Load driver

Abstract

To provide a load drive device which suppresses the influence of a magnetic flux generated with electric conduction of a wiring pattern on the induced voltage of a solenoid.SOLUTION: A substrate 50 is connected to a DC power source and is formed with a power source wiring pattern 51 and a ground wiring pattern 52 constituting an electric conduction path to a motor (load). Two solenoids 21, 22 are electrically connected to the substrate 50 and coil axial lines are arranged so as to be parallel to each other. In the projection to a surface of the substrate 50, a distance between the first center P being the coil center of the first solenoid 21 and the second center Q being the coil center of the second solenoid 22 is defined as "an inter-solenoid distance A", and a region formed by combining an interior S1 of a circle with the inter-solenoid distance A from the first center P as the radius and an interior S2 of the circle with the inter-solenoid distance A from the second center Q as the radius is defined as "an influence region S". The power source wiring pattern 51 and the ground wiring pattern 52 are formed into the linear shape in the influence region S.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a load driving device. [Background technology]

[0002] 2. Description of the Related Art A known load driving device supplies electricity to a load via a power supply wiring pattern and a ground wiring pattern on a circuit board, and has a plurality of solenoids electrically connected to the circuit board.

[0003] For example, Patent Document 1 discloses a circuit board on which a drive circuit for a motor that rotates a pump in a brake hydraulic pressure control device is mounted, and solenoids that constitute multiple solenoid valves that open and close hydraulic paths in the pump are electrically connected to this circuit board. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2020-96001 A Summary of the Invention [Problem to be solved by the invention]

[0005] For example, by comparing the voltages at the ground end when a power supply voltage is applied to each solenoid with the drive switches connected in series to each solenoid turned off, it is possible to detect an abnormality in which current is leaking from the path passing through any of the solenoids. However, when this abnormality is detected, changes in magnetic flux caused by the current flowing through the power supply wiring pattern and ground wiring pattern on the board can cause noise in the induced voltage of the solenoid, which could result in an erroneous detection.

[0006] The present invention was created in consideration of these points, and its purpose is to provide a load driving device that suppresses the effect of magnetic flux generated by the passage of current through a wiring pattern on the induced voltage of a solenoid. [Means for solving the problem]

[0007] The load driving device of the present invention includes a substrate (50), two solenoids, a first solenoid (21) and a second solenoid (22) of the same size, and a control circuit (60).

[0008] The circuit board is connected to a DC power supply (Bt) and has a power wiring pattern (51) and a ground wiring pattern (52) formed thereon, which form a current path to the load (18). The two solenoids are electrically connected to the circuit board, and their coil axes are arranged parallel to each other. The control circuit switches on and off solenoid drive switches (23, 24) connected in series to each solenoid, and controls the current flow to the load.

[0009] When projected onto the surface of the substrate, the distance between the first center (P), which is the coil center of the first solenoid, and the second center (Q), which is the coil center of the second solenoid, is defined as the "solenoid distance (A)". Preferably, the solenoid distance is set to three times the outer diameter of the solenoid coil or less.

[0010] The area inside the circle (S1) whose radius is the distance from the first center to the solenoids and the area inside the circle (S2) whose radius is the distance from the second center to the solenoids are combined to form the "area of ​​influence (S)." If magnetic flux is generated within the area of ​​influence due to the flow of current through the power supply wiring pattern and ground wiring pattern, it may affect the induced voltage of at least one of the solenoids.

[0011] In a first aspect of the present invention, the power supply wiring pattern and the ground wiring pattern are formed outside the influence area, so that even if a magnetic flux is generated outside the influence area due to the current passing through the wiring patterns, it does not affect the induced voltage of the solenoid.

[0012] In a second aspect of the present invention, the power supply wiring pattern and the ground wiring pattern are formed in a straight line within the affected area. Since the magnetic flux generated in the straight line portions of the wiring patterns is smaller than that generated in the curved portions, even if magnetic flux is generated within the affected area by energizing the wiring patterns, the effect on the induced voltage of the solenoid is small.

