JP2011152875A - Steering system and rotation transmission mechanism operation position dislocation recognizing method for steering device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To cope with the dislocation when a reference operation position of a rotation transmission mechanism is dislocated from a normal position, in a steering device having the rotation transmission mechanism 140 for transmitting rotation of an operation side shaft 60 rotating by operation of a steering wheel to a steered side shaft 18 and varying the rotation transmission ratio in its rotation transmission so as to become a specified value in response to a variation from the reference operation position of an operation position of itself. <P>SOLUTION: In respective lateral turning operations, when a rotation quantity of the steered side shaft becomes a preset quantity, a rotation quantity of an operation side shaft is detected, and these are compared, to recognize a dislocation quantity of the reference operation position of the rotation transmission mechanism. The rotation transmission ratio is recognized based on its recognized dislocation quantity, and operation force of the steering wheel is properly estimated based on its recognized rotation transmission ratio, and encouragement force by an encouragement device 82 is controlled based on its proper operation force. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a steering system having a transmission mechanism configured such that the ratio of wheel steering with respect to operation of an operation member varies according to the operation, and displacement of the operating position of the transmission mechanism included in the system Regarding the method of certification.

  In recent years, a steering system provided in a vehicle includes a so-called variable gear ratio system (VGRS) as described in the following patent documents. Such a system has a rotation transmission mechanism for transmitting the rotation of the operation side shaft connected to the operation member to the steering side shaft connected to the steering device for turning the wheel, In the rotation transmission mechanism, the rotation transmission ratio that is the ratio of the rotation angular velocity of the steered side shaft to the rotation angular velocity of the operation side shaft can be changed. According to the gear ratio variable system, for example, when the operation amount is relatively small, the operation amount is relatively large when the rotation transmission ratio is decreased to increase the running stability of the vehicle or when the vehicle makes a U-turn. In this case, the rotation transmission ratio can be increased and the vehicle can be easily turned.

JP 2006-96187 A JP 2007-131214 A

  In the gear ratio variable system, there is also a system having a rotation transmission mechanism in which its own operation position changes according to the operation amount of the operation member, and the rotation transmission ratio fluctuates according to the change in the operation position. In such a rotation transmission mechanism, when the reference operation position is shifted from the normal position and assembled, the relationship between the operation amount of the operation member and the rotation transmission ratio is shifted from the normal relationship. For example, the operation feeling is different between the left turn operation and the right turn operation. Therefore, grasping the deviation is effective for maintaining a good operation feeling.

  On the other hand, the steering system includes an assisting device for assisting the steering of the wheel, and the assisting force generated by the assisting device is generally an assisting force corresponding to the operating force of the operating member. When the steering system is equipped with the above rotation transmission mechanism, the rotational torque of the steered side shaft located on the wheel side of the rotation transmission mechanism is detected, the operation force is certified based on the rotation torque, and the certified operation There is also a system that controls the assisting force according to the force. In such a system, when the rotation transmission ratio changes, the rotation torque transmission ratio between the operation side shaft and the steered side shaft also changes, so that the operation force changes according to the operation amount of the operation member. The result is given to the operator. Therefore, in order to improve the operation feeling, in addition to the rotation torque of the steered side shaft, the operation force of the operation member is estimated based on the rotation transmission ratio, and the assisting force is calculated based on the estimated operation force. Control is being considered.

  However, when the above-described displacement of the rotation transmission mechanism occurs, as described above, the relationship between the operation amount of the operation member and the rotation transmission ratio is deviated from the normal relationship. Even if the operating force of the operating member is estimated based on the rotation transmission ratio, the operating force cannot be estimated appropriately. If the assisting force is controlled based on an operating force that is not properly estimated, not only can the operating feeling be improved, but the operating feeling may be worsened.

  As described above, the deviation of the rotation transmission mechanism is one factor that deteriorates the feeling of the steering operation, and grasping the deviation and dealing with the deviation fluctuate the rotation transmission ratio. It leads to improving the practicality of the steering system provided with the rotation transmission mechanism. The present invention has been made in view of such circumstances, and an object thereof is to improve the practicality of such a steering system.

  In order to solve the above problems, the steering system of the present invention includes (a) an operation member operated by a driver, (b) an operation side shaft that rotates by operation of the operation member, and (c) an operation side thereof. A steering-side shaft disposed on the wheel side of the shaft, (d) a steering device that steers the wheel by rotation of the steering-side shaft, and (e) a steering-side shaft that rotates the operation-side shaft. As the operation side shaft rotates, its own operation position changes, and the rotation transmission ratio in the rotation transmission from the operation side shaft to the steered side shaft becomes the amount of change of the operation position from the reference operation position. A rotation transmission mechanism configured to vary so as to vary according to the value, (f) a torque detector that detects the rotational torque of the steered side shaft, and (g) a drive source, By the assisting force that generates the wheel itself Based on the rotation transmission ratio, the operating force applied to the operating member by the driver is estimated from the assisting device that assists and (h) (i) the rotational torque of the steered side shaft detected by the torque detector (Ii) a target assisting force determining unit that determines a target assisting force based on the operating force estimated by the operating force estimating unit; and (iii) a target assisting force determining unit that determines the target assisting force determining unit. A steering system including an assisting device operation control unit that controls the operation of the assisting device based on the target assisting force, wherein the operation force estimating unit includes a reference operation of the rotation transmission mechanism. When the position is shifted from the normal position, the operation force of the operation member is estimated based on the amount of the shift.

  In order to solve the above-described problem, the rotation transmission mechanism operation position deviation recognition method for a steering device according to the present invention includes: (a) an operation member operated by a driver; and (b) rotating by operating the operation member. An operation side shaft, (c) a steering side shaft disposed closer to the wheel than the operation side shaft, (d) a steering device that steers the wheel by the rotation of the steering side shaft, and (e ) The rotation of the operation side shaft is transmitted to the steered side shaft, and (f) the operation position of the operation side changes with the rotation of the operation side shaft, and the rotation transmission in the rotation transmission from the operation side shaft to the steered side shaft The ratio is applied to a steering device having a rotation transmission mechanism configured to vary so that the ratio becomes a value defined in accordance with an amount of change of the operation position from the reference operation position. Canonical position (A) One of the operation force of the operation member and the turning amount of the wheel from the straight traveling state, and (B) the operation amount of the operation member from the straight traveling state. When one is defined as the detected dependency amount and the other is defined as the detection target amount, when the detected dependency amount becomes the set amount when operating one of the left turn and right turn operation members The first detection target amount that is the detection target amount is detected, and the first detection target amount is the detection target amount when the detected dependence amount becomes the set amount when the other operation member of the left turn and the right turn is operated. (2) Detecting the detection target amount and determining that the reference operation position of the rotation transmission mechanism is deviated from the normal position when the difference between the first detection target amount and the second detection target amount exceeds the set difference. It is characterized by.

  According to the steering system of the present invention, even when the reference operation position of the rotation transmission mechanism is deviated from the normal position, the operation force of the operation member is estimated on the basis of the amount of the deviation. An appropriate assisting force is generated by the device, and as a result, the feeling of steering operation is well maintained. Further, according to the rotation transmission mechanism operation position deviation recognition method for a steering device of the present invention, it is possible to recognize a deviation of the reference operation position of the rotation transmission mechanism by a simple method, and the result of the authorization is good. It will contribute to the maintenance of a comfortable operation feeling.

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, item (1) corresponds to item 1, item (2) and item (3) are combined in item 2, item (7) in item 3, The combination of the items (10) and (11) corresponds to claim 4 and the item (14) corresponds to claim 5. The (21) term corresponds to claim 6 and the (22) term corresponds to claim 7.

(1) an operation member operated by a driver;
A first shaft that is rotated by operation of the operating member;
A second shaft disposed closer to the wheel than the first shaft;
A steering device for turning the wheel by rotation of the second shaft;
While transmitting the rotation of the first shaft to the second shaft, the operation position of the first shaft changes with the rotation of the first shaft, and the rotation transmission ratio in the rotation transmission from the first shaft to the second shaft. Is a rotation transmission mechanism configured to vary so as to be a value defined according to a change amount from the reference operation position of the operation position,
A torque detector for detecting rotational torque of the second shaft;
An assisting device that has a drive source and assists the steering of the wheel by an assisting force generated by itself; (a) from the rotational torque of the second shaft detected by the torque detector, to the rotational transmission ratio; An operation force estimation unit that estimates an operation force applied to the operation member by the driver, and (b) a target that determines a target assisting force based on the operation force estimated by the operation force estimation unit. An assisting force determining unit, and (c) an assisting force control device having an assisting device operation control unit that controls the operation of the assisting device based on the target assisting force determined by the target assisting force determining unit. A steering system,
A steering system configured to estimate the operating force of the operating member based on an amount of the shift when the reference operation position of the rotation transmission mechanism is shifted from a normal position.

  In the present steering system, roughly speaking, an operation torque, which is a rotational torque for rotating the first shaft, is generated on the first shaft by a force applied to an operation member such as a steering wheel by the driver, that is, an operation force. The operation torque is transmitted as the rotation torque of the second shaft by the rotation transmission mechanism. The rotational torque of the second shaft is converted into a force for turning the wheel in the turning device. On the other hand, in the present steering system, the assisting force is generated by the assisting device, and the steering of the wheel by the steering device is performed by the operating force transmitted as the transmission torque and the assisting force.

  Many of the steering systems detect the rotational torque of the second shaft, that is, the transmission torque, and determine the assisting force to be generated by the assisting device based on the detected transmission torque. However, in this steering system, since the rotation transmission mechanism is configured so that the rotation transmission ratio varies, the magnitude of the transmission torque is influenced by the rotation transmission ratio and is not necessarily dependent on the operation torque. Must not. In view of this, in the present steering system, the operation force is estimated based on the rotation transmission ratio in addition to the rotation torque of the second shaft, and the assisting force is determined based on the operation force.

