JP2010105434A - Steering force transmission device for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a highly practical steering force transmission device for a vehicle. <P>SOLUTION: The steering force transmission device for the vehicle includes (a) a first shaft 18; (b) a second shaft 54 placed so as to deviative from the shaft 18; (c-1) an engaging part 150 disposed at the end of the first shaft 18 at the rear side of the vehicle and located at a position radially separated from a rotary axis of the first shaft; and (c-2) a guide passage permitting the radial movement of the second shaft 54 of the engaging part 150 which is disposed at the end of the second shaft 54 at the front side of the vehicle. The steering force transmission device includes a mechanism for transmitting the rotation of the second shaft 54 to the first shaft 18. An engaging part holding part 64 of the second shaft 54 having the guide passage is constituted to extend from a partial circumferential region of the second shaft body 62 only in a direction to permit the movement of the engaging part 150. Thus, the weight of the second shaft 54 can be reduced and the moment of inertia of the second shaft 54 can also be reduced. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a vehicle steering force transmission device that transmits a steering force input to a steering operation member to a steering device.

In recent years, a rotation phase of a shaft (hereinafter sometimes referred to as a “first shaft”) connected to one of a steering operation member operated by a driver and a steering device for turning a wheel and the other is connected to the other. Rotation that transmits the rotation of one of the first shaft and the second shaft to the other while changing the rotation phase difference, which is the difference from the rotation phase of the shaft to be rotated (hereinafter also referred to as “second shaft”) Development of a vehicle steering force transmission device including a transmission mechanism is underway. The following patent document describes an example of a steering force transmission device including the rotation transmission mechanism.
JP-A-3-227772

  The steering force transmission device provided with the rotation transmission mechanism has problems of deterioration in mountability and increase in weight due to an increase in size of the steering force transmission device due to the provision of the rotation transmission mechanism. The vehicle steering force transmission device including the rotation transmission mechanism is still under development, has various problems including such problems, and leaves much room for improvement. Therefore, it is considered that the practicality of the steering force transmission device is improved by making various improvements. This invention is made | formed in view of such a situation, and makes it a subject to provide the steering force transmission device for vehicles with high practicality.

  In order to solve the above-described problems, a vehicle steering force transmission device according to the present invention includes: (a) a first shaft; and (b) a rotation axis of the first shaft and its own rotation axis are parallel and rotate. A second shaft disposed in a state where the axial line is deviated by a predetermined distance; and (c-1) the predetermined distance from the rotation axis of the first shaft in the radial direction of the first shaft at the other end of the first shaft. An engaging portion provided at a more distant position; and (c-2) provided at the other end portion of the second shaft so as to extend in the radial direction of the second shaft. And a rotation transmission mechanism configured to include a guide passage that allows the engagement portion to move in the radial direction of the second shaft, and the second shaft is (b-1) the second shaft. (B-2) from the end of the second shaft main body on the first shaft side, It is provided so as to extend in a direction in which movement is allowed, and includes a pair of side wall surfaces that extend parallel to the direction and face each other, and the pair of side wall surfaces serve as guide passages of the rotation transmission mechanism. It has an engaging part clamping part comprised so that it might partition and may engage an engaging part, It is characterized by the above-mentioned.

  In the vehicle steering force transmission device of the present invention, the engaging portion clamping portion, which is the portion that engages the engaging portion of the first shaft in the second shaft, extends over the entire region in the circumferential direction of the second shaft main body portion. Instead, it is provided so as to extend only in a specific direction from a partial region in the circumferential direction. That is, the portion protruding in the radial direction from the second shaft main body portion is made relatively small, and according to the steering force transmission device of the present invention, the weight of the second shaft is reduced, and hence the steering force transmission device is reduced in weight. And the inertial force of the second shaft can be reduced. By having such advantages, the vehicle steering system of the present invention becomes highly practical.

Aspects of the Invention

  In the following, some aspects of the invention that can be claimed in the present application (hereinafter sometimes referred to as “claimable invention”) will be exemplified and described. As with the claims, each aspect is divided into sections, each section is numbered, and is described in a form that cites the numbers of other sections as necessary. This is merely for the purpose of facilitating the understanding of the claimable inventions, and is not intended to limit the combinations of the constituent elements constituting those inventions to those described in the following sections. In other words, the claimable invention should be construed in consideration of the description accompanying each section, the description of the embodiments, etc., and as long as the interpretation is followed, another aspect is added to the form of each section. In addition, an aspect in which some constituent elements are deleted from the aspect of each item can be an aspect of the claimable invention. In each of the following items, each of items (1) to (6) corresponds to each of claims 1 to 6.

(1) a first shaft having one end connected to one of a steering operation member operated by a driver and a steering device that steers a wheel, and rotatably disposed;
One end is connected to the other of the steering operation member and the steering device, and the rotation axis of the first shaft and the rotation axis of the first shaft are parallel to each other, and the rotation axis is rotatable by a predetermined distance. A second shaft disposed on
(A) at the other end of the first shaft, an engaging portion provided at a position away from the predetermined distance in the radial direction of the first shaft from the rotation axis of the first shaft; The other end of the two shafts is provided so as to extend in the radial direction of the second shaft, and engages with the engaging portion of the first shaft, and the engaging portion in the radial direction of the second shaft. And a guide passage that allows movement, and by rotating one of the first shaft and the second shaft, a rotation phase difference that is a difference between rotation phases of the first shaft and the second shaft is obtained. A vehicle steering force transmission device comprising a rotation transmission mechanism configured to rotate while the other is rotating,
The second shaft is
A second shaft body portion which is a body portion thereof;
A pair of sides that are provided so as to extend from the end on the first shaft side of the second shaft main body portion in a direction in which the movement of the engaging portion is allowed, and each of the second shaft main body portions extend in parallel to the direction and face each other And a pair of side wall surfaces including an engagement portion holding portion configured to partition the guide passage of the rotation transmission mechanism and sandwich the engagement portion. Steering force transmission device.

  In the conventional steering force transmission device, the end of the second shaft on the first shaft side is formed in a disc shape extending radially from the entire region in the circumferential direction, and in the radial direction as a guide passage. It has been common to provide extending grooves. However, the second shaft only needs to have a function of guiding the engagement portion of the first shaft in the radial direction of the shaft as the second shaft rotates. That is, only a range necessary for configuring the guide passage only needs to extend from the second shaft main body portion in the radial direction thereof.