[0013] In a third aspect of the present invention, within the affected area, the power supply wiring pattern and the ground wiring pattern have a main straight portion (53) that extends straight in a common longitudinal direction, and at least one of the power supply wiring pattern and the ground wiring pattern has a bent portion (54) that bends from the main straight portion to a lateral extension portion (55). The first center and the second center are located on the opposite side of the main straight portion from the lateral extension portion. A relatively large magnetic flux is generated at the bent portion, but by moving the coil center of the solenoid away from the lateral extension portion, the effect of the bent portion on the induced voltage of the solenoid can be minimized. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a partial cross-sectional view showing the overall configuration of a brake fluid pressure control device; [Figure 2] FIG. 2 is a diagram showing brake fluid pressure paths in a vehicle. [Figure 3] FIG. 1 is a circuit diagram of a motor drive device. [Figure 4] 4(a) is a plan view of the substrate of the first embodiment as seen from the arrow IVa in Fig. 1. (b) is a cross-sectional view taken along the line IVb-IVb in Fig. 4(a). [Figure 5] 1A and 1B are plan views of a substrate according to a first modification of the first embodiment; [Figure 6] 10A and 10B are plan views of a substrate according to a third and fourth modified example of the first embodiment. [Figure 7] Schematic diagram showing magnetic flux generated when current is applied to an L-shaped wiring pattern. [Figure 8] 10A and 10B are diagrams showing (a) the first solenoid monitoring voltage, (b) the second solenoid monitoring voltage, and (c) the monitoring potential difference for an L-shaped wiring pattern. [Figure 9] FIG. 4 is a schematic diagram showing magnetic flux generated when a current is passed through a linear wiring pattern. [Figure 10] 1A and 1B are diagrams showing (a) the first solenoid monitoring voltage, (b) the second solenoid monitoring voltage, and (c) the monitored potential difference for a linear wiring pattern. [Figure 11] FIG. 10 is a plan view of a substrate according to a second embodiment. [Figure 12] 10A and 10B are plan views of a substrate according to a first and second modification of the second embodiment. [Figure 13] 10A and 10B are plan views of a substrate according to a third and fourth modified example of the second embodiment. [Figure 14] FIG. 10 is a plan view of a substrate according to a third embodiment. [Figure 15] FIG. 11 is a plan view of a substrate according to a modified example of the third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0015] A load driving device according to multiple embodiments of the present invention will be described with reference to the drawings. Substantially identical components in multiple embodiments are designated by the same reference numerals, and description thereof will be omitted. The first to third embodiments, which differ in the layout of the wiring pattern on the board, are collectively referred to as "the present embodiment." The load driving device of the present embodiment is a motor driving device. This motor driving device is applied to a brake fluid pressure control device of a vehicle, and drives a DC motor as a "load."

[0016] The overall configuration of the brake fluid pressure control device 10 will be described with reference to Figures 1 and 2. The brake fluid pressure control device 10 includes a DC motor 18, a hydraulic block 15, a motor drive device 70, etc. The motor drive device 70 supplies electricity to the motor 18 via a motor conductor 17. The motor 18 is driven by electricity from the motor drive device 70, and rotates a hydraulic pump 19 incorporated inside the hydraulic block 15. Typically, hydraulic pressure is used as the hydraulic pressure.

[0017] The solenoid valves 210, 220 are provided in hydraulic lines corresponding to a pair of left and right wheels 95, 96 of the vehicle 90. The solenoids 21, 22 constituting the solenoid valves 210, 220 each have a cylindrical coil (shown by a broken line in FIG. 1) housed inside a substantially rectangular parallelepiped package. The solenoid valves 210, 220 generate an electromagnetic attractive force when current is applied to the coil, thereby opening and closing the hydraulic line.

