JP2016043790A - Operation characteristic adjusting device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an operation characteristic adjusting device for a vehicle that achieves excellent nonlinear characteristics with respect to relation between displacement and operation force of a braking operation member and the device can be downsized.SOLUTION: An operation characteristic adjusting device for a vehicle comprises: a spring member which generates spring force for a braking operation member; an electric motor MTR which applies adjusting force to the braking operation member; control means of controlling the adjusting force through the electric motor MTR; and operation displacement acquiring means of acquiring operation displacement Bpa of the braking operation member. The control means is configured to drive the electric motor MTR in a first direction Rvs when the operation displacement Bpa is less than a predetermined value bpx, and to drive the electric motor MTR in a second direction Fwd opposite to the first direction Rvs when the operation displacement Bpa exceeds the predetermined value bpx.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a vehicle operation characteristic adjusting device.

  Patent Document 1 states that “an additional adjusting force that acts in the return direction of a control mechanism formed as a pedal is generated by an electromechanical actuator. The excessive stepping means includes an electric motor, and this electric motor To be electrically driven in the first movement direction to output the adjusting force of the actuator, and on the other hand, to be mechanically movable in a direction opposite to the first movement direction by a sufficiently large operating force. The excessive depression is a process in which the driver should be able to operate the accelerator pedal in a higher speed direction or a brake pedal in a direction that increases braking. " ing.

JP 2005-508060 A

  By the way, in the operation characteristic of the braking operation member, it is preferable that the operation force is increased with a non-linear characteristic of “convex downward” as the displacement of the braking operation member is increased. It is desired that the above characteristics be achieved even in an apparatus in which the operation characteristics of the braking operation member are adjusted by an electric motor (electric motor). In addition, a simple configuration such as the adoption of a small electric motor is desired in the apparatus.

  An object of the present invention is to provide a vehicle operation characteristic adjusting device that can change a displacement-force characteristic of a braking operation member by a driver, which can achieve a preferable non-linear characteristic and can be miniaturized.

  The vehicle operating characteristic adjusting device according to the present invention includes a braking operation member BP that is operated to reduce the speed of the vehicle, a spring member DSB that generates a spring force Fds for the braking operation member BP, and the braking Based on the operation displacement Bpa via the electric motor MTR, the operation displacement acquisition means BPA for acquiring the operation displacement Bpa of the braking operation member BP, and the operation displacement Bpa through the electric motor MTR. Control means CTL for controlling the adjustment force Fmt.

  The feature of the present invention is that the control means CTL drives the electric motor MTR in the first direction Rvs when the operation displacement Bpa is less than a predetermined value bpx, and the operation displacement Bpa exceeds the predetermined value bpx. In some cases, the electric motor MTR is configured to be driven in a second direction Fwd that is opposite to the first direction Rvs.

  According to the above feature of the present invention, the electric motor MTR is driven in the first direction (MTR reverse rotation direction Rvs) and the second direction (the normal rotation direction Fwd opposite to the MTR reverse rotation direction Rvs). By combining the driving of the above, the “downwardly convex” nonlinear characteristic desirable in the relationship between Bpa and Fbp can be efficiently formed. This is because “the reaction force Fbp of the braking operation member BP is relatively lightened in the range of 0 ≦ Bpa <bpx, and Fbp is relatively heavy in the range of Bpa ≧ bpx”. This non-linear characteristic is preferable in the operation of the braking operation member.

1 is an overall configuration diagram of an embodiment of an operation characteristic adjusting device according to the present invention. It is a block diagram for demonstrating the reaction force adjustment means shown in FIG. It is a block diagram for demonstrating the restriction | limiting means shown in FIG. It is a functional block diagram for demonstrating the process in a control means and a drive means shown in FIG. It is a block diagram for demonstrating the 4-joint link mechanism shown in FIG. FIG. 6 is a characteristic diagram for explaining the link ratio of the four-bar linkage mechanism shown in FIG. 5. It is a characteristic view for demonstrating the effect | action and effect of this invention.

  Hereinafter, embodiments of an operation characteristic adjusting device according to the present invention will be described. In each figure, what is represented by the same symbol has the same function, and therefore description thereof may be omitted.

<Whole structure of a vehicle provided with the operation characteristic adjusting device according to the present invention>
As shown in FIG. 1, a vehicle including an operation characteristic adjusting device according to the present invention includes a braking operation member BP, a limiting unit SG2, a spring member DSB, an operation displacement acquisition unit BPA, a vehicle state quantity acquisition unit JPA, and an electronic control unit. An ECU, a power source (battery) BAT, a reaction force adjusting means (reaction force adjusting actuator) ACT, and a braking means BRK are provided.

  The braking operation member BP (for example, a brake pedal) is operated by a driver's foot. By operating the braking operation member BP, the braking means BRK of the vehicle is adjusted, and the deceleration state of the vehicle (as a result, the vehicle speed) is controlled. The braking operation member BP is fixed to the vehicle body BDY in a rotatable state. The braking operation member BP includes an operation surface (tread surface) PTM for the driver to operate with his / her feet and a first link LN1 which is rotatably attached to the vehicle body BDY. The operation surface PTM is fixed to the first link LN1.

  The operation (movement) of the braking operation member BP is restricted by the restriction means SG2. The restricting means SG2 is a so-called stopper and is fixed to the vehicle body BDY. When the amount of operation of the braking operation member BP by the driver is gradually increased, the braking operation member BP is brought into contact with the limiting means SG2, and its operation is limited. The braking operation member BP is strongly pressed against the limiting means SG2, but further movement is prevented.

  The first fixed end joint KT1 is an attachment portion of the first link LN1 on the vehicle body BDY, and the first link LN1 (that is, the operation surface PTM) is rotatable around the first fixed end joint KT1. The braking operation member BP is provided with a spring member (for example, a coil spring or a torsion spring) DSB in order to generate an operation force Fbp corresponding to the displacement of the operation surface PTM (that is, the rotation angle of the first link LN1).

  The spring member (for example, a coil spring, a torsion spring) DSB is a so-called passive (passive that does not require external energy supply) spring element, and an operation force Fbp (with respect to the displacement of the brake operation member BP). The generated force Fds) of the spring member DSB alone is generated. In addition, the operating force Fbp in the entire braking operation member BP is also generated by the electric motor MTR of the reaction force adjusting means ACT. Therefore, the operation characteristics of the braking operation member BP (relationship between the operation displacement Bpa and the operation force Fbp) can be adjusted by the force (output) Fmt generated by the electric motor MTR by the spring force Fds generated by the spring member DSB. The That is, the entire operation force Fbp is generated by a component (spring force) Fds by the spring member DSB and a component (adjustment force) Fmt by the electric motor MTR (Fbp = Fds + Fmt).

  An operation displacement acquisition means BPA is provided to acquire (detect) the operation displacement Bpa of the braking operation member BP operated by the driver. For example, the operation displacement acquisition means BPA is a rotation angle sensor in the first fixed end joint KT1 of the first link LN1, and is attached to the first fixed end joint KT1. The first link LN1 can rotate around the first fixed end joint KT1, but the rotation angle of the first link LN1 relative to the first fixed end joint KT1 is acquired as the operation displacement Bpa (A on the right side of FIG. 1). View). Further, the rotation angle acquisition means MKA of the electric motor MTR can be adopted as the operation displacement acquisition means BPA (that is, the rotation angle Mka of the MTR can be adopted as the operation displacement Bpa). The operation displacement Bpa is input to the electronic control unit ECU.