  The “second shaft” of the steering force transmission device described in this section is configured to move the engaging portion of the first shaft in the engaging portion holding portion in the radial direction of the shaft as the second shaft rotates. To guide you. Because of this function, the engaging portion clamping portion of the second shaft is provided to allow the movement of the engaging portion, and from the end on the first shaft side of the second shaft main body portion, Rather than extending in the radial direction from the entire area in the circumferential direction of the two-shaft main body part, it extends only from the partial area in the circumferential direction of the second shaft main body part in the direction in which the movement of the engaging part is allowed Has been. Therefore, according to the steering force transmission device described in this section, it is possible to make the portion extending in the radial direction from the end portion on the first shaft side of the second shaft smaller than in the conventional device. . Therefore, it is possible to reduce the weight of the second shaft, and hence the weight of the steering force transmission device, and to reduce the moment of inertia of the second shaft, thereby reducing the driver's operation feeling. It is possible to improve.

  Further, the shape, configuration, and the like of the engagement portion clamping portion of the second shaft are not particularly limited, but from the viewpoint of reducing the weight as described above and reducing the moment of inertia, the movement of the engagement portion is performed. In consideration of the magnitude of the force applied to the pair of side wall surfaces when transmitting the range and the steering force, it is desirable to set the size in the radial direction and the circumferential direction of the shaft to the minimum necessary size.

  The “first shaft” described in this section is not particularly limited in its structure and configuration. For example, as will be described in detail later, a portion that extends in the radial direction from the main body portion of the first shaft and a portion that protrudes from the portion toward the second shaft in the rotation axis direction of the first shaft are provided. The portion to be operated can function as an engaging portion. Further, for example, a portion that protrudes in the radial direction from the main body portion of the first shaft may be provided, and a tip portion of the protruding portion may function as an engaging portion.

  The “rotation transmission mechanism” described in this section changes the difference between the rotation angle of the first shaft and the rotation angle of the second shaft. Here, the shaft connected to the steering operation member of the two shafts in a state where there is no rotation angle difference (rotation phase difference) between the two shafts (hereinafter sometimes referred to as “operation member side shaft”). The rotation angle is defined as a reference rotation angle, and the rotation transmission mechanism will be specifically described. For example, when the operating member side shaft rotates from the reference rotation angle, a shaft (hereinafter referred to as the “steering device side”) connected to the steering device of the two shafts until the operating member side shaft rotates 180 °. In some cases, the shaft is sometimes referred to as a “rotating angle” smaller than the rotating angle of the operating member side shaft. Alternatively, the turning device side shaft has a rotation angle larger than that of the operation member side shaft. When the operating member side shaft rotates 180 °, the steered device side shaft also rotates 180 °, and the difference between the rotation angles of the two shafts disappears.

  That is, when the operating member side shaft rotates from the reference rotation angle to 180 °, the rotation angle difference increases from 0 and decreases from the middle to reach 0. In this case, if the ratio of the rotation speed of the steering device side shaft to the rotation speed of the operation member side shaft is called a steering gear ratio, the gear ratio increases as the operation member side shaft rotates from the reference rotation angle to 180 °. Or smaller. For example, the gear ratio is configured to increase as the operation member side shaft rotates, and the reference rotation angle is set to a position corresponding to the steering neutral position of the wheel, that is, the neutral operation position. If the rotation angle of the operation member side shaft in a certain state is used, when the operation angle of the steering operation member is small, a gentle and stable handling is realized, and as the operation angle of the steering operation member increases, It is possible to realize handling with good response.

  Therefore, in a vehicle equipped with the “steering force transmission device” described in this section, a steering system that relies on an actuator such as an electromagnetic motor to change the steering amount of the wheel with respect to the operation amount of the steering operation member, so-called steering. The operation feeling of the steering operation member can be changed as described above without mounting a steering ratio variable steering system (VGRS (Variable Gear Ratio Steering) system) or the like. Incidentally, the connection between the one end of the steering device side shaft and the steering device, or the connection between the one end of the operation member side shaft and the operation member may be directly connected, It may be connected between them via an damage shaft, a universal joint or the like.

(2) The engagement portion clamping portion is
A plate-like second shaft extending portion extending from the end of the second shaft main body on the first shaft side in a direction in which movement of the engaging portion is allowed, and perpendicular to the rotation axis of the second shaft; ,
Each of the pair of uprights standing from the second shaft extension part toward the first shaft side and extending in parallel with the direction in which the engagement part is allowed to move so as to sandwich the engagement part. And includes
One surface of the pair of upright portions and the other surface of the pair of upright portions facing the surface are configured to function as the pair of side wall surfaces ( The vehicle steering force transmission device according to 1).

  The mode described in this section is a mode in which the configuration of the engaging unit clamping unit is embodied. The shape of the engaging portion holding portion described in this section is not particularly limited. For example, a pair of standing portions are provided on one plate-like second shaft extending portion. Alternatively, a pair of standing portions may be provided on each of the arms on the second shaft extending portion shaped like a pair of arms extending from the shaft main body portion. .

(3) The engagement portion clamping portion is
Each includes a pair of arm portions extending in parallel to a direction in which the engagement portion is allowed to move,
One surface of the pair of arm portions and the other surface of the pair of arm portions facing the surface are configured to function as the pair of side wall surfaces (1). Or the steering force transmission device for a vehicle according to item (2).

  The aspect described in this section is an aspect in which the shape of the engaging part clamping part is embodied. For example, the end part on the first shaft side of the second shaft is generally U-shaped when viewed from the rotational axis direction of the shaft. It can be set as the aspect which was made. The aspect of this term is an aspect in which, for example, the engaging portion clamping portion is configured by the extending portion having the pair of arms as described above and the pair of standing portions provided on each of the arms. There may be a mode in which a plate formed in a generally U shape is fixed to the shaft main body.

