Electromagnetic valve drive control device

Abstract

To achieve, with a single control circuit, the drive control of a solenoid valve with a plurality of driving coils without generating the malfunction of the solenoid valve, while decreasing the number of wires.SOLUTION: A solenoid valve drive control device 20 adopts a common positive electrode wiring 30 that is commonly and electrically connected to one ends of a first driving coil 11 and a second driving coil 12, and is electrically connected to a control circuit 21. A first branch wiring 61 is provided with a first current interruption element 71, and a second branch wiring 62 is provided with a second current interruption element 72. Therefore, a first negative electrode wiring 31 and a second negative electrode wiring 32 are prevented from conducting through the first branch wiring 61 and the second branch wiring 62. Consequently, there is no possibility that the first driving coil 11 and the second driving coil 12 are simultaneously turned on to generate the malfunction of a solenoid valve 10.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a solenoid valve drive control device that controls the drive of a solenoid valve having a plurality of drive coils. [Background technology]

[0002] A solenoid valve drive control device that controls the drive of a solenoid valve having multiple drive coils is disclosed in, for example, Patent Document 1. Such a solenoid valve drive control device includes a control circuit that controls the energization of the drive coils. The control circuit controls the energization of the multiple drive coils. For example, if the solenoid valve is a double solenoid type solenoid valve with two drive coils, the control circuit controls the energization of the two drive coils so that the two drive coils are alternately energized. This operates the valve element of the solenoid valve, switching the flow of the fluid through the flow path. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-177818 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in such a solenoid valve drive control device, it is difficult to provide a control circuit for each of the multiple drive coils, due to considerations such as miniaturization of the solenoid valve drive control device and limitations on the space available for arranging the control circuit. Therefore, it is desirable to control the energization of the multiple drive coils with a single control circuit, as in Patent Document 1. Furthermore, in such a solenoid valve drive control device, there is a demand for minimizing the number of wires as much as possible. Therefore, it is desirable to achieve drive control of a solenoid valve having multiple drive coils with a single control circuit without causing malfunction of the solenoid valve, while still reducing the number of wires. [Means for solving the problem]

[0005] The solenoid valve drive control device for solving the above problems is a solenoid valve drive control device that controls the drive of a solenoid valve having a plurality of drive coils, and includes a single control circuit that performs energization control of the plurality of drive coils and has only one ground terminal, and a plurality of switching elements provided one by one corresponding to the plurality of drive coils and performing on / off control of energization to each drive coil, a common positive electrode wiring commonly and electrically connected to the first ends of the plurality of drive coils respectively and also electrically connected to the control circuit, a plurality of negative electrode wirings provided one by one corresponding to the plurality of drive coils and electrically connected to the second ends of the plurality of drive coils respectively, a plurality of constant voltage circuits provided one by one corresponding to the plurality of negative electrode wirings and respectively provided between the common positive electrode wiring and each negative electrode wiring to apply a constant voltage from the common positive electrode wiring to the control circuit, a plurality of branch wirings provided one by one corresponding to the plurality of negative electrode wirings and electrically connected to the ground terminal and branched to be electrically connected to the plurality of negative electrode wirings respectively, and a current interruption element provided in each of the branch wirings and interrupting the current flowing from each negative electrode wiring through each branch wiring toward the branching point of the ground terminal in the branch wiring.

[0006] In the above solenoid valve drive control device, the current interruption element may be a diode. In the above solenoid valve drive control device, the current interruption element may be a switching element.

Advantages of the Invention

[0007] According to this invention, while reducing the number of wirings, the drive control of a solenoid valve having a plurality of drive coils can be achieved by a single control circuit without causing malfunction of the solenoid valve.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0009] [First Embodiment] Hereinafter, a first embodiment in which the electromagnetic valve drive control device is embodied will be described with reference to FIGS. 1 to 3.

[0010] <Electromagnetic valve 10> As shown in FIG. 1, the electromagnetic valve 10 has a first drive coil 11 and a second drive coil 12 which are drive coils. Therefore, the electromagnetic valve 10 of the present embodiment is of a double solenoid type having two drive coils. And the electromagnetic valve 10 is configured such that a valve body (not shown) operates by alternately energizing the first drive coil 11 and the second drive coil 12 to switch the flow of the fluid flow path. Since such an electromagnetic valve 10 is already known, the description of its detailed configuration will be omitted.