[0018] When the hydraulic pressure path is opened and the pump 19 rotates, hydraulic pressure is supplied from the hydraulic pressure source 16 to the brake calipers 91, 92 via the hydraulic pressure path, pressing against the brake discs of the wheels 95, 96. When braking the vehicle, the driver applies pressure to the brake pedal, and the motor 18 drives the hydraulic pump 19 to increase the brake hydraulic pressure, thereby braking the vehicle.

[0019] The motor drive device 70 contains a substrate 50, an IC 60 as a "control circuit", two solenoids 21 and 22, etc., inside a resin housing 30 and cover 40. The first solenoid and the second solenoid 22 are electrically connected to the substrate 50. The first solenoid and the second solenoid 22 are the same size, and the coil axes P and Q are arranged parallel to each other.

[0020] The housing 30 has a partition wall 34 between the hydraulic block 15 side and the cover 40 side. A solenoid accommodating section 33 is formed on the hydraulic block 15 side of the partition wall 34, and a board accommodating section 35 is formed on the cover 40 side of the partition wall 34. In addition, a connector 38 to which a power cable from a DC power source and various signal lines are connected is formed in a position that does not interfere with the hydraulic block 15.

[0021] The substrate 50 is made of an insulating material such as glass epoxy or ceramic. The substrate 50 of this embodiment is a multilayer substrate in which pattern layers are stacked. An IC 60 and other electronic elements (not shown) are mounted on the substrate 50.

[0022] The power supply terminal 81 and the ground terminal 84 connect the board 50 to the connector 38. The power supply side motor terminal 82 and the ground side motor terminal 83 connect the board 50 to the motor conductor 17. The power supply side solenoid terminals 85, 87 and the ground side solenoid terminals 86, 88 connect the board 50 to the solenoids 21, 22.

[0023] The circuit configuration of the motor drive device 70 will be described with reference to Figure 3. The motor drive device 70 is, more accurately, a "motor and solenoid drive device" and has the function of driving the motor 18 and the function of turning on and off the solenoids 21 and 22. The power supply terminal 81 of the circuit board 50 is connected to the positive pole of the DC power supply Bt via a power cable, and the ground terminal 84 is grounded.

[0024] The motor drive switch circuit 68 includes semiconductor switching elements (e.g., MOSFETs) provided between a power supply terminal 81 and a power supply-side motor terminal 82, between the power supply-side motor terminal 82 and a ground-side motor terminal 83, and between the ground-side motor terminal 83 and a ground terminal 84. The power supply terminal 81 and the motor drive switch circuit 68 are connected via a power supply wiring pattern 51 formed on the substrate 50. The motor drive switch circuit 68 and the ground terminal 84 are connected via a ground wiring pattern 52 formed on the substrate 50. In other words, the power supply wiring pattern 51 and the ground wiring pattern 52 of the substrate 50 form a current path to the motor 18.

[0025] A motor drive control unit 67 of the IC 60 controls the supply of electricity to the motor 18. A motor drive switch circuit 68 operates based on a command from the motor drive control unit 67, and the motor 18 is driven to rotate the hydraulic pump 19 at a desired output.

[0026] The power supply side of each solenoid 21, 22 is connected to power supply side solenoid terminals 85, 87 of the circuit board 50, and the ground side of each solenoid 21, 22 is connected to ground side solenoid terminals 86, 88 of the circuit board 50. Within the circuit board 50, solenoid drive switches 23, 24 are connected in series between the ground side solenoid terminals 86, 88 and the ground terminal 84. In the example of FIG. 3, the solenoid drive switches 23, 24 are provided inside the IC 60, but in other examples, the solenoid drive switches 23, 24 may be provided outside the IC 60.

[0027] The solenoid drive control unit 65 of the IC 60 switches the solenoid drive switches 23 and 24 ON and OFF. This allows the solenoid drive switches 23 and 24 to block current flowing from the DC power supply Bt to ground via the solenoids 21 and 22. However, even if the solenoid drive switches 23 and 24 are turned OFF, if the solenoid drive switches 23 and 24 are stuck ON or if the solenoids 21 and 22 are faulted to ground, leakage current may flow to ground. The broken arrow indicates leakage current Ileak when it is assumed that there is an abnormality in the current path on the second solenoid 22 side.

