Patent Publication Number: US-11385042-B2

Title: Position detection device

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation application of International Patent Application No. PCT/JP2019/011424 filed on Mar. 19, 2019, which designated the U.S. and based on and claims the benefits of priority of Japanese Patent Application No. 2018-071471 filed on Apr. 3, 2018. The entire disclosure of all of the above applications is incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to a position detection device. 
     BACKGROUND 
     A position detection device detects a rotation angle of a throttle valve included in an electronic control throttle used in a vehicle or the like, a rotation angle of an accelerator pedal included in an accelerator pedal module, or a stroke amount of a clutch actuator. 
     SUMMARY 
     An object of the present disclosure is to provide a position detection device that improves the accuracy of position detection. 
     The position detection device of the present disclosure includes a magnetic detection element, wiring, a first mold resin, a terminal, and a second mold resin. The magnetic detection element can detect a change in magnetic field. The wiring is connected to the magnetic detection element. The first mold resin molds the magnetic detection element and the wiring so that the wiring is exposed. The terminal is connected to the wiring. 
     The second mold resin molds the first mold resin and the terminal so that the first mold resin on which the magnetic detection element is located is exposed, and has a deformation suppressing portion. The deformation suppressing portion suppresses the deformation of the first mold resin when the second mold resin is deformed. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       The above and other objects, features and advantages of the present disclosure will become more apparent from the following detailed description made with reference to the accompanying drawings. In the drawings: 
         FIG. 1  is a cross-sectional view of an electronic control throttle in which a position detection device according to the present embodiment is used; 
         FIG. 2  is a perspective view of a position detection device according to a first embodiment; 
         FIG. 3  is a cross-sectional view taken along line III-Ill of  FIG. 2  showing a main part; 
         FIG. 4  is a view viewed from a direction IV of  FIG. 3 ; 
         FIG. 5  is a cross-sectional view taken along line V-V of  FIG. 4  showing a main part; 
         FIG. 6  is a cross-sectional view taken along line VI-VI of  FIG. 4  showing a main part; 
         FIG. 7  is a cross-sectional view of a main part of the position detection device according to a second embodiment; 
         FIG. 8  is a cross-sectional view of the main part of the position detection device according to the second embodiment; 
         FIG. 9  is a top view of a main part of a position detection device according to another embodiment; 
         FIG. 10  is a top view of a main part of a position detection device according to another embodiment; 
         FIG. 11  is a top view of a main part of a position detection device according to another embodiment; and 
         FIG. 12  is a cross-sectional view of an electronic control throttle in which a position detection device of a comparative example is used. 
     
    
    
     DETAILED DESCRIPTION 
     Several embodiments of a position detection device will be described below with reference to the drawings. In the description of the plurality of embodiments, substantially the same configuration is denoted by the same reference numeral. When referred to as the present embodiment, a plurality of embodiments may be included. A position detection device according to the present embodiment is used, for example, in an electronic control throttle  81  that controls the amount of air taken into a cylinder of an engine of a vehicle. First, the electronic control throttle  81  will be described. 
     As shown in  FIG. 1 , the electronic control throttle  81  includes a housing  83 , an intake passage  84 , a throttle valve  85 , a valve shaft  86 , a motor  87 , a holder  88  and magnets  89 . The intake passage  84  for introducing air into the engine is formed in the housing  83 . The throttle valve  85  is formed in a disc shape and is provided in the intake passage  84 . 
     The valve shaft  86  is fixed to the throttle valve  85 . Both ends of the valve shaft  86  are connected to the motor  87  and the holder  88  so as to be rotatable with respect to the housing  83 . As a result, the throttle valve  85  can rotate about the center of the valve shaft  86  as a rotation axis. The motor  87  is connected to one end of the valve shaft  86 . The motor  87  is drive-controlled by a command from an electronic control unit (ECU) of the engine (not shown). The opening of the throttle valve  85  is controlled by driving the motor  87 , and the amount of intake air supplied to the engine is adjusted. 