(4) The engagement portion clamping portion is
The engaging portion of the first shaft passes through a portion of the engaging portion that is farthest from the rotational axis of the second shaft at a position that is the farthest from the rotational axis of the second shaft, and is centered on the rotational axis of the second shaft. The steering force transmission device for a vehicle according to any one of the items (1) to (3), which is configured so as not to go outside the circle.

  According to the aspect described in this section, it is possible to reduce the size of the second shaft in the radial direction, and thus to make the steering force transmission device compact in the radial direction. Therefore, according to the aspect of this item, it becomes possible to improve the mounting property to a vehicle.

  (5) The second shaft is configured to be rotatably held at a position closer to the one end portion than a position where the engaging portion holding portion of the second shaft main body portion extends (1) The vehicle steering force transmission device according to any one of items) to (4).

  In the conventional steering force transmission device, the portion extending in the radial direction from the second shaft main body is a disc-shaped portion, and a bearing or the like is fitted to the outer periphery of the disc-shaped portion, and the end portion of the second shaft Was holding. The aspect of this section is an aspect suitable for an apparatus configured such that the second shaft extends in a specific direction from a partial region in the circumferential direction of the main body portion thereof. Therefore, the device described in this section is a steering force transmission device as compared with a device configured to be held via a bearing or the like on the outer periphery of the disk-shaped portion extending in the radial direction from the second shaft main body. Thus, a reduction in size in the radial direction is achieved.

  In addition, the aspect described in this section is an aspect in which the second shaft is held by a part of the vehicle body via a bearing or the like in the shaft main body portion thereof. For example, when the steering force transmission device forms a part of the steering column, the second shaft is rotatably held by the steering column housing attached to a part of the vehicle body. It is suitable for a steering force transmission device constituting a part of

(6) The first shaft is
A first shaft body portion which is a body portion thereof;
A first shaft extending portion provided integrally with the first shaft main body, and extending from the first shaft main body in the radial direction of the first shaft;
In a direction in which the rotation axis of the first shaft and the rotation axis of the second shaft extend from the standing portion at a position away from the predetermined distance in the radial direction of the first shaft from the rotation axis of the first shaft. The vehicle steering force according to any one of (1) to (5), further including: a protruding portion that protrudes toward the second shaft in a certain rotational axis direction and functions as an engaging portion of the rotation transmission mechanism. Transmission device.

  The aspect described in this section is an aspect in which the structure of the first shaft is limited. The “first shaft extension” described in this section does not extend in the radial direction from the entire area in the circumferential direction of the first shaft main body, but extends in a specific direction from a partial region in the circumferential direction. It is. That is, according to the aspect of this section, it is possible to reduce the weight of the first shaft and reduce the moment of inertia of the first shaft. Note that, from the viewpoint of reducing the weight of the steering force transmission device, the first shaft extension portion may be a minimum necessary size in order to connect the protruding portion and the first shaft main body portion. desirable.

  Hereinafter, embodiments of the claimable invention will be described in detail with reference to the drawings. In addition to the following examples, the claimable invention is implemented in various modes including various modifications and improvements based on the knowledge of those skilled in the art, including the mode described in the above [Mode of Invention]. can do. Moreover, it is also possible to constitute the modification of the following Example using the technical matter described in the description of each item of [Aspect of the Invention].

<Overall configuration of vehicle steering system>
FIG. 1 shows an overall configuration of a steering system including a vehicle steering force transmission device according to an embodiment. The steering system includes a steering wheel 10 as a steering operation member operated by a driver, a steering force transmission device 12 that holds the steering wheel 10 at one end, a steering device 14 that steers a wheel, and a steering force. An intermediate shaft (hereinafter, may be abbreviated as “I / M shaft”) 16 positioned between the transmission device 12 and the steering device 14 is configured. Further, one end of the I / M shaft 16 and the output shaft 18 included in the steering force transmission device 12 are connected by a universal joint 20, and the other end of the I / M shaft 16 and the input shaft 22 included in the steering device 14. Is connected to one end of the other joint by another universal joint 24.

  In FIG. 1, the system is arranged so that the right side, that is, the steering wheel 10 side faces the rear of the vehicle, and the left side, that is, the steering device 14 side faces the front of the vehicle. A portion of the I / M shaft 16 passing through the hole is covered with a boot 28 so as to pass through a hole provided in the dash panel 26 that partitions the engine chamber.

  The steered device 14 includes an input shaft 22, a housing 30 as an outer shell member, and a steered rod 32 for steering a wheel, and the steered rod 32 moves in the axial direction thereof. It is possible to be held by the housing 30 and to extend in the vehicle width direction. Both ends of the steered rod 32 are connected to a steering knuckle (not shown) that holds each of the left and right front wheels. The input shaft 22 is rotatably held by the housing 30 and is engaged with the steered rod 32 in the housing 30. A pinion (not shown) is formed at the end portion of the input shaft 22 on the vehicle front side, and a rack (not shown) formed at an intermediate portion in the axial direction of the steered rod 32 meshes with the pinion. The steered rod 32 and the input shaft 22 are engaged.

  The steering force transmission device 12 is configured as a so-called steering column, and is fixedly supported on a part of the vehicle body by a steering support 36 provided in the instrument panel reinforcement 34. In the supported state, the steering force transmission device 12 is disposed in an inclined posture so that the front side of the vehicle is positioned downward as shown in the drawing. The steering force transmission device 12 is provided with a front bracket 38 at the front portion thereof, and a breakaway bracket (hereinafter sometimes abbreviated as “B.A.BKT”) 40 on the vehicle rear side of the front bracket 38. And the front bracket 38 and the B.A.BKT 40 are attached to the steering support 36, whereby the steering force transmission device 12 is supported at two locations. The supported steering force transmission device 12 is in a state in which a rear portion projects from the instrument panel 42 toward the vehicle rear side, and a steering wheel 10 is attached to the projecting rear end portion. A portion of the steering force transmission device 12 that protrudes from the instrument panel 42 is covered with a column cover 44, and a lower part is covered with an instrument panel lower cover 46.

  FIG. 2 shows a side sectional view of the steering force transmission device 12. The steering force transmission device 12 can be roughly divided into a column section 50 that holds the steering wheel 10 and can be expanded and contracted in the axial direction, and an EPS section 52 that is a main body that realizes an electric power steering function. The two sections 50 and 52 are integrated. Hereinafter, each of these sections will be described in order.