  Vehicle state quantity acquisition means JPA is provided, and the vehicle state quantity Jpa is acquired. The vehicle state quantity Jpa is a state quantity (variable) used for driving control of the reaction force adjusting means ACT. Specifically, the vehicle state quantity Jpa is an operation characteristic instruction state Swa by the driver. Further, as the vehicle state quantity Jpa, the vehicle running state Jva (for example, the vehicle speed Vxa, the turning state of the vehicle) can be adopted. That is, as the JPA, at least one of an instruction state acquisition unit (manual switch) SWA by the driver and a travel state acquisition unit JVA (for example, vehicle speed acquisition unit VXA) is employed. The vehicle state quantity Jpa is input to the electronic control unit ECU.

  The instruction state acquisition unit SWA acquires (inputs) the instruction state Swa of the operation characteristics desired by the driver. Specifically, the instruction state acquisition unit SWA is a multi-stage input switch, and the instruction state Swa is instructed by one stage (selection stage) determined by the driver from among the above-described multi stages. . Therefore, the above selection stage is acquired as the instruction state Swa.

  The row state acquisition means JVA acquires (detects) the vehicle running state amount Jva. Specifically, the running state quantity Jva is at least one of the running speed of the vehicle and the turning state quantity of the vehicle. Therefore, the wheel speed Vwa acquired by the wheel speed acquisition means VWA, the yaw rate Yra acquired by the yaw rate acquisition means YRA, the lateral acceleration Gya acquired by the lateral acceleration acquisition means GYA, and the steering angle acquisition means SAA. At least one of the steering angles Saa of the steering wheel SW is adopted as the travel state quantity Jva.

  In the electronic control unit ECU, signals (Imt etc.) for controlling the reaction force adjusting means ACT and the braking means BRK are calculated based on various input signals (operation displacement Bpa etc.). The arithmetic processing is executed by control means (control algorithm) CTL programmed in a microcomputer in the electronic control unit ECU. A control means CTL in the electronic control unit ECU calculates a target energization amount Imt for driving the electric motor MTR of the reaction force adjusting means ACT based on the operation displacement Bpa and the vehicle state quantity Jpa. The target energization amount Imt is determined based on a calculation map that changes as the operation displacement Bpa increases. The calculation map is configured such that the change amount of the target energization amount Imt with respect to the increase amount of the operation displacement Bpa is adjusted based on the vehicle state amount Jpa. The target energization amount Imt is transmitted to the reaction force adjusting unit ACT (for example, the driving unit DRV of the electric motor MTR).

  Further, the electronic control unit ECU (that is, the control means CTL) calculates a target braking torque Brt for controlling the braking means BRK (braking actuator). Specifically, the target braking torque Brt is determined based on the braking operation displacement Bpa and the calculation characteristics (calculation map). The calculation map is set so that the target braking torque Brt increases as the operation displacement Bpa increases. The target braking torque Brt is transmitted to the braking means BRK.

  A storage battery (battery) BAT is provided to supply power to the electronic control unit ECU, the braking means BRK, and the reaction force adjusting means ACT. That is, the storage battery BAT is a power source for the operation characteristic adjusting device and the braking means BRK.

  The reaction force adjusting means (actuator) ACT adjusts the elastic force (spring force) Fds generated by the spring member DSB, and the final operation force Fbp of the braking operation member BP is determined. Here, the “operation force Fbp” is a force that opposes the driver's operation of the braking operation member BP, and is a reaction force that attempts to return the braking operation member BP to the initial position (position that contacts the restriction means SG1). is there. Basically, the operating force Fbp is generated by the spring force Fds of the spring member DSB. The spring force Fds always acts in the direction (one direction) for returning the braking operation member BP to the initial position. The spring force Fds is increased or decreased by the output torque of the electric motor MTR constituting the reaction force adjusting means ACT, and the operating force Fbp is adjusted. The reaction force adjusting means ACT is composed of an electric motor MTR and a power transmission mechanism DDB.

  The electric motor MTR generates a force (adjustment force) Fmt for adjusting the operation force Fbp. The adjustment force Fmt is generated in the direction in which the spring force (elastic force) Fds of the spring member DSB is increased (the direction in which the operation force Fbp increases and the BP operation is felt heavy). In other words, the influence degree of the spring force Fds on the braking operation member BP is increased by the force (adjustment force) Fmt generated by the electric motor MTR.

  The adjustment force Fmt is generated in a direction in which the spring force Fds is reduced (a direction in which the operation force Fbp is reduced and the operation of the BP is felt lightly). That is, the influence degree of the spring force Fds on the braking operation member BP is reduced by the force (adjustment force) Fmt generated by the electric motor MTR. In this way, the forward drive / reverse drive of the electric motor MTR is used, and the adjustment force Fmt acts in both directions (two directions).

  The electric motor MTR is provided with a driving means DRV, and a power element (for example, a MOS-FET, IGBT) is switching-driven based on the target energization amount Imt. As a result, the output (the magnitude and direction of the generated torque) of the electric motor MTR is controlled. The output (torque) of the electric motor MTR is transmitted to the braking operation member BP (specifically, the first link LN1) via the power transmission mechanism DDB.

  The output of the electric motor MTR is transmitted to the braking operation member BP by the power transmission mechanism DDB. For example, the torque of the output shaft MTJ of the electric motor MTR is decelerated and transmitted as torque around the first fixed end joint KT1. Since the first fixed end joint KT1 is fixed to the first link LN1, the output of the electric motor MTR is transmitted to the braking operation member BP.

  Braking means BRK is provided on each wheel WH of the vehicle. The braking means BRK is driven based on the target braking torque Brt (signal) transmitted from the electronic control unit ECU. The braking torque of each wheel WH is controlled by the braking means BRK, and the deceleration of the vehicle is adjusted (finally, the speed of the vehicle is controlled). As the braking means BRK, at least one of braking torque adjustment (so-called hydraulic system) using braking fluid (brake fluid) and braking torque adjustment (so-called EMB; Electro-Mechanical Brake) using an electric motor is adopted. .

<Reaction force adjustment means (reaction force adjustment actuator)>
The reaction force adjusting means (reaction force adjusting actuator) ACT when the four-bar linkage mechanism LNK is employed as the power transmission mechanism DDB will be described with reference to the configuration diagram of FIG. Here, the “link mechanism” is a mechanical mechanism configured by combining a plurality of links, and an undeformed object called a link (node) is a movable part called a joint (joint). Are connected to form one or more closed circuits. Therefore, the “four-bar linkage mechanism” is a mechanism having four links. Specifically, in three actual links (first link LN1, second link LN2, and intermediate link LNC) and fixed link LNV which is a virtual link by being fixed to vehicle body floor FLR. A four-bar linkage mechanism LNK is configured.