  In the steering system including the rotation transmission mechanism as described above, the rotation transmission ratio is a value defined according to the amount of change from the reference operation position of the operation position of the rotation transmission mechanism accompanying the rotation of the first shaft. Therefore, when the reference operation position is deviated from the normal position, even if it is simply based on the rotation angle (rotation phase) of the first shaft or the second shaft, the rotation transmission ratio corresponding to the rotation angle is accurately set. I can no longer be certified. For this reason, the operating force cannot be estimated appropriately, and the assisting force becomes a magnitude based on the operating force that is not properly estimated. Even in the case where there is such a deviation, the present steering system can appropriately estimate the operating force based on the amount of the deviation and generate an appropriate assisting force based on the operating force.

  The “rotation transmission ratio” in this section can be considered as the ratio of the change amount of the rotation angle of the second shaft to the change amount of the rotation angle of the first shaft. In other words, it can be considered as the ratio of the rotational angular velocity of the second shaft to the rotational angular velocity of the first shaft. The reciprocal of this rotation transmission ratio can be considered as the ratio of the transmission torque to the operating torque, that is, the torque transmission ratio. Therefore, the torque transmission ratio decreases as the rotation transmission ratio increases, and the torque transmission ratio increases as the rotation transmission ratio decreases.

  The “operation position” in this section is not particularly limited as long as it is the position of the rotation transmission mechanism that operates with the rotation of the first shaft. Typically, the operation position can be indicated by the rotation angle of the first shaft or the one rotating with the first shaft, and the “change amount” in this case is the rotation phase that is the rotation angle from the reference operation position. Can be indicated by

  The “reference operation position” in this section can be defined as the operation position of the rotation transmission mechanism when the steering state is a specific state. For example, it can be defined as the operating position of the rotation transmission mechanism in a state where the turning amount of the wheel, the operation amount of the operation member, and the like are the amounts when the vehicle is traveling straight.

  The “rotation transmission mechanism” included in the steering system of this section is one in which the rotation transmission ratio fluctuates so as to become a value defined according to the amount of change from the reference operation position, that is, the first shaft or the second shaft. Depending on the rotational phase and the like, the state of the fluctuation is assumed to fluctuate according to a certain rule. In the rotation transmission mechanism, for example, as will be described in detail later, the first shaft and the second shaft are arranged in an eccentric state, and the rotation of each of the first shaft and the second shaft is interlocked by the cam mechanism. It is realizable by comprising.

  In the steering system of this section, the specific structure of the “assistance device” is not particularly limited. For example, the structure may be such that the steering is assisted by the force generated by the electromagnetic motor, or the structure may be such that the steering is assisted using the pressure of hydraulic oil or the like. Good. Further, there is no particular limitation on which part of the steering system assists. What is necessary is just to assist on the wheel side of the torque detector (meaning the side opposite to the operation member in the transmission of force), for example, it is configured to assist the rotation of the second shaft. Also, it may be configured to assist the operation of a so-called steered rod (also referred to as a link rod). The “torque detector” is configured to detect the second torque by, for example, arranging a torsion bar as a part of the second shaft and detecting the torsional elastic deformation amount of the torsion bar. Is possible.

  (2) The operating force estimation unit estimates the rotation torque of the first shaft by dividing the rotation torque of the second shaft detected by the torque detector by the rotation transmission ratio, and the estimated The steering system according to (1), wherein the operating force is estimated based on a rotational torque of the first shaft.

  The aspect of this section is an aspect in which the rotational torque of the first shaft is estimated from the detected rotational torque of the second shaft based on the idea that the reciprocal of the rotational transmission ratio is the torque transmission ratio. In the case of a steering wheel that is coupled to the end of the first shaft and rotates together with the first shaft, the operating force that is the force that rotates the steering wheel is the rotational torque of the first shaft. Can be considered equivalent to Therefore, according to the steering system of the aspect of this section, the operating force can be estimated by a simple method from the rotational torque of the second shaft detected by the torque detector.

  (3) When the reference operation position of the rotation transmission mechanism is deviated from a normal position, the operating force estimation unit determines the value of the rotation transmission ratio that divides the rotation torque of the second shaft as the amount of deviation. And the operation force is estimated based on the rotation torque of the first shaft estimated by dividing the rotation torque of the second shaft by the corrected value. The steering system according to item 2).

  The rotation transmission mechanism in the steering system has a predetermined amount of rotation of the first shaft and a change amount of the operation position of the rotation transmission mechanism from the reference operation position when the reference operation position is a normal position. It is configured to change each other in accordance with the determined relationship. However, when the reference operation position is deviated from the normal position, the relationship between the rotation amount and the amount of change is different from the relationship in the case where the reference operation position is at the normal position. The value of the rotation transmission ratio with respect to a certain rotation amount of the first shaft also becomes a value different from the value when the reference operation position is at the normal position. Therefore, when the reference motion position is deviated from the normal position, the operating force is appropriately estimated even if it is based on the relationship between the rotation amount and the rotation transmission ratio when the reference motion position is at the normal position. You will not be able to do it. If the amount of rotation is corrected based on the amount of deviation as in this aspect, the relationship between the corrected amount of rotation and the rotation transmission ratio is the same as the relationship when the reference operation position is at the normal position. Can be. Therefore, in the aspect of this section, it is possible to appropriately estimate the operating force by correcting the rotation transmission ratio based on the amount of deviation.

  (4) In the rotation transmission mechanism, when the reference operation position is the regular position, the rotation transmission ratio is the smallest when the vehicle is traveling straight, and the rotation phase when the first shaft is traveling straight Any one of (1) to (3), wherein the rotation transmission ratio is maximized when the operation member is operated so that the phase is rotated by 180 ° from Steering system.

  According to the aspect of this section, traveling stability in a state close to straight traveling, that is, straight traveling stability is ensured well, and the turning characteristic of the vehicle when the operation amount of the operation member is increased, that is, a slight operation is performed. Thus, it is possible to realize a steering system in which the characteristic of easily changing the direction of the vehicle is ensured.

(5) The first shaft and the second shaft are arranged in a state where the respective rotation axes are parallel to each other and in a state where the rotation axes are shifted by a predetermined distance,
The rotation transmission mechanism is
(a) an engagement portion provided on one of the first shaft and the second shaft at a position spaced apart from the predetermined distance in the radial direction from the one rotation axis; and (b) the first shaft. A guide passage that is provided on the other side of the second shaft and that engages the engaging portion and allows the other radial movement of the engaging portion; and by rotation of the first shaft, Any of the items (1) to (4), wherein the second shaft rotates while changing a rotation phase difference which is a difference between the rotation phase of the first shaft and the rotation phase of the second shaft. The steering system as described in any one.

  The aspect of this section is an aspect to which a limitation relating to the structure of the rotation transmission mechanism is added, and is an aspect illustrating a specific structure that can be employed in the steering system. The details of the rotation transmission mechanism in the aspect of this section will be described in detail later, and the description thereof will be omitted here.

  (6) In the plane including the rotation axis of the first shaft and the rotation axis of the second shaft when the reference transmission position is the normal position, and the rotation transmission mechanism includes a rotation axis of the first shaft and a rotation axis of the second shaft, The engagement portion is positioned at a position where the engagement portion is positioned away from the plane in a straight vehicle state when the reference operation position is deviated from the normal position. The steering system according to (5).

  The aspect of this section is an aspect in which the normal position of the reference operation position is limited as the specific position in the rotation transmission mechanism having the specific structure. According to the aspect of this section, the same rotation transmission ratio is obtained if the first shaft is rotated by the same rotation angle regardless of whether the vehicle is steered left or right from the straight traveling state of the vehicle. Further, according to the aspect of this section, when the reference operation position is in the normal position, the rotation transmission ratio can be minimized or maximized in the straight traveling state of the vehicle.

(7) (A) One of the operation force of the operation member and the turning amount of the wheel from the straight traveling state, and (B) the operation amount of the operation member from the straight traveling state is defined as a detected dependence amount However, when the other is defined as a detection target amount,
The steering system includes a detection dependency amount detector that detects the detection dependency amount, and a detection target amount detector that detects the detection target amount,
The assisting force control device comprises:
i) In the operation of the one of the operation members of the left turn and the right turn, the detected amount detected by the detection target amount detector when the detected dependency amount detected by the detection dependency amount detector becomes a set amount. The first detection target amount that is a detection target amount, and ii) the operation of the other operation member of the left turn and the right turn, the detection dependency amount detected by the detection dependency amount detector becomes the set amount. The difference between the detection target amount detected by the detection target amount detector and the second detection target amount, the change amount of the operation position from the reference operation position with respect to the rotation transmission mechanism, and the rotation transmission ratio. And a deviation amount certifying unit for certifying the deviation amount of the reference operation position based on the relationship with the value of
The operation force estimation unit is configured to estimate the operation force of the operation member based on the amount of deviation of the reference operation position certified by the deviation amount authorization unit. The steering system according to any one of the above.

  The aspect of this section is an aspect in which the steering system has a function of authorizing the amount of deviation. According to the steering system of the aspect of this section, the rotation transmission ratio becomes a value defined according to the amount of change of the operation position from the reference operation position, and from the normal position of the reference operation position. It is possible to certify the amount of deviation.

  More specifically, the magnitude of the operation force changes depending on the torque transmission ratio, that is, the rotation transmission ratio, for example, when the force necessary for turning the wheel is assumed to be constant. The turning amount with respect to a certain operation amount of the member also changes according to the rotation transmission ratio. On the other hand, the amount of rotation of the first shaft, that is, the amount of change in the operating position changes depending on the amount of operation of the operating member. Therefore, the rotation transmission ratio changes according to the operation amount, and the operation force or the steering amount changes according to the change of the rotation transmission ratio. That is, the operation force or the steering amount and the operation amount are changed according to a predetermined relationship. Therefore, when the reference motion position is at the normal position, each of the first detection target amount and the second detection target amount is a value defined according to the set amount. It is desirable that the turning characteristics of the left turn and the right turn of the vehicle are the same, and in many systems, the first detection target amount and the second detection target amount when the reference operation position is in the normal position are Be made equal. Therefore, in such a system, when the difference between the first detection target amount and the second detection target amount exceeds the set value, it is determined that the reference operation position of the rotation transmission mechanism is deviated from the normal position. The amount of deviation can be recognized from the value of the difference between the first detection target amount and the second detection target amount.

