JP6505399B2 - Load sensor for vehicle brake device, electric linear actuator and electric brake device - Google Patents

Description

  The present invention relates to a load sensor, an electric linear actuator using the load sensor, and an electric brake device.

  A hydraulic brake device that presses a friction pad with a hydraulic cylinder has been adopted as a vehicle brake device, but in recent years, with the introduction of brake control such as ABS (antilock brake system), an electric brake device that does not use a hydraulic circuit Is being watched.

  Generally, the electric brake device converts rotation of the electric motor into axial movement of the linear moving member, and presses the friction pad axially forward by the linear moving member to generate a braking force. In order to control the braking force to a desired magnitude, a load sensor is often incorporated in a portion of the electric brake device that receives the reaction force of the axial load applied to the friction pad. Then, based on the output of the load sensor, the electric motor is controlled so as to generate an appropriate braking force according to the driver's pedal operation and the state of the vehicle.

  As a load sensor incorporated in the above-mentioned electric brake devices, the thing of patent documents 1-3 is known, for example. Each of the load sensors described in Patent Documents 1 to 3 is an elastic member that receives an axial load from the outside to generate elastic deformation, and a single magnetic sensor unit that outputs a signal according to the amount of deformation of the elastic member. And the magnitude of the axial load is calculated based on the output of the magnetic sensor unit.

JP 2013-257000 A JP, 2014-016307, A JP, 2014-134450, A

  By the way, when the driver operates the brake pedal to decelerate the vehicle, during normal braking with a deceleration of 0.2 G or less, it is considered that the driver operates the pedal finely according to the behavior of the vehicle. , Fine load control is required. On the other hand, at the time of rapid braking where the deceleration exceeds 0.3 G, although it is necessary to generate a large braking force in a short time, fine load control is not required.

  On the other hand, when the load sensors of Patent Documents 1 to 3 are adopted for the vehicle brake device, the load of the entire load area is detected using a single magnetic sensor unit, and therefore the driver's It is not possible to obtain sufficient load detection resolution to cope with various pedal operations, and as a result, there is a possibility that the behavior of the vehicle may be uncomfortable.

  Therefore, it is possible to use a load sensor that has a high detection resolution and can detect the load over the entire load area of the vehicle brake device, but such a load sensor has a problem of high cost.

  The problem to be solved by the present invention is to provide a load sensor suitable for a vehicle brake device.

In order to solve the above-mentioned subject, in the present invention, a load sensor of the following composition is provided.
An elastic member that receives an axial load from the outside to cause elastic deformation;
And two or more load detection units that output a signal according to the amount of deformation of the elastic member,
The two or more load detection units are
A first load detection unit that outputs a signal according to the amount of deformation of the elastic member in a first load region in which the magnitude of the axial load input to the elastic member is smaller than a predetermined upper limit value;
And a second load detection unit that outputs a signal according to the amount of deformation of the elastic member in a second load region including an axial load larger than the upper limit value of the first load region,
The first load detection unit and the second load detection unit are load sensors configured such that the first load detection unit has detection resolution higher than that of the second load detection unit.

  In this way, in the first load region in which the magnitude of the axial load is small, the load can be detected by the first load detection unit having high detection resolution. Therefore, when this load sensor is used in a vehicle brake system, it is possible to obtain a load detection resolution sufficient to correspond to the driver's fine pedal operation at the time of normal braking with a relatively small deceleration. On the other hand, at the time of sudden braking with relatively large deceleration, the second load detection unit can detect an axial load greater than the upper limit value of the first load area.

  The second load area is preferably set to at least partially overlap the first load area.

  In this way, the axial load can be detected in a continuous load area that spans the upper limit value of the first load area.

The first load region is a region where the magnitude of the axial load input to the elastic member is from zero to the upper limit value,
It is preferable that the second load region be a region where the magnitude of the axial load input to the elastic member is from zero to the upper limit value that is twice or more the upper limit value.

  In this way, in the first load region, the axial load can be detected by both the first load detection unit and the second load detection unit. Therefore, even when one of the first load detection unit and the second load detection unit fails, the other load detection unit can detect the axial load of the first load region. , Excellent redundancy can be obtained.

  The two or more load detection units are preferably arranged at equal intervals in the circumferential direction around the center of action of the axial load on the elastic member.

  In this case, even when the axial load input to the elastic member from the outside becomes a biased load, the effects of the biased load can be eliminated by using the signals output from the load detectors in combination. It becomes possible.

  In addition, respective signals output from the first load detection unit and the second load detection unit are input, and the load value and the second load detection in the first load detection unit are detected based on the respective signals. The load value in each section is calculated, and in the first load area, the axial value obtained by averaging the load value in the first load detection section and the load value in the second load detection section. It is preferable to provide a control unit that outputs as the size of the load.

  In this way, even when the axial load input to the elastic member from the outside becomes a biased load, it is possible to eliminate the influence of the biased load.

