JP4440018B2 - Power steering device - Google Patents

Description

  The present invention relates to a power steering device provided in a steering device for a vehicle, and more particularly to a power steering device including a belt-type transmission mechanism that transmits an auxiliary steering force generated by an actuator to a steering member.

For example, Patent Literatures 1 and 2 disclose power steering devices including a belt-type transmission mechanism.
The power steering device disclosed in Patent Document 1 includes a belt wound around a drive pulley attached to a motor shaft of an electric motor and a driven pulley connected to a rack shaft, and the drive pulley is connected to the motor shaft via the motor shaft. The lid is rotatably supported by a lid that closes the opening of the motor case of the electric motor and a bracket that is attached to the lid. The lid is coupled to the housing by a bolt.
The power steering device disclosed in Patent Document 2 includes an input pulley attached to a rotating shaft of an electric motor and a belt wound around an output pulley connected to the steering shaft, and the input pulley is connected via the input shaft. , And is rotatably supported by a connecting housing or a movable housing coupled to the rack housing. For example, the connecting housing is coupled to the rack housing by bolts at a position corresponding to the center of the belt in the rotation center line direction of the input pulley, and the movable housing is on both sides of the belt in the rotation center line direction. It is fitted and held in the rack housing.
Japanese Patent Laying-Open No. 2003-291830 (FIGS. 5 and 6) Japanese Unexamined Patent Publication No. 2003-220959 (FIGS. 5, 7, and 8)

  By the way, in the prior art disclosed in Patent Document 1, the driving pulley has a rotation center line direction (hereinafter referred to as “shaft”) of the driving pulley with respect to the belt by a support member in which a lid and a bracket are coupled and integrated by a bolt. Is supported on both sides in the direction. At this time, one end of the bracket serves as a constraining end coupled to the housing via the lid, while the other end serves as a free end. Therefore, if the rigidity of the bracket is not sufficiently secured, The bracket is bent by the tension, and the parallel positional relationship between the rotation center lines of the driving pulley and the driven pulley is lost. As a result, the torque transmission efficiency is reduced due to the contact of the belt, and the steering feeling is lowered. Therefore, if the rigidity of the bracket is increased in order to prevent the bending due to the belt tension, the bracket is increased in size and the power steering device is increased in size.

  Further, as in the prior art disclosed in Patent Document 2, the coupling housing is coupled to the housing at the center of the belt in the axial direction, or the movable housing is fitted and held on both sides of the belt in the axial direction. It is conceivable to prevent or suppress the occurrence of bending due to the tension of the belt in the support member (corresponding to a connecting housing or a movable housing) that supports the drive pulley. However, if such a connecting housing or a movable housing is applied to the prior art disclosed in Patent Document 1, it is difficult to use the housing, which requires a significant design change of the support member or the housing, and the cost. Will increase.

  The present invention has been made in view of such circumstances, and the invention according to claims 1 to 4 is a power steering device including a belt-type transmission mechanism, wherein the support member of the input pulley is bent by the tension of the belt. An object is to prevent or suppress the problem and to secure a good steering feeling and to suppress the enlargement of the power steering device. The invention described in claims 2 and 3 further aims to prevent or suppress the generation of noise due to vibration of the support member, and to further reduce the cost. The invention described in claim 4 further includes The purpose is to improve the belt tension setting accuracy.

According to a first aspect of the present invention, there is provided a belt that is stretched over an actuator that generates an auxiliary steering force, an input pulley that is rotationally driven by the actuator, and an output pulley that is coupled to a steering member that applies a steering force to a steering wheel. A transmission mechanism, a support member that rotatably supports the input pulley, and a housing member that forms a transmission chamber in which the transmission mechanism is accommodated, and the support member is coupled to the housing member by coupling means. In the power steering apparatus, the support member has a first part on one side and a second part on the other side in the axial direction with respect to the belt, and the housing member is connected to the housing member only by the first part. And the first portion is coupled by the coupling means so that the second portion pushes the housing member in the axial direction. To a power steering apparatus characterized by occupying a predetermined position where the pressing force is obtained which prevents or restricts the said second portion is moved by the tension of the belt.

  According to this, in the state where the power steering device is assembled, only the first portion is coupled to the housing member by the coupling means, so that the support member can perform the second operation even when the belt tension does not act on the support member. Since the pressing force that presses the housing member in the axial direction is applied at the portion, the movement of the second portion by the belt tension is prevented or greatly restricted by the frictional force based on the pressing, and the support member is bent. Is prevented or suppressed. In addition, since the prevention or suppression of the bending is not based only on the rigidity of the support member, an increase in the size of the support member is suppressed.