     The holder  88  is formed in a cylindrical shape with a bottom, and is provided at the other end of the valve shaft  86 . Two magnets  89  as a magnetism generating means, and two yokes (not shown) that connect the two magnets  89  in a circumferential direction are provided on an inner wall of the holder  88 . The two magnets  89  are provided so as to face in the radial direction with respect to the rotation axis of the throttle valve  85 . The two magnets  89  respectively give an N-pole magnetic flux to one yoke and an S-pole magnetic flux to the other yoke. A magnetic flux flows inside the holder  88  from one yoke to the other yoke, whereby a magnetic field in which the magnetic flux flows in a direction perpendicular to the rotation axis of the throttle valve  85  is generated. When the throttle valve  85  rotates, the direction of the magnetic field inside the holder  88  changes. A position detection device  1  is provided on the holder side of the housing  83 . 
     First Embodiment 
     The position detection device  1  includes a sensor cover  30  as a second mold resin, a first component  10  and a second component  20  as a first mold resin, and two terminals  60 . 
     As shown in  FIG. 2 , the sensor cover  30  is made of resin in a dish shape or a plate shape, and is fixed to the housing  83  by screws  31  or the like. The sensor cover  30  integrally molds the first component  10 , the second component  20 , and the terminals  60  so that the first component  10  on which the first magnetic detection element  11  is located is exposed and the second component  20  on which the second magnetic detection element  21  is located is exposed. 
     Further, the sensor cover  30  supports the first component  10  and the second component  20 , and has a plurality of ribs  32 . The rigidity of the sensor cover  30  is improved by the plurality of ribs  32 . Hereinafter, a longitudinal direction of the sensor cover  30  will be simply referred to as a longitudinal direction. A lateral direction of the sensor cover  30  will be simply referred to as a lateral direction. A plate thickness direction of the sensor cover  30  is simply referred to as a plate thickness direction. 
     As shown in  FIG. 3 , the first component  10  has a first magnetic detection element  11  as a magnetic detection element, a first lead wire  12 , a first wiring  13 , a first resin portion  14  and a first convex portion  15 . The first component  10  molds the first magnetic detection element  11 , the first lead wire  12  and the first wiring  13  with resin so that the first wiring  13  is exposed. 
     The first magnetic detection element  11  is a Hall element and is integrated with the signal amplification circuit. The first magnetic detection element  11  can detect a change in magnetic field. When the throttle valve  85  rotates, the first magnetic detection element  11  detects a change in the magnetic field inside the holder  88 . 
     The first lead wire  12  is connected to the first magnetic detection element  11 , and is connected to the first wiring  13  by welding. The first wiring  13  is provided so that the end portion of the first wiring  13  on the side opposite to the first lead wire  12  is exposed from the first resin portion  14 . The first convex portion  15  is formed on the surface that contacts the second component  20 , and projects toward a second concave portion  25 . Further, the first convex portion  15  is formed in a tapered shape so that an outer diameter becomes smaller toward a tip. 
     The second component  20  is formed in the same manner as the first component  10 , and includes a second magnetic detection element  21 , which is a magnetic detection element, a second lead wire  22 , a second wiring  23 , a second resin portion  24 , and a second concave portion  25 . Like the first component  10 , the second component  20  molds the second magnetic detection element  21 , the second lead wire  22 , and the second wiring  23  with resin so that the second wiring  23  is exposed. 
     The second magnetic detection element  21  is a Hall element like the first magnetic detection element  11 , and is integrated with the signal amplification circuit. The second magnetic detection element  21  can detect a change in magnetic field. When the throttle valve  85  rotates, the second magnetic detection element  21  detects a change in the magnetic field inside the holder  88 . 
     The second lead wire  22  is connected to the second magnetic detection element  21 , and is connected to the second wiring  23  by welding. The second wiring  23  is provided so that the end portion of the second wiring  23  on the side opposite to the second lead wire  22  is exposed from the second resin portion  24 . 
     The second concave portion  25  is formed on the surface that comes into contact with the first component  10 , and is concave corresponding to the first convex portion  15 . The first convex portion  15  and the second concave portion  25  are fitted to each other, and the first component  10  and the second component  20  couple together. 