As the first load detection unit, one comprising a magnetic target generating a magnetic field and a magnetic sensor unit arranged so that the relative position to the magnetic target changes according to the amount of deformation of the elastic member ,
As the magnetic target, two permanent magnets magnetized in a direction orthogonal to the relative displacement direction of the magnetic target and the magnetic sensor unit due to the deformation of the elastic member, the N pole of one permanent magnet and the other permanent magnet The one in which the S pole is disposed adjacent to the magnetic target and the relative displacement direction of the magnetic sensor unit is adopted.
It is preferable that the magnetic sensor unit be disposed in the vicinity of the boundary between the adjacent N pole and S pole.

  In this case, a high density magnetic flux is generated near the boundary between the N pole and the S pole, and the magnetic flux penetrates the magnetic sensor portion. Therefore, the output signal of the magnetic sensor unit changes sharply according to the minute relative movement of the magnetic target and the magnetic sensor unit, and as a result, high detection resolution can be realized. In addition, the output signal of the magnetic sensor unit changes sharply relative to the relative displacement of the magnetic target and the magnetic sensor unit due to the deformation of the elastic member, while the relative displacement between the other magnetic targets and the magnetic sensor unit Since the directivity of not changing so much occurs, the output signal of the magnetic sensor unit is not easily influenced by external vibration, and it becomes possible to detect the size of the load with stable accuracy.

Moreover, in this invention, the thing of the following structures is provided as an electrically driven linear actuator using the said load sensor.
In an electric linear actuator including an electric motor and a motion conversion mechanism which converts rotation of the electric motor into axial movement of the linear movement member,
An electric linear actuator characterized in that the load sensor is incorporated in a portion receiving an axial backward reaction force acting on the linear moving member when the linear moving member presses an object forward in the axial direction. .

  As the motion conversion mechanism, a rotation shaft to which the rotation of the electric motor is input, a plurality of planet rollers rollingly contacting the outer diameter surface of the rotation shaft, and a plurality of planet rollers are rotatably and rotatably supported. A carrier, an outer ring member as the linear moving member disposed so as to surround the plurality of planet rollers, a helical ridge provided on an inner diameter surface of the outer ring member, and the helical ridge It is possible to employ one having a spiral groove or a circumferential groove provided on the outer diameter surface of each of the planetary rollers. In this case, the elastic member can be a member that restricts the rearward movement of the carrier by supporting the carrier via a thrust bearing.

Moreover, in this invention, the thing of the following structures is provided as an electrically-driven brake device which uses the said load sensor.
An electric brake having an electric motor and a motion converting mechanism for converting rotation of the electric motor into axial movement of the linear moving member, wherein the linear moving member axially presses the friction pad forward to generate a braking force. In the device
An electric brake device, wherein the load sensor is incorporated in a portion which receives an axial backward reaction force acting on the linear moving member when the linear movement member presses the friction pad forward in the axial direction.

  In the load sensor of the present invention, the first load detection unit having high detection resolution detects the load in the first load region in which the magnitude of the axial load is small. Therefore, when this load sensor is used in a vehicle brake system, it is possible to obtain a load detection resolution sufficient to correspond to the driver's fine pedal operation at the time of normal braking with a relatively small deceleration. On the other hand, at the time of sudden braking with relatively large deceleration, the second load detection unit can detect an axial load greater than the upper limit value of the first load area. Therefore, the load sensor of the present invention is suitable for a vehicle brake device.

Sectional view showing a load sensor according to an embodiment of the present invention A view of the load sensor shown in FIG. 1 viewed from the front side in the axial direction An enlarged sectional view in the vicinity of the first load detection unit of the load sensor shown in FIG. 1 Diagram showing the correspondence between the magnitude of the axial load input to the elastic member and the magnetic flux detected by the magnetic sensor unit Block diagram of control unit for calculating axial load magnitude based on output signals of magnetic sensor units of each load detection unit Diagram showing the correspondence between the output signal of the magnetic sensor unit of each load detection unit and the load value A diagram schematically showing a state in which a load is applied to the load sensor shown in FIG. The figure which shows the correspondence of the output signal of the magnetic sensor part of each load detection part in the state shown in FIG. 7, and load value The figure which shows the example which changed the 2nd load area | region Lb shown in FIG. 4 so that it may overlap with 1st load area | region La only in part. An enlarged sectional view showing an example in which the arrangement of the magnetic target and the magnetic sensor unit shown in FIG. 3 is changed Sectional view showing an electric brake device for a vehicle using the load sensor shown in FIG. Enlarged sectional view of the vicinity of the linear actuator shown in FIG. Sectional view along line XIII-XIII in FIG. 12 A sectional view showing an electric brake device adopting a ball screw mechanism as a motion conversion mechanism in place of the planetary roller mechanism shown in FIG. A sectional view showing an electric brake device adopting a ball ramp mechanism as a motion conversion mechanism in place of the planetary roller mechanism shown in FIG. Sectional view along line XVI-XVI in FIG. (A) shows the relationship between the ball and the inclined groove shown in FIG. 16, (b) shows a state in which the rotating disc and the linear moving disc are relatively rotated from the state shown in (a) and the distance between both discs is enlarged Figure

  1 to 3 show a load sensor 1 according to an embodiment of the present invention. The load sensor 1 receives signals according to the amount of deformation of the elastic member 2 that receives an input from the front in the axial direction and causes elastic deformation, the stationary member 3 that supports the elastic member 2 from the axial rear, and the elastic member 2. It has the 1st load detection part 4a and the 2nd load detection part 4b which output.