  The “steering amount” in this section is not limited to the operation amount of the wheel itself, but may be the operation amount of the steering device, the rotation amount of the second shaft that operates the steering device, or the like. Good. Similarly, the “operation amount” in this section is not limited to the operation amount of the operation member itself, but the operation amount of the member operated according to the operation of the operation member, for example, the rotation amount of the first shaft, etc. It may be.

(8) The detection dependency amount is one of the steering amount and the operation amount, and the detection target amount is the other of them,
Based on the difference between the other value of the steering amount and the operation amount that is the first detection target amount and the other value that is the second detection target amount, The steering system according to paragraph (7), which is configured to certify the amount of

(9) The detection dependency amount is one of the operation amount and the operation force, and the detection target amount is the other of them,
(A) the other value of the operation amount and the operation force, which is the first detection target amount, and (b) the second detection, which are detected by the deviation amount recognition unit during left turn and right turn, respectively. The steering system according to item (7), configured to recognize the amount of deviation based on a difference from the other value as the target amount.

  In the above-described two aspects, the detection dependence amount and the detection target amount used in the determination of the deviation amount are specifically limited. According to the two aspects, it is possible to easily recognize the amount of deviation.

  (10) The target assisting force determination unit is configured to determine the target assisting force so that the target assisting force has a magnitude corresponding to the operation force. Steering system described in one.

  The mode of this section is a mode which limited the determination method of the target assistance power in the target assistance power determination part. In this section, “determining the target assisting force to have a magnitude corresponding to the operating force” means, for example, that the target assisting force is related to the operating force, and the target assisting force is determined according to the relationship. Means that. Specifically, a mode in which the target assisting force is determined with reference to a function, a map, or the like using the operating force as a parameter is included. Typically, for example, it is desirable that the target assisting force be determined so as to increase as the operating force increases. In a steering system that does not include a rotation transmission mechanism configured so that the rotation transmission ratio can be changed or fluctuated, that is, in a steering system with a fixed rotation transmission ratio, the target assisting force is generally related to the operation force. ing. In the steering system in this section, since the relationship in the steering system with a fixed rotation transmission ratio can be used, it is not necessary to create a new relationship. Therefore, the system can be simplified. is there.

  (11) The target assisting force determination unit combines the target assisting force with a component based on the operating force transmitted from the first shaft to the second shaft and a component based on the assisting force by the assisting device. The steering system according to any one of (1) to (9), wherein the combined force is determined so as to have a magnitude corresponding to the operation force.

  The mode of this section is a mode in which the method for determining the target assisting force in the target assisting force determining unit is limited to a determination method different from the mode of the previous section. In this section, “determining the target assisting force so that the resultant force has a magnitude corresponding to the operating force” means, for example, that the resultant force is related to the operating force, and the resultant force according to the relationship It means that the target helping power is determined so that As in the previous section, for example, it is desirable to determine the target assisting force so that the synthetic force increases as the operating force increases.

  (12) The assist force control apparatus according to any one of (1) to (11), wherein the assist force control device includes an operation speed-dependent correction unit that corrects the target assist force based on an operation speed of the operation member. Steering system.

  The operation speed of the operation member is an index indicating the state of the steering operation such as the operation force and the operation amount, in other words, a parameter relating to the state of the steering operation. According to the steering system of this section, it is possible to generate an appropriate assisting force reflecting the operation state of the operation member by correcting the target assisting force based on the operation speed.

  The term “correction based on the operation speed of the operation member” in this section should be broadly interpreted and includes not only correction based on the actual operation speed of the operation member but also a substantial index of the operation speed, for example, The correction based on the rotational speed of the first shaft or the second shaft is also included. Further, the correction mode is not particularly limited. For example, the target assisting force is changed stepwise depending on whether the operation speed is high or low across each of one or more set threshold speeds. For example, the correction may be such that the magnitude of the target assisting force is continuously changed according to the operation speed. Furthermore, “correcting the target assisting force” should be interpreted broadly and is not limited to directly correcting the target assisting force determined by the target assisting force determining unit. For example, the target assisting force is corrected. Alternatively, the target assisting force may be corrected indirectly by correcting the operating force that is relied upon in the determination, that is, the operating force estimated by the operating force estimation unit.

  (13) In the item (12), the operation speed-dependent correction unit is configured to correct the target assisting force so that the target assisting force is increased when the operation speed of the operation member is high compared to when the operation speed is low. The described steering system.

  Generally, when a fast steering operation is performed, a phenomenon may occur in which the operation of the assisting device cannot follow the steering operation. This phenomenon gives a feeling of being caught in the operation. In particular, when the assisting device is configured to generate the assisting force by the force of the electromagnetic motor, the phenomenon is likely to occur. In the aspect of this section, when the operation speed of the operation member is high, the assisting force is increased, thereby promoting the operation of the assisting device and suppressing the above phenomenon.

(14) The steering system includes a connection mechanism that has at least one universal joint and connects the second shaft and the input shaft of the steering device;
The assisting force control device comprises:
Coupling mechanism-induced torque fluctuation that corrects the target assisting force so as to cancel out fluctuations in rotational torque transmitted from the second shaft to the input shaft of the steered device caused by the structure of the coupling mechanism. The steering system according to any one of items (1) to (13), which includes a dependency correction unit.

  When the second shaft and the steering device are connected via the universal joint, the input shaft of the steering device is changed from the second shaft in accordance with the change in the rotational phase of the second shaft, that is, the rotational phase of the universal joint. Rotational torque transmitted to changes. That is, the torque transmission ratio that is the ratio of the rotational torque of the input shaft to the rotational torque of the second shaft fluctuates periodically. According to the steering system of this section, even if the system has a universal joint, correction is performed to eliminate the influence of fluctuations in the torque transmission ratio, so that the steering operation feeling is good. Will be kept. Specifically, in a system in which the assist device is disposed on the operation member side of the universal joint, for example, by correcting the target assist force by multiplying the target assist force by the inverse of the torque transmission ratio, Good.

  (15) The coupling mechanism-induced torque fluctuation dependence correction unit may calculate the target assisting force based on the rotational phase of any of the input shaft, the second shaft, the first shaft, and the operating member of the steering device. The steering system according to item (14) configured to be corrected.

  Since the rotation phases of the input shaft and the second shaft connected by the universal joint are in correspondence with each other, the correction can be appropriately performed even if any of the rotation phases is used. In the system employing the rotation transmission mechanism in which the rotation transmission ratio depends on the rotation phase of the first shaft, the rotation phase of each of the operating member and the first shaft and the rotation phase of the second shaft are mutually Since there is a correspondence relationship, the correction can be appropriately performed even if the rotational phases of the operation member and the first shaft are used. Note that the steering system generally includes a sensor for detecting the rotational phase of the operating member or the first shaft as a sensor for detecting the steering operation angle (operation amount). Therefore, if the steering system according to this aspect is configured to perform the correction using the rotation phase of the operation member or the first shaft, it is not necessary to provide a separate sensor for the correction. Simplification can be achieved.

(21) (a) an operation member operated by the driver, (b) a first shaft that is rotated by operation of the operation member, and (c) a second shaft disposed closer to the wheel than the first shaft. A shaft, (d) a steering device that steers the wheel by the rotation of the second shaft, (e) the rotation of the first shaft is transmitted to the second shaft, and (f) the first shaft The operation position changes with rotation, and the rotation transmission ratio in the rotation transmission from the first shaft to the second shaft is a value defined according to the amount of change of the operation position from the reference operation position. Applied to a steering device having a rotation transmission mechanism configured to vary as follows:
A method for recognizing a deviation from a normal position of a reference operation position of the rotation transmission mechanism,
(A) One of the operation force of the operation member and the steering amount of the wheel from the straight travel state, and (B) the operation amount of the operation member from the straight travel state is defined as the detection dependence amount, and the other Is defined as the amount to be detected,
In the operation of one of the operation members of the left turn and the right turn, a first detection target amount that is the detection target amount when the detection dependence amount becomes a set amount is detected,
In the operation of the other operation member of the left turn and the right turn, a second detection target amount that is the detection target amount when the detection dependency amount becomes the set amount is detected,
When the difference between the first detection target amount and the second detection target amount exceeds a set difference, the rotation transmission for the steering device that recognizes that the reference operation position of the rotation transmission mechanism deviates from the normal position. Mechanism operation position deviation recognition method.

  A steering device to which the present rotation transmission mechanism operating position deviation recognition method is applied roughly includes a first shaft and a second shaft, as in the above-described steering system, and the second shaft is a first shaft. It is structured to be rotated via a rotation transmission mechanism whose rotation transmission ratio varies with the rotation of the shaft. Therefore, in the same manner as the steering system described above, in the steering device to which the rotation transmission mechanism operation position deviation recognition method for the steering device is applied, the rotation transmission ratio changes according to the operation amount, and the operation force or the steering amount is , And changes according to the change in the rotation transmission ratio. Therefore, in the left and right steering operations, it is possible to easily recognize the deviation from the normal position of the reference operation position of the rotation transmission mechanism by comparing the detection target amount when the detection dependency amount becomes the same value. is there.

  In general, since the steering system is configured to have the same steering characteristics for the left turn and the right turn, for example, the setting difference is set to 0 or a value close to 0, and the first detection target is set. When the difference between the amount and the second detection target amount exceeds the set difference value, it can be determined that the reference operation position of the rotation transmission mechanism is deviated from the normal position.

  Note that the “setting difference” in this section does not necessarily have to be a value corresponding to the difference between the first detection target amount and the second detection target amount when the reference motion position is at the normal position, and the detection error For example, the value may be a value obtained by adding some margin to the value. In addition, even if there is a deviation, when it is considered that the deviation is not large enough to adversely affect the operation feeling, it is set as a dead zone from the viewpoint that the deviation may be allowed. A margin may be provided for the difference.

