JP5311862B2 - Steering device - Google Patents

Description

  The present invention relates to a steering device that converts rotation of a rotating shaft of a motor into expansion and contraction of an output rod by a feed screw mechanism and changes a toe angle of a wheel connected to the output rod.

By controlling expansion and contraction of the upper link and lower link of the suspension system of the vehicle with an actuator to suppress changes in the camber angle and the ground tread due to the bump and rebound of the wheel, the steering stability performance is improved with a motor. The one constituted by a feed screw mechanism provided with a male screw member and a female screw member that rotate relative to each other is known from Patent Document 1 below.
Japanese Examined Patent Publication No. 6-47388

  By the way, in this type of actuator using a feed screw mechanism, since there is a small backlash between the member receiving the thrust force and the housing among the male screw member and the female screw member that rotate relative to each other, noise is generated by the backlash. In other words, the male screw member and the female screw member are relatively rotated by a vibrational load or a large load that is reversely transmitted from the output side, causing the actuator to expand and contract unintentionally. Therefore, when such an actuator is used in a steering device, not only noise is generated, but the actuator may be expanded and contracted by a load that is transmitted back from the wheel side, and the toe angle of the wheel may become unstable. In order to prevent this, it is only necessary to generate a holding torque that restricts the relative rotation of the male screw member and the female screw member in the motor. However, this causes a new problem that the power consumption of the motor increases. .

  The present invention has been made in view of the above circumstances, and an object thereof is to mechanically restrict the expansion / contraction actuator of a steering device using a feed screw mechanism from generating noise or expanding / contracting due to external force.

In order to achieve the above object, according to the first aspect of the present invention, the rotation of the rotating shaft of the motor is converted into the expansion and contraction movement of the output rod by the feed screw mechanism, and the toe of the wheel connected to the output rod is converted. A steering device for changing an angle, wherein one of a male screw member and a female screw member of the feed screw mechanism is connected to the output rod, and the other of the male screw member and the female screw member is connected to a rotating shaft of the motor. In the apparatus, a thrust receiving flange for transmitting a thrust force acting from one of the male screw member and the female screw member to the other through a thrust bearing and a washer is provided on the other of the male screw member and the female screw member, and the thrust the receiving flange, of the thrust receiving flange, from the output rod in the axial direction of the feed screw mechanism On the side surface of the stomach-side only, said by the thrust receiving flange engaging the resiliently urging means consisting of a spring or rubber for resiliently urging said axially, said by the elastic biasing force of the resiliently urging means There is proposed a steering device that suppresses backlash in the axial direction between a side surface of the thrust receiving flange closer to the output rod in the axial direction and the housing.

According to the invention described in claim 2, in addition to the first aspect, comprising a coupling for transmitting the rotation of the rotation shaft of the motor to the male screw member, said resilient within said coupling steering apparatus characterized by disposing the urging means Ru been proposed.

According to the invention described in claim 3 , in addition to the configuration of the invention of claim 1 or 2 , the wheel is a rear wheel, and the output rod is provided at the rear part of the knuckle that rotatably supports the rear wheel. A steering apparatus characterized by being connected is proposed.

  The second housing 32 of the embodiment corresponds to the housing of the present invention, and the rear wheel W of the embodiment corresponds to the wheel of the present invention.

  According to the configuration of the first aspect, when the motor is driven, the rotation of the rotating shaft is converted into the expansion / contraction motion of the output rod by the feed screw mechanism, and the toe angle of the wheel connected to the output rod can be changed. When the motor stops and the toe angle of the wheel is maintained, if there is play between the feed screw mechanism and the housing, the output rod will expand and contract with respect to the housing, causing the toe angle of the wheel to become unstable. The thrust receiving flange provided on the other side (the side not connected to the output rod) of the male screw member and female screw member of the feed screw mechanism is attached to the housing by the elastic biasing means. By supporting elastically in the direction of thrust force and preventing backlash, the output rod is prevented from unintentionally expanding and contracting, and the toe angle of the wheel becomes unstable and noise is generated. Can be prevented. In addition, since it is not necessary to prevent the expansion and contraction of the output rod by supplying a holding current to the motor at that time, there is no problem of increasing the power consumption of the motor. Furthermore, since the thrust receiving flange is elastically supported by the bullet urging means, it is possible to effectively prevent the play by supporting the thrust receiving flange having a large area.