  The elastic member 2 is an annular plate member made of metal such as iron. A load input unit 5 to which an axial load is input is provided on an axial front surface of the elastic member 2. In the figure, the load input unit 5 is a rolling surface of rolling elements of a thrust bearing 43 (see FIG. 12) described later. A supported portion 6 supported by the stationary member 3 is provided on the axial rear surface of the elastic member 2.

  The stationary member 3 is formed of the same metal as the elastic member 2. The stationary member 3 has an annular support 7 for supporting the supported portion 6 of the elastic member 2 from the axial direction rear, and a fitting formed on the outer diameter side of the support 7 so as to fit on the outer periphery of the elastic member 2 The combined cylinder portion 8, the cylindrical portion 9 provided to face the inner diameter side of the elastic member 2, and the connecting portion 10 connecting the cylindrical portion 9 and the support portion 7 in the axial direction rear of the elastic member 2 Have. An interference is set between the inner periphery of the fitting cylindrical portion 8 and the outer periphery of the elastic member 2. By this interference, the elastic member 2 is integrated with the stationary member 3, and the handling of the magnetic load sensor 1 is facilitated.

  The supported portion 6 of the elastic member 2 is disposed at a position radially outward of the load input portion 5. As a result, when a load is input, the elastic member 2 is caused to deflect axially rearward with the position of the supported portion 6 as a fulcrum.

  As shown in FIG. 2, the first load detection unit 4 a and the second load detection unit 4 b are provided at positions shifted by 180 degrees in the circumferential direction, and the center of the elastic member 2 (that is, the axial direction with respect to the elastic member 2) They are arranged at equal intervals in the circumferential direction around the load acting center). The first load detection unit 4a includes a magnetic target 11a that generates a magnetic flux and a magnetic sensor unit 12a that detects a magnetic flux generated by the magnetic target 11a.

  Since the first load detection unit 4a and the second load detection unit 4b have the same configuration, the configuration of the first load detection unit 4a will be described below, and for the second load detection unit 4b, the first load detection unit 4a and the second load detection unit 4b will be described. The parts corresponding to the load detection unit 4a are denoted by the same reference numerals or symbols obtained by replacing the suffix alphabet a with b, and the description will be omitted.

  As shown in FIG. 3, the magnetic target 11 a is fixed to the inner periphery of the elastic member 2. The magnetic sensor unit 12a is fixed to the outer periphery of the cylindrical portion 9 of the stationary member 3 so as to radially face the magnetic target 11a. The magnetic target 11a is formed of two permanent magnets 13 magnetized in a direction (here, radial direction) perpendicular to the axial direction which is a relative displacement direction of the magnetic target 11a and the magnetic sensor unit 12a due to the deflection of the elastic member 2. Become. The two permanent magnets 13 are disposed such that the N pole of one permanent magnet 13 and the S pole of the other permanent magnet 13 are axially adjacent to each other.

  As the permanent magnet 13, for example, using neodymium magnet can generate strong magnetic flux in a space-saving manner, but use samarium cobalt magnet, samarium iron nitride magnet, alnico magnet, ferrite magnet, praseodymium magnet, etc. May be The use of a samarium cobalt magnet, samarium iron nitride magnet, or alnico magnet can suppress the decrease in magnetic flux due to the temperature rise of the permanent magnet 13. Moreover, the mechanical strength of the permanent magnet 13 can be improved by using a praseodymium magnet.

  The magnetic sensor unit 12a is disposed in the vicinity of the boundary between adjacent N and S poles of two permanent magnets 13 so as to face the magnetic target 11a in a direction orthogonal to the magnetic target 11a (radial direction in the drawing). Although it is possible to use a magnetoresistive element (so-called MR sensor) or a magnetic impedance element (so-called MI sensor) as the magnetic sensor unit 12a, the use of a Hall IC is advantageous in cost and heat resistance The high Hall effect IC is commercially available, which is suitable for the application of an electric brake for a vehicle.

  As shown by the arrows in FIG. 1, when an axial load directed from the front to the rear in the axial direction is input to the elastic member 2, the elastic load is axially rearward with the outer diameter side end as a fulcrum by the axial load. Deflection With this deflection, the magnetic target 11a and the magnetic sensor unit 12a are displaced relative to each other in the axial direction, and the output signal of the magnetic sensor unit 12a changes in accordance with the amount of deflection of the elastic member 2. Therefore, if the relationship between the magnitude of the axial load input to the elastic member 2 and the output signal of the magnetic sensor unit 12a is grasped in advance, the elastic member 2 is input based on the output signal of the magnetic sensor unit 12a. It is possible to detect the magnitude of the axial load being carried out.