[0011] <Overall configuration of the electromagnetic valve drive control device 20> The electromagnetic valve drive control device 20 controls the drive of the electromagnetic valve 10 having the first drive coil 11 and the second drive coil 12. Therefore, the electromagnetic valve drive control device 20 controls the drive of the electromagnetic valve 10 having a plurality of drive coils. The electromagnetic valve drive control device 20 controls the drive of the electromagnetic valve 10 based on a drive signal from the external control device 15.

[0012] The electromagnetic valve drive control device 20 includes one control circuit 21. The control circuit 21 performs energization control of the first drive coil 11 and the second drive coil 12. The control circuit 21 is, for example, an MPU (Micro Processor Unit). The control circuit 21 includes a memory composed of a read-only memory (ROM) that stores various programs, maps, etc. in advance, a random access memory (RAM) that temporarily stores calculation results, etc. Further, the control circuit 21 includes a timer counter, an input interface, an output interface, etc.

[0013] The control circuit 21 has a power input terminal 22, a first signal input terminal 23, a second signal input terminal 24, a first signal output terminal 25, a second signal output terminal 26, and a ground terminal 27. Therefore, the control circuit 21 has only one ground terminal 27.

[0014] The electromagnetic valve drive control device 20 includes a common positive electrode wiring 30. The first end of the common positive electrode wiring 30 is electrically connected to the positive electrode terminal 16 of the external control device 15. The second end of the common positive electrode wiring 30 is commonly and electrically connected to the first end of the first drive coil 11 and the first end of the second drive coil 12.

[0015] The electromagnetic valve drive control device 20 includes a first negative electrode wiring 31 and a second negative electrode wiring 32 which are negative electrode wirings. The first negative electrode wiring 31 is provided corresponding to the first drive coil 11. The second negative electrode wiring 32 is provided corresponding to the second drive coil 12.

[0016] The first end of the first negative electrode wiring 31 is electrically connected to the first negative electrode terminal 17 of the external control device 15. The second end of the first negative electrode wiring 31 is electrically connected to the second end of the first drive coil 11. The first end of the second negative electrode wiring 32 is electrically connected to the second negative electrode terminal 18 of the external control device 15. The second end of the second negative electrode wiring 32 is electrically connected to the second end of the second drive coil 12. Therefore, the solenoid valve drive control device 20 includes a plurality of negative electrode wirings that are provided one by one corresponding to the plurality of drive coils and are connected to the second ends of the plurality of drive coils respectively.

[0017] The common positive electrode wiring 30 is electrically connected to the first negative electrode wiring 31 via the first resistor R1 and the first Zener diode ZD1. The cathode terminal of the first Zener diode ZD1 is electrically connected to the first resistor R1. The anode terminal of the first Zener diode ZD1 is electrically connected to the first negative electrode wiring 31. A first capacitor C1 is connected in parallel to the first Zener diode ZD1.

[0018] A first connection line 33 is electrically connected to the midpoint between the first resistor R1 and the first Zener diode ZD1. The first end of the first connection line 33 is electrically connected to the midpoint between the first resistor R1 and the first Zener diode ZD1. The second end of the first connection line 33 is electrically connected to the anode terminal of the first diode D1. The cathode terminal of the first diode D1 is electrically connected to the circuit power supply line 34. A first signal line 35 is connected in the middle of the first connection line 33. The first end of the first signal line 35 is electrically connected in the middle of the first connection line 33. The second end of the first signal line 35 is electrically connected to the first signal input terminal 23.

[0019] The first Zener diode ZD1 and the first capacitor C1 constitute a first constant voltage circuit 41 which is a constant voltage circuit provided between the common positive electrode wiring 30 and the first negative electrode wiring 31. The first constant voltage circuit 41 is provided between the common positive electrode wiring 30 and the first negative electrode wiring 31 in order to apply a constant voltage from the common positive electrode wiring 30 to the control circuit 21.

