JP2005329809A - Cable type steering device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the rigidity feeling at the time of operating a steering handle as well as compensate elongation of an operation cable of a cable type steering device. <P>SOLUTION: Energizing a stopper 49 fixed with an outer tube 16o of the operation cable 16 by a spring 61 pushes out the outer tube 16o by an amount of permanent elongation of an inner cable 16i so as to secure a tensile force and prevent deterioration of the steering feeling. A piston 48b integrated with the stopper 49 is slidably fitted to a cylinder 46b provided for a driving pulley housing 12. A check valve 61 is arranged in parallel with a choke 48c for communicating first/second oil chambers 53, 54 zoned on both sides of the piston 48b with each other. At the time of returning the piston 48b to the initial position by an elastic force of the depressed spring 51, the tensile force of the inner cable 16i can be quickly restored by opening the check valve 61 for invalidating the choke 48c. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a cable-type steering device in which a driving pulley connected to a steering handle and a driven pulley connected to a steering gear box for turning a wheel are connected via an operation cable.

  Such a cable-type steering device is known from Patent Document 1 and Patent Document 2 below.

  The operation cable of the cable-type steering device is an inner cable slidably housed in the outer tube, and the inner cable that transmits the steering torque input to the steering handle to the steering gear box is composed of a metal wire. Therefore, permanent elongation is inevitable with long-term use. When permanent elongation occurs in the inner cable, the play of the steering handle is increased and the steering feeling is lowered. Therefore, the one described in Patent Document 1 below uses an end portion of the outer tube supported by the pulley housing as a compression coil spring. By urging in the direction of pushing out from the pulley housing with the elastic force, the outer tube follows the permanent elongation of the inner cable to compensate for the decrease in tension.

  However, when the end of the outer tube is biased by a compression coil spring to compensate for the permanent elongation of the inner cable, when the steering handle is suddenly operated and the tension of the inner cable increases, the compression coil Since the spring is compressed and the outer tube is drawn into the pulley housing, the tension of the inner cable is reduced and the steering wheel has a feeling of rigidity, which causes a problem that steering feeling is lowered.

Therefore, the applicant of the present invention has provided a cylinder provided in one of the drive pulley housing and the driven pulley housing, a piston connected to the end of the outer tube of the operation cable and slidably fitted to the cylinder, and a cylinder. A cable type provided with damping force generating means which is composed of first and second oil chambers which are partitioned by a piston and separated by a piston, and a choke which is formed in the piston and which communicates the first and second oil chambers A steering device has already been proposed in Japanese Patent Application No. 2003-272986.
Japanese Patent Laid-Open No. 11-11325

  However, as proposed in Japanese Patent Application No. 2003-272986, when the steering handle is rotated to the limit position and held for a long time, the outer tube is pulled due to an increase in the tension of the inner cable, so that the first oil chamber The hydraulic oil moves from the first oil chamber to the second oil chamber via the choke, and the position of the piston changes. Even after the steering handle is returned to the neutral position, the spring force that applies tension to the inner cable is Even if it tries to return to the original position, it takes time for the piston to return to the original position due to the flow resistance of the hydraulic oil passing through the choke, and the inner cable remains loose during that time, and the steering feeling is lowered. there is a possibility.

  The present invention has been made in view of the above-described circumstances, and an object thereof is to further enhance the rigidity feeling when the steering handle is operated while compensating for the extension of the operation cable of the cable type steering apparatus.

  In order to achieve the above object, according to the invention described in claim 1, a driving pulley connected to a steering handle and rotating, a driven pulley connected to a steering gear box for turning a wheel and rotated, An operation cable that connects the drive pulley and the driven pulley, a tension adjusting means that generates elastic force to apply tension to the operation cable, and an operation when the tension of the operation cable increases due to the steering torque input to the steering handle. A cable type steering apparatus having a damping force generating means for applying a damping force to the tension adjusting means to keep the tension of the cable in an increased state, wherein the damping force generating means decreases the tension when the tension of the operation cable increases. A cable-type steering device is proposed that generates a damping force that is greater than the time.

  According to the invention described in claim 2, in addition to the configuration of claim 1, the operation cable has both ends inside the outer tube supported by the drive pulley housing and the driven pulley housing, and both ends have the drive pulley and The inner cable wound around the driven pulley is slidably accommodated, and the tension adjusting means is a spring that urges the end of the outer tube in a direction away from either the drive pulley housing or the driven pulley housing. There is proposed a cable-type steering device characterized by that.