  The magnetic sensor unit 12a of the first load detection unit 4a is a sensor having a resolution of 16 bits (4096 steps) with respect to full scale (magnetic detection range). As shown in FIG. 4, the full scale Sa of the magnetic sensor unit 12 a has a fluctuation range of the magnetic flux when the magnitude of the axial load input to the elastic member 2 fluctuates in the first load region La. It is set.

  The magnetic sensor unit 12b of the second load detection unit 4b is also a sensor having a resolution of 16 bits (4096 steps) with respect to full scale (magnetic detection range). The full scale Sb of the magnetic sensor unit 12 b is set so as to fall within the fluctuation range of the magnetic flux when the magnitude of the axial load input to the elastic member 2 fluctuates in the second load region Lb.

  The first load area La is an area in which the magnitude of the axial load is from zero to the upper limit value Fa. The second load area Lb is an area in which the magnitude of the axial load is from zero to the upper limit Fmax. Here, the second load area Lb is a range including an axial load larger than the upper limit value Fa of the first load area La, and the upper limit Fmax of the second load area Lb is the first load area Lb. The size is set to be twice or more the upper limit value of the load area La. In this embodiment, the upper limit value Fmax of the second load area Lb is set to the magnitude of the maximum load that can be generated by the vehicle brake device.

  When full scale Sa of magnetic sensor unit 12a of first load detection unit 4a is set to 1/3 of full scale Sb of magnetic sensor unit 12b of second load detection unit 4b, first load detection unit 4a The detection resolution of the load according to the second embodiment is three times the detection resolution of the load by the second load detection unit 4b. For example, if the full scale Sa of the magnetic sensor unit 12a of the first load detection unit 4a is 10 kN and the full scale Sb of the magnetic sensor unit 12b of the second load detection unit 4b is 30 kN, the first load detection unit 4a The detection resolution of the load is about 2.4 N equivalent to 1/409 of full scale Sa, and the detection resolution of the load by the second load detection unit 4 b is about 7.3 N equivalent to 1/4096 of full scale Sb The first load detection unit 4a has a detection resolution three times that of the second load detection unit 4b.

  When this load sensor 1 is used for an electric brake device for a vehicle, the first load region La is a load range that generates deceleration 0 to 0.2 G during normal braking that is frequently used as a vehicle brake. The second load area Lb can be set to the entire load area that can be generated by the vehicle brake.

  As shown in FIG. 5, the magnetic sensor units 12 a and 12 b are electrically connected to the control unit 14, and a signal output from the magnetic sensor unit 12 a and a signal output from the magnetic sensor unit 12 b are respectively controlled by the control unit 14. It is supposed to be input to In the control unit 14, as shown in FIG. 6, the correspondence between the output signal of each of the magnetic sensor units 12a and 12b and the load value is set in advance. The control unit 14 is, for example, an electronic control unit that controls an electric motor 29 (see FIG. 11) of the electric brake device described later, and is a load value output based on output signals Va and Vb of the magnetic sensor units 12a and 12b. Control the electric motor 29 on the basis of

  The control unit 14 calculates the load value fa of the first load detection unit 4a based on the output signal Va of the magnetic sensor unit 12a, and the second load detection unit based on the output signal Vb of the magnetic sensor unit 12b. The load value fb at 4b is calculated. And, when both of the load value fa in the first load detection unit 4a and the load value fb in the second load detection unit 4b are in the first load area La, the first load detection unit 4a What averaged the load value fa and the load value fb in the 2nd load detection part 4b is output as a size of an axial direction load. On the other hand, when the load value fa in the first load detection unit 4a or the load value fb in the second load detection unit 4b exceeds the upper limit value Fa of the first load region La, the second load detection unit 4b The load value fb at is output as it is as the magnitude of the axial load.

  In the load sensor 1, in the first load region La in which the magnitude of the axial load is small, the first load detection unit 4 a having high detection resolution detects the load. Therefore, when the load sensor 1 is used in a vehicle brake device, it is possible to obtain a load detection resolution sufficient for the driver's fine pedal operation at the time of normal braking with a relatively small deceleration. . On the other hand, at the time of sudden braking with relatively large deceleration, the second load detection unit 4b can detect an axial load larger than the upper limit value Fa of the first load area La. Thus, the load sensor 1 is suitable for a vehicle brake device.

  Further, in the first load region La, the load sensor 1 can detect an axial load in both of the first load detection unit 4 a and the second load detection unit 4 b. Therefore, even when one of the first load detection unit 4a and the second load detection unit 4b breaks down, the other load detection unit detects the axial load of the first load area La. Yes, with excellent redundancy.

  In addition, even when a partial load (axial load with uneven distribution) is input to the elastic member 2, the load sensor 1 can eliminate the influence of the partial load. It will be described below.

  That is, as shown by the arrow in FIG. 1, the distribution of the axial load input to the elastic member 2 is uniform between the position of the first load detection unit 4a and the position of the second load detection unit 4b. As shown in FIG. 6, a load value fa calculated based on the output signal Va of the first load detection unit 4a and a load value fb calculated based on the output signal Vb of the second load detection unit 4b. And agree with each other.