[0020] The common positive electrode wiring 30 is electrically connected to the second negative electrode wiring 32 via the second resistor R2 and the second Zener diode ZD2. The cathode terminal of the second Zener diode ZD2 is electrically connected to the second resistor R2. The anode terminal of the second Zener diode ZD2 is electrically connected to the second negative electrode wiring 32. A second capacitor C2 is connected in parallel to the second Zener diode ZD2.

[0021] A second connection line 36 is electrically connected to the intermediate point between the second resistor R2 and the second Zener diode ZD2. The first end of the second connection line 36 is electrically connected to the intermediate point between the second resistor R2 and the second Zener diode ZD2. The second end of the second connection line 36 is electrically connected to the anode terminal of the second diode D2. The cathode terminal of the second diode D2 is electrically connected to the circuit power supply line 34. The circuit power supply line 34 is electrically connected to the power input terminal 22. A second signal line 37 is connected in the middle of the second connection line 36. The first end of the second signal line 37 is electrically connected in the middle of the second connection line 36. The second end of the second signal line 37 is electrically connected to the second signal input terminal 24.

[0022] The second Zener diode ZD2 and the second capacitor C2 constitute a second constant voltage circuit 42 which is a constant voltage circuit provided between the common positive electrode wiring 30 and the second negative electrode wiring 32. The second constant voltage circuit 42 is provided between the common positive electrode wiring 30 and the second negative electrode wiring 32 in order to apply a constant voltage from the common positive electrode wiring 30 to the control circuit 21.

[0023] Therefore, a plurality of constant voltage circuits are provided one by one corresponding to a plurality of negative electrode wirings. And the plurality of constant voltage circuits are respectively provided between the common positive electrode wiring 30 and each negative electrode wiring in order to apply a constant voltage from the common positive electrode wiring 30 to the control circuit 21.

[0024] The electromagnetic valve drive control device 20 includes a first switching element 51 and a second switching element 52, which are switching elements. The first switching element 51 is provided corresponding to the first drive coil 11. The second switching element 52 is provided corresponding to the second drive coil 12. Therefore, the switching elements are provided one by one corresponding to a plurality of drive coils.

[0025] The first switching element 51 is provided on the first negative wiring 31. The first switching element 51 is an n-channel MOSFET (MOS field effect transistor). The gate terminal of the first switching element 51 is electrically connected to the first signal output terminal 25 via the third resistor R3. The drain terminal of the first switching element 51 is electrically connected to the second end of the first drive coil 11. The source terminal of the first switching element 51 is electrically connected to the first negative terminal 17 of the external control device 15. Note that the first switching element 51 has a first body diode 51a.

[0026] The second switching element 52 is provided on the second negative wiring 32. The second switching element 52 is an n-channel MOSFET (MOS field effect transistor). The gate terminal of the second switching element 52 is electrically connected to the second signal output terminal 26 via the fourth resistor R4. The drain terminal of the second switching element 52 is electrically connected to the second end of the second drive coil 12. The source terminal of the second switching element 52 is electrically connected to the second negative terminal 18 of the external control device 15. Note that the second switching element 52 has a second body diode 52a.

[0027] As shown in FIG. 2, for example, assume that the first negative terminal 17 of the external control device 15 is in the on state and the second negative terminal 18 is in the off state. In this case, current flows from the positive terminal 16 of the external control device 15 in the order of the common positive wiring 30, the first resistor R1, the first Zener diode ZD1, the first negative wiring 31, and the first negative terminal 17. Then, power is supplied to the power input terminal 22 via the first connection line 33, the first diode D1, and the circuit power line 34. As a result, the control circuit 21 is driven. Further, a drive signal is input to the first signal input terminal 23 via the first connection line 33 and the first signal line 35.

[0028] When a drive signal is input to the first signal input terminal 23, the control circuit 21 outputs a signal from the first signal output terminal 25 to the first switching element 51. As a result, the first switching element 51 becomes in the on state. Therefore, the first switching element 51 is in the on state when a signal is output from the first signal output terminal 25. The first switching element 51 is in the off state when no signal is output from the first signal output terminal 25. The signal output from the first signal output terminal 25 is a PWM control signal.