     The terminal  60  is connected to the first wiring  13  on the side opposite to a place to which the first lead wire  12  is connected and the second wiring  23  on the side opposite to a place to which the second lead wire  22  is connected, respectively. The first component  10  and the second component  20  are provided in the magnetic field inside the holder  88 . The first component  10  and the second component  20  output a voltage signal according to the magnetic flux density passing through the first component  10  and the second component  20  according to the direction of the magnetic field in the holder  88 . This voltage signal is transmitted to the ECU through the terminal  60  molded in the sensor cover  30 . The ECU controls each part of the vehicle. 
     As shown in  FIG. 12 , in the position detection device  90  of a comparative example, a primary molded article  91  having the magnetic detection element is fixed to a secondary molded article  92 . In a temperature environment used for a vehicle or the like, the secondary molded article may be deformed due to linear expansion. When the secondary molded article  92  is deformed, the primary molded article  91  warps and the position of the primary molded article  91  is displaced. When a position of the primary molded article  91  deviates, the position of the magnetic detection element deviates from a magnetic circuit formed by the position detection device  90 , so that the position detection accuracy of the position detection device  90  deteriorates. On the other hand, in the position detection device  1  of the present embodiment, an accuracy of the position detection is improved. 
     As shown in  FIGS. 4 and 5 , the sensor cover  30  further includes a step portion  33 , a deformation suppressing portion  40 , a first weld line  51 , a second weld line  52 , and a third weld line  53  as a weld line. 
     An outermost one end surface of the first component  10  extending in the longitudinal direction is referred to as a first end surface  101 . A straight line passing through the first end surface  101  and extending in the longitudinal direction is referred to as a first straight line L 1 . An outermost one end surface of the second component  20  extending in the longitudinal direction is referred to as a second end surface  202 . The second end surface  202  is provided on the side opposite to the first end surface  101 . A straight line that passes through the second end surface  202  and extends in the longitudinal direction is referred to as a second straight line L 2 . In the figure, the first straight line L 1  and the second straight line L 2  are indicated by alternate long and two short dashes lines. 
     One side surface of the first component  10  adjacent to the first end surface  101  is referred to as a first side surface  111 . A side surface of the first component  10  opposite to the first side surface  111  is referred to as a second side surface  112 . One side surface of the second component  20  adjacent to the second end surface  202  is referred to as a third side surface  213 . A side surface of the second component  20  opposite to the third side surface  213  is referred to as a fourth side surface  214 . The first side surface  111  is adjacent to the third side surface  213 . The second side surface  112  is adjacent to the fourth side surface  214 . 
     The step portion  33  is formed at a position where the first straight line L 1  and the second straight line L 2  pass. A plurality of step portions  33  are formed and have a convex shape or a concave shape so that the plate thickness of the sensor cover  30  becomes large or small. 
     One step portion  33  is formed on the first side surface  111  or the third side surface  213  side. The step portion  33  on the first side surface  111  side or the third side surface  213  side is formed so that the plate thickness of the sensor cover  30  is increased. Further, one step portion  33  is formed on the second side surface  112  side or the fourth side surface  214  side. The step portion  33  on the second side surface  112  side or the fourth side surface  214  side is formed so that the plate thickness of the sensor cover  30  is decreased. 
     The deformation suppressing portion  40  suppresses the deformation of the first component  10  or the second component  20  when the sensor cover  30  is deformed. Further, the deformation suppressing portion  40  includes a first groove portion  41  and a second groove portion  42 . One first groove portion  41  is formed on the first side surface  111  side or the third side surface  213  side. One second groove portion  42  is formed on the second side surface  112  side or the fourth side surface  214  side. 
     The first groove portion  41  and the second groove portion  42  extend in the longitudinal direction while being recessed in a plate thickness direction. Further, the first groove portion  41  extends in the longitudinal direction from the first side surface  111  or the third side surface  213  to the step portion  33 . The second groove portion  42  extends in the longitudinal direction from the second side surface  112  or the fourth side surface  214  to the step portion  33 . 