[0028] Here, the voltage on the solenoid drive switch 23 side of the first solenoid 21 is defined as a first solenoid monitoring voltage V_SOL1, and the voltage on the solenoid drive switch 24 side of the second solenoid 22 is defined as a second solenoid monitoring voltage V_SOL2. The solenoid drive control unit 65 compares the first solenoid monitoring voltage V_SOL1 with the second solenoid monitoring voltage V_SOL2, and detects an abnormality such as current leakage in the current path of either solenoid.

[0029] The "absolute value of the difference between the first solenoid monitor voltage V_SOL1 and the second solenoid monitor voltage V_SOL2" is referred to as the monitor potential difference ΔV. When the monitor potential difference ΔV is equal to or less than the potential difference threshold ΔVth and formula (1a) is satisfied, the solenoid drive control unit 65 determines that both of the current paths of the two solenoids 21, 22 are normal. On the other hand, when the monitor potential difference ΔV is greater than the potential difference threshold ΔVth and formula (1b) is satisfied, the solenoid drive control unit 65 determines that the current path of one of the solenoids is abnormal.

[0030] ΔV=|V_SOL1-V_SOL2|≦ΔVH ···(1a) ΔV=|V_SOL1-V_SOL2|>ΔVH ···(1b)

[0031] However, if voltage noise is superimposed on the first solenoid monitoring voltage V_SOL1 or the second solenoid monitoring voltage V_SOL2 when detecting a current leakage abnormality, it may be erroneously detected as an abnormality even though it is normal. The mechanism behind this will be described later with reference to Figures 7 to 10. In this embodiment, in order to avoid this erroneous detection, it is an object of the present invention to prevent voltage noise from being superimposed on the solenoid monitoring voltages V_SOL1 and V_SOL2.

[0032] In this embodiment, attention is focused on the fact that magnetic flux generated by energizing the power supply wiring pattern 51 and the ground wiring pattern 52 affects the induced voltage of the solenoids 21, 22 in the OFF state. When projected onto the surface of the substrate 50, an "influence area S" of the two solenoids 21, 22 is defined, and the positional relationship between the power supply wiring pattern 51 and the ground wiring pattern 52 and the influence area S is specified for each embodiment. Next, the configuration of the substrate 50 of each embodiment will be explained in order. The reference numerals for the substrates of the first to third embodiments have the embodiment number added as the third digit following "50."

[0033] (First embodiment) The configuration of the substrate 501 of the first embodiment will be described with reference to Figures 4 to 6. The plan views of the substrate of each embodiment, including Figure 4(a), are mainly intended to show the shapes of the power supply wiring pattern 51 and the ground wiring pattern 52, and the arrangement of the solenoids 21 and 22, and do not show electronic elements mounted on the substrate or terminals connected to the wiring patterns.

[0034] The cross-sectional view shown in FIG. 4(b) is common to the substrate 50 of each embodiment, which is configured as a multilayer substrate. The substrate 50 has a power supply wiring pattern 51 formed on one surface of an insulating layer 57, and a ground wiring pattern 52 formed on the other surface. In FIG. 4(a), the power supply wiring pattern 51 on the front side is indicated by a solid line. Except for the left and right ends of the figure, the ground wiring pattern 52 on the back side is indicated by a dashed line. Except for the left end of the figure, the ground wiring pattern 52 is formed directly below and parallel to the power supply wiring pattern 51.

[0035] The rectangular packages of the solenoids 21 and 22 are represented by rectangles, and the cylindrical coils housed within the packages are represented by circles. Here, the distance between the first center P, which is the coil center of the first solenoid 21, and the second center Q, which is the coil center of the second solenoid 22, is defined as the "solenoid distance A." The combined area of ​​the interior S1 of a circle whose radius is the solenoid distance A from the first center P and the interior S2 of a circle whose radius is the solenoid distance A from the second center Q is defined as the "influence area S." When magnetic flux is generated within the influence area S due to the passage of current through the power supply wiring pattern 51 and the ground wiring pattern 52, it may affect the induced voltage of at least one of the solenoids.