  According to a second aspect of the present invention, in the power steering device according to the first aspect, the second part is configured to connect the housing member via an elastic member held by at least one member of the second part and the housing member. Press.

  According to this, the vibration generated in the support member and the housing member due to the fluctuation of the auxiliary steering force generated by the actuator and the vibration transmitted from the vehicle body to the power steering device is absorbed by the elastic member. Collision between the second part based on and the housing member is prevented or suppressed. Further, in order for the second portion to press the housing member, it is only necessary to provide a structure for holding the elastic member. Therefore, by making a small structural change to the existing support member or the existing housing member, That's it.

  According to a third aspect of the present invention, in the power steering device according to the second aspect, the elastic member is a wave washer disposed surrounding a rotation center line of the input pulley, or a rubber-like ring made of a material exhibiting rubber-like elasticity. It is a member.

  According to this, the vibration of the support member and the housing member is effectively absorbed by the rubber-like elasticity of the rubber-like annular member such as the O-ring or the elasticity of the wave washer, and the collision between the second portion and the housing member is prevented. Or suppressed. Further, in order to hold the rubber-like annular member or the wave washer, a small structural change to the existing support member or the existing housing member, such as forming a groove, is sufficient.

  According to a fourth aspect of the present invention, in the power steering apparatus according to any one of the first to third aspects, the rotation center line of the input pulley and the rotation center line of the output pulley are used to adjust the tension of the belt. A tension adjuster for adjusting the distance between the centerlines between the support member and the housing member relative to the housing member for adjusting the distance between the centerlines in the first coupling state. The support member and the housing member are relatively movably coupled in a second coupled state so as to be movable in a specific direction, and the second portion is configured to be in the first coupled state. Then, the housing member is pressed with a smaller pressing force than when the predetermined position is occupied, and the predetermined position is occupied in the second coupled state.

  According to this, when the coupling means is in the first coupled state in which the belt tension is adjusted, the second portion pushes the housing member with a pressing force smaller than the pressing force when the coupling means is in the second coupled state. Since the pressing is performed, the bending of the support member due to the tension of the belt is suppressed compared to when the second portion is not pressed, so that the tension can be adjusted with higher accuracy.

  According to invention of Claim 1, the following effect is show | played. That is, the second portion of the support member presses the housing member, so that the support member is prevented from being bent due to the tension of the belt, so that the transmission efficiency of the auxiliary steering force by the belt is prevented from being lowered. A sufficient steering feeling can be secured, and the increase in the size of the support member and the increase in the size of the power steering device can be suppressed.

  According to invention of Claim 2, in addition to the effect of the invention of the cited claim, there exists the following effect. That is, since the collision between the second portion and the housing member based on the vibration of the support member is prevented or suppressed, the generation of noise due to the vibration is prevented or suppressed. Moreover, since the structure for the second portion to press the housing member is only a small structural change with respect to the existing power steering apparatus, no significant design change is required, and the cost can be reduced. .

  According to invention of Claim 3, the effect which the effect of the invention of Claim 2 was further heightened is show | played.

  According to invention of Claim 4, in addition to the effect of the invention of the cited claim, there exists the following effect. That is, since the tension can be adjusted with high accuracy by the tension adjusting unit, the belt tension setting accuracy is improved.

Hereinafter, embodiments of the present invention will be described with reference to FIGS.
Referring to FIG. 1, a vehicle steering apparatus S including a power steering apparatus P to which the present invention is applied includes a handle 1 operated by a driver, and an interlocking mechanism in which a steering force applied to the handle 1 has a steering shaft. 2, a transmission mechanism 4 that transmits the steering force from the gear box 3 to the steering wheel 5, and a power steering device P that generates an auxiliary steering force that assists the steering force by the driver, Is provided.

  The gear box 3 is connected to the gear housing 6 attached to the vehicle body, the input portion 7 attached to the gear housing 6 and transmitting the steering force from the handle 1, and housed in the gear housing 6 and connected to the input portion 7. And an output unit including a conversion mechanism that converts the direction of the steering force from the input unit 7.