     Further, the first groove portion  41  and the second groove portion  42  are formed between the first straight line L 1  and the second straight line L 2 . The outer edges of the first groove portion  41  and the second groove portion  42  may be located on the first straight line L 1  or the second straight line L 2 . In addition, the first groove portion  41  includes a first facing surface  411  that faces the first side surface  111  or the third side surface  213 . The second groove portion  42  includes a second facing surface  421  that faces the second side surface  112  or the fourth side surface  214 . 
     As shown in  FIG. 5 , the first groove portion  41  includes a first groove portion bottom surface  415  that is a bottom surface of the first groove portion  41 . The first groove portion bottom surface  415  is adjacent to the first facing surface  411 . Further, the first groove portion  41  is formed such that the outer edge of the first corner portion  416  of the first groove portion bottom surface  415  is curved in the cross section in the plate thickness direction. 
     As shown in  FIG. 6 , the second groove portion  42  includes a second groove portion bottom surface  425  that is the bottom surface of the second groove portion  42 . The second groove portion bottom surface  425  is adjacent to the second facing surface  421 . Further, the second groove portion  42  is formed such that the outer edge of the second corner portion  426  of the second groove portion bottom surface  425  is curved in the cross section in the plate thickness direction. In  FIGS. 5 and 6 , hatching of the cross section of the sensor cover  30  is omitted to clarify each part. 
     As shown in  FIGS. 5 and 6 , an end surface of the first component  10  on the terminal  60  side is referred to as a first component bottom surface  105 . The first component bottom surface  105  is adjacent to the first end surface  101 , the first side surface  111 , and the second side surface  112 . An end surface of the second component  20  on the terminal  60  side is referred to as a second component bottom surface  205 . The second component bottom surface  205  is adjacent to the second end surface  202 , the third side surface  213 , and the fourth side surface  214 . The first component bottom surface  105  is adjacent to the second component bottom surface  205 . A maximum length of each of the first component  10  and the second component  20  in a lateral direction is referred to as a component width Dp. 
     The first weld line  51 , the second weld line  52 , and the third weld line  53  are lines generated when the molten resin merges when the sensor cover  30  is resin-molded. In the present embodiment, the molten resin flows and merges in two directions in the lateral direction and one direction in the plate thickness direction. A point where the first weld line  51 , the second weld line  52 , and the third weld line  53  intersect is defined as a merging point  54 . In the figure, the positions of the first weld line  51 , the second weld line  52 , and the third weld line  53  are indicated by alternate long and two short dashes lines. Further, in the figure, the merging point  54  is indicated by a black circle. 
     The first weld line  51  extends from the merging point  54  in the plate thickness direction. The second weld line  52  is formed on the first component  10  side and extends from the merging point  54  toward the corner of the first component  10  on the terminal  60  side. The third weld line  53  is formed on the second component  20  side and extends from the merging point  54  toward the corner of the second component  20  on the terminal  60  side. 
     A distance from the first component bottom surface  105  or the second component bottom surface  205  to the first groove portion bottom surface  415  is defined as a first groove portion distance Dg 1 . A distance from the first component bottom surface  105  or the second component bottom surface  205  to the merging point  54  is defined as a first merging distance Dc 1 . The first merging distance Dc 1  is equal to the component width Dp, that is, Dc 1 =Dp. In the present specification, “equal” includes a common error range. The first groove portion  41  is formed such that the first merging distance Dc 1  is larger than the first groove portion distance Dg 1 , that is, Dc 1 &gt;Dg 1 . 
     Similarly to the first groove portion  41 , a distance from the first component bottom surface  105  or the second component bottom surface  205  to the second groove portion bottom surface  425  is defined as a second groove portion distance Dg 2 . A distance from the first component bottom surface  105  or the second component bottom surface  205  to the merging point  54  is defined as a second merging distance Dc 2 . The second merging distance Dc 2  is equal to the component width Dp and the first merging distance Dc 1 , that is, Dc 1 =Dc 2 =Dp. The second groove portion  42  is formed such that the second merging distance Dc 2  is larger than the second groove portion distance Dg 2 , that is, Dc 2 &gt;Dg 2 . 