  According to the second aspect of the present invention, since the bullet urging means is disposed inside the coupling that transmits the rotation of the rotating shaft of the motor to the feed screw mechanism, the bullet urging means is arranged in a compact manner for steering. The apparatus can be miniaturized.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

  1 to 6 show a first embodiment of the present invention. FIG. 1 is a perspective view of a suspension device for a left rear wheel, FIG. 2 is a view in the direction of the arrow 2 in FIG. 1, and FIG. FIG. 4 is an enlarged view of part 4 of FIG. 3, FIG. 5 is an enlarged view of part 5 of FIG. 3, and FIG. 6 is an exploded perspective view of the speed reducer and coupling.

  As shown in FIGS. 1 and 2, a double wishbone type rear suspension S for a four-wheel steering vehicle includes a knuckle 11 that rotatably supports a rear wheel W, and an upper that connects the knuckle 11 to a vehicle body so as to be movable up and down. The arm 12 and the lower arm 13, a toe control actuator 14 for connecting the knuckle 11 and the vehicle body to control the toe angle of the rear wheel W, a damper 15 with a suspension spring for buffering the vertical movement of the rear wheel W, and the like.

  The distal ends of the upper arm 12 and the lower arm 13 whose base ends are connected to the vehicle body by rubber bush joints 16 and 17, respectively, are connected to the upper and lower portions of the knuckle 11 via ball joints 18 and 19, respectively. The toe control actuator 14 has a proximal end connected to the vehicle body via a rubber bush joint 20 and a distal end connected to the rear portion of the knuckle 11 via a rubber bush joint 21. The lower end of the suspension spring-equipped damper 15 whose upper end is fixed to the vehicle body (upper wall 22 of the suspension tower) is connected to the upper portion of the knuckle 11 via the rubber bush joint 23.

  When the toe control actuator 14 is driven to extend, the rear portion of the knuckle 11 is pushed outward in the vehicle width direction, the toe angle of the rear wheel W changes in the toe-in direction, and when the toe control actuator 14 is driven to contract, the rear portion of the knuckle 11 is Pulled inward in the width direction, the toe angle of the rear wheel W changes in the toe-out direction. Therefore, in addition to normal steering of the front wheels by operating the steering wheel, by controlling the toe angle of the rear wheel W according to the vehicle speed and the steering angle of the steering wheel, the straight running stability performance and turning performance of the vehicle can be improved. it can.

  Next, the structure of the toe control actuator 14 will be described in detail with reference to FIGS.

  As shown in FIGS. 3 and 4, the toe control actuator 14 includes a first housing 31 integrally provided with a rubber bush joint 20 connected to the vehicle body side, and a rubber bush joint 21 connected to the knuckle 11 side. And a second housing 32 that supports the integrally provided output rod 33 so that the output rod 33 can extend and contract. The opposing portions of the first and second housings 31 and 32 are in a state where they are inlay-fitted through a seal member 34. The coupling flanges 31a and 32a are integrated by fastening with a plurality of bolts 35. A motor 36 with a brush as a driving source is housed in the first housing 31, and a planetary gear type reduction gear 37, an elastic coupling 38, and a trapezoidal screw are used in the second housing 32. The feed screw mechanism 39 is housed.

  The outer shell of the motor 36 includes a yoke 40 having a flange 40a and formed in a cup shape, and a bearing holder 42 fastened to the flange 40a of the yoke 40 with a plurality of bolts 41. Bolts 41 for fastening the yoke 40 and the bearing holder 42 are screwed into the end face of the first housing 31, and the motor 36 is fixed to the first housing 31 using the bolts 41.