[0029] When the first switching element 51 becomes in the on state, current flows from the positive terminal 16 of the external control device 15 in the order of the common positive wiring 30, the first drive coil 11, the first negative wiring 31, and the first negative terminal 17. As a result, the first drive coil 11 is energized. On the other hand, when the first switching element 51 becomes in the off state, the energization of the first drive coil 11 is cut off. In this way, the first switching element 51 performs on / off control of the energization of the first drive coil 11.

[0030] As shown in Fig. 3, for example, assume that the first negative terminal 17 of the external control device 15 is in the off state and the second negative terminal 18 is in the on state. In this case, current flows from the positive terminal 16 of the external control device 15 in the order of the common positive wiring 30, the second resistor R2, the second Zener diode ZD2, the second negative wiring 32, and the second negative terminal 18. Then, power is supplied to the power input terminal 22 via the second connection line 36, the second diode D2, and the circuit power supply line 34. Thereby, the control circuit 21 is driven. Further, a drive signal is input to the second signal input terminal 24 via the second connection line 36 and the second signal line 37.

[0031] When a drive signal is input to the second signal input terminal 24, the control circuit 21 outputs a signal from the second signal output terminal 26 to the second switching element 52. Thereby, the second switching element 52 becomes the on state. Therefore, the second switching element 52 is in the on state when a signal is output from the second signal output terminal 26. The second switching element 52 is in the off state when no signal is output from the second signal output terminal 26. The signal output from the second signal output terminal 26 is a PWM control signal.

[0032] When the second switching element 52 becomes the on state, current flows from the positive terminal 16 of the external control device 15 in the order of the common positive wiring 30, the second drive coil 12, the second negative wiring 32, and the second negative terminal 18. Thereby, the second drive coil 12 is energized. On the other hand, when the second switching element 52 becomes the off state, the energization of the second drive coil 12 is cut off. In this way, the second switching element 52 performs on / off control of the energization of the second drive coil 12. Therefore, the solenoid valve drive control device 20 includes a plurality of switching elements that perform on / off control of the energization of each drive coil.

[0033] <The first branch wiring 61 and the second branch wiring 62> As shown in FIG. 1, the electromagnetic valve drive control device 20 includes a first branch wiring 61 and a second branch wiring 62 which are branch wirings. The first branch wiring 61 is provided corresponding to the first negative electrode wiring 31. The first branch wiring 61 is electrically connected to the ground terminal 27. The first branch wiring 61 branches with respect to the ground terminal 27 and is electrically connected to the first negative electrode wiring 31. The second branch wiring 62 is provided corresponding to the second negative electrode wiring 32. The second branch wiring 62 is electrically connected to the ground terminal 27. The second branch wiring 62 branches with respect to the ground terminal 27 and is electrically connected to the second negative electrode wiring 32. Therefore, the branch wirings are provided one by one corresponding to a plurality of negative electrode wirings and are electrically connected to the ground terminal 27, branch with respect to the ground terminal 27, and are electrically connected to the plurality of negative electrode wirings respectively.

[0034] As shown in FIG. 2, for example, assume that the first negative electrode terminal 17 of the external control device 15 is in an on state and the second negative electrode terminal 18 is in an off state. In this case, the current flowing from the ground terminal 27 flows through the first branch wiring 61 and the first negative electrode wiring 31 to the first negative electrode terminal 17 of the external control device 15.

[0035] As shown in FIG. 3, for example, assume that the first negative electrode terminal 17 of the external control device 15 is in an off state and the second negative electrode terminal 18 is in an on state. In this case, the current flowing from the ground terminal 27 flows through the second branch wiring 62 and the second negative electrode wiring 32 to the second negative electrode terminal 18 of the external control device 15.