     [1] When the sensor cover  30  is deformed, the deformation of the first component  10  or the second component  20  is suppressed. Thereby, the warp of the first component  10  and the second component  20  is suppressed, and the displacement of the first component  10  and the second component  20  is suppressed. Therefore, the displacement of the first magnetic detection element  11  and the second magnetic detection element  21  is suppressed. Therefore, the position detection accuracy of the position detection device  1  is improved. 
     [2] The deformation suppressing portion  40  has the first groove portion  41  and the second groove portion  42 . While the amount of resin used for manufacturing is suppressed by the first groove portion  41  and the second groove portion  42 , the resin can be spread on the sensor cover  30  around the first component  10  and the second component  20 . Since the resin is spread on the sensor cover  30 , the rigidity of the sensor cover  30  is increased. Therefore, the sensor cover  30  is less likely to be deformed, and the displacement between the first component  10  and the second component  20  is further suppressed. Therefore, the positional deviation between the first magnetic detection element  11  and the second magnetic detection element  21  is suppressed, and the position detection accuracy of the position detection device  1  is further improved. 
     [3] The first groove portion  41  is formed such that the first merging distance Dc 1  is larger than the first groove portion distance Dg 1 . The second groove portion  42  is formed such that the second merging distance Dc 2  is larger than the second groove portion distance Dg 2 . As a result, when the sensor cover  30  is resin-molded, the molten resin merges for a short period of time, and the molten resin merges when the temperature of the molten resin is high. Therefore, the strength of the weld portion of the sensor cover  30  is improved. The strength of the sensor cover  30  is improved, and the rigidity of the sensor cover  30  is also improved. Therefore, the positional deviation between the first magnetic detection element  11  and the second magnetic detection element  21  is easily suppressed, and the position detection accuracy of the position detection device  1  is further improved. 
     [4] The first groove portion  41  is formed such that the outer edge of the first corner portion  416  is curved in the cross section in the plate thickness direction. The second groove portion  42  is formed such that the outer edge of the second corner portion  426  is curved in the cross section in the plate thickness direction. Thereby, when the sensor cover  30  is deformed, the stress in the first groove portion  41  and the second groove portion  42  is dispersed. The stress is dispersed and the sensor cover  30  is less likely to be deformed. The positional deviation between the first magnetic detection element  11  and the second magnetic detection element  21  is easily suppressed, and the position detection accuracy of the position detection device  1  is further improved. 
     Second Embodiment 
     The second embodiment is the same as the first embodiment except that the shape of the deformation suppressing portion is different. The position detection device  2  of the second embodiment does not include the second component  20 , but includes the first component  10 . The other end surface of the first component  10  opposite to the first end surface  101  is referred to as a third end surface  103 . The second weld line  52  is formed on the first end surface  101  side and extends from the merging point  54  toward one corner of the first component  10  on the terminal  60  side. The third weld line  53  is formed on the third end surface  103  side and extends from the merging point  54  toward the other corner of the first component  10  on the terminal  60  side. 
     As shown in  FIGS. 7 and 8 , the deformation suppressing portion  240  has a first groove portion  241  and a second groove portion  242 . The positions of the first component  10  and the sensor cover  30  are adjusted so that the first merging distance Dc 1  is half the component width Dp, that is, Dc 1 =Dp/2. The positions of the first component  10  and the sensor cover  30  are adjusted so that the second merging distance Dc 2  is half the component width Dp, that is, Dc 2 =Dp/2. 
     The first groove portion  241  is formed such that the first merging distance Dc 1  is larger than the first groove portion distance Dg 1 , that is, Dp/2&gt;Dg 1 . The second groove portion  242  is formed such that the second merging distance Dc 2  is larger than the second groove portion distance Dg 2 , that is, Dp/2&gt;Dg 2 . The second embodiment also achieves the same effects as achieved by the first embodiment. 