  On the other hand, as shown by the arrows in FIG. 7, the distribution of axial load input to the elastic member 2 is uneven, and as a result, the axial load acting on the position of the first load detection unit 4a When it becomes larger than the axial load acting on the position of the load detection unit 4b of 2, the load value fa calculated based on the output signal Va of the first load detection unit 4a is the original value, as shown in FIG. The load value fb becomes larger than the value f, and the load value fb calculated based on the output signal Vb of the second load detection unit 4b becomes smaller than the original value f. That is, when a partial load is input to the elastic member 2, one of the load value fa of the first load detection unit 4a and the load value fb of the second load detection unit 4b is essentially the same. The other load value tends to be smaller than the original value f.

  At this time, if it is assumed that the load is detected only by either one of the first load detection unit 4a and the second load detection unit 4b, it is determined whether the axial load input to the elastic member 2 is a biased load or not. It can not be known, and the value of the detected load also contains a large error.

  On the other hand, the load sensor 1 described above is based on the load value fa detected based on the signal Va output from the first load detection unit 4a and the signal Vb output from the second load detection unit 4b. Since the average of the detected load values fb is output as the magnitude of the axial load, even when the axial load input to the elastic member 2 becomes a biased load, it is output from the load sensor 1 The magnitude of the load generally corresponds to the magnitude f of the actual axial load, and it is possible to eliminate the effect of the offset load.

  Further, the load sensor 1 is disposed in the vicinity of the boundary between the magnetic target 11a in which two permanent magnets 13 are arranged side by side so that the N pole and the S pole are adjacent in the axial direction, and the adjacent N pole and S pole. Since the load detection units 4a and 4b having the magnetic sensor unit 12a are employed, a magnetic flux of high density is generated near the boundary between the N pole and the S pole, and the magnetic flux penetrates the magnetic sensor unit 12a. Therefore, the output signal of the magnetic sensor unit 12a sharply changes according to the minute relative movement of the magnetic target 11a and the magnetic sensor unit 12a, and as a result, high detection resolution can be realized. Further, the output signal of the magnetic sensor unit 12a sharply changes with respect to the relative displacement of the magnetic target 11a and the magnetic sensor unit 12a due to the deformation of the elastic member 2, while the other magnetic targets 11a and 12a Directivity does not change much with respect to relative displacement, so that the output signal of the magnetic sensor unit 12a is not easily influenced by external vibration, and it becomes possible to detect the size of the load with stable accuracy.

  In the above embodiment, the second load area Lb is set to overlap with the entire first load area La, but as shown in FIG. 9, the second load area Lb is a first load area La. It may be set to overlap only with. Also in this manner, the axial load can be detected in the continuous load area that spans the upper limit value Fa of the first load area La.

  In the above embodiment, the magnetic target 11a is fixed to the elastic member 2 and the magnetic sensor unit 12a is fixed to the stationary member 3. However, the relationship between the magnetic target 11a and the magnetic sensor unit 12a may be reversed. . That is, as shown in FIG. 10, the magnetic sensor unit 12 a may be fixed to the elastic member 2 and the magnetic target 11 a may be fixed to the stationary member 3.

  In the above embodiment, the load sensor 1 in which the two load detectors 4a and 4b are provided at an interval of 180 degrees has been described as an example, but three or more load detectors may be arranged in the circumferential direction. It may be provided at equal intervals.

  The load detection units 4a and 4b may employ, for example, a strain gauge or the like configured to detect a load by another method. Further, as the first load detection unit 4a having high detection resolution, a magnetic type is employed as in the above embodiment, and a strain gauge is used as the second load detection unit 4b that detects a load in the entire load region. It is also possible to adopt.

  11 to 13 show a motor-driven brake system for a vehicle using the above-described magnetic load sensor 1.

  This electric brake device includes a caliper body 24 having a shape in which opposing pieces 21 and 22 opposed to each other with a brake disc 20 rotating integrally with wheels interposed therebetween by a bridge 23 and an opposing face of the opposing piece 21 to the brake disc 20 The linear motion actuator 26 incorporated in the housing hole 25 which opens in the above, and a pair of friction pads 27 and 28 on the left and right.

  The friction pad 27 is provided between the facing piece 21 and the brake disc 20, and is a mount (not shown) that supports the caliper body 24 slidably in the axial direction with respect to the brake disc 20. It is movably supported in the direction. The other friction pad 28 is attached to the opposing piece 22 on the opposite side. The linear actuator 26 has an electric motor 29 and a motion conversion mechanism 31 for converting the rotation of the electric motor 29 into axial movement of the outer ring member 30.

  As shown in FIG. 12, the motion conversion mechanism 31 includes a rotation shaft 32 to which the rotation of the electric motor 29 is input, a plurality of planet rollers 33 in rolling contact with the outer diameter surface of the rotation shaft 32, and a plurality of planets It has a carrier 34 for holding the roller 33 in a rotatable manner and in a rotatable manner, and an outer ring member 30 as a linear moving member disposed so as to surround the plurality of planet rollers 33.