[0036] <The first current cutoff element 71 and the second current cutoff element 72> As shown in FIG. 1, the electromagnetic valve drive control device 20 includes a first current cutoff element 71 and a second current cutoff element 72, which are current cutoff elements. The first current cutoff element 71 is provided on the first branch wiring 61. The first current cutoff element 71 is a diode. The anode terminal of the first current cutoff element 71 is electrically connected to the ground terminal 27. The cathode terminal of the first current cutoff element 71 is electrically connected to the first negative electrode wiring 31. The first current cutoff element 71 allows a current flowing from the ground terminal 27 through the first branch wiring 61 toward the first negative electrode wiring 31. On the other hand, the first current cutoff element 71 blocks a current flowing from the first negative electrode wiring 31 through the first branch wiring 61 toward the branch point 63 with respect to the ground terminal 27 in the first branch wiring 61.

[0037] The second current cutoff element 72 is provided on the second branch wiring 62. The second current cutoff element 72 is a diode. The anode terminal of the second current cutoff element 72 is electrically connected to the ground terminal 27. The cathode terminal of the second current cutoff element 72 is electrically connected to the second negative electrode wiring 32. The second current cutoff element 72 allows a current flowing from the ground terminal 27 through the second branch wiring 62 toward the second negative electrode wiring 32. On the other hand, the second current cutoff element 72 blocks a current flowing from the second negative electrode wiring 32 through the second branch wiring 62 toward the branch point 63 with respect to the ground terminal 27 in the second branch wiring 62. Therefore, the current cutoff elements are provided on each branch wiring respectively, and block a current flowing from each negative electrode wiring through each branch wiring toward the branch point 63 with respect to the ground terminal 27 in the branch wiring. Note that the "branch point 63" is the branch point with respect to the ground terminal 27 in the first branch wiring 61 and is also the branch point with respect to the ground terminal 27 in the second branch wiring 62.

[0038] [Operation of the First Embodiment] Next, the operation of the first embodiment will be described. Here, in the solenoid valve drive control device 20 having only one control circuit 21, it is common for the control circuit 21 to have only one ground terminal 27. In this case, in order to reduce the number of wirings drawn from the solenoid valve drive control device 20, it is necessary to electrically connect the ground terminal 27 to each of the first negative electrode wiring 31 and the second negative electrode wiring 32. For this reason, the solenoid valve drive control device 20 needs to have a configuration including a first branch wiring 61 and a second branch wiring 62.

[0039] Here, for example, consider the case where the second current cutoff element 72 is not provided in the second branch wiring 62. In this case, even when the second negative electrode terminal 18 of the external control device 15 is in the off state, as indicated by the dashed arrow in FIG. 2, current will flow in by detouring. Specifically, current will flow in the order of the positive electrode terminal 16 of the external control device 15, the common positive electrode wiring 30, the second resistor R2, the second constant voltage circuit 42, the second negative electrode wiring 32, the second branch wiring 62, the first branch wiring 61, the first negative electrode wiring 31, and the first negative electrode terminal 17.

[0040] Then, even though the second negative electrode terminal 18 is in the off state, a drive signal is input to the second signal input terminal 24 via the second connection line 36 and the second signal line 37, and the second switching element 52 becomes in the on state. As a result, energization of the second drive coil 12 is performed, and the first drive coil 11 and the second drive coil 12 simultaneously become in the on state, causing a malfunction of the solenoid valve 10.

[0041] Also, for example, consider the case where the first current cutoff element 71 is not provided in the first branch wiring 61. In this case, even when the first negative electrode terminal 17 of the external control device 15 is in the off state, as indicated by the dashed arrow in FIG. 3, current will flow in by detouring. Specifically, current will flow in the order of the positive electrode terminal 16 of the external control device 15, the common positive electrode wiring 30, the first resistor R1, the first constant voltage circuit 41, the first negative electrode wiring 31, the first branch wiring 61, the second branch wiring 62, the second negative electrode wiring 32, and the second negative electrode terminal 18.

[0042] Then, although the first negative terminal 17 is in the off state, a drive signal is input to the first signal input terminal 23 via the first connection line 33 and the first signal line 35, and the first switching element 51 is turned on. As a result, energization of the first drive coil 11 is performed, and the first drive coil 11 and the second drive coil 12 are simultaneously turned on, causing a malfunction of the solenoid valve 10.