     Other Embodiments 
     [i] The position detection device of the present embodiment may be used to detect a rotation angle of an accelerator pedal included in an accelerator pedal module. Further, the position detection device of the present embodiment may be used to detect a rotation angle of a tamper control valve. Further, the position detection device of the present embodiment may be used to detect a stroke amount of a clutch actuator. 
     [ii] The first magnetic detection element  11  and the second magnetic detection element  21  are not limited to Hall elements, and may be MR elements or the like. MR is an abbreviation for Magnet Resistive. 
     [iii] As shown in  FIG. 9 , the position detection device  1  of the first embodiment may be configured by one first component  10  without including the second component  20 . The first straight line L 1  is set on the first end surface  101 . The second straight line ′ is set on the third end surface  103  on the side opposite to the first end surface  101 . The first groove portion  41  and the second groove portion  42  are formed so as to be between the first straight line L 1  and the second straight line L 2 ′. Similarly, the position detection device  1  of the present embodiment may not include the first component  10  and may be configured by one second component  20 . 
     [iv] The position detection device  2  of the second embodiment may include the second component  20  instead of the first component  10 . 
     [v] As shown in  FIG. 10 , the first groove portion  41  and the second groove portion  42  of the deformation suppressing portion  40  in the position detection device  1  of the present embodiment may be separated from the first component  10  and the second component  20 . At this time, the first groove portion  41  includes a third facing surface  413  facing the first facing surface  411 . The second groove portion  42  includes a fourth facing surface  424  facing the second facing surface  421 . The third facing surface  413  is inclined so that the first groove portion  41  becomes smaller toward the first groove portion bottom surface  415 . Similarly, the fourth facing surface  424  is inclined so that the second groove portion  42  becomes smaller toward the second groove portion bottom surface  425 . 
     [vi] As shown in  FIG. 11 , the deformation suppressing portion  40  may have a plurality of first groove portions  41  and second groove portions  42 . 
     The present disclosure should not be limited to the embodiment described above. Various other embodiments may be implemented without departing from the scope of the present disclosure. 
     The present disclosure has been described based on the embodiments. However, the present disclosure is not limited to the embodiments and structures. This disclosure also encompasses various modifications and variations within the scope of equivalents. Furthermore, various combination and formation, and other combination and formation including one, more than one or less than one element may be made in the present disclosure. 
     In an assumable example, a position detection device detects a rotation angle of a throttle valve included in an electronic control throttle used in a vehicle or the like, a rotation angle of an accelerator pedal included in an accelerator pedal module, or a stroke amount of a clutch actuator. Further, in the position detection device, a primary molded article obtained by primary molding a magnetic detection element and a wiring is connected to a terminal, and the primary molded article and the terminal are secondary molded. 
     In the example, the primary molded article is fixed to the secondary molded article. In a temperature environment used for a vehicle or the like, the secondary molded article of the position detection device may be deformed due to linear expansion. When the secondary molded article is deformed, the primary molded article warps and the position of the primary molded article is displaced. When a position of the primary molded article deviates, the position of the magnetic detection element deviates from a magnetic circuit formed by the position detection device, so that the position detection accuracy of the position detection device deteriorates. An object of the present disclosure is to provide a position detection device that improves the accuracy of position detection. 
     The position detection device of the present disclosure includes a magnetic detection element, wiring, a first mold resin, a terminal, and a second mold resin. The magnetic detection element can detect a change in magnetic field. The wiring is connected to the magnetic detection element. The first mold resin molds the magnetic detection element and the wiring so that the wiring is exposed. The terminal is connected to the wiring. 
     The second mold resin molds the first mold resin and the terminal so that the first mold resin on which the magnetic detection element is located is exposed, and has a deformation suppressing portion. The deformation suppressing portion suppresses the deformation of the first mold resin when the second mold resin is deformed. 
     With this configuration, the warp of the first mold resin is suppressed, and the displacement of the first mold resin is suppressed. Therefore, the displacement of the magnetic detection element is suppressed. Therefore, the position detection accuracy of the position detection device is improved.