  The rotation shaft 32 is rotationally driven by the rotation of the electric motor 29 shown in FIG. The rotary shaft 32 is inserted into the housing hole 25 with one end projecting from the opening on the rear side in the axial direction of the housing hole 25 formed by penetrating the opposing piece 21 in the axial direction, The gear 35 is spline fitted and prevented from rotating. The gear 35 is covered with a lid 36 fixed by a bolt so as to close an opening on the rear side in the axial direction of the accommodation hole 25.

  As shown in FIG. 13, the planetary roller 33 is in rolling contact with the cylindrical surface of the outer periphery of the rotating shaft 32, and when the rotating shaft 32 rotates, the planetary roller 33 is rotated by friction between the planetary roller 33 and the rotating shaft 32. Is also supposed to rotate. A plurality of planet rollers 33 are provided at regular intervals in the circumferential direction.

  As shown in FIG. 12, the outer ring member 30 is slidably supported in the axial direction on the inner periphery of the housing hole 25. At the axial direction front end of the outer ring member 30, an engagement concave portion 38 engaged with the engagement convex portion 37 formed on the back surface of the friction pad 27 is formed. The engagement convex portion 37 and the engagement concave portion 38 are engaged. Thus, the outer ring member 30 is locked against the caliper body 24.

  A spiral ridge 39 is provided on the inner diameter surface of the outer ring member 30, and a circumferential groove 40 engaged with the spiral ridge 39 is provided on the outer diameter surface of the planetary roller 33, and the planet roller 33 is rotated. At the same time, the helical ridges 39 of the outer ring member 30 are guided by the circumferential groove 40 so that the outer ring member 30 moves in the axial direction. Here, a circumferential groove 40 having a lead angle of 0 degree is provided on the outer diameter surface of the planetary roller 33, but instead of the circumferential groove 40, a spiral groove having a lead angle different from that of the spiral ridges 39 may be provided. .

  The carrier 34 incorporates a thrust bearing 41 that rotatably supports the axial rear surface of each of the planetary rollers 33. The load sensor 1 is fitted in the accommodation hole 25 at the axial direction rear of the carrier 34. A spacer 42 revolving integrally with the carrier 34 and a thrust bearing 43 rotatably supporting the spacer 42 are incorporated between the carrier 34 and the load sensor 1.

  The thrust bearing 43 is provided so as to be axially supported by the load input portion 5 of the elastic member 2, and the axial load on the load input portion 5 of the elastic member 2 from the spacer 42 through the thrust bearing 43 Is to be input. The rotating shaft 32 is rotatably supported by a bearing 44 incorporated in the cylindrical portion 9 of the stationary member 3.

  Movement of the load sensor 1 in the axial direction is restricted by locking the outer peripheral edge of the stationary member 3 with a projection 45 formed on the inner periphery of the rear end portion of the accommodation hole 25. The load sensor 1 axially supports the carrier 34 via the spacer 42 and the thrust bearing 43, thereby restricting the rearward movement of the carrier 34 in the axial direction. Further, the forward movement of the carrier 34 is also restricted by a snap ring 46 attached to the axial front end of the rotary shaft 32. Therefore, the movement of the carrier 34 in the axial forward direction and in the axial direction is both restricted, and the planetary rollers 33 held by the carrier 34 are also in a state in which the axial movement is restricted.

  Next, an operation example of the above-described electric brake device will be described.

  When the electric motor 29 is operated, the rotating shaft 32 is rotated, and the planetary roller 33 revolves around the rotating shaft 32 while rotating. At this time, although the outer ring member 30 and the planetary roller 33 relatively move in the axial direction due to the engagement of the spiral ridges 39 and the circumferential groove 40, the movement of the planetary roller 33 with the carrier 34 is restricted. The roller 33 does not move in the axial direction, and the outer ring member 30 moves in the axial direction. In this manner, the linear actuator 26 converts the rotation of the rotary shaft 32 driven by the electric motor 29 into axial movement of the outer ring member 30, and presses the friction pad 27 axially forward with the outer ring member 30. Thus, the friction pad 27 is pressed against the brake disc 20 to generate a braking force.

  Here, when the friction pad 27 is pressed forward in the axial direction by the outer ring member 30, a reaction force directed rearward in the axial direction acts on the outer ring member 30, and the reaction force is obtained by the planetary roller 33, the carrier 34, and the spacer 42. , And is received by the load sensor 1 via the thrust bearing 43. Then, the elastic member 2 of the load sensor 1 is bent rearward in the axial direction by the reaction force, and the output signals Va and Vb of the first load detection unit 4a and the second load detection unit 4b according to the deflection amount of the elastic member 2 Changes, and the magnitude of the axial load (the pressing force of the friction pad 27) is detected based on the output signals Va and Vb.