[0036] In the first embodiment, the distance A between the solenoids is set to be three times or less the coil outer diameter D of the solenoids 21 and 22. As shown in equation (2) described below, the magnetic flux generated by energizing is inversely proportional to the distance from the current. When the distance A between the solenoids is greater than three times the coil outer diameter D, the solenoids 21 and 22 are sufficiently far from the current path, so the effect on the induced voltage is small and there is no need to consider the configuration of the wiring patterns 51 and 52. Therefore, in the first embodiment, the effect of the magnetic flux on the induced voltage of the solenoids 21 and 22 is suppressed by specifying the configuration of the wiring patterns 51 and 52 within the affected area S under the condition "3D≧A."

[0037] In the substrate 501 of the first embodiment, the power supply wiring pattern 51 and the ground wiring pattern 52 are formed in a straight line within the affected area S. Note that the power supply wiring pattern 51 is formed in an L-shape outside the affected area S at the left end of the figure, but this point will not be noted. The key point of the first embodiment is that the power supply wiring pattern 51 and the ground wiring pattern 52 are straight within the affected area S. Furthermore, the first center P and the second center Q are arranged diagonally across the straight line direction of the wiring patterns 51 and 52.

[0038] 7 to 10, the magnetic flux generated in the straight portions of the wiring patterns 51 and 52 is smaller than that generated in the curved portions. Therefore, even if magnetic flux is generated within the affected area S by energizing the wiring patterns 51 and 52, the effect on the induced voltage of the solenoids 21 and 22 is small.

[0039] FIGS. 5 and 6 show modified examples (variations) of the first embodiment. The reference numeral "501" is used to designate the substrate of the modified example. The same applies to the modified examples of the second and third embodiments. In Modification 1 shown in FIG. 5(a), Modification 2 shown in FIG. 5(b), and Modification 3 shown in FIG. 6(a), the power supply wiring pattern 51 and the ground wiring pattern 52 are formed linearly both inside and outside the affected area S. In Modification 1, the first center P and the second center Q are arranged along one side of the linear portion of the wiring patterns 51 and 52. In Modification 2, the first center P and the second center Q are arranged across the linear direction of the wiring patterns 51 and 52 in a direction perpendicular to the linear direction of the wiring patterns 51 and 52. In Modification 3, the first center P and the second center Q are arranged across the linear direction of the wiring patterns 51 and 52 in a diagonal direction.

[0040] In the fourth modification shown in FIG. 6(b), in contrast to FIG. 4(a), the power supply wiring pattern 51 is formed in a straight line both inside and outside the affected area S, and the ground wiring pattern 52 is formed in an L-shaped bend outside the affected area S.

[0041] Next, the technical significance of forming the wiring patterns 51, 52 in the affected area S in a linear shape in the first embodiment will be described with reference to Figs. 7 and 8 show the principle of magnetic flux generation when current is applied and the effect of voltage noise due to magnetic flux on a substrate 509 with an L-shaped wiring pattern, which is a comparative example of the first embodiment. Figs. 9 and 10 show similar matters for a substrate 501 with a linear wiring pattern in the first embodiment.

[0042] 7 and 9, only the power supply wiring pattern 51 is shown as a wiring pattern, and the dashed line of the ground wiring pattern 52 is omitted. The white block arrows indicate current paths, and the solid curved arrows indicate leakage magnetic flux. In the L-shaped wiring pattern of FIG. 7, the straight line portion extending straight in the longitudinal direction (left-right direction in the figure) is called a main straight line portion 53. The L-shaped wiring pattern has a bent portion 54 that bends from the main straight line portion 53 to a lateral extension portion 55 on the side. This term is also used in the third embodiment.