  The column section 50 includes a main shaft 54 that holds the steering wheel 10 at an end on the vehicle rear side, and a column tube 56 that rotatably holds the main shaft 54 in a state where the main shaft 54 is inserted. The main shaft 54 includes an upper shaft 58 positioned on the vehicle rear side, that is, on the upper side, and a lower shaft 60 positioned on the vehicle front side, that is, on the lower side. The upper shaft 58 is formed in a pipe shape and the lower shaft 60 is formed in a rod shape, and the rear portion of the lower shaft 60 is inserted into the front portion of the upper shaft 58. The upper shaft 58 and the lower shaft 60 are spline-fitted, and the upper shaft 58 and the lower shaft 60 are connected in a state in which they can be relatively moved in the rotation axis direction but cannot be relatively rotated. That is, the main shaft 54 has a structure that can be expanded and contracted in the rotation axis direction. The lower shaft 60 is connected to an shaft section 62 and an EPS section 52 that extends from the front end of the shaft body 62 in the radial direction of the shaft body 62 and is described in detail later. Part 64. In the steering force transmission device 12, the shaft main body portion 62 of the lower shaft 60 and the upper shaft 58 constitute a shaft main body portion of the main shaft 54.

  The column tube 56 includes an upper tube 66 positioned on the vehicle rear side (upper side) and a lower tube 68 positioned on the vehicle front side (lower side). The upper tube 66 and the lower tube 68 are both cylindrical, and the rear portion of the lower tube 68 is fitted into the front portion of the upper tube 66. The lower tube 68 has a stepped shape, a small-diameter portion 70 having an outer diameter smaller than the inner diameter of the upper tube 66 in a rear portion thereof, and a large-diameter portion having an outer shape larger than the inner diameter of the upper tube 66 in a front portion thereof. 72, and a stepped portion 74 that connects the small diameter portion 70 and the large diameter portion 72. A liner (not shown) is provided between the small-diameter portion 70 of the lower tube 68 and the upper tube 66, and the lower tube 68 is inserted into the upper tube 66 without rattling through the liner. At the same time, the relative movement of the upper tube 66 and the lower tube 68 in the rotational axis direction is facilitated. That is, the column tube 56 has a structure that can be expanded and contracted in the rotation axis direction.

  Further, radial bearings 76 and 78 are provided at the rear end portion of the upper tube 66 and the front end portion of the lower tube 68, respectively, and the column tube 56 is connected to the main shaft 54 via the bearings 76 and 78, respectively. It is rotatably held in its shaft body. With such a structure, the column section 50 can be expanded and contracted while ensuring the rotation of the main shaft 54.

  FIG. 3 shows a side cross-sectional view of the EPS section 52. The EPS section 52 includes an output shaft 18 for outputting an operation force applied to the steering wheel 10 to the steering device 14 and an electromagnetic motor 80 as a power source. It includes an assisting device 82 that assists the rotational output, and an EPS housing 84 as a housing that holds the output shaft 18 rotatably and accommodates the assisting device 82. The output shaft 18 is configured by integrating an output side shaft 86, an input side shaft 88, and a torsion bar 90. The output side shaft 86 extends from the front side of the vehicle of the EPS housing 84 and is connected to the I / M shaft 16 via the universal joint 20 at the extended portion, and outputs rotation to the steering device 14. To do.

  The output side shaft 86 has a hollow structure, and the input side shaft 88 is inserted into a portion of the output side shaft 86 on the vehicle rear side. A bearing 92 is interposed between the inner peripheral surface of the output side shaft 86 and the outer peripheral surface of the input side shaft 88, and the output side shaft 86 and the input side shaft 88 can be relatively rotated coaxially. ing. The input side shaft 88 has a bottomed hole that opens in the end surface on the vehicle front side and extends in the rotation axis direction, and is formed by the bottomed hole of the input side shaft 88 and the hole of the output side shaft 86. A torsion bar 90 is disposed in the space formed. One end of the torsion bar 90 is fixed to the bottom of the low hole by a pin 94, and the other end of the torsion bar 90 is a through hole that penetrates the output side shaft 86 in the rotation axis direction. It is fixed to the front end by a pin 96. With such a configuration, the output shaft 18 allows the torsion bar 90 to be twisted, and is itself twisted accordingly. Further, the output side shaft 86 is rotatably held by the EPS housing 84 via two radial bearings 98 and 100 on the outer periphery thereof, and the input side shaft 88 is attached to the EPS housing 84 via the needle bearing 102 on the outer periphery thereof. It is held rotatably.

  The assisting device 82 includes the electromagnetic motor 80, a worm 104 connected to the motor shaft of the electromagnetic motor 80, and a worm wheel 106 engaged with the worm 104. The worm wheel 106 is fixed to the output side shaft 86 of the output shaft 18 and cannot be rotated relative to the output side shaft 86. With such a structure, a rotational force is applied to the worm 104 by the electromagnetic motor 80, and a rotational force is applied to the worm wheel 106. That is, the assisting device 82 is configured to generate a steering assisting force (also referred to as a “steering assisting force”) that assists the turning of the wheels by assisting the rotation output of the output shaft 18 by the electromagnetic motor 80. Has been.

  The EPS section 52 includes a rotation angle sensor 108. The rotation angle sensor 108 is a difference between the rotation angle position of the output side shaft 86 to which the vehicle front portion of the torsion bar 90 is fixed and the rotation angle position of the input side shaft 88 to which the vehicle rear portion of the torsion bar 90 is fixed. It is a device for detecting a certain amount of relative rotational displacement. The steering torque can be estimated on the basis of the relative rotational displacement amounts of the two shafts 86 and 88, and the operation of the electromagnetic motor 80 is performed so as to generate a steering assist force according to the magnitude of the steering torque. Be controlled.

  The output shaft 18 is disposed in a state where the rotation axis of the main shaft 54 and the axis of the output shaft 18 are parallel to each other, and the rotation axes are shifted by a predetermined amount. Part, that is, connected to the connecting part 64 of the lower shaft 60 described above. The connecting structure will be described in detail with reference to FIG. 4 which is a sectional view taken along the line A-A ′ in addition to FIG. 3.