  This rotation transmission mechanism operation position deviation recognition method for a steering apparatus includes a device for executing this method by the vehicle itself, like the deviation amount recognition unit described above, and this method is executed by the apparatus. Alternatively, it may be executed by using a device outside the vehicle at the time of manufacturing the vehicle or checking the vehicle at a dealer, or by attaching a predetermined device to the vehicle and using the device.

  (22) Further, the relationship between the difference between the first detection target amount and the second detection target amount, the amount of change from the reference operation position of the operation position for the rotation transmission mechanism, and the value of the rotation transmission ratio. The steering apparatus rotation transmission mechanism operation position deviation recognition method according to item (21), wherein an amount of deviation of the reference operation position is authorized based on

  The aspect of this section relates to the function provided in the above-described deviation amount authorization unit described in the steering system, and the deviation amount authorization part executes the rotation transmission mechanism operation position deviation authorization method for the steering device of this aspect. It becomes a functional part. The explanation of this section is the same as the explanation given in the above-described deviation amount recognition unit, and is omitted here.

(23) The detection dependency amount is one of the steering amount and the operation amount, and the detection target amount is the other of them,
The amount of deviation is recognized based on the difference between the other value of the steered amount and the manipulated variable that is the first detection target amount and the other value that is the second detection target amount (22 ) The rotational transmission mechanism operation position deviation recognition method for a steering device according to the item.

(24) The detected dependence amount is one of the operation amount and the operation force, and the detection target amount is the other of them,
(A) the other value of the operation amount and the operation force that are the first detection target amount, and (b) the other value that is the second detection target amount that is detected when turning left and turning right, respectively. The steering apparatus rotation transmission mechanism operation position deviation recognition method according to item (22), wherein the deviation amount is authorized based on a difference from the value.

  The above two modes are modes in which the detection dependency amount and the detection target amount used in the rotation transmission mechanism operation position deviation recognition method for the steering device are specifically limited. According to the two aspects, it is possible to easily recognize the amount of deviation.

It is a schematic diagram showing a steering system as a first embodiment of the claimable invention. It is sectional drawing of the steering column with which the steering system of 1st Example is provided. It is sectional drawing of the rotation transmission mechanism and assistance apparatus with which the steering system of 1st Example 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 A-A ′ shown in FIG. 3 when the operation member is rotated. It is a graph which shows the relationship between the rotation angle of a 1st shaft, and the rotation angle of a 2nd shaft. It is a graph which shows the rotation transmission ratio in the rotation transmission from a 1st shaft to a 2nd shaft. It is a graph of the coefficient for correct | amending the rotational torque of a 1st shaft. It is a graph which shows the relationship of the target assistance torque with respect to the rotational torque of a 1st shaft. It is a graph which shows the relationship of the combined torque which combines the rotational torque based on the operating force transmitted from the 1st shaft to the 2nd shaft with respect to the rotational torque of a 1st shaft, and the rotational torque based on an assisting force. It is a graph which shows the relationship between the rotational phase of a 2nd shaft, and the transmission torque ratio which is ratio of the rotational torque of the input shaft of a steering apparatus with respect to the rotational torque of a 1st shaft. It is a figure which shows the state which the reference | standard operation position of a rotation transmission mechanism has shifted | deviated from the regular position. It is a graph which shows the quantity of gap certified in the steering system of the 1st example. It is a flowchart of the program for recognition of the amount of deviation performed in the steering system of the 1st example. It is a block diagram of a control device with which the steering system of the 1st example is provided. It is a block diagram of the control apparatus with which the steering system of 2nd Example is provided. It is a graph which shows the fluctuation | variation according to the rotation angle of the rotational torque of a 1st shaft, when the rotational torque of a 2nd shaft is made constant. It is a graph which shows the quantity of gap certified in the steering system of the 2nd example.

  Hereinafter, as a mode for carrying out the claimable invention, some of the steering systems of the embodiments will be described in detail with reference to the drawings. It should be noted that the steerable invention steering system is not limited to the following embodiments, and can be in various forms with various modifications and improvements based on the knowledge of those skilled in the art.

≪Overall configuration of vehicle steering system≫
FIG. 1 shows the overall configuration of the steering system of the first embodiment. The steering system includes a steering device. The steering device includes a steering wheel 10 as an operation member operated by a driver, a steering column 12 having the steering wheel 10 attached to one end thereof, and a wheel. A steering device 14 that steers the vehicle, and an extendable intermediate shaft (hereinafter sometimes abbreviated as “I / M shaft”) 16 that is positioned between the steering column 12 and the steering device 14. It consists of Furthermore, one end of the I / M shaft 16 and the steered side shaft 18 provided in the steering column 12 are connected by a universal joint 20, and the other end of the I / M shaft 16 and the input shaft 22 provided in the steered device 14. Is connected to one end of the other joint by another universal joint 24. In addition, this steering system is arrange | positioned so that the right side in FIG. 1, ie, the steering wheel 10 side may become a vehicle rear side, and the left side, ie, the steering device 14 side, may become a vehicle front side.

  The steered device 14 includes an input shaft 22, a steered rod 30 for steering wheels, and a housing 32 that houses the steered rod 30 therein. The steered rod 30 is formed in a rod shape extending in the vehicle width direction, and is held by the housing 32 so as to be movable in the vehicle width direction. Both ends of the steering rod 30 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 32, and a pinion (not shown) is formed at the end of the input shaft 22 in the housing 32. On the other hand, the steered rod 30 is formed with a rack (not shown) that meshes with the pinion.

  The steering column 12 is supported by the vehicle body at a steering support 36 provided in the instrument panel reinforcement 34. The steering column 12 is provided with a front bracket 38 at a front portion thereof, and a breakaway bracket 40 is provided at a rear side of the vehicle. The steering column 12 is attached to the steering support 36 by the front bracket 38 and the breakaway bracket 40.

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

  The column section 50 includes an operation side shaft 60 as a first shaft to which the steering wheel 10 is attached to a rear end portion, and a column tube 62 that holds the operation side shaft 60 in a state where the operation side shaft 60 is inserted. ing. The operation side shaft 60 includes a shaft portion 64 that can be expanded and contracted, and a flange portion 66 provided at the front end portion of the shaft portion 64. The column tube 62 includes a pipe-shaped cylindrical portion 68 and a large-diameter portion 70 that is provided at the front end portion of the cylindrical portion 68 and has a larger outer diameter than the cylindrical portion 68. A rear end portion of a housing 72 of the EPS section 52 described later is fitted into the large diameter portion 70, and the flange portion 66 of the operation side shaft 60 is rotatably held by the housing 72 via a bearing 74. ing. Further, the rear end portion of the operation side shaft 60 is rotatably held by the rear end portion of the column tube via the bearing 76.

  Although not shown, the column section 50 includes an operation angle sensor 78 for detecting the rotation angle of the operation side shaft 60 and a turning angle sensor 79 for detecting the rotation angle of the turning side shaft 18. Are provided (see FIG. 1). The operation angle sensor 78 is configured as an absolute angle sensor so that the rotation angle of the operation side shaft 60 is 0 ° when the steering wheel 10 is in the neutral position (the rotation position when the vehicle is traveling straight). The operation side phase α, which is the rotation angle of the operation side shaft 60, is detected. Further, the turning angle sensor 79 detects the turning side phase β that is the rotation angle of the turning side shaft 18.

  FIG. 3 shows a side cross-sectional view of the EPS section 52. The EPS section 52 is rotatably held in the housing 72 and outputs a steering side shaft 18 as a second shaft for outputting an operation force applied to the steering wheel 10 to the steering device 14, and an electromagnetic as a drive source. An assisting device 82 that has a motor 80 and assists the rotation of the steered side shaft 18 by the motor 80 is provided. The steered side shaft 18 includes a shaft portion 92 in which three of an output side shaft 86, an input side shaft 88, and a torsion bar 90 are combined, and an annular portion 94 attached to the rear side of the shaft portion 92 in the vehicle. It consists of The output side shaft 86 extends to the vehicle front side of the housing 72, and is connected to the universal joint 20 at the extending portion.

  The front part of the input side shaft 88 that constitutes the shaft portion 92 of the steered side shaft 18 is inserted into the rear part of the output side shaft 86, and these shafts 86, 88 can be rotated relative to each other via a bearing 96. ing. The shafts 86 and 88 are both hollow, and a through hole 98 is formed through the shafts 86 and 88. In the through hole 98, the torsion bar 90 is disposed in a state where both ends are fixed to the shafts 86 and 88, respectively. The shaft portion 92 configured as described above is rotatably held by the housing 72 via the bearings 100, 102, and 104. The torsion bar 90 is twisted by an amount corresponding to the rotational torque of the shaft portion 92, and the output side shaft 86 and the input side shaft 88 are relatively rotated by an amount corresponding to the amount. The EPS section 52 is provided with a torque sensor 106 as a torque detector that detects the rotational torque of the shaft portion 92, that is, the rotational torque of the steered side shaft 18 by detecting the relative rotational amount. As described above, the steered side shaft 18 is configured such that the output side shaft 86 and the input side shaft 88 rotate relative to each other, but the relative rotation amount is ignored with respect to the steered side phase β. In this specification, the rotation angle of the input side shaft 88 is treated as the rotation angle of the steered side shaft 18 in order to simplify the explanation.

  The assisting device 82 includes the electromagnetic motor 80, a worm 112 connected to the motor shaft of the electromagnetic motor 80, and a worm wheel 114 that meshes with the worm 112. The worm wheel 114 is fixed to an output side shaft 86 constituting the steered side shaft 18. The force of the electromagnetic motor 80 acts on the output side shaft 86 via the worm 112 and the worm wheel 114. This force serves as an assisting force for assisting the rotation of the steered side shaft 18, more specifically, an assisting force for assisting the steering of the wheel.