[0043] Therefore, a first current cutoff element 71 is provided in the first branch wiring 61, and a second current cutoff element 72 is provided in the second branch wiring 62. According to this, the first current cutoff element 71 cuts off the current flowing from the first negative wiring 31 through the first branch wiring 61 toward the branch point 63 with respect to the ground terminal 27 in the first branch wiring 61. Also, the second current cutoff element 72 cuts off the current flowing from the second negative wiring 32 through the second branch wiring 62 toward the branch point 63 with respect to the ground terminal 27 in the second branch wiring 62. Therefore, it is avoided that the first negative wiring 31 and the second negative wiring 32 are electrically connected through the first branch wiring 61 and the second branch wiring 62. As a result, there is no such thing that the first drive coil 11 and the second drive coil 12 are simultaneously turned on, causing a malfunction of the solenoid valve 10.

[0044] [Effects of the First Embodiment] In the first embodiment, the following effects can be obtained. (1-1) The solenoid valve drive control device 20 employs a common positive wiring 30 that is commonly and electrically connected to the first ends of the first drive coil 11 and the second drive coil 12, and is also electrically connected to the control circuit 21. For this reason, for example, compared with the case where one positive wiring is provided for each of the first drive coil 11 and the second drive coil 12, and furthermore, a positive wiring is separately provided for the control circuit 21, the number of wirings can be reduced.

[0045] A first current interruption element 71 is provided in the first branch wiring 61, and a second current interruption element 72 is provided in the second branch wiring 62. According to this, it is possible to avoid the first negative electrode wiring 31 and the second negative electrode wiring 32 from being electrically connected through the first branch wiring 61 and the second branch wiring 62. Therefore, there is no such problem that the first drive coil 11 and the second drive coil 12 are simultaneously turned on and the solenoid valve 10 malfunctions. As described above, it is possible to achieve the drive control of the solenoid valve 10 having a plurality of drive coils with one control circuit 21 without causing a malfunction of the solenoid valve 10 while reducing the number of wirings.

[0046] (1-ii) The first current interruption element 71 and the second current interruption element 72 are diodes. The diode is suitable as a current interruption element used to avoid the first negative electrode wiring 31 and the second negative electrode wiring 32 from being electrically connected through the first branch wiring 61 and the second branch wiring 62.

[0047] (1-iii) When energizing the first drive coil 11 and the second drive coil 12 at different timings, the driving of the first drive coil 11 and the second drive coil 12 can be controlled by turning on and off the first switching element 51 and the second switching element 52, respectively. For this reason, even in a configuration employing the common positive electrode wiring 30, the power consumption for each of the first drive coil 11 and the second drive coil 12 can be suppressed. Therefore, it is possible to avoid problems such as insufficient starting current for the first drive coil 11 and the second drive coil 12, or an increase in the energization time for the first drive coil 11 and the second drive coil 12.

[0048] [Second Embodiment] Hereinafter, a second embodiment in which the solenoid valve drive control device is embodied will be described with reference to FIGS. 4 to 6. In the embodiment described below, the same components as those in the first embodiment already described are denoted by the same reference numerals, and the overlapping description is omitted or simplified. In the second embodiment, the configuration of the current interruption element is different from that in the first embodiment.

[0049] <First current cutoff element 81 and second current cutoff element 82> As shown in FIG. 4, the solenoid valve drive control device 20 includes a first current cutoff element 81 and a second current cutoff element 82, which are current cutoff elements. The first current cutoff element 81 is provided in the first branch wiring 61. The first current cutoff element 81 is a switching element. Specifically, the first current cutoff element 81 is an n-channel MOSFET (MOS field effect transistor). The gate terminal of the first current cutoff element 81 is electrically connected to the first signal line 35. The drain terminal of the first current cutoff element 81 is electrically connected to a branch point 63 with respect to the ground terminal 27 in the first branch wiring 61. The source terminal of the first current cutoff element 81 is connected to the first negative electrode wiring 31.