  First, as shown in FIG. 3, the connecting portion 64 of the lower shaft 60 constituting the main shaft 54 is provided so as to be orthogonal to the shaft main body portion 62 from the end portion on the vehicle front side of the shaft main body portion 62. A plate-like extension portion 109 and a standing portion 110 that stands up toward the vehicle front side of the extension portion 109. Further, the lower shaft 60 has a generally U-shaped end portion on the front side of the vehicle as shown in FIG. 4 which is a viewpoint from the rotational axis direction of the shaft. That is, the extended portion 109 has a pair of arm portions 112, and a pair of the standing portions 110 are provided at the tips of the pair of arm portions 112. In addition, the pair of standing portions 110 are provided so as to extend in parallel to the radial direction of the shaft body portion 62, and the passage 114 extending in the radial direction of the shaft body portion 62 by the pair of standing portions 110. Is formed.

  On the other hand, the extension plate 116 is fixedly fitted to the input side shaft 88 of the output shaft 18 at the rear end portion thereof. The extension plate 116 is provided so as to extend in a radial direction from an end portion of the input side shaft 88 on the vehicle rear side, and a pin 118 projects toward the vehicle rear side at the extended end portion. It is fixed in the state. In addition, the extension plate 116 has shown the position and shape with the dashed-two dotted line in FIG. A cylindrical roller 122 is provided at the tip of the pin 118 via a needle bearing 120 so as to be rotatable around the pin 118. The roller 122 is fitted between the pair of upright portions 110 of the lower shaft 60, so that the input side shaft 88, that is, the output shaft 18, and the lower shaft 60 constituting the main shaft 54 are connected. It is connected.

  The roller 122 will be described in detail with reference to FIG. 5 which is a B-B ′ sectional view of FIG. 3. The roller 122 includes a stepped cylindrical member 124 and an annular member 126, and the annular member 126 is press-fitted into a portion of the stepped cylindrical member 124 having the smallest outer diameter. The stepped cylindrical member 124 connects the large-diameter cylindrical surface 128 that functions as the outer peripheral surface of the roller 122, the small-diameter cylindrical surface 130 having a smaller diameter than the large-diameter cylindrical surface 128, and the large-diameter cylindrical surface 128 and the small-diameter cylindrical surface 130. It has a step surface 132 and a press-fit cylindrical surface 134 into which the annular member 126 is press-fitted. A circumferential groove 136 is formed on the outer periphery of the roller 122 so as to extend in the circumferential direction of the roller 122 by the small-diameter cylindrical surface 130, the step surface 132, and the end surface of the annular member 126 on the vehicle rear side. An O-ring 138 as an annular elastic body is provided in the circumferential groove 136 as the small diameter portion. A Teflon ring 140, which is an annular low friction member, is fitted on the O-ring 138.

  The roller 122 is engaged with the Teflon ring 140 between the pair of standing portions 110 of the lower shaft 60, that is, in the passage 114. The width of the passage 114 is slightly larger than the diameter of the outer peripheral surface of the roller 122, and a clearance (gap) exists between the roller 122 and the pair of standing portions 110. On the other hand, the outer diameter of the Teflon ring 140 is slightly larger than the width of the passage 114, and the Teflon ring 140 engages with the passage 114 in a state of being deformed in the radial direction. The inner diameter of the Teflon ring 140 and the outer diameter of the O-ring 138 are substantially the same. As the Teflon ring 140 is deformed in the radial direction, the O-ring 138 is also deformed in the radial direction. For this reason, the Teflon ring 140 is in contact with both the pair of standing portions 110 while being urged by the elastic force of the O-ring 138. That is, in the present steering force transmission device 12, the direction in which the rotation axis of the input side shaft 88 extends from the extension plate 116 as the extension portion by the pin 118, the needle bearing 120, the roller 122, the O-ring 138, the Teflon ring 140, and the like. A projecting portion 150 projecting in the direction is configured to engage with the passage 114 without rattling and function as an engaging portion. And in this steering force transmission device 12, the steering device side shaft comprised by the said protrusion part 150, the extension plate 116 as an extension part, and the output shaft 18 which is a shaft main-body part is 1st. It functions as a shaft. On the other hand, the main shaft 54 that is the shaft on the operation member side functions as a second shaft.

  When the steering wheel 10 is rotated by the driver, the main shaft 54 rotates about its own rotation axis. At this time, the projecting portions 150 that engage with the passages 114 formed in the connecting portion 64 of the lower shaft 60 are a pair of standing portions 110 that form the passages 114, specifically, the pair of standing portions 110. The pair of side wall surfaces 152 which are the surfaces facing each other in the circumferential direction of the lower shaft 60 restrict displacement of the lower shaft 60 in the circumferential direction and allow the lower shaft 60 to move in the radial direction. Is done. That is, the passage 114 functions as a guide passage, and the pair of side wall surfaces 152 define the guide passage. Furthermore, the connecting portion 64 of the lower shaft 60 having the pair of side wall surfaces 152 and configured so that the pair of side wall surfaces 152 sandwich the protruding portion 150 that is the engaging portion of the first shaft. It functions as an engaging portion clamping portion.

  When the projecting portion 124 is moved in the passage 114 as the lower shaft 60 rotates, the rotational force of the lower shaft 60 is input via the roller 122, the pin 118, the extension plate 116, and the like. It is transmitted to the side shaft 88 and the input side shaft 88 rotates around its own rotation axis. That is, the steering force transmission device 12 includes a rotation transmission mechanism that transmits the rotation around the rotation axis of the lower shaft 60 to the input side shaft 88 that is disposed with its own rotation axis shifted from the rotation axis of the lower shaft 60. It is supposed to be. In the present steering force transmission device 12, the rotation transmission mechanism includes a connecting portion 64 having a guide passage and a protruding portion 150 that functions as an engaging portion. With the structure as described above, the steering force transmission device 12 transmits the steering force input to the steering wheel 10 to the steering device 18 via the I / M shaft 16 or the like.