[0043] A magnetic field H [A / m] generated at a point a distance r from the current path on the substrate 50 by a current I [A] flowing through the wiring patterns 51 and 52 is expressed by equation (2) according to Ampere's law. H=I / 2πr (2)

[0044] The magnetic flux Φ [Wb] is proportional to the magnetic field H. The voltage noise V [V] generated by the time change of the magnetic field Φ is expressed by equation (3) according to Faraday's law. V=dΦ / dt (3)

[0045] 7, the first solenoid 21 is disposed inside the corner of the bent portion 54 of the L-shaped wiring pattern, and the second solenoid 22 is disposed on the opposite side of the main straight portion 53 from the lateral extension portion 55. Inside the corner of the bent portion 54 where the first solenoid 21 is disposed, approximately twice as much magnetic flux is generated as in the main straight portion 53 where the second solenoid 22 is disposed.

[0046] Therefore, when current is applied to the L-shaped wiring pattern when a current leakage abnormality is detected, voltage noise is superimposed on the first solenoid monitoring voltage V_SOL1, as shown in Figure 8(a). On the other hand, as shown in Figure 8(b), almost no voltage noise is superimposed on the second solenoid monitoring voltage V_SOL2. Strictly speaking, slight voltage noise is also superimposed on the second solenoid monitoring voltage V_SOL2, but for convenience, Figure 8(b) is represented by a flat straight line.

[0047] As a result, as shown in Fig. 8(c), a noise waveform remains in the monitored potential difference ΔV, and the peaks intermittently exceed the potential difference threshold ΔVth. Therefore, there is a risk that the current paths of the solenoids 21 and 22 may be erroneously detected as abnormal even though they are normal.

[0048] In contrast to this, in the linear wiring pattern shown in FIG. 9, the magnetic flux generated near the positions where the first solenoid 21 and the second solenoid 22 are disposed is relatively small.

[0049] Therefore, even if current is applied to the linear wiring pattern when detecting a current leakage anomaly, almost no voltage noise is superimposed on either the first solenoid monitoring voltage V_SOL1 or the second solenoid monitoring voltage V_SOL2, as shown in Figures 10(a) and 10(b). Therefore, as shown in Figure 10(c), the waveform of the monitoring potential difference ΔV becomes a flat straight line, thereby preventing erroneous detection.

[0050] As described above, in the first embodiment, the power supply wiring pattern 51 and the ground wiring pattern 52 are formed in a straight line within the affected area S. Since the magnetic flux generated in the straight line portions of the wiring patterns 51 and 52 is smaller than that generated in the curved portions, even if magnetic flux is generated within the affected area S due to the energization of the wiring patterns 51 and 52, the effect on the induced voltage of the solenoids 21 and 22 is small.

[0051] (Second embodiment) Next, a second embodiment will be described with reference to Figures 11 to 13. In a substrate 502 of the second embodiment shown in Figure 11, the power supply wiring pattern 51 and the ground wiring pattern 52 are formed outside the influence area S of the solenoids 21, 22 so that they do not overlap with the influence area S. As in the first embodiment, the distance A between the solenoids is set to be three times or less the outer diameter D of the coils of the solenoids 21, 22.

[0052] Even if magnetic flux is generated outside the affected area S due to energization of the wiring patterns 51, 52, it does not affect the induced voltage of the solenoids 21, 22. Therefore, it is possible to appropriately prevent erroneous detection due to voltage noise when detecting leakage current.

[0053] 12(a), (b) and 13(a), (b) show modifications 1 to 4 of the second embodiment, in which the solenoids 21 and 22 are offset from the modifications 1 to 4 of the first embodiment. In this way, the second embodiment can also be realized with a variety of arrangement variations.