  The steered side shaft 18 and the operation side shaft 60 are arranged in a state of being shifted from each other, that is, in a state where the respective rotation axes are parallel to each other and the rotation axes are shifted by a predetermined distance. The predetermined distance is shown as a shift amount d in FIG. As shown in FIG. 4 which is a cross-sectional view taken along the line A-A ′ of FIG. 3, a groove 130 extending in the radial direction is formed on the front end face of the flange portion 66 of the operation side shaft 60. On the other hand, in the annular portion 94 of the input side shaft 88, the pin 132 is erected and fixed rearward in a state parallel to the axial direction of the shaft 88 at a position offset by an offset amount L from the axis of the shaft 88. Has been. A roller 136 is rotatably supported by the pin 132 via a bearing 138, and the roller 136 is disposed in a groove 130 formed in the flange portion 66. Incidentally, the width of the groove 130 is slightly larger than the outer diameter of the roller 136. As will be described in detail later, when the operation side shaft 60 rotates, the roller 136 moves in the radial direction of the operation side shaft 60 while being guided by the groove 130, and the rotation is transmitted to the steered side shaft 18. . That is, the steering column 12 is an engaging portion provided with the roller 136 on the steered side shaft 18 and a guide passage provided with the groove 130 on the operating side shaft 60 to allow the engaging portion to move. A functioning rotation transmission mechanism 140 is provided.

≪Function of rotation transmission mechanism≫
FIG. 5 shows a cross-sectional view (corresponding to the cross-sectional view taken along the line AA ′ of FIG. 3) of the circular flange portion 66 and the roller 136 engaged with the groove 130. FIG. 5A shows a state when the steering wheel 10 is in the neutral position (operation side phase = 0 °), and FIG. 5B shows that the steering wheel 10 is rotated 90 ° in the left turn direction from the neutral position. FIG. 5 (c) shows the state when the steering wheel 10 is at the position where the steering wheel 10 is rotated 90 ° clockwise from the neutral position, and FIG. The state when the steering wheel 10 is at a position rotated 180 ° in the right or left turning direction from the neutral position is shown. In consideration of the simplification of the description, in the following description, in the present steering system, the steering wheel 10 is treated as being operated only 180 degrees to the left and right.

  Here, regarding the operation of the rotation transmission mechanism 140, the concept of the operation position of the rotation transmission mechanism 140 will be introduced. The operating position is a position that changes in accordance with the operation of the steering wheel 10 and can be considered as the posture of the rotation transmission mechanism 140. Specifically, the operation position can be considered as, for example, a rotational phase around the axis of the steered side shaft 18 of the roller 136, or can be considered as a rotational phase of the operation side shaft 60 of the groove 130. Further, in the state where the rotation transmission mechanism 140 is shown in FIG. 5A, that is, in the state where the rotation axis of the roller 136 is located in a plane including the rotation axis of the operation side shaft 60 and the rotation axis of the steered side shaft 18. The operation position of the rotation transmission mechanism 140 is treated as a reference operation position. In the present steering system, when the reference operation position is in the normal position, the state shown in FIG. 5A is that the steering wheel 10 is in the neutral position and the vehicle is in a straight traveling state.

  As can be seen from the drawing, when the reference operation position of the rotation transmission mechanism is in the normal position, when the steering wheel 10 is rotated 90 ° in the right or left turning direction from the neutral position, the operation-side shaft 60 is its own. Although it rotates 90 ° around the rotation axis, the steered side shaft 18 does not rotate up to 90 ° around its rotation axis. When the steering wheel 10 is further rotated and rotated 180 ° in the right or left turning direction from the neutral position, both the operation side shaft 60 and the steered side shaft 18 rotate 180 °. When the reference operation position of the rotation transmission mechanism is in the normal position, the relationship between the operation-side phase α of the operation-side shaft 60 and the steered-side phase β of the steered-side shaft 18 is shown by a solid line in FIG. It has become a relationship. When the steering wheel 10 is rotated by less than 180 ° in the left turn direction from the neutral position, the steering side phase β is smaller than the operation side phase α, and when the steering wheel is rotated 180 °, the steering side phase β The operation side phase α is the same. That is, when the operation side phase α is 0 ° or 180 °, the steered side phase β is also 0 ° or 180 °, respectively, and the rotational phase difference is 0. On the other hand, while the operation side phase α changes from 0 ° to 180 °, the rotational phase difference gradually increases, and gradually decreases from a certain rotational angle to zero. The same applies to the case where the steering wheel 10 is rotated in the right turning direction from the neutral position.

  When the reference operation position of the rotation transmission mechanism is in the normal position, the rotation transmission ratio (dβ / dα) between the operation side shaft 60 and the steered side shaft 18, that is, the rotation angular velocity (dα / dt) of the operation side shaft 60. The ratio of the rotational angular velocity (dβ / dt) of the steered side shaft 18 to) varies according to the operation side phase α as shown by the solid line in FIG. As can be seen from the figure, when the operation-side phase α is 0 °, the rotation transmission ratio (dβ / dα) is the smallest. Further, as the operation side phase α increases, the rotation transmission ratio (dβ / dα) increases. When the operation side phase α is 180 °, the rotation transmission ratio (dβ / dα) becomes the largest. That is, when the operation angle (operation amount) of the steering wheel 10 is small, the ratio of the change amount of the wheel turning amount to the change amount of the operation angle becomes relatively small, and the straight running stability of the vehicle becomes good. . On the other hand, when the operation angle of the steering wheel 10 is increased, the ratio of the change in the wheel turning amount to the change in the operation angle is relatively large, and the direction of the vehicle can be easily changed with a small amount of operation. As described above, the rotation transmission mechanism 140 varies so that the rotation transmission ratio depends on the rotation phase α of the first shaft and the variation state follows a certain rule. As for the transmission of the rotational torque from the operation side shaft 60 to the steered side shaft 18, the transmitted rotational torque varies with the variation of the rotational transmission ratio. Here, if the rotation torque ratio of the steered side shaft 18 with respect to the rotation torque of the operation side shaft 60 is a torque transmission ratio, the torque transmission ratio is the reciprocal of the rotation transmission ratio.

≪Assistance control≫
i) Hardware Configuration of Control System The assist force generated by the assist device 82 described above is controlled by the assist force control device 150 shown in FIG. The assisting force has a magnitude corresponding to the magnitude of the current supplied to the motor 80 included in the assisting device 82. The motor 80 is connected to a power supply (not shown) via an inverter 152 as a drive circuit, and the assisting force control device 150 sends a command related to the current to be supplied to the motor to the inverter 152. Control the power.

  The assisting force control device 150 is a device mainly including a computer having a CPU, a ROM, a RAM, and the like, and controls the assisting force by executing a predetermined program. The ROM stores various data related to the control as well as the program. Further, the assisting force control device 150 includes the torque sensor 106 for detecting the rotational torque of the steering side shaft 18 described above, the operation angle sensor 78 for detecting the rotational phase of the operation side shaft 60, and the steering side. Various sensors such as a turning angle sensor 79 for detecting the rotation phase of the shaft 18 are connected, and the assisting force control device 150 controls the assisting force based on signals from these sensors.

ii) Estimation of operating force In the present steering stem, a target assisting force, which is an assisting force that should be generated by the assisting device 82, is determined based on the operating force of the steering wheel 10. The operating force is estimated by the torque sensor 106 based on the rotational torque of the steered side shaft 18. Specifically, the rotational torque of the operation side shaft 60 (hereinafter referred to as “operation torque T _S ”) is estimated as equivalent to the operation force. Incidentally, since the rotation torque of the steered side shaft 60 can be considered as the operation torque T _S transmitted by the rotation transmission mechanism 140, it is hereinafter referred to as a transmission torque T _D.

As described above, the ratio of the transmission torque T _D to the operation torque T _S is the reciprocal of the rotation transmission ratio (dβ / dα). Therefore, the operation torque T _S is estimated by dividing the detected transmission torque T _D by the rotation transmission ratio (dβ / dα) according to the following equation (1). Incidentally, the rotation transmission ratio (dβ / dα) is recognized using map data (see FIG. 7) stored in the ROM based on the operation side phase α.
T _S = T _D / (dβ / dα) (1)

In this steering system, the rotation transmission mechanism 140, the rotation transmission ratio (dβ / dα) is configured to vary with changes in the operating side phase alpha, the transmission torque T _D itself operating force magnitude Is not an appropriate representation. However, in the present steering system, as described above, on the basis of the transmission torque T _D to the rotation transmission ratio (dβ / dα), is the operating force is properly estimated.

iii) Correction based on operation speed When a fast steering operation is performed, it is considered that the operation of the motor 80 included in the assisting device 82 cannot follow the operation. In order to make the operation of the motor 80 follow a fast steering operation, it is desirable to increase the supply current to the motor 80. Considering this, the present steering system is configured to increase the target assisting force in order to increase the supply current to the motor 80 as the steering operation becomes faster. In order to increase the target assisting force, as will be described later, the determined target assist force may be directly corrected, but in the present steering system, to correct the operating torque T _S, which is the estimated Therefore, the method of correcting the target assisting force indirectly is adopted.

The correction is performed based on the operation speed v of the steering wheel 10. The operation speed v is calculated based on the change in the operation-side phase α detected by the operation angle sensor 78. The operation speed correction dependency coefficient K _V for correcting the operation torque T _S is stored in the ROM as map data as shown in FIG. Using the map data, the operation speed-dependent correction coefficient K _V is determined based on the calculated operation speed v. Then, using the determined operation speed-dependent correction coefficient K _V , the operation torque T _S is corrected according to the following equation (2).
T _S = K _V × T _S (2)

iv) Determination of target assisting force Since the present steering system is structured to assist the rotation of the steered side shaft 18, the assisting force can be regarded as an assisting torque for the rotation of the steered side shaft 18. Therefore, in the assist force control, the target assist torque is determined as equivalent to the target assist force. The ROM stores map data of the assist torque T _A with respect to the operation torque T _S as shown in FIG. 9, and the target assist torque T _A ^* is determined using the map data.