  In this electric brake device, a mechanism using the planetary roller 33 is adopted as the motion conversion mechanism 31 for converting the rotation of the rotary shaft 32 to which the rotation of the electric motor 29 is input into the axial movement of the outer ring member 30 The motion conversion mechanism 31 of the configuration of may be adopted.

  An example of an electric brake device employing a ball screw mechanism as the motion conversion mechanism 31 is shown in FIG. Hereinafter, portions corresponding to the above-described embodiment are denoted by the same reference numerals and description thereof is omitted.

  In FIG. 14, the motion conversion mechanism 31 has a screw shaft 50 integrally provided with the rotary shaft 32, a nut 51 provided so as to surround the screw shaft 50, and a screw groove 52 formed on the outer periphery of the screw shaft 50. And a plurality of balls 54 incorporated between the screw grooves 53 formed on the inner periphery of the nut 51, and a return tube (not shown) for returning the balls 54 from the end point of the screw groove 53 of the nut 51 to the start point.

  The nut 51 is axially slidably accommodated in the accommodation hole 25 provided in the facing piece 21 in a state where the nut 51 is prevented from rotating with respect to the caliper body 24. A spacer 42 that rotates integrally with the screw shaft 50 is provided at the axially rear end of the screw shaft 50, and the spacer 42 is supported by the load sensor 1 via a thrust bearing 43. Here, by supporting the screw shaft 50 in the axial direction via the spacer 42 and the thrust bearing 43, the load sensor 1 restricts the rearward movement of the screw shaft 50 in the axial direction.

  The electric brake device converts the rotation of the rotary shaft 32 into axial movement of a nut 51 as a linear moving member, and presses the friction pad 27 axially forward with the nut 51, thereby making the friction pad 27 a brake disc. Press on 20 to generate a braking force. At this time, a reaction force directed rearward in the axial direction acts on the nut 51, and the reaction force is received by the load sensor 1 via the screw shaft 50, the spacer 42, and the thrust bearing 43. Then, the elastic member 2 of the load sensor 1 is bent rearward in the axial direction by the reaction force, and the output signals Va and Vb of the first load detection unit 4a and the second load detection unit 4b according to the deflection amount of the elastic member 2 Changes, and the magnitude of the axial load (the pressing force of the friction pad 27) is detected based on the output signals Va and Vb.

  An example of an electric brake device adopting a ball ramp mechanism as the motion conversion mechanism 31 is shown in FIG.

  In FIG. 15, the motion conversion mechanism 31 includes a rotary shaft 32, a rotary disk 60 fixed to the outer periphery of the rotary shaft 32, and a linear motion disk 61 arranged to face the axial direction front of the rotary disk 60; It has a plurality of balls 62 sandwiched between the rotating disc 60 and the linear moving disc 61.

  The linear motion disc 61 is axially slidably accommodated in the accommodation hole 25 provided in the facing piece 21 in a state of being rotationally locked to the caliper body 24. A spacer 42 that rotates integrally with the rotary disk 60 is provided at the axial rear end of the rotary disk 60, and the spacer 42 is supported by the load sensor 1 via a thrust bearing 43. Here, the load sensor 1 axially supports the rotating disk 60 via the spacer 42 and the thrust bearing 43 to restrict the rearward movement of the rotating disk 60 in the axial direction.

  As shown in FIGS. 15 and 16, an inclined groove 63 is formed on the surface of the rotary disk 60 facing the linear motion disk 61 in such a manner that the depth gradually decreases along one circumferential direction. On the surface facing the rotary disk 60, there is formed an inclined groove 64 whose depth gradually decreases along the other direction in the circumferential direction. As shown in FIG. 17 (a), the ball 62 is incorporated between the inclined groove 63 of the rotary disk 60 and the inclined groove 64 of the linear motion disk 61, and as shown in FIG. 17 (b), When the rotary disk 60 rotates relative to the disk 61, the balls 62 roll in the inclined grooves 63, 64, and the distance between the rotary disk 60 and the linear motion disk 61 is expanded.

  This electric brake device converts the rotation of the rotary shaft 32 into axial movement of the linear moving disc 61 as a linear moving member, and presses the friction pad 27 axially forward by the linear moving disc 61, thereby providing a friction pad. 27 is pressed against the brake disc 20 to generate a braking force. At this time, a reaction force directed rearward in the axial direction acts on the rotating disk 60, and the reaction force is received by the load sensor 1 via the spacer 42 and the thrust bearing 43. Then, the elastic member 2 of the load sensor 1 is bent rearward in the axial direction by the reaction force, and the output signals Va and Vb of the first load detection unit 4a and the second load detection unit 4b are made Changes, and the magnitude of the axial load (the pressing force of the friction pad 27) is detected based on the output signals Va and Vb.

  It should be understood that the embodiments disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is indicated not by the above description but by the claims, and is intended to include all the modifications within the meaning and scope equivalent to the claims.