  According to the invention described in claim 3, in addition to the configuration of claim 1, the operation cable has both ends inside the outer tube supported by the drive pulley housing and the driven pulley housing, and both ends have the drive pulley and The inner cable wound around the driven pulley is slidably accommodated, and the damping force generating means is connected to the cylinder provided in either the drive pulley housing or the driven pulley housing and the end of the outer tube. A piston slidably fitted into the cylinder, first and second oil chambers partitioned inside the cylinder and separated by the piston, and the first and second oil chambers formed in the piston to communicate with each other. A cable-type steering device comprising a choke and a check valve arranged in parallel to the choke. The draft.

  Note that the spring 51 of the embodiment corresponds to the tension adjusting means of the present invention.

  According to the first aspect of the present invention, when the operation cable of the cable-type steering device is permanently stretched to reduce the tension, the tension is applied to the operation cable by the elastic force generated by the tension adjusting means to compensate for the permanent elongation. can do. When the driver applies a sudden steering torque to the steering handle and the tension of the operating cable increases, the damping force generating means acts on the tension adjusting means to keep the tension of the operating cable in an increased state. By suppressing the decrease in tension, it is possible to secure the steering wheel with a sense of rigidity and to prevent a decrease in steering feeling. The damping force generation means generates a larger damping force when the tension of the operation cable is increased than when the tension is decreased, so when the steering handle is rotated to the limit position and held for a long time and then returned to the neutral position, The tension of the operation cable once decreased against the large damping force can be quickly returned to the original value with the small damping force, and the deterioration of the steering feeling can be prevented more reliably.

  According to the configuration of claim 2, the tension of the inner cable of the operation cable is adjusted by the spring that urges the end of the outer tube of the operation cable in a direction away from the drive pulley housing or the driven pulley housing. The structure can be simplified.

  According to the configuration of the third aspect, the piston connected to the end of the outer tube of the operation cable is slidably fitted into the cylinder provided in the drive pulley housing or the driven pulley housing, and is divided into the cylinder. 1. Since the second oil chamber is communicated with a choke formed on the piston, and a check valve is arranged in parallel with the choke, a sudden steering torque is input to the steering handle, and the outer tube is connected to the inner cable of the operation cable. When pulled, the piston connected to the outer tube moves in the cylinder, so that the hydraulic oil in the first and second oil chambers is blocked by the check valve and passes through the piston choke. Can prevent the outer tube from moving suddenly and maintain the tension of the inner cable. .

  When the steering handle is rotated to the limit position and held for a long time, the hydraulic oil moves from the first oil chamber to the second oil chamber via the choke due to the increase in the tension of the inner cable, and the position of the piston changes. Therefore, if the tension adjusting means tries to return the piston to the original position after returning the steering handle to the neutral position, the check valve opens and the hydraulic oil is moved from the second oil chamber to the first oil chamber without passing through the choke. And the piston quickly returns to the original position, and the inner cable tension can be quickly increased to further prevent the steering feeling from being lowered.

  Hereinafter, embodiments of the present invention will be described based on examples of the present invention shown in the accompanying drawings.

  1 to 5 show an embodiment of the present invention. FIG. 1 is an overall perspective view of a cable type steering apparatus, FIG. 2 is an enlarged sectional view taken along line 2-2 of FIG. 1, and FIG. FIG. 4 is an enlarged sectional view taken along line 4-4 of FIG. 1, and FIG. 5 is an operation explanatory view corresponding to FIG.

  As shown in FIG. 1, a drive pulley housing 12 provided in front of a steering handle 11 of an automobile and a driven pulley housing 14 provided above a steering gear box 13 are composed of two operation cables 15, such as a Bowden cable. 16 is connected. Tie rods 17L, 17R extending in the left-right direction of the vehicle body from both ends of the steering gear box 13 are connected to knuckles (not shown) that support the left and right wheels WL, WR.

  As shown in FIGS. 1 and 2, a drive pulley shaft 21 connected to the steering handle 11 is rotatably supported by the drive pulley housing 12, and a drive pulley 22 is fixed to the drive pulley shaft 21. The two operation cables 15 and 16 are composed of outer tubes 15o and 16o and inner cables 15i and 16i that are slidably accommodated therein. A pulley groove 22a is formed in a spiral shape on the outer peripheral surface of the drive pulley 22, and cable guide grooves 22b and 22b are connected to both ends of the pulley groove 22a on both end faces, and are connected to the cable guide grooves 22b and 22b. Pin holes 22c and 22c are formed.