The wheel is steered by a combined force that is a combination of a component based on the operating force transmitted to the steered side shaft 18 and a component based on the assisting force. That is, it is performed by the combined torque T _{C in which the} transmission torque T _D and the assisting torque T _A are combined. FIG. 10 is a graph showing the relationship of the combined torque T _C with respect to the operating torque T _S. Incidentally, the graph shows the relationship when the rotation transmission ratio (dβ / dα) is fixed. Determining the target assisting torque T _A ^* so that the combined torque T _{C according} to the relationship can be obtained, that is, the combined torque _C corresponding to the operating torque T _S can maintain the operation feeling well. It contributes to that.

However, in this steering system, since the rotation transmission ratio (dβ / dα) of the rotation transmission mechanism 140 varies, the transmission torque T _D varies according to the variation, and the combined torque T _C does not necessarily satisfy the above relationship. It must not be followed. Considering this, in the present steering system, first, based on the estimated operation torque T _S , the map data set and stored based on the relationship shown in FIG. A certain reference assist torque T _A0 is determined, and a target assist torque T _A ^* is determined according to the following equation (3) based on the reference assist torque T _A0 and the recognized rotation transmission ratio (dβ / dα). Is done.
T _A ^* = T _A0 − {(dα / dβ) −1} × T _S (3)

Instead of the determination method as described above, the target assisting torque T _A ^* can be determined according to the following equation (4) based on the detected transmission torque T _D.
T _A ^* = T _A0 + {(dβ / dα) −1} × T _D (4)

v) Correction of target assisting torque by universal joint Two universal joints 20 and 24 are interposed between the steered side shaft 18 and the input shaft 22 of the steered device 14. Even if the rotational torque of the input shaft 22 is constant, the rotational torque of the input shaft 22 varies due to the structure of the universal joints 20 and 24. Specifically, in the present steering system, the transmission torque ratio that is the ratio of the rotational torque of the input shaft 22 to the rotational torque of the steered side shaft 18 is set to the steered side phase β that is the rotational phase of the steered side shaft 18. On the other hand, it fluctuates as shown in FIG.

In consideration of the above, in the present steering system, the target assisting torque T _A ^* is corrected in order to eliminate the torque fluctuation of the input shaft 22. Specifically, based on the steered side phase β detected by the steered angle sensor 79, the joint dependence correction coefficient K _J set as the reciprocal of the transmission torque ratio shown in FIG. 11 and stored in the ROM is set. Using the map data, the target assist torque T _A ^* is corrected according to the following equation (5).
^{_{T A * = K J × T}} A * ··· (5)
In vi) target supply current determining the steering system, based on the target assisting torque T _A ^*, the target supply current I _A to the motor 80 of the assisting device 82 ^* is determined, based on the target supply current I _A ^* command Is sent to the inverter 152. The inverter 152 operates so that a supply current based on the command flows to the motor 80, and an appropriate assisting force is applied to the wheel steering.

vii) Deviation of the Reference Operation Position of the Rotation Transmission Mechanism In this steering system, the steering column 12 to which the steering hole 10 is attached is connected to the steering device 14 by the I / M shaft 16 while the steering device 14 is disposed and fixed. And assembled to the steering support 36. Here, consider a case where the mounting angle of the steering wheel 10 with respect to the operation side shaft 60 is deviated from the normal angle. In this case, if the steering column 12 is assembled while the neutral position of the steering device 14 and the neutral position of the steering wheel 10 are aligned, the reference operation position of the rotation transmission mechanism 140 described above is shifted from the normal position. become. That is, when the steering wheel 10 is in the neutral position, as shown in FIG. 12, the rotation axis of the roller 136 is not in a plane including the rotation axis of the operation side shaft 60 and the rotation axis of the steered side shaft 18. It becomes. The state shown in FIG. 12 is a state where the reference operation position is shifted by about 30 ° in the operation side phase α, in other words, a state where the groove 130 formed in the flange portion 66 of the operation side shaft 60 is inclined by about 30 °. is there.

  In the rotation transmission mechanism 140, as described above, when the reference operation position is deviated from the normal position, the relationship between the operation side phase α and the steered side phase β is as shown by a two-dot chain line in FIG. Become. The relationship represented by the two-dot chain line in FIG. 6 is in a state shifted by 30 °, which is the above-described shift, in the operation side phase α with respect to the relationship in the case where the reference operation position indicated by the solid line is at the normal position. Similarly, the rotation transmission ratio (dβ / dα) is also shifted by 30 ° as shown by the two-dot chain line in FIG. Therefore, when the reference operation position is deviated from the normal position, even if the value of the rotation transmission ratio (dβ / dα) is simply recognized based on the value of the operation-side phase α, the value is not the actual rotation. It is different from the value of the transmission ratio (dβ / dα). As a result, even if the value of the certified rotation transmission ratio (dβ / dα) is used, the operating force cannot be estimated appropriately, and an appropriate assisting force can be applied to the wheel steering. It will disappear.

viii) Recognition of displacement and displacement amount This steering system recognizes the displacement even when the reference operation position is displaced from the normal position as described above, and considers the amount of displacement. The operation force is appropriately estimated. In the following, the authorization for displacement and the authorization method for the amount of deviation will be described in detail.

First, the wheel is steered in one direction from the vehicle straight traveling state, and the steered side phase β detected by the steered angle sensor 79 becomes the set steered side phase β ₁ as a preset set amount. Sometimes, the value of the operation side phase α detected by the operation angle sensor 78 is detected as the first operation side phase α ₁ . Next, when the wheel is steered in the opposite direction and the steered side phase β becomes the set steered side phase β ₁ , the value of the operating side phase α is detected as the second operating side phase α ₂ . If the first operation side phase when the reference operation position is in the normal position is α ₁ ′ and the second operation side phase is α ₂ ′, as shown in FIG. 6, these first operation side phases α ₁ ′ And the second operating side phase α ₂ ′ become equal. However, when the reference operation position is deviated from the normal position, the first operation side phase α ₁ and the second operation side phase α ₂ are not equal.

In this steering system, ½ of the difference between the first operation side phase α ₁ and the second operation side phase α ₂ is recognized as the detected phase difference dα according to the following equation (6):
dα = (α ₁ −α ₂ ) / 2 (6)
When the absolute value of the phase difference dα exceeds a preset difference dα ₀ that is a preset value, it is determined that the reference operation position of the rotation transmission mechanism 140 is deviated from the normal position. . This set difference dα ₀ (set as a positive value) is a margin set in consideration of the detection accuracy by the operation angle sensor 78 and the turning angle sensor 79, and is a relatively small value. Yes. As shown in FIG. 13, when it is determined that the reference operation position is deviated from the normal position, the shift angle Δα is determined according to the following equation (7) as the amount of the shift.
Δα = dα−dα ₀ (when dα> 0)
Δα = dα + dα ₀ (when dα <0) (7)
As can be seen, the range of d [alpha] is -dα ₀ ~ + dα ₀ is what is treated as a dead zone. Incidentally, when the absolute value of the detected phase difference dα is equal to or smaller than the set difference dα ₀ , the deviation angle Δα is set to 0 °. The operation side phase α is corrected according to the following equation (8) based on the deviation angle Δα,
α = α−Δα (8)
The control of the assisting force described above is performed using the corrected operation side phase α.

As described above, the present steering system has a function of recognizing a deviation from the normal position of the reference operation position of the rotation transmission mechanism 140. If supplemented with respect to this function, the present steering system is used as a detected dependence amount. By adopting the steering side phase β as the detection target amount and the operation side phase α, respectively, and comparing the operation side phase α when the steering side phase β becomes the same in the left and right turn of the vehicle, the deviation is It is certified and the amount of deviation is certified. Then, the turning angle sensor 79 that detects the steering side phase β functions as a detection-dependent amount detector, and the operation angle sensor 78 that detects the operation side phase α functions as a detection target amount detector. .
ix) Misalignment certification program

  Such displacement amount authorization is performed only once when the vehicle is started in the assisting force control device 150 by the displacement amount authorization program shown in the flowchart of FIG. In the processing according to the program, in step 1 (hereinafter abbreviated as “S1”, the same applies to other steps), the operation side phase α and the steered side phase β are detected. In S2 and S3, calibration processing of the turning angle sensor 79 is performed. This process is performed because the turning angle sensor 79 is not an absolute angle sensor. Specifically, in S2, it is determined whether or not the operation side phase α is 0 °, and when the operation side phase α is 0 °, the steering side phase β is set to 0 ° in S3. Thus, the reference value of the detected value of the turning angle sensor 79 is set. In S2 and S4, the steering flag Fβ indicating whether or not the reference has been set is also determined. After the flag Fβ is set to 1 in S3, the calibration process is skipped. Has been.

After the calibration process is performed, in S5, whether steered side phase beta exceeds the set steered side phase beta ₁ is determined. At that time, the vehicle is determined be whether a right turn flag F _R 0 is counted only if they are right turn. A right turn flag F _R is 0, and, when the steered side phase beta exceeds the set steered side phase beta _1, in S6, the operation-side phase alpha is detected as a first operating-side phase alpha ₁ is, clockwise turning flag F _R is set to 1. In S5, a right turn flag F _R is 0, and, if the case where the steered side phase beta exceeds the set steered side phase beta _1, in S7, only when the vehicle is turning left It is determined whether or not the counted left turn flag _FL is 0 and whether or not the steered side phase β exceeds the set steered side phase β ₁ . When the left turn flag _FL is 0 and the steered side phase β exceeds the set steered side phase β ₁ , the operating side phase α is detected as the second operating side phase α ₂ in S8. The left turn flag _FL is set to 1.