[0054] (Third embodiment) Next, a third embodiment will be described with reference to FIGS. 14 and 15. In a board 503 of the third embodiment shown in FIG. 14, a power supply wiring pattern 51 and a ground wiring pattern 52 have a main straight portion 53 that extends straight in a common longitudinal direction (the left-right direction in the figure) within an affected area S. At least one of the power supply wiring pattern 51 and the ground wiring pattern 52 (power supply wiring pattern 51 in the example shown in the figure) has a bent portion 54 that bends from the main straight portion 53 to a lateral extension portion 55. A first center P and a second center Q are disposed on the opposite side of the main straight portion 53 from the lateral extension portion 55. As in the first embodiment, the distance A between the solenoids is set to be three times or less the outer diameter D of the coils of the solenoids 21 and 22.

[0055] Ideally, the configuration of the first or second embodiment is preferable, but there are cases where it is unavoidable to provide the bent portion 54 due to layout reasons. A relatively large magnetic flux is generated at the bent portion 54, but by moving the coil centers P and Q of the solenoids 21 and 22 away from the lateral extension portion 55, the effect of this on the induced voltage of the solenoids 21 and 22 can be minimized.

[0056] In the modification of the third embodiment shown in Fig. 15, the distance A between the solenoids is set to be greater than three times the coil outer diameter D of the solenoids 21, 22. This increases the distance from the outer edge of the affected area S to the coil centers P, Q of the solenoids 21, 22, reducing the effect on the solenoids 21, 22 of the magnetic flux generated at the bent portion 54 near the outer edge of the affected area S. This makes it possible to overcome the disadvantages of the bent portion 54 and prevent erroneous detection due to voltage noise during leakage current detection.

[0057] (Other embodiments) (a) In order to define the area of ​​influence S, two solenoids, i.e., a pair, must be provided per board, not just one, but two pairs of solenoids. Furthermore, more than two pairs of solenoids may be provided per board. For example, in a configuration in which leakage current is detected by comparing the monitoring voltages of two solenoids out of a total of four solenoids, the area of ​​influence S may be defined for each pair of solenoids being compared. Also, solenoids other than the solenoids targeted for suppression of magnetic flux influence may be connected to the same board.

[0058] (b) The load energized via the power supply wiring pattern 51 and the ground wiring pattern 52 of the substrate 50 is not limited to a motor, but may also be an actuator other than a motor, or a load that converts electrical energy into heat, light, etc. The motor drive switch circuit 68 in Fig. 3 is not limited to a semiconductor switching element such as a MOSFET, but may be configured with a mechanical relay or the like.

[0059] (c) The load driving device of the present invention may be configured such that two solenoids of the same size are electrically connected to a substrate on which a wiring pattern forming a current path to the load is formed. The two solenoids are not limited to solenoid valves of a brake fluid pressure control device, and may be applied to any solenoid device of any device.

[0060] The present invention is not limited to such an embodiment, and can be implemented in various forms without departing from the spirit of the present invention. [Explanation of symbols]

[0061] 18···Motor (load), 21... First solenoid, 22... Second solenoid, 23, 24... Solenoid operated switch, 50 (501-503) ··· substrate, 51 Power supply wiring pattern, 52 Ground wiring pattern, 60···IC (control circuit), 70 Motor drive device (load drive device), Bt...battery, A: distance between solenoids, P··· 1st center (coil axis), Q··· 2nd center (coil axis), S...Area of ​​influence.

Claims

1. a substrate (50) connected to a DC power supply (Bt) and having a power supply wiring pattern (51) and a ground wiring pattern (52) formed thereon, the power supply wiring pattern (51) and the ground wiring pattern (52) forming a current path to a load (18); Two solenoids, a first solenoid (21) and a second solenoid (22), which are electrically connected to the substrate and have the same size and whose coil axes are arranged parallel to each other; a control circuit (60) that switches on / off solenoid drive switches (23, 24) connected in series to the solenoids and controls the supply of current to the loads; Equipped with In projection onto the plane of the substrate, The distance between a first center (P) that is the coil center of the first solenoid and a second center (Q) that is the coil center of the second solenoid is defined as an inter-solenoid distance (A), If an area obtained by combining the inside of a circle (S1) from the first center with a radius equal to the distance between the solenoids and the inside of a circle (S2) from the second center with a radius equal to the distance between the solenoids is defined as an influence area (S), When a magnetic flux is generated within the affected area due to the energization of the power supply wiring pattern and the ground wiring pattern, the induced voltage of at least one of the solenoids may be affected. The load driving device, wherein the power supply wiring pattern and the ground wiring pattern are formed outside the affected area.