  The rotor 44 disposed in the annular stator 43 supported on the inner peripheral surface of the yoke 40 is rotatably supported at one end of a rotating shaft 45 by a ball bearing 46 provided at the bottom of the yoke 40 and at the other end. A ball bearing 47 provided on the holder 42 is rotatably supported. A brush 49 that is in sliding contact with a commutator 48 provided on the outer periphery of the rotating shaft 45 is supported on the inner surface of the bearing holder 42. The conducting wire 50 extending from the brush 49 is drawn to the outside through a grommet 51 provided in the first housing 31.

  As apparent from FIGS. 4 and 6, the speed reducer 37 is configured by connecting the first planetary gear mechanism 61 and the second planetary gear mechanism 62 in two stages. The first planetary gear mechanism 61 includes a ring gear 63 that is fitted and fixed to the opening of the second housing 32, a first sun gear 64 that is directly formed at the tip of the rotating shaft 45 of the motor 36, and a disk-like shape. The first carrier 65 and the first pinion pins 66, which are cantilevered by press-fitting into the first carrier 65, are rotatably supported via ball bearings 67, and simultaneously mesh with the ring gear 63 and the first sun gear 64. And four first pinions 68. The first planetary gear mechanism 61 decelerates and transmits the rotation of the first sun gear 64 that is an input member to the first carrier 65 that is an output member.

  The second planetary gear mechanism 62 of the speed reducer 37 includes a ring gear 63 common to the first planetary gear mechanism 61, a second sun gear 69 fixed to the center of the first carrier 65, a disc-shaped second carrier 70, and the like. Four second pinion pins 71, which are cantilevered by press-fitting into the second carrier 70, are rotatably supported via slide bushes 72, and simultaneously mesh with the ring gear 63 and the second sun gear 69. 2 pinions 73... The second planetary gear mechanism 62 decelerates and transmits the rotation of the second sun gear 69 that is an input member to the second carrier 70 that is an output member.

  Thus, by connecting the first and second planetary gear mechanisms 61 and 62 in series, a large reduction ratio can be obtained, and the reduction gear 37 can be downsized. Further, since the sun gear 64 of the first planetary gear mechanism 61 is formed directly on the rotating shaft 45 without being fixed to the rotating shaft 45 of the motor 36, the parts are compared with the case where the first sun gear 64 separate from the rotating shaft 45 is used. Not only can the number of points be reduced, but also the diameter of the first sun gear 64 can be minimized and the reduction ratio of the first planetary gear mechanism 61 can be set large.

  The second carrier 70 that is an output member of the speed reducer 37 is connected to a thrust receiving flange 74 that is an input member of the feed screw mechanism 39 via a coupling 38. The substantially disc-shaped thrust receiving flange 74 is supported rotatably by being sandwiched between a pair of thrust bearings 75 and 76 at the outer periphery thereof. That is, an annular lock nut 78 is fastened to the inner peripheral surface of the second housing 32 so as to sandwich the spacer collar 77, and one thrust bearing 75 is a thrust load between the second housing 32 and the thrust receiving flange 74. The other thrust bearing 76 is arranged to support the thrust load between the lock nut 78 and the thrust receiving flange 74.

  A washer 111 is disposed between one thrust bearing 75 and the second housing 32, and a resilient urging force comprising a washer 112 and a disc spring provided with a set load between the other thrust bearing 76 and the lock nut 78. A means 113 is arranged.

  The coupling 38 includes two outer elastic bushes 79 and 79 made of, for example, polyacetal, and one inner elastic bush 80 made of, for example, silicon rubber, and each has eight on the outer periphery thereof. , 80a, and eight grooves 79b, 80b,... Protrude radially at equal intervals. On the other hand, on the opposing surfaces of the second carrier 70 and the thrust receiving flange 74, four claws 70a, 74a,... Protrude so as to face each other at equal intervals in the axial direction.

  The outer elastic bushes 79, 79 and the inner elastic bush 80 are overlapped so that the phases of the protrusions 79a, 80a,... Are aligned, and the second carrier 70 is placed in every other four of the eight grooves 79b, 80b,. Are engaged, and the remaining four of the eight grooves 79b, 80b are engaged with the four claws 74a of the thrust receiving flange 74.