  In FIG. 1, members denoted by the same reference numerals have the same functions in FIG. However, since there are some differences in the configuration of the apparatus, the differences will be described first.

  In the configuration of FIG. 1, the first link LN1 is suspended from the vehicle body BDY (so-called suspension type braking operation member BP), and the spring member DSB is fixed to the first link LN1. Therefore, the spring member DSB directly generates a force (spring force) Fds for returning the braking operation member BP to the initial position. On the other hand, in the configuration of FIG. 2, the first link LN1 is supported by the floor FLR of the vehicle body BDY (so-called organ pedal type braking operation member BP), and the spring member DSB is attached to the support link LNS integral with the second link LN2. Is fixed (fixing points Pd1, Pd2 of the spring member DSB). The spring member DSB is a spring element for applying a force to the first link LN1 (finally the operation surface PTM), and generates a force (spring force) Fds in a direction to return the braking operation member BP to the initial position. To do. Here, the “initial position” is a position where the movement of the BP is restricted by the restricting means SG1 when the braking operation member BP is not operated by the driver (that is, during non-operation). In the power transmission path between the first link LN1 of the four-bar linkage mechanism LNK and the output shaft MTJ of the electric motor MTR, a spring member DSB can be provided at an arbitrary location.

  The four-joint link mechanism LNK forming the power transmission mechanism DDB includes a first link LN1, a first fixed end joint KT1, an intermediate link LNC, a first free end joint JY1, a second link LN2, a second free end joint JY2, and The second fixed end joint KT2. Here, the “fixed end joint” is fixed to the vehicle body BDY in a rotatable state. The “free end joint” is not fixed to the vehicle body BDY and can be freely moved to a position constrained by each link.

  Power is transmitted between the first link LN1 and the electric motor MTR via the four-link mechanism LNK. An operation force by the driver is input to the first link LN1. The second link LN2 is connected to the electric motor MTR in order to generate a force (operation reaction force) that opposes the operation force of the driver. The first and second links LN1, LN2 are connected via an intermediate link LNC. Connection portions between the first and second links LN1, LN2 and the intermediate link LNC are the first and second free end joints JY1, JY2. The first and second links LN1, LN2 are supported by the vehicle body BDY in a rotatable state on the side opposite to the connection parts JY1, JY2. The support parts of the vehicle body BDY are the first and second fixed end joints KT1 and KT2.

  The force (operation force) to the operation surface PTM (the portion where the driver's foot touches) of the braking operation member BP is transmitted to the second link LN2 via the first link LN1 and the intermediate link LNC. The power (torque) of the electric motor MTR is transmitted to the second link LN2, and opposes the force transmitted from the operation surface PTM. A large-diameter gear DKH is fixed to the fixed end joint KT2 of the second link LN2. The large diameter gear DKH is meshed with a small diameter gear SKH fixed to the output shaft MTJ of the electric motor MTR. That is, the reduction gear GSK is configured by a combination of the large diameter gear DKH and the small diameter gear SKH. Accordingly, the generated force (output) of the electric motor MTR is decelerated by the reduction gear GSK (that is, the generated force is increased) and transmitted to the second fixed end joint KT2. The electric motor MTR is fixed to a mount MNT fixed to the vehicle body floor FLR. That is, the electric motor MTR is fixed to the vehicle body BDY.

  The reduction gear GSK is configured by gears (no backlash gear) DKH and SKH having a backlash removal mechanism. As will be described later, the electric motor MTR is first driven in the reverse rotation direction Rvs. Thereafter, the rotation direction of the electric motor MTR is changed (switched) to the forward rotation direction Fwd, which is the opposite direction to the reverse rotation direction Rvs. During the reversal of the rotation direction, the influence of the backlash of the reduction gear GSK can occur.

  Specifically, the backlash is defined as “the play between the tooth surfaces when meshing a pair of gears, the length represented by the arc length on the meshing pitch circle, and the circumferential backlash between the tooth surfaces. Is defined as “the normal direction backlash” (JIS terminology). That is, the backlash is a gap provided in the movement direction in mechanical elements that move together and move, such as a feed screw and a gear, and the screw and the gear can move by this gap. However, when an object that has been rotated in one direction is reversed and rotated in the other direction (for example, when reversing from the Rvs direction to the Fwd direction described above), due to backlash, dimensional deviation, impact, etc. May occur.

  In order to reduce the influence of backlash, a gear having a backlash removal mechanism (no backlash gear) may be employed for the reduction gear GSK. For example, as a no-backlash gear, a scissors gear is employed in which a preload is applied to the meshing gear by a spring or the like. Further, a friction gear can be adopted as the no-backlash gear. In the friction gear, a thin gear having one tooth less than that of the main gear is formed so as to be a disc spring, and is arranged so as to be pressed against the main gear. And backlash is reduced by the friction between the main gear and the thin gear. Furthermore, a wave gear device (a so-called harmonic drive (registered trademark), which uses a differential between an ellipse and a perfect circle) is adopted as the reduction gear GSK. Here, the harmonic gear includes a circular spline, a wave generator, and a flex spline.

  The movement of the four-bar linkage mechanism LNK is restricted by the first restriction member (first restriction means) SG1 and the second restriction member (second restriction means) SG2. In other words, the operable range of the four-bar linkage mechanism LNK (for example, the first link LN1) is limited by the first and second restriction members SG1 and SG2. The restricting means SG1 restricts the initial position (position corresponding to Bpa = 0) when the braking operation member BP is not operated (that is, during non-braking). For example, the first restricting member SG1 is installed on the mount MNT fixed to the floor FLR of the vehicle body BDY, and restricts the movement of the second link LN2 relative to the vehicle body BDY. The second restriction member SG2 restricts the maximum operation position (a position corresponding to Bpa = bp1 or Bpa = bp3) when the braking operation member BP is operated to the maximum. For example, the second restricting member (corresponding to restricting means) SG2 is fixed to the vehicle body floor FLR and restricts the operation of the first link LN1 with respect to the vehicle body BDY.

  In the first restricting member SG1, an elastic body (for example, a rubber member) is provided in a portion that can come into contact with the second link LN2, and the impact when the second link LN2 and the first restricting member SG1 come into contact is reduced. Can be done. Similarly, in the second restricting member SG2, an elastic body (for example, a rubber member) is provided in a portion that can come into contact with the first link LN1, and the first link LN1 and the second restricting member SG2 are in contact with each other. Impact can be mitigated. Since the limiting means (stoppers) SG1, SG2 limit the movable range of the four-link mechanism LNK, the first link LN1, the second link LN2, and the intermediate link LNC with respect to the vehicle body BDY. It may be configured to limit at least one movement.

<Limiting means SG2>
The restricting means (particularly, the second restricting member SG2) will be described with reference to the configuration diagram of FIG. The second restriction member (corresponding to the restriction means) SG2 restricts the operation (movement amount) of the braking operation member (brake pedal) BP when the braking operation member BP is operated, and functions as a so-called stopper. . Moreover, it has a function of smoothly increasing the operating force Fbp with nonlinear characteristics by the elastic force Fgm of SG2. The restricting means SG2 is fixed to the vehicle body BDY.