Next, in S9, the right turning flag F _R is 1, and whether the counterclockwise turning flag F _L is 1 is determined. If the right turn flag F _R and the left turning flag F _L is being both 1, since the first operating-side phase alpha ₁ and the second operating-side phase alpha ₂ is that it is detected, in S10 whether the absolute value of d [alpha] exceeds the set differential d [alpha] ₀ is determined. If so, the deviation angle Δα is calculated in S11 based on the equation (7). In S12, the right turn flag F _R is 1 and the left turning flag F _L, and the flag F is reset to 0, certification of the deviation is completed. If the absolute value of dα does not exceed the set difference dα ₀ in S10, it is determined that the reference operation position is not deviated from the normal position. In S13, the deviation angle Δα is set to 0, and the program Ends

x) Estimation of operation force in consideration of deviation and determination of target assisting force The operation-side phase α is corrected based on the deviation angle Δα according to the above equation (8). The relationship between the corrected operation side phase α, which is the corrected operation side phase α, and the steered side phase β is the relationship indicated by the solid line in FIG. 6, and the corrected operation side phase α and the rotation transmission ratio (dβ / Dα) is the relationship indicated by the solid line in FIG. That is, if the correction operation side phase α is used, the relationship between the operation side phase α and the rotation transmission ratio (dβ / dα) when the reference operation position is at the normal position can be used. Therefore, the estimation of the operation torque T _S and the determination of the target assisting force described above are based on the correction operation side phase α and the value of the rotation transmission ratio (dβ / dα) that is certified with reference to the map data shown in FIG. It is done using. The operation speed v used in the correction of the operation torque T _S based on the above-described operation speed is calculated based on the change in the operation side phase α before correction.

As described above, according to the present steering system, even when the reference operation position is deviated from the normal position, the rotation transmission ratio (dβ / The value of dα) can be certified. Therefore, the operation torque T _S is appropriately estimated based on the rotation transmission ratio (dβ / dα), and an appropriate assisting force is generated by the assisting force control device 150. Therefore, according to the present steering system, even if the reference operation position is deviated from the normal position, if the driver applies the operation force to the steering wheel 10 in the same manner, It can be turned to the right and the operation feeling can be maintained well.

≪Functional structure of assisting force control device≫
As described above, the steering assist control in the present steering system is executed by the assist force control device 150. As shown in the block diagram of FIG. 15, the assisting force control device 150 may consider that each of the assisting force control devices 150 has a plurality of functional units that execute processes assigned to the assisting force control device 150. it can. Below, each of the several function part of the assisting force control apparatus 150 and the process by each are demonstrated, referring the previous description about steering assist control.

The deviation angle Δα is calculated by the deviation amount authorization unit 160 from the operation side phase α detected by the operation angle sensor 78 and the turning side phase β detected by the turning angle sensor 79 according to the equation (7). The In other words, the deviation amount authorization unit 160 is a functional unit that executes the above-described deviation amount authorization program. The deviation angle Δα is input to the operation side phase correction unit 161, and the correction operation side phase α is calculated by the operation side phase correction unit 161 according to the equation (8). The correction operation-side phase α is input to the rotation transmission ratio authorization unit 162, which refers to the map data stored in the data storage unit 163 and provides the rotation transmission ratio (dβ / dα). Certify. On the other hand, the torque sensor 106 detects the transmission torque T _D that is the rotational torque of the steered side shaft 18, and the transmission torque T _D and the certified rotation transmission ratio (dβ / dα) are the operation torque estimates. is input to the section 164, at its operating torque estimation unit 164, according to equation (1), operating torque T _S is estimated. The estimated operation torque T _S is input to the operation speed dependence correction unit 166. On the other hand, the operation speed phase correction unit 166 also receives the operation-side phase α before correction, and the operation speed dependency correction unit 166 determines the operation speed v of the steering wheel 10 based on the operation-side phase α. Based on the estimated operation speed v, the operation speed correction dependence coefficient K _V is certified with reference to the map data stored in the data storage unit 163. Then, the operation speed dependency correction unit 166 corrects the input operation torque T _S according to the equation (2) using the recognized operation speed correction dependency coefficient K _V.

The corrected operation torque T _S is input to the target assist torque determining unit 170, and the target assist torque determining unit 170 refers to the map data stored in the data storage unit 163 based on the input operation torque T _S. Then, the reference assist torque T _A0 is determined. Further, the target assist torque determining unit 170 also receives a rotation transmission ratio (dβ / dα), and the target assist torque determining unit 170 receives the determined reference assist torque T _A0 and the rotation transfer ratio (dβ / dα). ) And the target assisting torque T _A ^* is determined according to the equation (3). The determined target assisting torque T _A ^* is input to the coupling mechanism-induced torque fluctuation dependence correcting unit 172. The coupling mechanism-induced torque fluctuation dependency correcting unit 172 also receives the steering-side phase β detected by the turning angle sensor 79, and the coupling mechanism-induced torque fluctuation dependency correcting unit 172 is stored in the data storage unit 163. With reference to the map data, the joint dependent correction coefficient K _J is determined, and the target assisting torque T _A ^* is corrected based on the joint dependent correction coefficient K _J according to the equation (5). The assisting device operation control unit 174 determines the target supply current I _A ^* based on the target assist torque T _A ^* , and sends a command based on the target supply current I _A ^* to the inverter 152.

Incidentally, configured to transmit torque T _D to the target assisting torque determination unit 170 is input, the target assisting torque determination unit 170, based on the transmission torque T _D input, according to equation (4), target assisting It can also be configured to determine the torque T _A ^* .

≪Modification≫
The steering system of the above-described embodiment can be implemented as a system in a state in which the above-described deviation amount recognition unit is removed. The steering system as a modified example does not have a function of identifying the deviation angle Δα, and the deviation angle Δα may be stored in the data storage unit 163 in advance. In this case, the displacement angle Δα is recognized using equipment provided outside the vehicle, for example, at the time of vehicle manufacture or vehicle maintenance, and the recognized displacement angle Δα is stored in the data storage unit 163. That's fine. The recognition of the deviation angle Δα may be performed according to the deviation amount authorization method described above.

  Further, in the steering system of the above-described embodiment, the steering side phase β is adopted as the detection dependence amount, and the operation side phase α is adopted as the detection target amount, and the steering side phase β is the same in the left and right turn of the vehicle. By comparing the operation-side phase α at the time, the deviation is recognized and the amount of deviation is certified. Instead of such authorization, conversely, when the operation side phase α is adopted as the detection dependency amount and the steered side phase β is adopted as the detection target amount, and the operation side phase α becomes the same in the left and right turn of the vehicle By comparing the steering-side phase β, the deviation may be recognized and the amount of deviation may be recognized. In that case, the operation angle sensor 78 functions as a detection-dependent amount detector, and the turning angle sensor 79 functions as a detection target amount detector.

  The steering system of the present embodiment has an assisting force control device 200 as shown in FIG. 16 instead of the assisting force control device 150 included in the steering system of the first embodiment. The steering system of the present embodiment has the same configuration as that of the steering system of the first embodiment except that the configuration of the assisting force control device is different and that the steering angle sensor is not provided. The assisting force control device 200 does not have a function of authorizing the deviation of the reference operation position of the rotation transmission mechanism 140 from the normal position and the amount of the deviation. At times. In the following description, in consideration of the simplification of the description, the description will focus on the different parts of the assisting force control device 150 and the assisting force control device 200, and the method for determining the displacement and the amount of displacement of the rotation transmission mechanism 140. And

If you think that there is a vehicle on the road surface (standard road surface) where the force required for turning is constant even with changes in the turning amount, and if you think that no assisting force can be generated, since it can be regarded as constant torque T _D, when the steering system which is not provided with the rotation transmission mechanism 140, the operation force of the steering wheel 10, that is, operating torque T _S, the operation amount of the steering wheel 10, That is, it is constant regardless of the operation side phase α. On the other hand, in the steering system provided with the rotation transmission mechanism 140, as described above, the rotation transmission ratio (dβ / dα) varies depending on the operation side phase α, and therefore the operation torque T _S depends on the operation side phase α. As shown by a solid line in FIG. Here, considering the case where the reference operation position of the rotation transmission mechanism 140 is deviated from the normal position, the operation torque T _S fluctuates as indicated by a two-dot chain line so that the operation side phase α ₃ becomes the same. Even when the steering wheel 10 is operated to the left and right, the value of the operation torque T _S is different between the left turn operation and the right turn operation. In the steering system of the present embodiment, the deviation of the reference operation position of the rotation transmission mechanism 140 and the amount of deviation are certified using such a phenomenon. In the present embodiment, from the viewpoint of simplifying the explanation, torque fluctuations due to the universal joints 20 and 24 are not considered.

Upon certification of the amount of the deviation and shift, the operating torque sensor for detecting the operating torque T _S as an operating force, attached to the operating-side shaft 60, placing placing the vehicle on a stage which simulates the standard road. In this state, without making an assisting force, a left turn operation is performed until the operation side phase α detected by the operation angle sensor 78 reaches the setting operation side phase α ₃ as a preset setting amount. The operation torque T _S detected by the operation torque sensor is authorized as the first operation torque T _S1 . Next, a right turn operation is performed until the set operation side phase α ₃ is reached, the operation torque T _S at that time is recognized as the second operation torque T _S2 , and the first operation torque T _S1 and the second operation torque T _S2 are recognized. The torque difference dT _S , which is a difference from the above, is recognized according to the following equation (9).
dT _S = T _S1 −T _S2 (9)
Then, based on the certified torque difference dT _S , when the absolute value exceeds the preset difference dT _S0 , the reference operation position of the rotation transmission mechanism 140 deviates from the normal position. Authenticate.

The set difference dT _S0 (set as a positive value) is a margin (dead zone) set in consideration of the detection accuracy by the operation angle sensor 78 and the operation torque sensor, and is a relatively small value. Has been. The torque difference dT _S and the above-described deviation angle Δα, which is the deviation amount of the reference operation position of the rotation transmission mechanism 140, are related by map data as shown in FIG. When it is recognized that there is a deviation, the deviation angle Δα is certified by referring to the map data. That is, in the recognition of the deviation and the amount of deviation of the reference operation position of the rotation transmission mechanism 140 included in the steering system, the operation side phase α is adopted as the detection dependency amount, and the operation torque T _S is adopted as the detection target amount. By comparing the operation torque T _S when the operation side phase α becomes the set operation side phase α ₃ in the left and right turns, the deviation is recognized and the amount of deviation is recognized.