[0050] When a signal from the first signal line 35 is input to the gate terminal, the first current cutoff element 81 becomes on. When no signal from the first signal line 35 is input to the gate terminal, the first current cutoff element 81 is in an off state. Therefore, when the first negative terminal 17 of the external control device 15 is in an on state, the first current cutoff element 81 becomes on. When the first current cutoff element 81 is in an on state, it allows current to flow from the ground terminal 27 through the first branch wiring 61 toward the first negative electrode wiring 31. On the other hand, when the first current cutoff element 81 is in an off state, it cuts off the current flowing from the first negative electrode wiring 31 through the first branch wiring 61 toward the branch point 63 with respect to the ground terminal 27 in the first branch wiring 61.

[0051] The second current cutoff element 82 is provided in the second branch wiring 62. The second current cutoff element 82 is a switching element. Specifically, the second current cutoff element 82 is an n-channel MOSFET (MOS field effect transistor). The gate terminal of the second current cutoff element 82 is electrically connected to the second signal line 37. The drain terminal of the second current cutoff element 82 is electrically connected to a branch point 63 with respect to the ground terminal 27 in the second branch wiring 62. The source terminal of the second current cutoff element 82 is connected to the second negative electrode wiring 32.

[0052] The second current interruption element 82 turns on when a signal from the second signal line 37 is input to the gate terminal. The second current interruption element 82 is in an off state when a signal from the second signal line 37 is not input to the gate terminal. Therefore, when the second negative terminal 18 of the external control device 15 is in an on state, the second current interruption element 82 is in an on state. When the second current interruption element 82 is in an on state, it allows current to flow from the ground terminal 27 toward the second negative wiring 32 via the second branch wiring 62. On the other hand, when the second current interruption element 82 is in an off state, it blocks the current flowing from the second negative wiring 32 toward the branch point 63 with respect to the ground terminal 27 in the second branch wiring 62 via the second branch wiring 62.

[0053] [Operation of the Second Embodiment] Next, the operation of the second embodiment will be described. As shown by the dashed arrow in FIG. 5, for example, when the second current interruption element 82 is not provided in the second branch wiring 62, current will flow around even if the second negative terminal 18 of the external control device 15 is in an off state. Specifically, current will flow in the order of the positive terminal 16 of the external control device 15, the common positive wiring 30, the second resistor R2, the second constant voltage circuit 42, the second negative wiring 32, the second branch wiring 62, the first branch wiring 61, the first negative wiring 31, and the first negative terminal 17.

[0054] Then, even though the second negative terminal 18 is in an off state, a drive signal is input to the second signal input terminal 24 via the second connection line 36 and the second signal line 37, and the second switching element 52 turns on. As a result, current is supplied to the second drive coil 12, and the first drive coil 11 and the second drive coil 12 are simultaneously in an on state, causing a malfunction of the solenoid valve 10.

[0055] As shown by the dashed arrow in FIG. 6, for example, when the first current cutoff element 81 is not provided in the first branch wiring 61, even if the first negative terminal 17 of the external control device 15 is in the off state, current will flow around. Specifically, current will flow in the order of the positive terminal 16 of the external control device 15, the common positive wiring 30, the first resistor R1, the first constant voltage circuit 41, the first negative wiring 31, the first branch wiring 61, the second branch wiring 62, the second negative wiring 32, and the second negative terminal 18.

[0056] Then, even though the first negative terminal 17 is in the off state, a drive signal is input to the first signal input terminal 23 via the first connection line 33 and the first signal line 35, and the first switching element 51 becomes in the on state. As a result, energization to the first drive coil 11 is performed, and the first drive coil 11 and the second drive coil 12 simultaneously become in the on state, causing a malfunction of the solenoid valve 10.

[0057] Therefore, the first current cutoff element 81 is provided in the first branch wiring 61, and the second current cutoff element 82 is provided in the second branch wiring 62. According to this, for example, if the first negative terminal 17 is in the off state, the first current cutoff element 81 becomes in the off state. As a result, the current flowing from the first negative wiring 31 through the first branch wiring 61 toward the branch point 63 with respect to the ground terminal 27 in the first branch wiring 61 is blocked by the first current cutoff element 81. Also, for example, if the second negative terminal 18 is in the off state, the second current cutoff element 82 becomes in the off state. As a result, the current flowing from the second negative wiring 32 through the second branch wiring 62 toward the branch point 63 with respect to the ground terminal 27 in the second branch wiring 62 is blocked by the second current cutoff element 82. Therefore, conduction between the first negative wiring 31 and the second negative wiring 32 through the first branch wiring 61 and the second branch wiring 62 is avoided. As a result, there is no such situation that the first drive coil 11 and the second drive coil 12 simultaneously become in the on state and a malfunction of the solenoid valve 10 occurs.