  The inner cables 15i, 16i of the operation cables 15, 16 are respectively press-fitted into the pin holes 22c, 22c of the drive pulley 22 from the pin 23, 23 fixed to one end thereof, and then into the pulley groove 22a from the cable guide grooves 22b, 22b. It is wound and pulled out in substantially the same direction from both ends in the diameter direction of the drive pulley 22.

  As shown in FIGS. 1 and 4, a driven pulley 25 is fixed to a driven pulley shaft 24 that is rotatably supported by the driven pulley housing 14. The winding structure and the fixing structure of the inner cables 15i and 16i with respect to the driven pulley 25 are the same as those of the driving pulley 22 described in FIG. 2, and pins 26 and 26 fixed to the other ends of the inner cables 15i and 16i are provided. Inner cables 15 i and 16 i that are press-fitted into the pin holes 25 c and 25 c of the driven pulley 25 and are connected to the pins 26 and 26 are formed on the cable guide grooves 25 b and 25 b formed on the end face of the driven pulley 25 and on the outer peripheral surface of the driven pulley 25. It is wound around the spiral pulley groove 25a.

  A pinion 27 is provided at the tip of a driven pulley shaft 24 that protrudes from the driven pulley housing 14 into the steering gear box 13, and the pinion 27 is supported in the steering gear box 13 so as to be slidable left and right. It meshes with a rack 29 formed on 28. A power steering motor 30 is supported on the driven pulley housing 14, and a worm 32 provided on the output shaft 31 inside the driven pulley housing 14 meshes with a worm wheel 33 provided on the driven pulley shaft 24. Accordingly, the torque of the power steering motor 30 is transmitted to the driven pulley shaft 24 via the worm 32 and the worm wheel 33.

  As shown in FIG. 3, the outer tube 16o of one operation cable 16 includes a spirally wound rectangular cross-section metal wire 41, a synthetic resin coating 42 covering the inner peripheral surface of the metal wire 41, and a metal wire. 41 and a synthetic resin coating 43 covering the outer peripheral surface of the base 41, and a base 44 is fixed by caulking to the tip thereof. A synthetic resin bush 45 is housed on the inner peripheral surface of the base 44 projecting from the end of the outer tube 16o to improve slippage with the inner cable 16i.

  An outer pipe 46 is fitted in a mounting hole 12a formed in the drive pulley housing 12, and movement in the left direction in the figure is restricted by an annular stopper 47 screwed to the outer peripheral surface thereof. The base 44 of the outer tube 16o is fitted to the inner periphery of the inner pipe 48, and the left end of the base 44 is engaged with the stepped portion 48a at the left end of the inner pipe 48, so that the leftward movement in the figure is restricted. A stopper 49 is screwed into the inner periphery of the right end of the inner pipe 48, and the pressing portion 49a at the left end presses the right end of the base 44 leftward, so that the base 44, the inner pipe 48 and the stopper 49 are integrated. Is done.

  A spring 51 is housed in a compressed state between a spring seat 50 locked to a step 46a on the inner peripheral surface of the outer pipe 46 and a flange 49b of a stopper 49 screwed to the right end of the inner pipe 48. The inner pipe 48 is urged to the right with respect to the outer pipe 46 by the elastic force. At this time, the circlip 52 is attached to the left end of the inner pipe 48 so that the outer pipe 46 does not fall out of the inner pipe 48.

  A piston 48b formed on the outer peripheral surface of the inner pipe 48 is slidably fitted to a cylinder 46b formed on the inner peripheral surface of the outer pipe 46, and the first oil partitioned by the piston 48b inside the cylinder 46b. A chamber 53 and a second oil chamber 54 are partitioned. The left end of the first oil chamber 53 and the right end of the second oil chamber 54 are sealed by O-rings 55 and 56, respectively. A choke 48c that communicates the first oil chamber 53 and the second oil chamber 54 is formed in the piston 48b.