  The gear housing 6 includes cylindrical first and second housings 8 and 9 which are coupled to each other at the end portions 8b and 9a and accommodated across a rack shaft 13 which will be described later. In the longitudinal direction of the rack shaft 13, the input portion 7 is coupled to one end portion 8 a of the first housing 8 and a part of the input portion 7 is accommodated, and the transmission mechanism 40 is accommodated in the other end portion 8 b. A first housing portion 11 as a first housing member that forms a transmission chamber 18 (see FIG. 3) in which (see FIG. 3) is housed is provided, and one end portion 9a of the second housing 9 has a first housing portion 11a. A second housing portion 12 as a second housing member that forms the transmission chamber 18 in cooperation with the housing portion 11 is provided. The first and second accommodating portions 11 and 12 are respectively constituted by a part of the housings 8 and 9 made of a single member, and the peripheral portions 11a and 12a of the accommodating portions 11 and 12 (see FIGS. 2 and 3 as well). And a plurality of bolts B1 are detachably coupled.

  The input unit 7 includes an input shaft 7a that is rotationally driven by the handle 1 via the interlocking mechanism 2, an output shaft that is coupled to the input shaft 7a via the torsion bar so as to be relatively rotatable, and a twist amount of the torsion bar. And a torque sensor 7b that detects a steering torque based on the torque.

  The conversion mechanism includes a pinion as a rotational drive unit provided on the output shaft, a rack unit as a driven unit driven by the pinion, and a rack shaft 13 as a steering member provided with the rack unit. The rack shaft 13 extends in the left-right direction of the vehicle with the steering device S mounted on the vehicle, and is driven by a rotating input shaft 7a by a rack and pinion mechanism composed of the pinion and the rack portion. 1. Reciprocating linear motion is performed in the longitudinal direction in the second housings 8 and 9.

  The transmission mechanism 4 includes a pair of tie rods 14 connected to both ends of the rack shaft 13 via ball joints, and a link mechanism 15 connected to each tie rod 14. Then, the steering force from the rack shaft 13 is transmitted through each tie rod 14 and the link mechanism 15 and acts on each steering wheel 5 of the vehicle, and the steering wheel 5 is steered.

  1 to 3, a power steering device P that applies an auxiliary steering force to the rack shaft 13 at the time of turning is a rotary actuator controlled by an electronic control unit to which a steering torque detected by a torque sensor 7b is input. As an electric motor 20, a belt-type transmission mechanism 40 to which an auxiliary steering force generated by the electric motor 20 is input, a ball screw mechanism 50 as a transmission mechanism for transmitting the output of the transmission mechanism 40 to the rack shaft 13, and a transmission And a tension adjusting unit A that adjusts the tension of the belt 43 of the mechanism 40.

  Referring also to FIG. 4, the electric motor 20 coupled to the mounting portion 16 constituted by a part of the first housing portion 11 via the collar 30 has a flange coupled to the collar 30 coupled to the mounting portion 16. A cylindrical case 21 having a mounting portion 22 made of a rotating shaft 23 for rotating an input pulley 41 described later is provided. In the electric motor 20, a pair of bolts B <b> 2 that are respectively inserted into a pair of insertion holes provided at positions facing the mounting portion 22 across the rotation center line L <b> 1 of the rotary shaft 23 are provided in the collar 30. By being respectively screwed into a pair of screw holes 31c (see FIG. 4), the rotation center line L1 is attached to the collar 30 and thus to the attachment portion 16 so as to be substantially parallel to the longitudinal direction.

  2 and 3, a transmission mechanism 40, which is also a speed reduction mechanism, is connected to a rotary shaft 23 via a shaft coupling 24 and is driven to rotate by the electric motor 20, and a rack screw 13 is connected to a ball screw. An output pulley connected via a mechanism 50, and a belt 43 formed of an input pulley 41 and a toothed belt stretched around an output pulley 42 having a larger diameter than the input pulley 41 are provided.

  The columnar input pulley 41 is rotatably coupled to the input pulley 41 and is rotatably supported by the collar 30 via an input shaft 48 that extends parallel to the rotation center line L2 of the input pulley 41. In this embodiment, the input shaft 48 is formed integrally with the input pulley 41, and a pair of shaft end portions 48a, 48b extending across the input pulley 41 is interposed via a bearing 45 formed of a radial ball bearing. The collar 30 is rotatably supported by a pair of bearing portions 33 and 34, respectively. On the other hand, the cylindrical output pulley 42 is rotatably coupled to the pulley 42 and supported by the first accommodating portion 11 via an output shaft 49 extending in parallel with the rotation center line L3 of the output pulley 42. The Note that tooth portions 41d and 42d having a large number of teeth meshing with the teeth of the belt 43 are formed on the outer peripheral surfaces of the pulleys 41 and 42, respectively. In this embodiment, the cylindrical output shaft 49 is formed integrally with the output pulley 42 and is coupled to a ball nut 52 described later so as to be integrally rotatable.