  The steering force transmission device 12 is attached to a part of the vehicle body at the front end portion of the EPS section 52 and the upper tube 66 of the column section 50. The EPS bracket 84 of the EPS section 52 is fixedly provided with the front bracket 38 described above, and the front bracket 38 is provided with a shaft insertion hole 160. A bearing member 164 having a shaft hole 162 is fixed to the steering support 36, and the support shaft 166 is inserted into the shaft insertion hole 160 of the front bracket 38 and the shaft hole 162 of the bearing member 164. Thus, the steering force transmission device 12 is supported so as to be swingable about the support shaft 166.

  On the other hand, the column section 50 is held by the B.A.BKT 40, and the B.A.BKT 40 is attached to the steering support 36. More specifically, as shown in FIG. 6, the B.A.BKT 40 includes a holding member 172 that holds a held member 170 fixed to the upper tube 66, and a steering member 36 that is fixed to the holding member 172. The mounting plate 174 is attached to the steering support 36 using a slot 176 provided in the mounting plate 174. In the held member 170 and the holding member 172, elongated holes 178 and 180 are formed, respectively, and a rod 182 passes through them. Although not shown in the drawing, the holding member 172 is made of the rod 182. The held member 170 is clamped. This clamping force prevents the upper tube 66 from being displaced. By operating the operation lever 184, the clamping force can be weakened. When the clamping force is weakened, the movement along the elongated hole 178 of the rod 182 is allowed, so that the upper tube 66 is allowed to move in the axial direction with respect to the lower tube 68 together with the axial movement of the upper shaft 58 relative to the lower shaft 60, and the column section 50 is allowed to expand and contract. Further, the movement of the rod 182 along the elongated hole 180 is allowed, so that the steering force transmission device 12 is allowed to swing around the support shaft 166 inserted through the front bracket 38. That is, the steering force transmission device 12 includes the tilt / telescopic mechanism 186 having such a structure.

  When the driver collides with the steering wheel 10 due to the collision of the vehicle, the B.A.BKT 40 is detached from the steering support 36 and the column section 50 is contracted. The steering force transmission device 12 is provided with an impact absorbing mechanism 187 that absorbs the impact of the secondary collision, and the EA plate 188 is deformed as the steering column 56 contracts, whereby the impact of the secondary collision is obtained. Is effectively absorbed.

<Function of rotation transmission mechanism>
In the present steering force transmission device 12, the output shaft 18 as the first shaft and the main shaft 54 as the second shaft, which are arranged in a state where their axes are shifted in parallel, will be described in detail. The input side shaft 88 and the lower shaft 60 of the main shaft 54 are connected by the rotation transmission mechanism. Therefore, the rotational phase of the lower shaft 60 and the rotational phase of the input side shaft 88 are shifted, and the rotational phase difference that is the difference between the rotational phases of the two shafts 60 and 88 is changed. This will be specifically described with reference to the drawings.

  FIG. 7 is a cross-sectional view (corresponding to a cross-sectional view taken along line A-A ′ in FIG. 3) of a portion where the connecting portion 64 of the lower shaft 60 and the protruding portion 150 of the input side shaft 88 are engaged. FIG. 7A shows a position corresponding to the steering neutral position of the wheel, that is, a state when the steering wheel 10 is in the neutral operation position. FIG. 7B shows a state where the steering wheel 10 is rotated counterclockwise from the neutral operation position. FIG. 7C shows the state when the steering wheel 10 is rotated 90 ° in the clockwise direction from the neutral operation position. FIG. 7D shows the state when the steering wheel 10 is in a position rotated 180 ° in the right or left turning direction from the neutral operation position.

  As can be seen from the figure, when the steering wheel 10 is rotated 90 degrees in the right or left turning direction from the neutral operation position, the lower shaft 60 rotates 90 degrees about its own rotation axis. The shaft 88 does not rotate up to 90 ° about its own rotation axis, and the rotation angle of the input side shaft 88 is less than 90 °. When the steering wheel 10 is further rotated and rotated 180 degrees in the right or left turning direction from the neutral operation position, both the lower shaft 60 and the input side shaft 88 rotate 180 degrees. The relationship between the rotation angle α of the lower shaft 60 and the rotation angle β of the input side shaft 88 is as shown in FIG. 8 when the steering wheel 10 is rotated less than 180 ° from the neutral operation position. The rotation angle β of 88 is smaller than the rotation angle α of the lower shaft 60. When the steering wheel 10 is rotated 180 ° from the neutral operation position, the rotation angle β of the input side shaft 88 is the same as the rotation angle α of the lower shaft 60. It becomes. That is, when the rotational phase of the lower shaft 60 is a specific rotational phase in which the rotational phase of the lower shaft 60 and the rotational phase of the input side shaft 88 coincide with each other, specifically, the rotational angle α of the lower shaft 60 is 0. When the angle is 180 ° or 180 °, the rotation angles α and β are the same, and the rotation phase difference is zero. On the other hand, while the rotation angle α of the lower shaft 60 changes from 0 ° to 180 °, the rotation phase difference gradually increases, and gradually decreases from a certain rotation angle to zero. The gear ratio (dβ / dα) of the two shafts 60 and 88 in this case, that is, the ratio (dβ / dt) of the rotational speed (dβ / dt) of the input side shaft 88 to the rotational speed (dα / dt) of the lower shaft 60. As shown in FIG. 8, dα) varies according to the rotation angle α of the lower shaft 60.

  As can be seen from the figure, when the rotation angle α of the lower shaft 60 is 0 °, the gear ratio (dβ / dα) is the smallest, and the gear ratio (dβ / dα) increases as the rotation angle α of the lower shaft 60 increases. Becomes bigger. That is, in the present steering force transmission device 12, when the operation angle of the steering wheel 10 is small, gentle and stable handling is realized, and as the operation angle of the steering wheel 10 increases, a response with good response is achieved. It is realized. In the present system, the operation range of the steering wheel 10 is limited to about 180 ° left and right from the neutral operation position by an operation range limiting mechanism (not shown).

  Incidentally, e shown on the vertical axis in FIG. 9 is the rotation of the input side shaft 88 with respect to the offset amount L (FIG. 4) from the rotation axis of the input side shaft 88 at the position where the protrusion 150 is engaged with the passage 114. This is the ratio (d / L) of the shift amount d (FIG. 4) between the axis and the rotation axis of the lower shaft 60, and affects the operational feeling of the steering wheel 10.