  A check valve 61 including a valve seat 58, a valve body 59 and a valve spring 60 provided in the drive pulley housing 12 is arranged in parallel with a choke 48 c provided in the inner pipe 48. Both ends of the check valve 61 provided in the drive pulley housing 12 communicate with the first oil chamber 53 via the first oil passage 62 and also communicate with the second oil chamber 54 via the second oil passage 63. The check valve 61 is arranged in such a direction as to prevent the hydraulic oil from moving from the first oil chamber 53 to the second oil chamber 54 and to allow the hydraulic oil to move from the second oil chamber 54 to the first oil chamber 53. . The outer pipe 46 surrounds the first and second oil passages 62 and 63 so as to seal the portion where the first and second oil passages 62 and 63 penetrate the boundary surface between the outer pipe 46 and the drive pulley housing 12. O-rings 64 and 65 are mounted in an annular groove formed on the outer peripheral surface of the ring. The choke 48c and the check valve 61 constitute damping force generating means 57.

  The structure of the outer tube 15o of the other operation cable 15 is the same as the structure of the outer tube 16o of the one operation cable 16 described above.

  Next, the operation of the embodiment of the present invention having the above configuration will be described.

  When the driver operates the steering handle 11, the rotation of the drive pulley 22 connected to the steering handle 11 is transmitted to the driven pulley 25 via the operation cables 15 and 16, and the rotation of the driven pulley 25 is driven to the driven pulley shaft 24 and the pinion 27. The wheels WL and WR that are transmitted to the tie rods 17L and 17R via the rack 29 and the steering rod 28 and connected to the tie rods 17L and 17R are steered.

  At this time, the steering torque input by the driver to the steering handle 11 is detected by a steering torque sensor (not shown), and the driving force of the power steering motor 30 is adjusted so that the steering torque is determined according to the vehicle speed or the like. By being transmitted to the driven pulley shaft 24 through the worm 32 and the worm wheel 33, the steering operation of the driver is assisted by the driving force of the power steering motor 30.

  When the cable type steering device is assembled, initial tension is applied to the inner cables 15i and 16i, and the flange 49b of the stopper 49 is in contact with the right end of the outer pipe 46 (see FIG. 3). When permanent elongation occurs in the inner cables 15i, 16i from this state and the tension decreases, the stopper 49 is urged to the right by the elastic force of the spring 51 set in the compressed state, and the inner pipe 48 integrated with the stopper 49 is provided. The base 44 and the outer tubes 15o, 16o are pushed out to the right (see FIG. 5). Thus, the outer tubes 15o, 16o move to the right relative to the inner cables 15i, 16i, whereby the tension of the inner cables 15i, 16i can be increased to compensate for the permanent elongation. Moreover, since the outer tubes 15o and 16o are only urged to the right side by the spring 51, the structure is very simple.

  Since the moving speed of the piston 48b accompanying the permanent extension of the inner cables 15i, 16i is extremely small, the movement of the hydraulic oil from the second oil chamber 54 to the first oil chamber 53 is obstructed via the choke 46b or the check valve 61. Done without.

  Now, when the driver suddenly operates the steering handle 11, the tension of the inner cables 15i, 16i increases, so the outer tubes 15o, 16o pulled by the inner cables 15i, 16i compress the spring 51 by the flange 49b of the stopper 49. While trying to move to the left. If the outer tubes 15o, 16o are moved to the left in this way, the tension of the inner cables 15i, 16i is reduced, so that the steering handle 11 is lightened and the rigidity is lost, and the steering feeling is lowered. End up.

  However, in this embodiment, the inner pipe 48 integrated with the outer tubes 15o, 16o is pulled to the left side, so that the piston 48b provided on the inner pipe 48 is inside the cylinder 46b provided on the outer pipe 46 fixed to the drive pulley housing 12. If the check valve 61 is closed, it is difficult for the hydraulic oil in the first and second oil chambers 53 and 54 to pass through the choke 48c formed in the piston 48b. A large resistance is generated that prevents the outer tubes 15o, 16o from moving to the left.

  In this way, resistance is provided to the movement of the piston 48b by the hydraulic damping force generated by the damping force generating means 57, so that the outer tubes 15o, 16o are not pulled suddenly to the left side by being pulled by the inner cables 15i, 16i. The tension of the inner cables 15i, 16i can be prevented from abruptly decreasing to secure the rigidity of the steering handle 11, and the steering feeling can be prevented from being lowered.