2. a substrate (50) connected to a DC power supply (Bt) and having a power supply wiring pattern (51) and a ground wiring pattern (52) formed thereon, the power supply wiring pattern (51) and the ground wiring pattern (52) forming a current path to a load (18); Two solenoids, a first solenoid (21) and a second solenoid (22), which are electrically connected to the substrate and have the same size and whose coil axes are arranged parallel to each other; a control circuit (60) that switches on / off solenoid drive switches (23, 24) connected in series to the solenoids and controls the supply of current to the loads; Equipped with In projection onto the plane of the substrate, The distance between a first center (P) that is the coil center of the first solenoid and a second center (Q) that is the coil center of the second solenoid is defined as an inter-solenoid distance (A), If an area obtained by combining the inside of a circle (S1) from the first center with a radius equal to the distance between the solenoids and the inside of a circle (S2) from the second center with a radius equal to the distance between the solenoids is defined as an influence area (S), When a magnetic flux is generated within the affected area due to the energization of the power supply wiring pattern and the ground wiring pattern, the induced voltage of at least one of the solenoids may be affected. A load driving device in which the power supply wiring pattern and the ground wiring pattern are formed linearly within the affected area.

3. a substrate (50) connected to a DC power supply (Bt) and having a power supply wiring pattern (51) and a ground wiring pattern (52) formed thereon, the power supply wiring pattern (51) and the ground wiring pattern (52) forming a current path to a load (18); Two solenoids, a first solenoid (21) and a second solenoid (22), which are electrically connected to the substrate and have the same size and whose coil axes are arranged parallel to each other; a control circuit (60) that switches on / off solenoid drive switches (23, 24) connected in series to the solenoids and controls the supply of current to the loads; Equipped with In projection onto the plane of the substrate, The distance between a first center (P) that is the coil center of the first solenoid and a second center (Q) that is the coil center of the second solenoid is defined as an inter-solenoid distance (A), If an area obtained by combining the inside of a circle (S1) from the first center with a radius equal to the distance between the solenoids and the inside of a circle (S2) from the second center with a radius equal to the distance between the solenoids is defined as an influence area (S), When a magnetic flux is generated within the affected area due to the energization of the power supply wiring pattern and the ground wiring pattern, the induced voltage of at least one of the solenoids may be affected. Within the affected area, the power supply wiring pattern and the ground wiring pattern have a main straight line portion (53) extending straight in a common longitudinal direction, and at least one of the power supply wiring pattern or the ground wiring pattern has a bending portion (54) bending from the main straight line portion to a lateral extension portion (55), and the first center and the second center are arranged on the opposite side of the main straight line portion from the lateral extension portion.

4. 4. The load driving device according to claim 1, wherein the distance between the solenoids is set to be equal to or less than three times the outer diameter of the coils of the solenoids.

5. The load driving device according to any one of claims 1 to 3, wherein the control circuit compares a first solenoid monitoring voltage (V_SOL1), which is the voltage on the solenoid drive switch side of the first solenoid, with a second solenoid monitoring voltage (V_SOL2), which is the voltage on the solenoid drive switch side of the second solenoid, when the solenoid drive switch is turned OFF, and detects an abnormality in which current is leaking in the current path of any of the solenoids.

6. It is applied to a vehicle brake fluid pressure control device, The load is a motor that rotates a hydraulic pump (19), 6. The load drive device according to claim 5, wherein the two solenoids constitute solenoid valves (210, 220) that open and close hydraulic paths corresponding to a pair of left and right wheels.

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