Reference Signs List 2 elastic member 4a first load detection unit 4b second load detection unit 11a magnetic target 12a magnetic sensor unit 13 permanent magnet 14 control unit 26 motorized linear actuator 27 friction pad 29 electric motor 30 outer ring member 31 motion conversion mechanism 32 Rotating shaft 33 Planetary roller 34 Carrier 39 Helical ridge 40 Circumferential groove 43 Thrust bearing Fa, Fmax Upper limit value La First load area Lb Second load area Va, Vb Output signal fa, fb Load value

Claims (8)

One elastic member (2) which receives an axial load from the outside and causes elastic deformation;
And two or more load detection units (4a, 4b),
The two or more load detection units (4a, 4b) are provided on the one common elastic member (2) so as to respectively output signals according to the amount of deformation of the one elastic member (2).
The two or more load detection units (4a, 4b)
A signal corresponding to the amount of deformation of the elastic member (2) in a first load area (La) in which the magnitude of the axial load input to the elastic member (2) is smaller than a predetermined upper limit value (Fa) A first load detection unit (4a) that outputs (Va);
In a second load area (Lb) including an axial load larger than the upper limit value (Fa) of the first load area (La), a signal (Vb) corresponding to the amount of deformation of the elastic member (2) And a second load detection unit (4b) to output
In the first load detection unit (4a) and the second load detection unit (4b), the first load detection unit (4a) has a detection resolution higher than that of the second load detection unit (4b). Configured and
The respective signals (Va, Vb) output from the first load detection unit (4a) and the second load detection unit (4b) are input, and the first signal is input based on the respective signals (Va, Vb). The load value (fa) in the load detection unit (4a) and the load value (fb) in the second load detection unit (4b) are calculated respectively, and the first load area (La) A control unit that outputs an average of the load value (fa) of the load detection unit (4a) of 1 and the load value (fb) of the second load detection unit (4b) as the magnitude of the axial load further load sensor for cars two brake devices that have a (14).   The vehicle brake device load sensor according to claim 1, wherein the second load area (Lb) is set so as to at least partially overlap with the first load area (La). The first load area (La) is an area in which the magnitude of the axial load input to the elastic member (2) is from zero to the upper limit value (Fa).
In the second load area (Lb), the magnitude of the axial load input to the elastic member (2) is from zero to the upper limit value (Fmax) at least twice the upper limit value (Fa) The vehicle brake device load sensor according to claim 1 or 2, wherein   The two or more load detection parts (4a, 4b) are arranged at equal intervals in the circumferential direction around the action center of the axial load on the elastic member (2) The load sensor for vehicle brake devices according to any of the above. The first load detection unit (4a) is arranged such that the relative position with respect to the magnetic target (11a) generating the magnetic field and the magnetic target (11a) changes according to the amount of deformation of the elastic member (2) And the magnetic sensor unit (12a)
The magnetic target (11a) is two permanent magnets (13) magnetized in a direction orthogonal to the relative displacement direction of the magnetic target (11a) and the magnetic sensor unit (12a) due to the deformation of the elastic member (2) Are arranged such that the N pole of one permanent magnet (13) and the S pole of the other permanent magnet (13) are adjacent to each other in the relative displacement direction of the magnetic target (11a) and the magnetic sensor portion (12a) Yes,
The load sensor for a vehicle brake device according to any one of claims 1 to 4 , wherein the magnetic sensor unit (12a) is disposed in the vicinity of the boundary between the adjacent N pole and S pole. An electric linear actuator comprising: an electric motor (29); and a motion conversion mechanism (31) for converting rotation of the electric motor (29) into axial movement of the linear movement member (30),
The part which receives the reaction force to the axial direction back which acts on a linear movement member (30) when an object (27) is pressed forward in the axial direction by the linear movement member (30), any one of claims 1 to 5 An electric linear actuator characterized in that the load sensor for a vehicle brake device according to the present invention is incorporated. The motion conversion mechanism (31) includes a rotation shaft (32) to which the rotation of the electric motor (29) is input, and a plurality of planet rollers (33) in rolling contact with the outer diameter surface of the rotation shaft (32). A carrier (34) for holding the plurality of planetary rollers (33) rotatably and revolvably, and an outer ring member (30) as the linear moving member disposed so as to surround the plurality of planetary rollers (33) And a helical ridge (39) provided on the inner diameter surface of the outer ring member (30) and an outer diameter surface of each of the planet rollers (33) so as to engage with the helical ridge (39) And spiral grooves or circumferential grooves (40),
Said elastic member (2) is according to claim 6 is a member for regulating the movement in the axial direction behind the carrier by supporting the carrier (34) via a thrust bearing (43) (34) Electric linear actuator. An electric motor (29) and a motion conversion mechanism (31) for converting rotation of the electric motor (29) into axial movement of the linear movement member (30), wherein the linear movement member (30) is a friction pad In an electric brake device which generates a braking force by pressing (27) axially forwardly,
The part which receives the reaction force to the axial direction back which acts on the linear movement member (30) when the friction pad (27) is pushed forward in the axial direction by the linear movement member (30), any one of claims 1 to 5 An electric brake device incorporating the load sensor for a vehicle brake device according to any of the preceding claims.

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