  Referring to FIGS. 3 and 5, the shaft coupling 24 is integrated with the rotary shaft 23 through the ring 25 so as to be integrally rotatable with the rotary shaft 23, and with the input pulley 41 at the shaft end portion 48b. An output member 24b that is rotatably coupled, and a star-shaped buffer member 24c made of synthetic rubber that is interposed between the input member 24a and the output member 24b and is connected to drive the two. The buffer member 24c is sandwiched between a plurality of teeth 24a1 and 24b1 provided on the input member 24a and the output member 24b in the circumferential direction, and prevents the shaft joint 24 from generating noise.

  Referring to FIG. 3, a ball screw mechanism 50 as a motion conversion mechanism that converts the rotational motion of the output pulley 42 into the linear motion of the rack shaft 13 is provided in the sub-accommodating portion 17 constituted by a part of the first accommodating portion 11. Be contained. The ball screw mechanism 50 includes a ball screw shaft portion 51 formed on the rack shaft 13, a ball nut 52 disposed so as to surround the ball screw shaft portion 51, and a thread groove formed on the outer peripheral surface of the ball screw shaft portion 51. 51a and a large number of balls 53 that rolls accommodated across the thread groove 52a formed on the inner peripheral surface of the ball nut 52. A group of balls 53 roll on a return path (not shown) provided in the ball nut 52 and circulate between the ball screw shaft 51 and the ball nut 52. A ball nut 52 accommodated in the transmission chamber 18 is rotatably supported by the first accommodating portion 11 via a bearing 54 formed of a double row angular ball bearing fixed to the sub accommodating portion 17 by an annular lock screw 55. Is done. The ball nut 52 has an output shaft 49 and a bearing 54 arranged on the outer peripheral surface thereof in series along a direction of a rotation center line L4 of the ball nut 52 (also an axial direction T1 described later). Are coupled in a state in which movement in the axial direction T1 is prevented. Thereby, the ball nut 52 rotates integrally with the output pulley 42 so as to have a rotation center line L4 that coincides with the rotation center line L3 of the output pulley 42.

Referring also to FIGS. 2 and 4, the cylindrical collar 30 is capable of rotating the input pulley 41 and the mounting portion C <b> 1 including a flange attached to the mounting portion 16 of the first housing 8 as well as the electric motor 20. It is a single member in which the attachment portion C1 and the support portion C2 are formed by integral molding. The attachment part C1 having a larger diameter than the support part C2 has an annular mating surface 31f with the attachment part 22 of the electric motor 20, and the first attachment part 31 to which the electric motor 20 is attached, and the first accommodating part 11 The second mounting portion 32 has an annular mating surface 32 f with the mounting portion 16 and is attached to the mounting portion 16. The first mounting portion 31 is provided with a pair of screw holes 31c in the pair of fastening portions 31a and 31b, respectively, and the second mounting portion 32 is rotated in the vicinity of the pair of fastening portions 31a and 31b. A pair of fastening portions 32a and 32b formed by stepping back from the mating surface 31f toward the mating surface 32f in the direction (axial direction) T1 of the center line L2 from each screw hole 31c in the circumferential direction. A pair of first and second insertion holes 32c and 32d are provided at an interval. The fastening parts 31a and 31b and the fastening parts 32a and 32b are constituted by projecting portions that project radially outward at the first mounting part 31 and the second mounting part 32, respectively.
In this specification or claims, the “axial direction” means a direction in which the rotation center line L2 of the input pulley 41 extends.

The support portion C2 includes a bearing portion 34 that holds the bearing 45 and a bearing portion 33 that holds the bearing 44 in the order closer to the mounting portion C1 in the axial direction T1. Then, the output member 24b is coupled to the input shaft 48, subjected to the belt 43 is input pulley 41, is disposed, respectively Re between Niso the respective bearings 44, 45 and a pair of belt guide 46 is input pulley 41, Further, the bearing 45 is prevented from moving in the axial direction T 1 by the lock screw 47 with respect to the bearing portion 34. At this time, the belt 43 extends to the outside of the collar 30 through the opening 35 of the support portion C2 provided partially in the circumferential direction between the bearing portions 33 and 34.