  By the way, when the steering handle 11 is rotated to the limit position, the outer tubes 15o and 16o pulled by the inner cables 15i and 16i tend to move to the left while compressing the spring 51 by the flange 49b of the stopper 49. If this state is maintained for a long time, the check valve 61 is closed, so that the hydraulic oil in the first oil chamber 53 gradually moves to the second oil chamber 54 via the choke 48c, and the first oil The volume of the chamber 53 decreases and the volume of the second oil chamber 54 increases.

  When the steering handle 11 is returned to the neutral position, the tension of the inner cables 15i, 16i decreases, so that the stopper 49 is urged to the right side by the elastic force of the spring 51, and the hydraulic oil in the second oil chamber 54 becomes the first oil. Returning to the chamber 53, tension reduction of the inner cables 15i, 16i is prevented. At this time, if the check valve 61 does not exist, the hydraulic oil in the second oil chamber 54 passes through the choke 48c and returns to the first oil chamber 53, so that the stopper 49 can quickly return to the original position. Therefore, there is a possibility that the tension of the inner cables 15i and 16i may remain reduced.

  However, according to the present embodiment, the hydraulic oil is returned from the second oil chamber 54 to the first oil chamber 53 via the opened check valve 61 without passing through the choke choke 48c. The stopper 49 quickly returns to the original position by the force, and the tension of the inner cables 15i, 16i increases rapidly, and the steering feeling due to the decrease in the tension of the inner cables 15i, 16i can be prevented more reliably.

  The embodiments of the present invention have been described above, but various design changes can be made without departing from the scope of the present invention.

  For example, in the embodiment, the drive pulley housing 12 is provided with springs 51 and 51 and damping force generating means 57 and 57. They may be provided on the driven pulley housing 14 side.

Overall perspective view of cable-type steering device 2-2 line enlarged sectional view of FIG. Part 3 enlarged view of FIG. 4-4 enlarged cross-sectional view of FIG. Action explanatory diagram corresponding to FIG.

Explanation of symbols

11 Steering handle 12 Drive pulley housing 13 Steering gear box 14 Driven pulley housing 15 Operation cable 15i Inner cable 15o Outer tube 16 Operation cable 16i Inner cable 16o Outer tube 22 Drive pulley 25 Driven pulley 46b Cylinder 48b Piston 48c Choke 51 Spring (Tension adjustment) means)
53 First oil chamber 54 Second oil chamber 57 Damping force generating means 61 Check valve WL Wheel WR Wheel

Claims (3)

A driving pulley (22) connected to the steering handle (11) for rotation, a driven pulley (25) connected to the steering gear box (13) for turning the wheels (WL, WR), and a driving pulley ( 22) and an operation cable (15, 16) for connecting the driven pulley (25), a tension adjusting means (51) for generating an elastic force for applying tension to the operation cable (15, 16), and a steering handle (11). When the tension of the operation cables (15, 16) is increased by the steering torque input to the tension torque), a damping force for maintaining the tension of the operation cables (15, 16) in an increased state is applied to the tension adjusting means (51). A cable-type steering device comprising damping force generating means (57),
The cable-type steering device, wherein the damping force generating means (57) generates a damping force larger when the tension of the operation cables (15, 16) is increased than when the tension is decreased.   The operation cables (15, 16) have both ends inside the outer tube (15o, 16o) supported by the drive pulley housing (12) and the driven pulley housing (14), and both ends are driven pulley (22) and driven pulley ( 25) The inner cable (15i, 16i) wound around 25) is slidably accommodated, and the tension adjusting means (51) is connected to the drive pulley housing (12) and the driven end of the outer tube (15o, 16o). The cable type steering apparatus according to claim 1, wherein the spring is urged in a direction away from one of the pulley housings (14).   The operation cables (15, 16) have both ends inside the outer tube (15o, 16o) supported by the drive pulley housing (12) and the driven pulley housing (14), and both ends are driven pulley (22) and driven pulley ( 25) The inner cable (15i, 16i) wound around 25) is slidably accommodated, and the damping force generating means (57) is provided in either the drive pulley housing (12) or the driven pulley housing (14). A cylinder (46b) provided, a piston (48b) connected to the end of the outer tube (15o, 16o) and slidably fitted to the cylinder (46b), and a partition inside the cylinder (46b) And the first and second oil chambers (53, 54) separated by the piston (48b) and the piston (48b) The choke (48c) for communicating the two oil chambers (53, 54) and a check valve (61) arranged in parallel to the choke (48c), according to claim 1, Cable-type steering device.

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