  The operation displacement Bpa at the moment when the braking operation member BP and the limiting means SG2 come into contact with each other is referred to as “contact operation displacement bp1”. Although the limiting means SG2 is elastically deformed, the operation displacement Bpa of the braking operation member BP in a state in which the braking operation member BP cannot move any more by the limiting means SG2 is referred to as “maximum operation displacement bp3”. . The movable region of the braking operation member BP is a range from the initial position (corresponding to non-operation, Bpa = 0) to the maximum operation displacement (Bpa = bp3). A contact operation displacement bp1 exists within the movable range of the braking operation member BP (0 <bp1 <bp3). Since the contact operation displacement bp1 and the maximum operation displacement bp3 are determined by the specifications of the reaction force adjusting means ACT, these values are predetermined values set in advance.

  As shown in FIG. 3A, the second restricting member (corresponding to the restricting means) SG2 includes a rubber part SG2a and a metal part SG2b. In other words, the rubber member SG2a and the metal member SG2b are joined to form the second limiting member SG2. The end portion (the top portion) Tpa of the rubber member SG2a is a portion that comes into contact with the braking operation member BP. Second limiting member SG2 is fixed to vehicle body BDY by metal member SG2b. In a state where the rubber member SG2a starts to contact the braking operation member BP (that is, a state where Bpa = bp1), the rubber member SG2a does not generate the force Fgm. Further, when the braking operation member BP is operated and Bpa is increased, the elastic force Fgm of the rubber member SG2a is gradually increased. As the rubber member SG2a is compressed and deformed, the amount of increase in the elastic force Fgm generated by the rubber member SG2a (the amount of change in the force Fgm with respect to the change in the operation displacement Bpa) increases and reaches its limit (ie, Bpa = In the state of bp3), the movement of the braking operation member BP is completely restricted (restrained). In the range where the braking operation member BP is in contact with the rubber member SG2a, the operation force Fbp is determined by the DSB spring force Fds, the MTR adjustment force Fmt, and the SG2a elastic force Fgm.

  FIG. 3B shows another embodiment of the limiting member SG2. As shown in the left diagram of FIG. 3B, a second restricting member (corresponding to restricting means) SG2 can be constituted by a metal member SG2c having a recess and a rubber member SG2a joined in the recess. Similarly to the above, the metal member SG2c is fixed to the vehicle body BDY, and the end (head portion) Tpa of the rubber member SG2a comes into contact with the braking operation member BP, and the operation of the braking operation member BP is restricted. For example, the end of the metal member SG2c (on the side opposite to the fixed portion of BDY) is counterbored to provide a counterbore. The rubber member SG2a is fixed to the counterbore with a clearance Skm. At this time, the height of the rubber member SG2a is higher than the depth of the counterbore, and the end portion (head portion) Tpa of the rubber member SG2a protrudes outside the counterbore.

  It is assumed that the braking operation member BP is operated by the driver and the operation displacement Bpa is sequentially increased. First, when the operation displacement Bpa becomes the contact operation displacement bp1, the top portion Tpa of the second limiting member SG2a starts to contact the braking operation member BP. At this moment, since the rubber member SG2a is not yet deformed, the rubber member SG2a does not generate the elastic force Fgm. When the operation displacement Bpa is gradually increased, the rubber member SG2a starts to compress and deform. At this time, the rubber member SG2a starts to generate the elastic force Fgm. Further, along with the compression deformation of the rubber member SG2a, the gap Skm is gradually filled (filled) with the rubber member SG2a. As the rubber member SG2a is compressed and deformed, the amount of change (increase) in the elastic force Fgm generated by the rubber member SG2a with respect to the change in the operation displacement Bpa is increased.

  3B, when the end portion Tpc of the metal member SG2c comes into contact with the braking operation member BP, the movement of the braking operation member BP is completely restricted (restrained). Movement is hindered. That is, the operation displacement Bpa when the braking operation member BP is in contact with the end portion Tpc of the metal member SG2c is the maximum operation displacement bp3. In this state, the gap Skm between the rubber member SG2a and the recess (counterbore hole) of the metal member SG2c is substantially filled. Similarly to the above, in the configuration shown in FIG. 3B, the operating force Fbp is the DSB spring force Fds and the MTR adjusting force Fmt within the range where the braking operation member BP is in contact with the rubber member SG2a. And the elastic force Fgm of SG2a. That is, Fbp is obtained by adding Fgm to the resultant force of Fds and Fmt.

<Calculation processing of target energization amount Imt and drive control processing of electric motor MTR>
With reference to the functional block diagram of FIG. 4, calculation processing of the target energization amount Imt in the control means CTL (control algorithm) and drive control processing of the electric motor MTR in the drive means DRV based on the target energization amount Imt explain.

  A target energization amount calculation block IMT is provided in the control means CTL, and the target energization amount Imt is calculated. Here, the “energization amount” is a state amount (variable) for controlling the force (output torque) generated by the electric motor MTR. Since the electric motor MTR outputs a torque approximately proportional to the current, the current target value of the electric motor MTR can be used as the target value of the energization amount (target energization amount). Further, if the supply voltage to the electric motor MTR is increased, the current is increased as a result, so that the supply voltage value can be used as the target energization amount. Furthermore, since the supply voltage value can be adjusted by the duty ratio in the pulse width modulation, this duty ratio (ratio of energization time in one cycle) can be used as the energization amount.

  The electric motor MTR generates output in both directions (forward rotation direction or reverse rotation direction), but the rotation direction of the electric motor MTR is based on the sign (positive sign or negative sign) of the target energization amount Imt. It is determined. For example, the rotation direction of the electric motor MTR is set such that the forward rotation direction Fwd is a positive (plus) value and the reverse rotation direction Rvs is a negative (minus) value. Based on the magnitude of the target energization amount Imt, the force (that is, output torque) generated by the electric motor MTR is determined.

  An operation displacement Bpa of the braking operation member BP and a vehicle state quantity Jpa are input to the target energization amount calculation block IMT. The target energization amount calculation block IMT stores calculation characteristics (calculation map) for determining the target energization amount Imt. In the calculation characteristic (calculation map) of the target energization amount Imt, the target energization amount Imt is made smaller than zero when the braking operation displacement Bpa is from zero to a predetermined value bpx, as in the characteristic CHt indicated by the broken line. “Mode Mdg” and “Increase mode Mdz” in which the braking operation displacement Bpa is greater than or equal to the predetermined value bpx and the target energization amount Imt is greater than zero. Specifically, the decrease mode Mdg is a characteristic that increases toward zero again after the target energization amount Imt is decreased from zero as the operation displacement Bpa increases. The increase mode Mdz is a characteristic in which the target energization amount Imt is simply increased from zero.

  In the decrease mode Mdg (Imt <0), the electric motor MTR is driven in the reverse rotation direction Rvs (corresponding to the first direction). In the decrease mode Mdg, the adjustment force (MTR generation force) Fmt acts in a direction (a direction opposite to Fds) to cancel the spring force (DSB generation force) Fds. Therefore, the operation force Fbp of the braking operation member BP is reduced as compared with the case where the operation force Fbp is generated only by the spring force Fds. In other words, in the reduction mode Mdg, the degree of influence of the spring force Fds on the braking operation member BP is reduced by the adjustment force Fmt.