<Characteristics of this steering force transmission device>
i) Conventional Steering Force Transmission Device In the vehicle steering force transmission device 12, as described above, the main shaft 54, which is the second shaft, includes a shaft main body portion and an end portion of the shaft main body portion on the vehicle front side. From the partial region in the circumferential direction of the shaft main body portion, the connecting portion 64 as the engaging portion clamping portion provided so as to extend only in the direction in which the movement of the protruding portion 150 is allowed is provided. Yes. On the other hand, like the steering force transmission device 200 shown in FIG. 10, the connecting portion 204 of the lower shaft 202 constituting the second shaft extends in the radial direction from the entire region in the circumferential direction of the shaft main body portion 206 of the lower shaft 202. There is also a device that is formed in a disk shape.

  In the steering force transmission device 200, the lower shaft 202 is configured to be held by the column tube 210 via the radial bearing 208 at the connecting portion 204 thereof. The connecting portion 204 will be described in more detail. The connecting portion 204 is a disc-shaped flange portion, and a groove 220 extending in the radial direction is formed on an end face on the front side. And the input side shaft 222 and the lower shaft 202 are connected by the protrusion part 224 as an engaging part of the input side shaft 222 which comprises a 1st shaft engaging with the groove | channel 220. FIG. Incidentally, the amount of deviation of the rotational axes of the two shafts 202 and 222 is the same as the amount of deviation d of the rotational axes of the two shafts 60 and 88 in the steering force transmission device 12 of this embodiment, The offset amount from the rotation axis of the input side shaft 222 at the position where the portion 224 engages with the groove 220 is the input side shaft 88 at the position where the protruding portion 150 in the steering force transmission device 12 of this embodiment engages with the passage 114. This is the same as the offset amount L from the rotation axis. That is, the steering force transmission device 200 has the same operation feeling as the steering force transmission device 12 of the present embodiment.

ii) Determination of the shape of the connecting portion in the present steering force transmission device In the steering force transmission device 12 of this embodiment, the main shaft 54 as the second shaft is connected to the shaft main body portion 62 of the lower shaft 60 via the bearing 78. It is held by the column tube 56. Accordingly, the connecting portion 64 of the lower shaft 60 is provided so as to extend only from the partial region in the circumferential direction of the shaft main body portion in the direction in which the movement of the protruding portion 150 is allowed. In other words, in the steering force transmission device 200 of the comparative example, the unnecessary portion of the connecting portion 204 having a disc shape is removed.

Next, a method for determining the shape of the connecting portion 64 in the steering force transmission device 12 of this embodiment will be described in detail. The connecting portion 64 has a radial position and length of the pair of side wall surfaces 152 that the connecting portion 64 has in consideration of a radial moving range in the lower shaft 60 of the protruding portion 150 that is an engaging portion of the first shaft. Has been determined. Specifically, first, the radially inner ends of the pair of side wall surfaces 152 pass through the rotation axis of the lower shaft 60 as shown in FIG. 11A corresponding to FIG. distance L ₁ between the straight line l ₁ perpendicular to the moving direction of the projecting portion 150 with respect to the lower shaft 60, from the offset amount L from the rotation axis of the input side shaft 88 of the projecting portion 150, and the rotation axis of the input side shaft 88 The length is determined to be slightly shorter than the length obtained by subtracting the amount of deviation d from the rotational axis of the lower shaft 60. That is, the distance L ₁ is set so as to satisfy the following formula.
L ₁ <L−d (1)

Further, the radial outer end of the pair of side wall surface 152, as shown in FIG. 11 (b) which corresponds to FIG. 7 (d), the distance L ₂ between the straight lines l ₁ is, two shafts 60 , 88 and the offset amount L of the protrusion 150 are determined to be slightly longer than the total length. That is, the distance L ₂ is set to satisfy the following mathematical formula.
L ₂ > L + d (2)
Incidentally, if the outer diameter of the input shaft 88 is D ₁ and the outer diameter of the protrusion 150 is D _2, considering that L> (D ₁ + D ₂ ) / 2, equation (2) is Can be expressed as:
L ₂ > (1 + e) · (D ₁ + D ₂ ) / 2 (3)
That is, the connecting portion 64 of the lower shaft 60 passes through a point where the protruding portion 150 is farthest from the rotational axis of the lower shaft 60 of the protruding portion 60 at a position where the protruding portion 150 is farthest from the rotational axis of the lower shaft 60. It is comprised so that it may not come out of the circle | round | yen centering on a rotating shaft line. Note that the circumferential width of each of the pair of standing portions 110 having the pair of side wall surfaces 152 is between the pair of standing portions 110 and the projecting portion 150 by the steering force applied to the steering wheel 10. It is determined in consideration of the force acting on.

  And the extension part 109 of the connection part 64 has the two arm parts 112 so that the pair of standing parts 110 determined in this way and the shaft main body part 62 of the lower shaft 60 may be connected. It is formed into a shape.

iii) Advantages of the Steering Force Transmission Device As described above, in the steering force transmission device 12 of the present embodiment, the size of the connection 64 of the lower shaft 60 determines the rotational phase difference between the lower shaft 60 and the input side shaft 88. In order to transmit the rotation between the two shafts 60 and 88 while changing, the size is set to a minimum necessary size. Therefore, in the present steering force transmission device 12, the weight of the main shaft 54 as the second shaft is reduced compared to the steering force transmission device 200 of the comparative example, and as a result, the weight of the steering force transmission device 12 itself is reduced. It is alleviated. Further, since the weight of the main shaft 54 is reduced, the moment of inertia of the main shaft 54 is reduced, and the operation feeling of the driver is improved.

  Further, in the present steering force transmission device 12, as shown by a two-dot chain line in FIG. 4, an extending plate 116 that extends in the radial direction from the end of the output shaft 18 that is the first shaft on the vehicle rear side is also provided. Instead of extending from the entire region of the shaft main body of the output shaft 18 in the circumferential direction, it extends from a partial region in the circumferential direction only in a specific direction. Therefore, in the steering force transmission device 12 of the present embodiment, the extension plate 116 is made smaller than the annular extension portion 230 in the steering force transmission device 200 of the comparative example, and the second shaft described above. In addition to the weight of the main shaft 54 being reduced, the weight of the output shaft 18 as the first shaft is also reduced.