  The collar 30 has a first portion located on the electric motor side which is one side in the axial direction T1 with respect to the belt 43 and a second portion located on the opposite side to the electric motor side in the axial direction T1. Have. The first portion includes first and second mounting portions 31 and 32 and a bearing portion 34 constituting the mounting portion C1, and the second portion includes a bearing portion 33. The attachment portion C1 and the bearing portion 33 are a proximal end portion and a distal end portion of the collar 30 in the axial direction T1, respectively.

  In the annular bearing portion 33 in which the bearing 44 is mounted, the end surface 33a facing the second housing portion 12 in the axial direction T1 projects in the axial direction T1 from the end surface 33a toward the second housing portion 12. An annular O-ring 60 as an elastic member constituting the contact portion is held. An O-ring 60, which is a rubber-like annular member made of a material exhibiting rubber-like elasticity, for example, a synthetic rubber, is fitted into an annular groove 33b formed on the end face 33a, and surrounds the rotation center line L2, and the rotation center line L2 Arranged concentrically.

  Further, the collar 30 penetrates through a through hole 16e provided in the mounting portion 16 from the side where the electric motor 20 is arranged in a state where the input pulley 41 on which the belt 43 is hung is supported by the support portion C2. Bolts B3 disposed in the transmission chamber 18 and inserted into the first and second insertion holes 32c and 32d are screwed into a pair of screw holes 16c and 16d provided in the attachment part 16, respectively. It is attached.

  In this way, the input pulley 41 is rotatably supported by the collar 30 as the input side support member via the input shaft 48, and the output pulley 42 is the first accommodating portion 11 or the first first as the output side support member. The housing 8 is rotatably supported via an output shaft 49 and a ball nut 52.

  Referring to FIGS. 2, 4, and 6, the tension adjusting unit A is a structure for adjusting a centerline distance D that is a distance between the rotation centerline L2 and the rotation centerline L3 that are parallel to each other. The tension of the belt 43 is adjusted by adjusting the distance D between the center lines using the tension adjusting section A.

  In the first coupled state, the tension adjusting unit A has the collar 30 and the first housing unit such that the distance D between the center lines and the distance E (see FIG. 3) between the bearing unit 33 and the rotation center line L3 are both changed. 11 is configured to be coupled so as to be relatively movable in a specific direction and to couple the collar 30 and the first housing portion 11 so that relative movement is impossible in the second coupled state. Therefore, the collar 30 attached to the attachment portion 16 by the bolt B3 inserted through the first and second insertion holes 32c and 32d is connected to the gear housing in the first and second accommodation portions 11 and 12 forming the transmission chamber 18. 6, only the second mounting portion 32 included in the first portion is coupled to only the first accommodating portion 11 by the coupling means.

  The coupling means includes a pair of bolts B3, fastening portions 32a and 32b of the second attachment portion 32 provided with the first and second insertion holes 32c and 32d, and an attachment provided with a pair of screw holes 16c and 16d. It is comprised from the fastening part 16a, 16b of the part 16. FIG.

The first insertion hole 32c formed of a circular hole having a center line L5 coinciding with the axis of the bolt B3 when the bolt B3 is inserted has a diameter substantially equal to the outer diameter of the shaft portion of the bolt B3. On the other hand, the second insertion hole 32d, which is a circular hole as an adjustment hole, is larger than the outer diameter of the shaft portion of the bolt B3, and the collar 30 is relative to the first housing portion 11 in order to adjust the tension of the belt 43. It is set to such a size that it can be moved, in this case, relatively swung to adjust the distance D between the center lines. For this reason, in a state where the bolt B3 is partially screwed into the screw holes 16c and 16d to such an extent that the collar 30 is not tightened with respect to the mounting portion 16, that is, in the first coupled state, one fastening portion 32a and the center line L5 (Or the axis of the bolt B3) as the fulcrum part 32a and the oscillating center line L5 of the fulcrum part 32a, respectively, the collar 30 is relatively only in the single oscillating direction T2 with respect to the first housing part 11. It is restrained so that it can swing. Therefore, the specific direction is the swing direction T2 with the swing center line L5 as the center.