  On the other hand, in the increase mode Mdz (Imt> 0), the electric motor MTR is driven in the forward rotation direction Fwd (corresponding to a second direction that is opposite to the first direction). In the increase mode Mdz, the adjusting force Fmt (MTR generating force) acts in the same direction as the spring force Fds (DSB generating force). Therefore, the operation force Fbp of the braking operation member BP is increased as compared with the case where the operation force Fbp is generated only by the spring force Fds. In other words, in the increase mode Mdz, the degree of influence of the spring force Fds on the braking operation member BP is increased by the adjustment force Fmt.

  By combining the decrease mode Mdg and the increase mode Mdz, a non-linear characteristic in the operation characteristic of the braking operation member BP is formed. Here, the non-linear characteristic of the braking operation member BP is a characteristic in which the operation force Fbp is increased by “convex downward” with respect to an increase in the operation displacement Bpa. The spring member DSB generates a spring force Fds that is substantially proportional to the increase in the displacement Bpa. This spring force Fds is adjusted by the adjusting force Fmt, and a nonlinear characteristic of the operating force Fbp is formed. Specifically, in the range of 0 ≦ Bpa <bpx, the spring force Fds is reduced by the adjustment force Fmt and the operating force Fbp is determined by the reduction mode Mdg. That is, the operation reaction force Fbp of the braking operation member BP is lighter than that due to the spring member DSB alone. Further, in the range of Bpa ≧ bpx, the spring force Fds is increased by the adjustment force Fmt by the increase mode Mgz, and the operation force Fbp is determined. Therefore, the operation reaction force Fbp of the braking operation member BP is heavier than that by using only the spring member DSB.

  When the operation displacement Bpa reaches the contact operation displacement (predetermined value) bp1, it is no longer necessary to increase the operation force Fbp, and thus the target energization amount Imt is temporarily held. Further, when the operation displacement Bpa is increased, the operation force Fbp is generated by the elastic force Fgm of the rubber member SG2a. Therefore, when the operation displacement Bpa reaches the predetermined value bp2 (> bp1), the target energization amount Imt becomes zero. Begin to decrease towards. As the operation displacement Bpa is increased, the elastic force Fgm of the rubber member SG2a is increased with a non-linear characteristic convex downward, and the degree of influence is sequentially increased. That is, the influence of the elastic force Fgm becomes dominant in the operating force Fbp.

  When the braking displacement Bpa reaches the maximum operation displacement (predetermined value) bp3, the target energization amount Imt is substantially zero. Since the continuation of the maximum output state of the electric motor MTR is avoided, heat generation of the MTR can be suppressed. When the target energization amount Imt is reduced toward zero, the adjustment force Fmt in the forward rotation direction Fwd by the electric motor MTR is also reduced. The decrease in the force Fmt is compensated by the increase in the elastic force Fgm of the rubber member SG2a. Is called. As a result, in the operating force Fbp of the braking operation member BP, discontinuity due to the adjustment of the target energization amount Imt can be avoided, and the operation characteristics of the braking operation member BP can be suitably maintained.

  The specifications of the reaction force adjusting means ACT, including the spring constant of the spring member DSB and the characteristics of the limiting means SG2, are known. Therefore, a calculation characteristic CHt (calculation map) for calculating the target energization amount Imt from the operation displacement Bpa is set in advance and stored in the control means CTL.

  The calculation map CHt is adjusted based on the vehicle state quantity Jpa (instruction state quantity Swa, travel state quantity Jva) acquired by the vehicle state quantity acquisition means JPA. Here, the instruction state quantity Swa is a signal acquired (detected) by instruction acquisition means SWA operated by the driver (for example, a manual switch that can be set in multiple stages). The running state amount Jva is a variable (signal) that expresses the running state of the vehicle (the running speed of the vehicle, the turning state of the vehicle, etc.), and is acquired (detected) by the running state acquisition unit JVA.

  As an example, a case where the instruction state Swa acquired (detected) by the instruction acquisition unit SWA is employed as the vehicle state quantity Jpa will be described.

  When the instruction acquisition means SWA acquires “heavy operation feeling” as the instruction state quantity Swa, the target energization amount Imt is larger than the calculation characteristic CHt over the entire operation displacement Bpa based on the characteristic CHo. Calculated. In the calculation characteristic CHo, when the braking operation displacement Bpa is from zero to a predetermined value bpo (<bpx), the target energization is performed in the decrease mode Mdg (the electric motor MTR is driven in the reverse rotation direction Rvs corresponding to the first direction). The quantity Imt is determined. Here, in the decrease mode Mdg, as the operation displacement Bpa increases, the target energization amount Imt is decreased from zero and then increased to zero. When the braking operation displacement Bpa is equal to or greater than the predetermined value bpo, the target energization amount Imt is determined in the increase mode Mdz (the electric motor MTR is driven in the forward rotation direction Fwd corresponding to the second direction). In the increase mode Mdz, the target energization amount Imt is simply increased from zero as the operation displacement Bpa increases. In the calculation characteristic CHo, the target energization amount Imt is calculated as a relatively large value compared to the calculation characteristic CHt. For this reason, the driver needs to operate the braking operation member BP with a relatively large pedaling force, and the feeling of rigidity is improved in the operation of the braking operation member BP.

  On the other hand, when the instruction acquisition unit SWA acquires “light operation feeling” as the instruction state quantity Swa, the target energization amount Imt has a characteristic CHk that is smaller than the calculation characteristic CHt over the entire operation displacement Bpa. Calculated based on In the calculation characteristic CHk, the target energization amount Imt is determined in the decrease mode Mdg when the braking operation displacement Bpa is from zero to a predetermined value bpk (> bpx). Here, in the decrease mode Mdg, as the operation displacement Bpa increases, the target energization amount Imt is decreased from zero and then increased to zero, and the electric motor MTR is driven in the reverse rotation direction Rvs (corresponding to the first direction). . When the braking operation displacement Bpa is equal to or greater than the predetermined value bpk, the target energization amount Imt is determined in the increase mode Mdz. In the increase mode Mdz, the target energization amount Imt is simply increased from zero as the operation displacement Bpa increases, and the electric motor MTR is driven in the forward rotation direction Fwd (corresponding to the second direction). In the calculation characteristic CHk, the target energization amount Imt is calculated as a relatively small value compared to the calculation characteristic CHt. For this reason, the driver can operate the braking operation member BP with a relatively small pedaling force, and the lightness of the operation is improved.

  Similarly to the calculation characteristic CHt, the target energization amount Imt is temporarily held under the condition “Bpa = bp1” in the calculation characteristic CHo of “heavy operation” and the calculation characteristic CHk of “light operation”. Is done. When the condition “Bpa = bp2” is satisfied, the target energization amount Imt is decreased toward zero, and “Imt = 0” is set at “Bpa = bp3”. The continuous energization to the electric motor MTR can be suppressed, and the heat generation of the MTR can be reduced.