[0058] [Effect of the Second Embodiment] In the second embodiment, in addition to the effects (1-1) and (1-3) of the first embodiment, the following effects can be obtained.

[0059] (2-1) The first current cutoff element 81 and the second current cutoff element 82 are switching elements. The switching element is suitable as a current cutoff element used to avoid the first negative electrode wiring 31 and the second negative electrode wiring 32 from being conducted through the first branch wiring 61 and the second branch wiring 62.

[0060] [Modification Example] In addition, each of the above embodiments can be implemented with the following modifications. Each of the above embodiments and the following modification examples can be implemented in combination with each other as long as there is no technical contradiction.

[0061] · In each of the above embodiments, the solenoid valve 10 may include three or more drive coils. In this case, one negative electrode wiring may be provided corresponding to the number of drive coils. And one switching element may be provided corresponding to the number of drive coils. Further, one branch wiring may be provided corresponding to the number of negative electrode wirings. And the current cutoff element is provided in each branch wiring.

[0062] · In each of the above embodiments, the first switching element 51 and the second switching element 52 are not limited to n-channel MOSFETs (MOS field effect transistors).

[0063] · In each of the above embodiments, the configurations of the first constant voltage circuit 41 and the second constant voltage circuit 42 are not particularly limited. · In the second embodiment, the switching elements which are the first current cutoff element 81 and the second current cutoff element 82 are not limited to n-channel MOSFETs (MOS field effect transistors).

Explanation of Reference Numerals

[0064] 10... solenoid valve, 11... first drive coil which is a drive coil, 12... second drive coil which is a drive coil, 20... solenoid valve drive control device, 21... control circuit, 27... ground terminal, 30... common positive electrode wiring, 31... first negative electrode wiring which is a negative electrode wiring, 32... second negative electrode wiring which is a negative electrode wiring, 41... first constant voltage circuit which is a constant voltage circuit, 42... second constant voltage circuit which is a constant voltage circuit, 51... first switching element which is a switching element, 52... second switching element which is a switching element, 61... first branch wiring which is a branch wiring, 62... second branch wiring which is a branch wiring, 63... branch point, 71, 81... first current cutoff element which is a current cutoff element, 72, 82... second current cutoff element which is a current cutoff element.

Claims

1. An electromagnetic valve drive control device for controlling the drive of an electromagnetic valve having a plurality of drive coils, One control circuit that performs energization control of the plurality of drive coils and has only one ground terminal, A plurality of switching elements provided one by one corresponding to the plurality of drive coils and performing on / off control of energization to each drive coil, A common positive electrode wiring commonly and electrically connected to the first ends of the plurality of drive coils and also electrically connected to the control circuit, A plurality of negative electrode wirings provided one by one corresponding to the plurality of drive coils and electrically connected to the second ends of the plurality of drive coils respectively, A plurality of constant voltage circuits provided one by one corresponding to the plurality of negative electrode wirings and provided between the common positive electrode wiring and each negative electrode wiring to apply a constant voltage from the common positive electrode wiring to the control circuit, A plurality of branch wirings provided one by one corresponding to the plurality of negative electrode wirings and electrically connected to the ground terminal, branched with respect to the ground terminal and electrically connected to the plurality of negative electrode wirings respectively, An electromagnetic valve drive control device comprising current cutoff elements provided in each of the branch wirings for cutting off the current flowing from each negative electrode wiring through each branch wiring toward the branching point with respect to the ground terminal in each branch wiring.

2. The electromagnetic valve drive control device according to claim 1, wherein the current cutoff element is a diode.

3. The electromagnetic valve drive control device according to claim 1, wherein the current cutoff element is a switching element.

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