  Referring to FIG. 3, the collar 30 is coupled to the first accommodating portion 11 by the bolt B <b> 3 (see FIGS. 2 and 3) of the coupling means at the second mounting portion 32, whereby the O-ring 60 is connected to the second accommodating portion. 12, the bearing portion 33 occupies a predetermined position for pressing the second accommodating portion 12 in the axial direction T <b> 1 via the O-ring 60. This predetermined position is the friction generated between the O-ring 60 and the second accommodating portion 12 based on the pressure by the collar 30 when the tension of the belt 43 acts on the collar 30 via the input pulley 41 and the input shaft 48. Due to the force and deformation resistance, the first pressing force, which is a pressing force that prevents or greatly restricts the movement of the bearing portion 33 due to the tension of the belt 43, is obtained. In addition, the first pressing force is applied to the belt 43 in the assembled state of the power steering device P in which the collar 30 is coupled to the first housing portion 11 and the first and second housing portions 11 and 12 are coupled to each other. Even in a state in which is not acting, it is the force in the axial direction T1 when the bearing portion 33 presses the second accommodating portion 12 via the O-ring 60.

  Then, the protruding amount of the O-ring 60 in the axial direction T1 from the end face 33a is set so that the first pressing force is obtained. When the bearing portion 33 occupies the predetermined position, a clearance in the axial direction T1 is formed between the end surface 33a and the second housing portion 12.

  Further, when the second mounting portion 32 is coupled to the first accommodating portion 11 by the coupling means, the bearing portion 33 included in the second portion is smaller in the first coupled state than when occupying the predetermined position. The second receiving portion 12 is pressed through the O-ring 60 with the second pressing force, which is a pressing force, and occupies the predetermined position in the second coupled state. The second pressing force is set as large as possible within a range in which the collar 30 can swing in the swing direction T2 with respect to the first accommodating portion 11 in the first coupling state by the tension adjusting portion A.

Through the adjustment of the tension of the belt 43 by the tension adjusting unit A, the tension of the belt 43 is adjusted as follows, for example.
Referring to FIGS. 3, 4, and 6, the second accommodating portion 12 is coupled to the first accommodating portion 11, and the transmission mechanism 40 attached to the collar 30 and the ball nut 52 is accommodated in the transmission chamber 18. In this state, both bolts B3 are inserted into the first and second insertion holes 32c and 32d, respectively, so that the coupling structure is brought into the first coupling state. In this first coupled state, the collar 30 can swing in the swing direction T2 within the adjustment range R around the swing center line L5 defined by the fulcrum portion 32a. Next, the collar 30 is swung with respect to the first housing portion 11 within the adjustment range R, and the adjustment of the centerline distance D is completed when a predetermined tension of the belt 43 is obtained. After that, by tightening both bolts B3, the collar 30 and the first accommodating portion 11 are coupled so that relative movement is impossible, and the coupling means is brought into the second coupled state to set the tension. Is completed.

Next, operations and effects of the embodiment configured as described above will be described.
In a power steering apparatus P including a belt-type transmission mechanism 40 that transmits an auxiliary steering force generated by the electric motor 20 and first and second accommodating portions 11 and 12 that form a transmission chamber 18 in which the transmission mechanism 40 is accommodated. The collar 30 that rotatably supports the input pulley 41 has an attachment portion 32 on one side and a bearing portion 33 on the other side in the axial direction T1 with respect to the belt 43, and the bolt B3 can be received only by the second attachment portion 32. When the coupling means is coupled to the first accommodating portion 11 and the coupling means is in the second coupled state, the bearing portion 33 occupies the predetermined position for pressing the second accommodating portion 12 in the axial direction T1. In the state where the power steering device P is assembled, the collar 30 has the first pressing force applied to the second accommodating portion 12 by the bearing portion 33 even in the state where the tension of the belt 43 does not act on the collar 30 via the input pulley 41. Because of the addition of belt 4 The movement of the bearing portion 33 due to the tension of 3 is prevented or greatly restricted by the frictional force and deformation resistance generated between the O-ring 60 and the second housing portion 12 based on the pressing by the collar 30, and the collar 30 Therefore, it is possible to prevent or suppress the transmission efficiency of the auxiliary steering force by the belt 43 and to secure a good steering feeling. In addition, since the prevention or suppression of the bending is not only due to the rigidity of the collar 30 itself, an increase in the size of the collar 30 is suppressed, and thus an increase in the size of the collar 30 and thus an increase in the size of the power steering device P is suppressed. .