  The specifications of the reaction force adjusting means ACT, including the spring constant of the spring member DSB and the characteristics of the limiting means SG2, are known. Similar to the calculation characteristic CHt, the calculation characteristics CHo and CHk are set in advance and are stored in the control means CTL in association with the instruction state Swa.

  As described above, in a range where Bpa is relatively small (for example, 0 ≦ Bpa <bpx), the MTR is driven in the reverse rotation direction Rvs and acts in the direction in which Fmt and Fds oppose each other. Fbp is weakened. When Bpa becomes relatively large (for example, Bpa ≧ bpx), the MTR is driven to Fwd, Fmt and Fds act in the same direction, and the operation reaction force Fbp is strengthened. By controlling the rotation direction of one electric motor MTR, a non-linear characteristic of Fbp with respect to Bpa (characteristic that Fbp protrudes downward as Bpa increases) can be efficiently formed.

  Further, when the operation displacement Bpa reaches the contact operation displacement bp1, it is no longer necessary to increase the operation force Fbp, and thus the target energization amount Imt is temporarily held. When the operation displacement Bpa becomes larger than a predetermined value (contact operation displacement) bp1 at which the braking operation member BP and the limiting means SG2 start to contact, the target energization amount Imt is decreased toward zero. The For this reason, the maximum output state of the electric motor MTR is prevented from continuing for a long time, and the heat generation of the electric motor MTR can be suppressed.

  As in the case of the instruction state quantity Swa, the operation characteristic “heavy / light” is selected based on the running state quantity Jva. Here, the operation characteristics can be determined in stages according to the degree of the running state quantity Jva. When the vehicle speed Vxa is employed as the travel state amount Jva of the vehicle, the heavy characteristic is determined under a condition where the vehicle speed Vxa is relatively high (that is, when the vehicle is traveling at high speed). Conversely, light characteristics are determined under conditions where the vehicle speed Vxa is relatively low (that is, when the vehicle is traveling at a low speed, for example, when the vehicle is traveling in a traffic jam). For this reason, the rigidity feeling of the braking operation member BP is improved at a high speed. On the other hand, at low speed, the operability of the braking operation member BP is improved and convenience is increased.

  When the vehicle turning state amount Jva is a vehicle turning state amount (at least one of Saa, Yra, and Gya), a heavy characteristic is selected when the turning state amount is large, A light characteristic is selected when the amount of turning state is small. The same effect as described above is achieved.

  In the drive circuit (drive means) DRV for the electric motor MTR, the rotational power (output torque) of the electric motor MTR and its direction (rotational direction) are adjusted based on the target energization amount Imt. The driving unit DRV includes a bridge circuit configured by a plurality of switching elements for driving the electric motor MTR, a pulse width modulation block PWM, a switching control block SWT, and an energization amount acquisition unit IMA.

  When a brushless motor is employed as the electric motor MTR, the bridge circuit is configured by six switching elements (S1 to S6) (so-called three-phase bridge circuit). In the three-phase bridge circuit, the coil energization amounts of the U phase (terminal Tu), V phase (terminal Tv), and W phase (terminal Tw) are determined based on the detection result (rotation angle Mka) of the rotation angle acquisition unit MKA. The direction (that is, the excitation direction) is sequentially switched, and the electric motor MTR is driven. Note that the rotation direction (Fwd direction or Rvs direction) of the brushless motor is determined by the relationship between the rotor and the excitation position.

  In the pulse width modulation block PWM, based on the target energization amount Imt, an instruction value (target value) for performing pulse width modulation (PWM, Pulse Width Modulation) is calculated for each of the switching elements S1 to S6. For example, based on the target energization amount Imt and a preset characteristic (computation map), the pulse width duty ratio Dut (ratio of on-time to one cycle) is determined. At the same time, the rotation direction of the electric motor MTR is determined based on the sign (positive sign or negative sign) of the target energization amount Imt. The rotation direction of the electric motor MTR is set such that the forward rotation direction Fwd is a positive (plus) value and the reverse rotation direction Rvs is a negative (minus) value.

  In the switching control block SWT, drive signals for the switching elements S1 to S6 constituting the bridge circuit are calculated based on the duty ratio (target value) Dut. Based on these drive signals, the energization or non-energization states of the switching elements S1 to S6 are controlled. Specifically, the larger the duty ratio Dut, the longer the energization time per unit time in the switching elements S1 to S6, the larger current flows through the electric motor MTR, and the generation force (output torque) of the electric motor MTR. Is considered large.

  The drive unit DRV includes an energization amount acquisition unit (for example, a current sensor) IMA (not shown), and acquires (detects) an actual energization amount (for example, an actual current value) Ima. In the switching control block SWT, so-called current feedback control is executed. The duty ratio Dut is corrected (finely adjusted) based on the deviation ΔIm between the actual energization amount Ima and the target energization amount Imt. With this current feedback control, highly accurate motor control can be achieved.

<Torque transmission by four-bar linkage mechanism>
The power transmission by the four-link mechanism LNK will be described with reference to the configuration diagram of FIG. As in FIG. 2, the first fixed end joint KT1 of the first link LN1 and the second fixed end joint KT2 of the second link LN2 are fixed to the vehicle body floor FLR in a rotatable state. The first link LN1 and the second link LN2 are connected via an intermediate link LNC. Specifically, the first link LN1 and the intermediate link LNC are connected so as to be rotatable at the first free end joint JY1, and the second link LN2 and the intermediate link LNC are rotated at the second free end joint JY2. Connected as possible. In FIG. 2, the second fixed end joint KT2 and the electric motor MTR (MTJ) are connected via a reduction gear GSK (DKH, SKH), but in FIG. 5, the second fixed end joint KT2 is directly connected. It is connected to the output shaft MTJ of the electric motor MTR. That is, in the configuration of FIG. 5, a direct drive mechanism that is directly driven by the electric motor MTR is employed. Therefore, since the power transmission does not go through the reduction gear GSK, the influence of the backlash described above can be ignored.

  First, the geometric relationship of the four-bar linkage LNK is defined. To be precise, the point in the figure should be expressed as the rotation center (rotation axis) of each joint (such as KT1). However, in order to avoid the complexity of the description, when explaining the geometric relationship, the position of each joint (KT1, etc.) is determined by the center point of the rotation (the center axis of KT1, etc. and the four-bar linkage mechanism LNK). Intersection point of the surface to be performed). For example, “the distance between the first fixed end joint KT1 and the first free end joint JY1” is “the rotation center (rotation axis) of the first fixed end joint KT1” and the rotation center (rotation axis) of the first free end joint JY1. ) ”.

  The distance between the first fixed end joint KT1 and the first free end joint JY1 is L1 (also referred to as “the length L1 of the first link LN1”), and the distance between the second fixed end joint KT2 and the second free end joint JY2 is. L2 (also referred to as “the length L2 of the second link LN2”), the distance between the first free end joint JY1 and the second free end joint JY2 as Lc (also referred to as “the length Lc of the intermediate link LNC”), and The distance between the first fixed end joint KT1 and the second fixed end joint KT2 is Lv (also referred to as “the length Lv of the fixed link LNV”). A straight line connecting the first free end joint JY1 and the second fixed end joint KT2 is referred to as a “first straight line S1”. An angle formed by the first straight line S1 and the fixed link LNV is α1, and the first straight line S1. The angle formed by the second link LN2 is α2, the angle formed by the first straight line S1 and the first link LN1 is α3, and the angle formed by the first straight line S1 and the intermediate link LNC is α4.