Furthermore, the diameter D _A of the connecting portion of the two shafts 60 and 88 in the steering force transmission device 12 of the present embodiment is the diameter D of the connecting portion of the two shafts 202 and 222 of the steering force transmission device 200 of the comparative example. Compared to _B , it is smaller. Thus, in the steering force transmission device 12 of the present embodiment, as compared with the steering force transmission device 200 having the same operation feeling, the downsizing is achieved in the direction perpendicular to the rotation axis direction. The mountability to the vehicle is improved.

It is a mimetic diagram showing a steering system for vehicles provided with a steering force transmission device for vehicles which is an example of a claimable invention. It is sectional drawing which shows the steering force transmission device for vehicles with which the steering system for vehicles of FIG. 1 is provided. It is sectional drawing which shows the EPS section with which the steering force transmission device for vehicles is provided. FIG. 4 is a cross-sectional view taken along line A-A ′ shown in FIG. 3. FIG. 4 is a cross-sectional view taken along line B-B ′ shown in FIG. 3. It is a perspective view which shows the breakaway bracket which hold | maintains the column section with which the steering force transmission device for vehicles is provided. FIG. 4 is a cross-sectional view taken along line A-A ′ shown in FIG. 3 when a steering wheel is rotated. It is a graph which shows the relationship between the rotation angle of an operation member side shaft, and the rotation angle of a steering apparatus side shaft. It is a graph which shows the gear ratio of the operating member side shaft and the steering apparatus side shaft which change according to the rotation angle of the operating member side shaft. FIG. 3 is a diagram illustrating the vehicle steering force transmission device shown in FIG. 2 and a vehicle steering force transmission device of a comparative example side by side. It is a figure which shows the dimension of the connection part which is an engaging part clamping part of a 2nd shaft.

Explanation of symbols

  10: Steering wheel (steering operation member) 12: Steering force transmission device for vehicle 14: Steering device 18: Output shaft (first shaft) 54: Main shaft (second shaft) 56: Column tube 58: Upper shaft 60: Lower shaft 62: Shaft body portion 64: Connection portion (engaging portion clamping portion) 76, 78: Radial bearing 82: Auxiliary device 86: Output side shaft 88: Input side shaft 90: Torsion bar 109: Extension portion (second) 110: Standing portion 112: Arm portion 114: Passage (guide passage) 116: Extension plate (first shaft extension) 118: Pin 120: Needle bearing 122: Roller 150: Protruding portion 152: A pair of side wall surfaces

  α: rotation angle of the lower shaft β: rotation angle of the input side shaft dβ / dα: gear ratio L: offset amount of the engagement position d: displacement amount of the two shafts e: ratio

Claims (6)

A first shaft having one end connected to one of a steering operation member operated by a driver and a steering device for steering a wheel, and rotatably disposed;
One end is connected to the other of the steering operation member and the steering device, and the rotation axis of the first shaft and the rotation axis of the first shaft are parallel to each other, and the rotation axis is rotatable by a predetermined distance. A second shaft disposed on
(A) at the other end of the first shaft, an engaging portion provided at a position away from the predetermined distance in the radial direction of the first shaft from the rotation axis of the first shaft; The other end of the two shafts is provided so as to extend in the radial direction of the second shaft, and engages with the engaging portion of the first shaft, and the engaging portion in the radial direction of the second shaft. And a guide passage that allows movement, and by rotating one of the first shaft and the second shaft, a rotation phase difference that is a difference between rotation phases of the first shaft and the second shaft is obtained. A vehicle steering force transmission device comprising a rotation transmission mechanism configured to rotate while the other is rotating,
The second shaft is
A second shaft body portion which is a body portion thereof;
A pair of sides that are provided so as to extend from the end on the first shaft side of the second shaft main body portion in a direction in which the movement of the engaging portion is allowed, and each of the second shaft main body portions extend in parallel to the direction and face each other And a pair of side wall surfaces including an engagement portion holding portion configured to partition the guide passage of the rotation transmission mechanism and sandwich the engagement portion. Steering force transmission device. The engagement portion clamping portion is
A plate-like second shaft extending portion extending from the end of the second shaft main body on the first shaft side in a direction in which movement of the engaging portion is allowed, and perpendicular to the rotation axis of the second shaft; ,
Each of the pair of uprights standing from the second shaft extension part toward the first shaft side and extending in parallel with the direction in which the engagement part is allowed to move so as to sandwich the engagement part. And includes
The one surface of the pair of upright portions and the other surface of the pair of upright portions facing the surface are configured to function as the pair of side wall surfaces. Item 2. The vehicle steering force transmission device according to Item 1. The engagement portion clamping portion is
Each includes a pair of arm portions extending in parallel to a direction in which the engagement portion is allowed to move,
The one surface of the pair of arm portions and the other surface of the pair of arm portions facing the surface are configured to function as the pair of side wall surfaces. Alternatively, the vehicle steering force transmission device according to claim 2. The engagement portion clamping portion is
The engaging portion of the first shaft passes through a portion of the engaging portion that is farthest from the rotational axis of the second shaft at a position that is the farthest from the rotational axis of the second shaft, and is centered on the rotational axis of the second shaft. The vehicle steering force transmission device according to any one of claims 1 to 3, wherein the vehicle steering force transmission device is configured not to come out of an outer circle.   The second shaft is configured to be rotatably held at a position closer to the one end portion than a position where the engaging portion holding portion of the second shaft main body portion extends. Item 5. The vehicle steering force transmission device according to any one of Items 4 to 5. The first shaft is
A first shaft body portion which is a body portion thereof;
A first shaft extending portion provided integrally with the first shaft main body portion and extending in a radial direction from the first shaft main body portion;
The rotation axis of the first shaft and the rotation axis of the second shaft from the first shaft extension at a position away from the rotation axis of the first shaft in the radial direction of the first shaft from the predetermined distance. The vehicle steering according to any one of claims 1 to 5, further comprising: a protruding portion that protrudes toward the second shaft in a rotation axis direction that is an extending direction and functions as an engaging portion of the rotation transmission mechanism. Power transmission device.

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