  The bearing portion 33 presses the second accommodating portion 12 through an O-ring 60 as an elastic member held by the bearing portion 33, thereby generating an auxiliary steering force generated by the electric motor 20 attached to the collar 30. Since the vibration generated in the collar 30 and the second housing portion 12 due to the fluctuation and the vibration transmitted from the vehicle body to the power steering device P is absorbed by the O-ring 60, the bearing portion 33 and the second portion based on the vibration are absorbed. Collision with the accommodating portion 12 is prevented or suppressed, and generation of noise due to the vibration is prevented or suppressed. Further, in order for the bearing portion 33 to press the second housing portion 12, it is only necessary to provide a structure for holding the O-ring 60, so it is only necessary to make a small structural change to the existing collar. Therefore, a significant design change is not necessary, and the cost can be reduced.

  The O-ring 60 disposed around the rotation center line L2 of the input pulley 41 effectively absorbs the vibration of the collar 30 and the second housing portion 12 by its rubber-like elasticity, so that the bearing portion 33 and the second housing are accommodated. Collision with the part 12 is prevented or suppressed. Further, in order to hold the O-ring 60, only a small structural change to the existing collar, such as the formation of the groove 33b, is required, so that the cost reduction effect and the noise prevention effect are effectively achieved.

  The tension adjusting portion A constituted by the coupling means restrains the collar 30 to be movable relative to the first accommodating portion 11 in the swing direction T2 in order to adjust the centerline distance D in the first coupled state. The collar 30 and the first accommodating portion 11 are relatively immovably coupled in the second coupled state, and the bearing portion 33 is smaller in the first coupled state than when occupying the predetermined position. By pressing the second accommodating portion 12 with a pressing force and occupying the predetermined position in the second coupled state, the bearing portion 33 is in the first coupled state where the tension of the belt 43 is adjusted by the coupling means. When the coupling means is in the second coupling state, the bearing portion 33 presses the second housing portion 12 in order to press the second housing portion 12 with the second pressing force smaller than the first pressing force. Compared to when not, the bending of the collar 30 due to the tension of the belt 43 is suppressed. , And it is possible to adjust the tension with higher accuracy, thereby improving the setting accuracy of the tension of the belt 43.

Hereinafter, an embodiment in which a part of the configuration of the above-described embodiment is changed will be described with respect to the changed configuration.
As the elastic member, a wave washer 61 held by a bearing portion 33 may be used as shown in FIG. The wave washer 61 is fitted in an annular groove 33c formed in the outer peripheral edge portion of the end surface 33a of the bearing portion 33, and is disposed concentrically with the rotation center line L2 so as to surround the rotation center line L2. The wave washer 61 also provides the same noise prevention effect and cost reduction effect as the O-ring 60 due to its elasticity.

  The elastic member may be held by both members of the collar 30 and the second housing portion 12 or only by the second housing portion 12. Even when the elastic member is held in the second housing portion 12, noise is generated due to vibration of the collar 30 and the second housing portion 12, as in the case where the elastic member is held in the collar 30. In order to hold the elastic member, it is only necessary to make a small structural change to the existing second receiving portion, so that no significant design change is required and the cost is reduced. It becomes possible to do.

  The elastic member may be a spring including a disc spring or a rubber-like annular member other than the O-ring 60, for example. Further, the elastic member may have an arbitrary shape other than an annular shape, and may be arranged scattered on the end surface 33a of the bearing portion 33. The elastic member may be formed of a synthetic resin in addition to metal and rubber.

  The abutting portion may be a protruding portion having an arbitrary shape such as an annular shape or a partial annular shape integrally formed with the bearing portion 33 while projecting in the axial direction T1 on the end surface 33a and surrounding the rotation center line L2. Good. Such an abutting portion also provides an effect of preventing the collar 30 from being bent.

  The collar 30 is a member formed by integral molding. However, the collar 30 may be a single member integrated by joining a plurality of members by a joining means such as welding or a bolt. The input pulley 41 and the support shaft 48, or the output pulley 42 and the support shaft 49 may be configured by separate members.

  In the embodiment described above, the relative movement is a relative rocking movement, but may be a relative translational movement. A speed reduction mechanism may be provided between the rotating shaft 23 of the electric motor 20 and the input pulley 41, and the input pulley 41 may be directly connected to the rotating shaft 23. The second insertion hole 32d may be formed by an arc-shaped long hole centered on the swing center line L5. In addition to the electric motor 20, the rotary actuator may be a rotary machine such as a hydraulic motor.