The certified deviation angle Δα is stored in the data storage unit 163 of the assisting force control device 200 and used for controlling the assisting force by the assisting force control device 200. In the control by the steering system of the present embodiment, the shift angle according to the above equation (8) with respect to the operation side phase α detected by the operation angle sensor 78, as in the control by the steering system of the first embodiment. Correction based on Δα is performed. Based on the corrected operation side phase α, the operation torque T _S is estimated and the target assisting force is determined.

In the control of the assisting force by the assisting force control device 200 of the steering system, the correction based on the operation speed v of the steering wheel 10 described above is performed on the determined target assisting torque T _A ^* . Specifically, the target assist torque T _A ^* is corrected according to the following equation (10) based on the above-described operation speed-dependent correction coefficient K _V stored as map data.
T _A ^* = K _V × T _A ^* (10)

In addition, in the control of the assisting force by the assisting force control device 200, the target assisting torque T _A ^* is determined so that the assisting force has a magnitude corresponding to the operating force. Specifically, it is determined based on the estimated operation torque T _S using the map data set and stored based on the relationship shown in FIG. That is, the reference assist torque T _A0 determined in the same manner as in the control by the assist force control device 150 provided in the steering system of the first embodiment is determined as the target assist torque T _A ^* as it is. Even if the assisting force is determined in this way, a favorable steering feeling steering operation is realized. Incidentally, in the assisting force control device 200, the target assisting torque is not corrected by the universal joint.

  The functional configuration of the assisting force control device 200 will be described. The control device 200 has a configuration in which the displacement amount authorization unit 160 is deleted from the assisting force control device 150 of the first embodiment as shown in FIG. Yes. Therefore, in the assisting force control apparatus 200, the operation side phase α detected by the operation angle sensor 78 is directly input to the operation side phase correction unit 161.

In the assisting force control device 200, the operation torque T _S sent from the operation torque estimating unit 164 is input to the target assisting torque determining unit 202. The target assist torque determination unit 202 determines the reference assist torque T _A0 from the operation torque T _S by referring to the map data stored in the data storage unit 163, and sets the reference assist torque T _A0 as the target assist torque T _A ^*. This is sent to the dependency correction unit 204. The operation speed dependency correction unit 204 refers to the map data stored in the data storage unit 163, determines the operation speed correction dependency coefficient K _V, and corrects the target assisting torque T _A ^* . The corrected target assisting torque T _A ^* is sent to the assisting device operation control unit 174, and the assisting force control device 200 performs the same processing as the processing performed by the assisting force control device 150, and the target supply current I _A ^A command based on ^* is sent to the inverter 152.

  Although this steering system does not have a function of authorizing the deviation of the reference operation position of the rotation transmission mechanism 140 and the amount of deviation, a function unit for authorizing the deviation and the deviation amount by itself is provided as an assisting force control device. The steering system may be configured so as to prepare for 200. In other words, the above-described operation torque sensor is provided, and the assist control device 200 may be configured to include a displacement amount authorization unit similar to the displacement amount authorization unit included in the assist force control device of the steering system of the first embodiment. Is possible.

Moreover, certification shift and shift amount of the reference operating position of the rotation transmitting mechanism 140 in the steering system, as described above, employing respectively the operation side phase alpha, the operation torque T _S as the detection target amount as a detection relied amount The operation torque T _S is compared when the operation-side phase α is the same in turning left and right of the vehicle. Instead of this method, when the operation torque T _S is adopted as the detection dependency amount and the operation side phase α is adopted as the detection target amount, and the operation torque T _S becomes the set torque as the set amount in the left and right turn of the vehicle By comparing the operating-side phase α, the deviation and the amount of deviation may be recognized.

10: Steering wheel (operation member) 14: Steering device 18: Steering side shaft (second shaft) 20: Universal joint 22: Input shaft 24: Universal joint 60: Operation side shaft (first shaft) 80: Electromagnetic motor (Drive source) 82: Steering assistance device 106: Torque sensor 130: Groove 138: Engagement unit 140: Rotation transmission mechanism 150: Assisting force control device 164: Operation torque estimation unit (operation force estimation unit) 166: Operation speed dependence Correction unit 170: Target assisting torque determining unit (target assisting force determining unit) 172: Coupling mechanism-derived torque fluctuation dependency correcting unit 174: Auxiliary device operation control unit 200: Auxiliary force control device α: Operation side phase (rotation of first shaft Phase) β: Steering side phase (rotation phase of second shaft) (dβ / dα): Rotation transmission ratio T _A ^* : Target assist torque T _D : Transmission torque (rotary torque of the second shaft) v: Operating speed

Claims (7)

An operation member operated by a driver;
A first shaft that is rotated by operation of the operating member;
A second shaft disposed closer to the wheel than the first shaft;
A steering device for turning the wheel by rotation of the second shaft;
While transmitting the rotation of the first shaft to the second shaft, the operation position of the first shaft changes with the rotation of the first shaft, and the rotation transmission ratio in the rotation transmission from the first shaft to the second shaft. Is a rotation transmission mechanism configured to vary so as to be a value defined according to a change amount from the reference operation position of the operation position,
A torque detector for detecting rotational torque of the second shaft;
An assisting device that has a drive source and assists the steering of the wheel by an assisting force generated by itself; (a) from the rotational torque of the second shaft detected by the torque detector, to the rotational transmission ratio; An operation force estimation unit that estimates an operation force applied to the operation member by the driver, and (b) a target that determines a target assisting force based on the operation force estimated by the operation force estimation unit. An assisting force determining unit, and (c) an assisting force control device having an assisting device operation control unit that controls the operation of the assisting device based on the target assisting force determined by the target assisting force determining unit. A steering system,
A steering system configured to estimate the operating force of the operating member based on an amount of the shift when the reference operation position of the rotation transmission mechanism is shifted from a normal position.   The operating force estimation unit estimates the rotational torque of the first shaft by dividing the rotational torque of the second shaft detected by the torque detector by the rotational transmission ratio, and the estimated first The operation force is estimated based on the rotational torque of one shaft, and the rotational torque of the second shaft is divided when the reference operation position of the rotation transmission mechanism is deviated from the normal position. Based on the rotational torque of the first shaft estimated by correcting the value of the rotational transmission ratio based on the amount of deviation and dividing the rotational torque of the second shaft by the corrected value, The steering system according to item (2), which is configured to estimate an operation force. (A) One of the operation force of the operation member and the steering amount of the wheel from the straight travel state, and (B) the operation amount of the operation member from the straight travel state is defined as the detection dependence amount, and the other Is defined as the amount to be detected,
The steering system includes a detection dependency amount detector that detects the detection dependency amount, and a detection target amount detector that detects the detection target amount,
The assisting force control device comprises:
i) In the operation of the one of the operation members of the left turn and the right turn, the detected amount detected by the detection target amount detector when the detected dependency amount detected by the detection dependency amount detector becomes a set amount. The first detection target amount that is a detection target amount, and ii) the operation of the other operation member of the left turn and the right turn, the detection dependency amount detected by the detection dependency amount detector becomes the set amount. The difference between the detection target amount detected by the detection target amount detector and the second detection target amount, the change amount of the operation position from the reference operation position with respect to the rotation transmission mechanism, and the rotation transmission ratio. And a deviation amount certifying unit for certifying the deviation amount of the reference operation position based on the relationship with the value of
The said operation force estimation part is comprised so that the operation force of the said operation member may be estimated based on the amount of deviation | shift of the said reference | standard movement position recognized by the deviation | shift amount certification | authentication part. Steering system.   The target assisting force determining unit determines the target assisting force so that the target assisting force has a magnitude corresponding to the operation force, or the target assisting force is transferred from the first shaft to the second shaft. 2. The apparatus according to claim 1, wherein the combined force obtained by combining the component based on the transmitted operating force and the component based on the assisting force by the assisting device is determined so as to have a magnitude corresponding to the operating force. 4. The steering system according to any one of 3. The steering system includes a connection mechanism that has at least one universal joint and connects the second shaft and the input shaft of the steering device;
The assisting force control device comprises:
Coupling mechanism-induced torque fluctuation that corrects the target assisting force so as to cancel out fluctuations in rotational torque transmitted from the second shaft to the input shaft of the steered device caused by the structure of the coupling mechanism. The steering system according to any one of claims 1 to 4, further comprising a dependency correction unit. (a) an operation member operated by the driver, (b) a first shaft that is rotated by operation of the operation member, (c) a second shaft that is disposed closer to the wheel than the first shaft, (d) a steering device for turning the wheel by rotation of the second shaft; (e) transmitting the rotation of the first shaft to the second shaft; and (f) accompanying the rotation of the first shaft. So that its own operating position changes, and the rotation transmission ratio in the rotation transmission from the first shaft to the second shaft becomes a value defined according to the amount of change of the operating position from the reference operating position. Applied to a steering device having a rotation transmission mechanism configured to fluctuate,
A method for recognizing a deviation from a normal position of a reference operation position of the rotation transmission mechanism,
(A) One of the operation force of the operation member and the steering amount of the wheel from the straight travel state, and (B) the operation amount of the operation member from the straight travel state is defined as the detection dependence amount, and the other Is defined as the amount to be detected,
In the operation of one of the operation members of the left turn and the right turn, a first detection target amount that is the detection target amount when the detection dependence amount becomes a set amount is detected,
In the operation of the other operation member of the left turn and the right turn, a second detection target amount that is the detection target amount when the detection dependency amount becomes the set amount is detected,
When the difference between the first detection target amount and the second detection target amount exceeds a set difference, the rotation transmission for the steering device that recognizes that the reference operation position of the rotation transmission mechanism deviates from the normal position. Mechanism operation position deviation recognition method.   Furthermore, based on the relationship between the difference between the first detection target amount and the second detection target amount, the amount of change of the operation position of the rotation transmission mechanism from the reference operation position, and the value of the rotation transmission ratio. The method of claim 6, wherein the amount of deviation of the reference operation position is authorized.

Images