  As is clear from FIG. 5, the first slide bearing 91 is fixed to the inner peripheral surface of the axially intermediate portion of the second housing 32, and the end member 93 that is screwed to the axial end portion of the first housing 32 is inside. A second slide bearing 92 is fixed to the peripheral surface, and the output rod 33 is slidably supported by the first and second slide bearings 91 and 92. The feed screw mechanism 39 that converts the rotational movement of the thrust receiving flange 74 into the thrust movement of the output rod 33 includes a male screw member 95 that passes through the center of the thrust receiving flange 74 and is fastened by a nut 94 (see FIG. 4). A female screw member 96 that is screwed onto the outer periphery of the male screw member 95 and is fitted to the inner peripheral surface of the hollow output rod 33 and fixed by a lock nut 97 is provided.

  As described above, since the output rod 33 is supported by the second housing 32 via the first and second slide bearings 91 and 92, the radial load applied to the output rod 33 is reliably supported by the second housing 32. The feed screw mechanism 39 can be prevented from being damaged.

  A stroke sensor 102 provided in the second housing 32 for detecting the stroke position of the output rod 33 and feeding it back to the control device when the toe control actuator 14 is expanded and contracted is provided on the outer peripheral surface of the output rod 33 with a bolt 103. And a sensor main body 106 that houses a detection unit 105 such as a coil that magnetically detects the position of the detection unit 104. In the second housing 32, an opening 32 b extending in the axial direction is formed so as to prevent the detected portion 104 from interfering with the movement of the output rod 33.

  In order to prevent water and dust from entering the gap between the second housing 32 and the output rod 33, the boot 108 is inserted into the annular step 32 c formed in the second housing 32 and the annular groove 33 a formed in the output rod 33. The both ends are fitted and fixed by bands 109 and 110, respectively.

  When the output rod 33 extends, the volume of the internal space of the first and second housings 31 and 32 increases, and conversely, when the output rod 33 contracts, the volume of the internal space of the first and second housings 31 and 32 decreases. The pressure in the internal space may fluctuate and hinder the smooth operation of the toe control actuator 14. However, since the internal space of the hollow output rod 33 and the internal space of the boot 108 communicate with each other through the vent hole 33 b formed in the output rod 33, the pressure fluctuation is reduced by the deformation of the boot 108. The toe control actuator 14 can be smoothly operated.

  When an axial load is input from the output rod 33 of the toe control actuator 14 to the female screw member 96 of the feed screw mechanism 39 due to the load transmitted from the road surface unevenness to the rear wheel W, the male screw is connected to the second housing 32. When the member 95 has an axial backlash, a sufficient frictional force does not act on the meshing portion of the male screw member 95 and the female screw member 96, so that the male screw member 95 against the female screw member 96 that moves in the axial direction. May gradually rotate, and the toe angle of the rear wheel W may change. At this time, if the motor 36 connected to the male screw member 95 is energized to suppress rotation, it is possible to prevent a change in the toe angle of the rear wheel W. However, in this way, the power consumption of the motor 36 increases. There is a problem to do.

  However, according to the present embodiment, the thrust receiving flange 74 is urged so as to be pressed against the second housing 32 by the elastic urging means 113 formed of a disc spring, and the backlash between the male screw member 95 and the second housing 32 is increased. Therefore, even if a sufficient frictional force is applied to the meshing portion of the male screw member 95 and the female screw member 96 and the female screw member 96 tries to move in the axial direction by the load transmitted from the rear wheel W, the female screw member 96 In contrast, the male screw member 95 can be prevented from rotating and the toe angle of the rear wheel W can be prevented, and noise can be reduced by eliminating the play.

  Next, a second embodiment of the present invention will be described with reference to FIG.

  In the second embodiment, the bullet biasing means 113 made of a disc spring according to the first embodiment is replaced with a bullet biasing means 113 made of an annular rubber. This bullet urging means 113 is mounted in a compressed state by applying a set load in the axial direction. Also according to the second embodiment, it is possible to achieve the same effect as that of the first embodiment.

  Next, a third embodiment of the present invention will be described with reference to FIG.