1 is a schematic overall view of a steering apparatus including a power steering apparatus to which the present invention is applied, showing an embodiment of the present invention, and mainly showing a gear box and a power steering apparatus. It is the II-II sectional view taken on the line of FIG. It is the III-III sectional view taken on the line of FIG. It is a figure which shows the principal part in the state in which the color | collar of the power steering apparatus of FIG. 1 was mounted in the 1st accommodating part. It is a disassembled perspective view of the shaft coupling which connects the rotating shaft and input pulley of the electric motor of the power steering apparatus of FIG. It is a figure which shows the general | schematic mode when the collar and 1st accommodating part of the power steering apparatus of FIG. 1 are couple | bonded in the 1st coupling | bonding state by the coupling | bonding means. FIG. 4 shows another embodiment of the present invention and corresponds to the main part of FIG. 3.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Handle, 2 ... Interlocking mechanism, 3 ... Gear box, 4 ... Transmission mechanism, 5 ... Steering wheel, 6 ... Gear housing, 7 ... Input part, 8, 9 ... Housing, 11, 12 ... Housing part, 13 ... Rack Shaft, 14 ... Tie rod, 15 ... Link mechanism, 16 ... Mounting portion, 17 ... Sub-accommodating portion, 18 ... Transmission chamber, 20 ... Electric motor, 21 ... Case, 22 ... Mounting portion, 23 ... Rotating shaft, 24 ... Shaft coupling , 25 ... Ring, 30 ... Collar, 31, 32 ... Mounting part, 33, 34 ... Bearing part, 35 ... Opening, 40 ... Transmission mechanism, 41 ... Input pulley, 42 ... Output pulley, 43 ... Belt, 44, 45 ... Bearing, 46 ... Belt guide, 47 ... Lock screw, 48 ... Input shaft, 49 ... Output shaft, 50 ... Ball screw mechanism, 51 ... Ball screw shaft, 52 ... Ball nut, 53 ... Ball, 54 ... Bearing, 55 ... Lock screw, 56 ... Lock nut, 60 ... O-ring, 61 ... Wave washer,
S: Steering device, P: Power steering device, B1, B2, B3 ... Bolt, A ... Tension adjusting part, L1 to L4 ... Rotation center line, L5 ... Swing center line (center line), C1 ... Mounting part, C2 ... support part, D ... distance between center lines, E ... distance, T1 ... axial direction, T2 ... swinging direction, R ... adjustment range.

Claims (4)

A transmission mechanism having a belt stretched over an actuator that generates an auxiliary steering force, an input pulley that is rotationally driven by the actuator, and an output pulley that is coupled to a steering member that applies a steering force to the steering wheel; and the input In a power steering apparatus comprising: a support member that rotatably supports a pulley; and a housing member that forms a transmission chamber in which the transmission mechanism is accommodated, wherein the support member is coupled to the housing member by a coupling means.
The support member has a first portion on one side and a second portion on the other side in the axial direction with respect to the belt, and is coupled to the housing member by the coupling means only in the first portion. When the one portion is coupled by the coupling means, the second portion presses the housing member in the axial direction, and a pressing force that prevents or regulates the movement of the second portion due to the tension of the belt. A power steering device occupying a predetermined position to be obtained .   The power steering apparatus according to claim 1, wherein the second portion presses the housing member via an elastic member held by at least one member of the second portion and the housing member.   3. The power steering apparatus according to claim 2, wherein the elastic member is a wave washer disposed around a rotation center line of the input pulley or a rubber-like annular member made of a material exhibiting rubber-like elasticity.   A tension adjusting unit for adjusting a distance between the center lines of the rotation center line of the input pulley and the rotation center line of the output pulley in order to adjust the tension of the belt; In order to adjust the distance between the center lines in the coupled state, the support member is restrained so as to be movable in a specific direction relative to the housing member, and the support member and the housing member are relatively moved in the second coupled state. The second portion is configured by the coupling means to be immovably coupled, and the second portion presses the housing member with a smaller pressing force in the first coupled state than when occupying the predetermined position, and the second portion in the second coupled state. The power steering apparatus according to any one of claims 1 to 3, wherein the power steering apparatus occupies a predetermined position.

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