d, 9d) oriented downward, the terminal block (17) has the first connector (17b) and the second connector (17c) oriented upward so that the first and second connectors are in alignment with the connectors (7d, 9d).

Inventors: MATSUMOTO TSUYOSHI, MATSUMOTO, TSUYOSHI, Matsumoto, Tsuyoshi c/o Niles Parts Co. Ltd.
Applicants: NILES PARTS CO LTD, NILES PARTS CO., LTD.
Application year: 1999
Main classification: B60R16
IPC codes: H01H25, B62D1, H01H9, H01R35, B60R16, G01B11, B60Q1