  The third embodiment is a modification of the second embodiment, and its elastic urging means 113 has rubber rings 115 and 115 fixed to the outer peripheral portion and inner peripheral portion of an annular metal plate 114. Consists of. The rubber rings 115 and 115 are mounted in a compressed state by applying a set load in the axial direction. Also according to the third embodiment, it is possible to achieve the same operational effects as those of the first embodiment.

  Next, a fourth embodiment of the present invention will be described with reference to FIG.

  The fourth embodiment is a modification of the third embodiment, and the bullet urging means 113 includes a plurality of through holes 114a that are spaced apart from each other by a predetermined distance in the circumferential direction on the annular metal plate 114. The rubber bushes 116 are attached to the through holes 114a in a compressed state by applying a set load in the axial direction. Also according to the fourth embodiment, the same effect as that of the first embodiment can be achieved.

  Next, a first reference embodiment will be described based on FIG.

  In the first reference embodiment, the thrust receiving flange 74 is provided with an elastic urging means 113. That is, the thrust receiving flange 74 is formed with a plurality of through holes 74b spaced apart by a predetermined distance in the circumferential direction, and the rubber bushes 117 mounted in a compressed state by applying a set load to the through holes 74b in the axial direction. Are abutted against washers 118 and 119 disposed on the thrust receiving flange 74 side of one and the other thrust bearings 75 and 76. Also in the first reference embodiment, the elastic bushing 117... Is elastically stretched in the axial direction to suppress the backlash of the thrust receiving flange 74 and the male screw member 95 with respect to the second housing 32. The same effect as that of the embodiment can be achieved.

  Next, a second reference embodiment will be described based on FIG.

  This second reference embodiment is a modification of the first reference embodiment, and uses coil springs 120 instead of the rubber bushes 117. That is, a plurality of concave portions 74c that are spaced apart by a predetermined distance in the circumferential direction are formed on both side surfaces of the thrust receiving flange 74, and coil springs 120 that are mounted in a compressed state in these concave portions 74c are respectively attached to the washers 118 and 119. Abut. Also according to the second reference embodiment, the elastic force of the coil springs 120 to extend in the axial direction suppresses the backlash of the thrust receiving flange 74 and the male screw member 95 with respect to the second housing 32, and the first embodiment. The same effect as that of the embodiment can be achieved.

  Next, a fifth embodiment of the present invention will be described with reference to FIG.

  In the fifth embodiment, the bullet biasing means 113 is housed inside the coupling 38. That is, a dish in which a set load is applied between the second carrier 70 on which the outer elastic bushes 79, 79 of the coupling 38 and the claws 70a ... for supporting the inner elastic bush 80 are formed and the one outer elastic bush 79. A bullet biasing means 113 made of a spring is arranged. This elastic urging means 113 urges the thrust receiving flange 74 toward the second housing 32 via the outer elastic bushes 79 and 79 and the inner elastic bush 80, so that the play of the male screw member 95 with respect to the second housing 32 is reduced. It can suppress and can achieve the effect similar to 1st Embodiment. In addition, the toe control actuator 14 can be downsized by arranging the bullet urging means 113 using the space inside the coupling 38.

Next, a third reference embodiment will be described based on FIG.

In FIG. 13A , an elastic biasing means 113 is disposed between the thrust receiving flange 74 and the lock nut 78. However, when a strong compressive load is applied to the toe control actuator 14, an elastic spring made of a disc spring is provided. The thrust urging means 113 may be completely crushed and play may occur in the thrust receiving flange 74. To prevent this, the large-sized bullet urging means 113 is attached with a large set load. There is a need.

Therefore, in this embodiment, the compression load input to the toe control actuator 14 is smaller than the tensile load due to the characteristics of the rear suspension device S (see FIG. 13A) and the compression input to the toe control actuator 14. The mounting position of the elastic urging means 113 with respect to the thrust receiving flange 74 is changed with a load that is larger than the tensile load (see FIG. 13B).

  In FIG. 13A, attention is paid to the fact that the compression load input to the toe control actuator 14 is smaller than the tensile load, and the elastic urging means 113 is compressed when a relatively small compression load is applied. Thus, the bullet urging means 113 is arranged on the lock nut 97 side of the thrust receiving flange 74. Thereby, when a relatively large tensile load is applied, the bullet biasing means 113 is not completely crushed, and a small one can be used as the bullet biasing means 113.