  Further, a straight line obtained by extending the intermediate link LNC is referred to as an “extension line Sen”, the distance between the extension line Sen and the first fixed end joint KT1 is R1, and the distance between the extension line Sen and the second fixed end joint KT2 is R2. And In other words, the distance R1 is “the length from the intersection Pr1 to the point KT1 between the line passing through the point KT1 and orthogonal to the extension line Sen and the extension line Sen”, and the distance R2 is “extending through the point KT2. The length from the intersection Pr2 to the point KT2 of the line orthogonal to the line Sen and the extension line Sen ". In FIG. 5, symbols (for example, [L1] and [R1]) described in square brackets indicate that they relate to distance.

In the geometry of the four-bar linkage LNK, the following two expressions are established.
R1 = L1 × sin (π−α3−α4) = L1 × sin (α3 + α4) (1)
R2 = L2 × sin (π−α2−α4) = L2 × sin (α2 + α4) (2)

That is, the distance R1 matches the value obtained by multiplying the length L1 by the sine of “α3 + α4”, and the distance R2 matches the value obtained by multiplying the length L2 by the sine of “α2 + α4”. The torque around the first fixed end joint KT1 generated by the driver's pedaling force is T1. Further, the torque around the second fixed end joint KT2 generated to oppose T1 by the output torque of the electric motor MTR and the spring force of the spring member DSB is defined as T2. The relationship between the torque T1 and the torque T2 is expressed as follows.
T2 / T1 = R2 / R1 = {L2 × sin (α2 + α4)} / {L1 × sin (α3 + α4)} (3)

  As is clear from the equation (3), the value “R2 / R1” is determined by the geometry of the four-bar linkage LNK. Specifically, it is determined geometrically based on the position of each joint (such as KT1) and the length (such as L1) of each link (such as LN1). In this relationship, when the value “R2 / R1” is set small, the value of the torque T2 around the second fixed end joint KT2 is relatively small with respect to the torque T1 around the first fixed end joint KT1. That is, when the link ratio Hlnnk is formed with the value “R2 / R1” being relatively small, the maximum output of the electric motor MTR can be suppressed and the electric motor MTR can be downsized. Here, the value “R2 / R1” is referred to as “link ratio Hlnk”.

<Characteristics of link ratio in four-bar linkage mechanism>
The link ratio Hlnnk (= R2 / R1) will be described with reference to the characteristic diagram of FIG. As described above, the distance R1 is “the length from the intersection Pr1 of the line passing through the point KT1 and orthogonal to the extension line Sen and the extension line Sen to the point KT1”, and the distance R2 is “extending through the point KT2”. The value “R2 / R1” is defined as the “link ratio Hlnnk”, which is the “length from the intersection Pr2 to the point KT2 of the line perpendicular to the line Sen and the extension line Sen”. In FIG. 6, the adjustment (holding and reduction) of the target energization amount Imt after the contact operation displacement bp1 (within the range of bp1 <Bpa ≦ bp3) shown in FIG. 4 is not considered.

  In the operating region (operation range) of the braking operation member BP, the link ratio Hlnk is set with an upwardly convex characteristic CHha as the operation displacement Bpa of the braking operation member BP increases from zero. The operating region of the braking operation member BP is the maximum restricted by the second restriction means SG2 from the initial position restricted by the first restriction means SG1 (corresponding to Bpa = 0 in the non-operation state of the braking operation member BP). This is a range up to the operation position (the maximum operation state of the brake operation member BP, Bpa = bp3). That is, the operating region of the braking operation member BP corresponds to a movable range from non-operation to maximum operation.

  As the operation displacement Bpa increases, the target energization amount Imt is adjusted, and the output of the electric motor MTR is controlled. Multiplying the output of the electric motor MTR by the link ratio Hlnnk corresponds to the torque T2 around the second fixed end joint KT2. Within the operating range of the braking operation member BP, the geometry of the four-joint link mechanism LNK (position of each joint and link length) is set so that the link ratio Hlnk has an upwardly convex characteristic (characteristic CHha). . For this reason, at the maximum operation displacement (Bpa = bp3) at which the torque T1 is maximum, the link ratio Hlnnk is relatively small. As a result, the torque T2 to be opposed to the torque T1 becomes relatively small, and the electric motor MTR that is the power source (generation source) of the torque T2 can be downsized.

  Assuming a case where a reduction gear (for example, a gear transmission mechanism) that performs only deceleration is employed as the power transmission mechanism DDB, comparison is made with a case where a four-bar linkage mechanism LNK is employed. In the gear transmission mechanism, the value “R2 / R1” is determined by the diameter of each gear (for example, R1 is an effective radius of a gear having KT1 as a rotation axis, and R2 is an effective radius of a gear having KT2 as a rotation axis). Therefore, a value corresponding to the link ratio Hlnnk is a constant value hl0 (characteristic CHhb shown by a broken line). In this configuration, the target energization amount Imt is determined as the characteristic CHib (broken line) corresponding to the characteristic CHhb as the operation displacement Bpa increases. For this reason, the value imb is required as the maximum energization amount to the electric motor MTR.

  On the other hand, consider a case where a four-bar linkage LNK is employed as the power transmission mechanism DDB, and the link ratio Hlnk is set with the characteristic CHha. Here, the characteristic CHha indicates that “the link ratio Hlnk is upward with respect to the increase in the operation displacement Bpa, within the operation range from the initial position (Bpa = 0) of the operation displacement Bpa to the maximum operation position (Bpa = bp3). It is a characteristic that is maximal. In the characteristic CHha, the link ratio Hlnk becomes a maximum at “Bpa = bpb” (a maximum value hl2 is generated).

  In a region where the operation displacement Bpa is greater than or equal to the value bpa and less than the value bpc, the link ratio Hlnk of the four-bar linkage mechanism LNK is larger than the link ratio hl0 of a simple reduction gear (for example, a gear device). For this reason, the four-bar linkage mechanism LNK requires a relatively large energization amount (absolute value) as compared with a simple reduction gear. However, in the region where the operation displacement Bpa is greater than or equal to the value bpc, the link ratio Hlnk of the four-bar linkage LNK is smaller than the link ratio hl0 of a simple reducer with a constant link ratio. For this reason, the energization amount required for the four-bar linkage mechanism LNK is reduced. As a result, only the value ima (<imb) is required as the maximum energization amount to the electric motor MTR, and the energization amount can be greatly reduced as compared with the case where the link ratio is constant.