  In FIG. 13B, attention is paid to the fact that the compressive load input to the toe control actuator 14 becomes larger than the tensile load, and the elastic biasing means 113 is compressed when a relatively small tensile load is applied. In this manner, the bullet urging means 113 is arranged on the opposite side of the thrust receiving flange 74 from the lock nut 78. Thereby, when a relatively large compressive load is applied, the bullet urging means 113 is not completely crushed, and a small one can be used as the bullet urging means 113.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various design changes can be made without departing from the present invention described in the claims. Is possible.

  For example, in the embodiment, of the male screw member 95 and the female screw member 96 of the feed screw mechanism 39, the axial backlash of the male screw member 95 is suppressed by the elastic urging means 113. However, the female screw member 96 is connected to the motor 36. The male screw member 95 may be connected to the output rod 33 so that the axial play of the female screw member 96 may be suppressed by the elastic biasing means 113.

  In the seventh embodiment, the elastic biasing means 113 made of a disc spring is disposed inside the coupling 38, but the disc spring can be replaced with an elastic material such as rubber. Further, by applying a set load to the inner elastic bush 80 made of silicon rubber of the coupling 38 and compressing the inner elastic bush 80, the inner elastic bush 80 can function as the elastic urging means 113.

The perspective view of the suspension device of the left rear wheel concerning a 1st embodiment 2 direction view of FIG. 3-3 enlarged sectional view of FIG. 4 enlarged view of FIG. 5 enlarged view of FIG. Exploded perspective view of reducer and coupling The figure which shows the bullet urging means which concerns on 2nd Embodiment. The figure which shows the bullet energizing means which concerns on 3rd Embodiment The figure which shows the bullet urging means which concerns on 4th Embodiment The figure which shows the bullet urging means which concerns on 1st reference embodiment The figure which shows the bullet urging means which concerns on 2nd reference embodiment. The figure which shows the bullet urging means which concerns on 5th Embodiment The figure which shows the bullet biasing means which concerns on 3rd reference embodiment

32 Second housing (housing)
33 Output rod 36 Motor 38 Coupling 39 Feed screw mechanism 45 Rotating shaft 74 Thrust receiving flange
75,76 Thrust bearing 95 Male thread member 96 Female thread member
111, 112 washers 113 bullet urging means W rear wheels

Claims (3)

The rotation of the rotating shaft (45) of the motor (36) is converted into expansion and contraction of the output rod (33) by the feed screw mechanism (39), and the toe angle of the wheel (W) connected to the output rod (33) is changed. A steering device to change,
One of the male screw member (95) and the female screw member (96) of the feed screw mechanism (39) is connected to the output rod (33), and the other of the male screw member (95) and the female screw member (96) is connected to the output rod (33). In the steering device connected to the rotating shaft (45) of the motor (36), a thrust force acting on one of the male screw member (95) and the female screw member (96) is applied to a thrust bearing (75, 76) and a washer ( 111, 112) is provided on the other of the male screw member (95) and the female screw member (96) with a thrust receiving flange (74) that is transmitted to the housing (32) via
The thrust receiving flange (74) includes the thrust receiving flange (74) only on the side surface of the thrust receiving flange (74 ) that is farther from the output rod (33) in the axial direction of the feed screw mechanism (39). ) Is engaged with a spring urging means (113) made of a spring or rubber that urges and urges it in the axial direction, and the thrust receiving flange (113) is generated by the elastic urging force of the elastic urging means (113). 74), the axial play between the side surface close to the output rod (33) in the axial direction and the housing (32) is suppressed. Wherein a motor coupling rotating shaft rotation (45) for transmitting said external thread member (95) (36) (38), said resilient biasing means in the interior of the coupling (38) to (113) and wherein placing the steering equipment according to claim 1.   The wheel is a rear wheel (W), and the output rod (33) is connected to a rear portion of a knuckle (11) that rotatably supports the rear wheel (W). The steering apparatus as described in.

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