  The physique (size) of the electric motor MTR is determined based on the characteristics at the maximum output corresponding to the maximum energization amount. Therefore, a four-bar linkage mechanism LNK is adopted as the power transmission mechanism DDB, and the link ratio Hlnk of the LNK is “upper” within the operating range of the braking operation member BP (within the range where BP is limited by SG1 and SG2). The geometric relationship of the components of the LNK (that is, the length of each link and the position of each joint) is determined so as to be “convex” and “maximum”. As a result, the energization amount required at the maximum output of the electric motor MTR is reduced and the output is reduced. In other words, a small-sized electric motor MTR is adopted, and the entire apparatus including the four-bar linkage mechanism LNK can be made compact.

  The amount of energization required at the maximum output of the MTR can also be reduced by a geometry that satisfies the characteristic CHhc (single-dot chain line) in which the link ratio Hlnnk is substantially linear and simply decreases as the operation displacement Bpa increases. However, in order to employ the geometry of the characteristic CHhc, the links constituting the four-node link mechanism LNK are relatively long. As a result, the entire apparatus becomes large. Considering the maximum output of the electric motor MTR, it is necessary to reduce the link ratio Hlnnk only in a region where the energization amount to the MTR is large (that is, a region where the energization amount is small can be ignored). For this reason, the change characteristic of the link ratio Hlnk has two conditions (“convex upward” and “maximum (that is, has a maximum value)”) within the operation range of the braking operation member BP. In order to be satisfied, the geometry (each link length and each joint position) of the four-bar linkage LNK is determined. As a result, the output of the electric motor MTR can be reduced and the entire device including the four-bar linkage LNK can be downsized.

<Action / Effect (Relationship between Operation Displacement Bpa and Operation Force Fbp)>
The actions and effects of the present invention will be summarized with reference to the characteristic diagram of FIG. The characteristic diagram of FIG. 7 shows the relationship (operation characteristic) of the operation force Fbp to the operation displacement Bpa of the braking operation member BP corresponding to the calculation characteristic (calculation map) CHt in the target energization amount calculation block IMT shown in FIG. Represents.

  In the region where the braking operation displacement Bpa is from zero (contact position to SG1) to the predetermined value bpx, the target energization amount Imt is decreased from zero and increased again toward zero as the operation displacement Bpa increases. The In this region, the target energization amount Imt is made smaller than zero (non-energized state), and the electric motor MTR is driven in the reverse rotation direction Rvs (first direction). In a region where the braking operation displacement Bpa is not less than the predetermined value bpx and less than the predetermined value bp1, the target energization amount Imt is simply increased from zero as the operation displacement Bpa increases. In this region, the electric motor MTR is driven in the normal rotation direction Fwd (second direction). In other words, in the rotation direction of the electric motor MTR, when the operation displacement Bpa reaches the predetermined value bpx, the reverse rotation from the reverse rotation direction Rvs to the normal rotation direction Fwd (switching of the rotation direction) is executed.

  As indicated by the characteristic CHds, the spring force Fds of the spring member DSB increases linearly as Bpa increases. In a region where the braking operation displacement Bpa is from zero to a predetermined value bpx, the generated force (adjusting force) Fmt of the electric motor MTR acts in a direction to cancel the spring force Fds (DSB generated force). On the other hand, in the region where the braking operation displacement Bpa is equal to or greater than the predetermined value bpx, the adjustment force Fmt acts in the direction of increasing the spring force Fds. As a result of the adjustment by Fmt, as shown by the characteristic CHbp, the relationship between Bpa and Fbp is a nonlinear characteristic of “convex downward”. By combining driving of the electric motor MTR in the first direction (Rvs direction) and driving in the second direction (Fwd direction), nonlinearity of the operation characteristics can be efficiently formed. In this nonlinear characteristic, the operation reaction force Fbp of the braking operation member BP is relatively light in the range of 0 ≦ Bpa <bpx, and the operation reaction force Fbp is relatively heavy in the range of Bpa ≧ bpx. . This is because the characteristic is suitable for the operation of the braking operation member.

  When the rotation direction of the electric motor MTR is switched (for example, when the reverse rotation direction Rvs is changed from “Bpa = bpx” to the normal rotation direction Fwd), the operation characteristics are affected by backlash (backlash) in the power transmission member DDB. May receive. In order to eliminate this influence, a gear transmission mechanism in the power transmission member DDB (a reduction gear GSK for output of an electric motor, which is a mechanism represented by a combination of SKH and DKH in FIG. 2), “no backlash gear (backlash A gear equipped with a removal mechanism) ”may be employed. Here, as the no-backlash gear, “a scissors gear to which a preload is applied by a spring force”, “a friction gear having a backlash reduced by a friction force”, and “a wave gear device (so-called harmonic drive (registered trademark))”. At least one of the above may be employed. Further, a direct drive mechanism in which the output shaft MTJ of the electric motor MTR shown in FIG. 5 is directly fixed to the second fixed end joint KT2 may be employed.

  In the region (range) where the braking operation displacement Bpa is between the predetermined value bp1 and the predetermined value bp3, the target energization amount Imt is held / reduced. When the operation displacement Bpa reaches the contact operation displacement (predetermined value) bp1, it is no longer necessary to increase the operation force Fbp, and thus the target energization amount Imt is temporarily held. Further, when the operation displacement Bpa is increased, the target energization amount Imt starts to decrease toward zero when the operation displacement Bpa reaches a predetermined value bp2 (> bp1). When the braking displacement Bpa reaches the maximum operation displacement (predetermined value) bp3, the target energization amount Imt is substantially zero.

  As the operation displacement Bpa is increased from the contact displacement bp1, the elastic force Fgm of the rubber member SG2a is increased with a downwardly convex non-linear characteristic, and the influence of the operation force Fbp gradually becomes dominant. When the target energization amount Imt is reduced toward zero, the adjustment force Fmt in the forward rotation direction Fwd by the electric motor MTR is also reduced. The decrease in the force Fmt is compensated by the increase in the elastic force Fgm of the rubber member SG2a. Is called. Therefore, the continuation of the maximum output state of the electric motor MTR is avoided, the heat generation of the MTR is suppressed, the discontinuity of the operation force Fbp caused by the decrease in the target energization amount Imt is avoided, and the operation characteristics of the braking operation member BP Can be suitably maintained.

  BP ... braking operation member, PTM ... operation surface, ECU ... electronic control unit, CTL ... control means, ACT ... reaction force adjusting means, DDB ... power transmission mechanism, LNK ... four-bar linkage mechanism, MTR ... electric motor, DSB ... spring Member, BPA ... operation displacement acquisition means, JPA ... vehicle state quantity acquisition means, SWA ... instruction state acquisition means, JVA ... running state acquisition means, VXA ... vehicle speed acquisition means, MKA ... rotation angle acquisition means

Claims (1)

A braking operation member operated to reduce the speed of the vehicle;
A spring member that generates a spring force against the braking operation member;
An electric motor for applying an adjustment force to the braking operation member;
An operation displacement acquisition means for acquiring an operation displacement of the braking operation member;
Control means for controlling the adjustment force based on the operation displacement via the electric motor;
In a vehicle operation characteristic adjusting device comprising:
The control means includes
When the operation displacement is less than a predetermined value, the electric motor is driven in a first direction,
When the operation displacement exceeds the predetermined value, the operation characteristic adjusting device of the vehicle drives the electric motor in a second direction opposite to the first direction.

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