FAULT DETERMINATION PROCEDURE FOR A SWITCH

Abstract

Fault determination method for determining a fault occurring in a switch having: an actuating element (10, 20, 30) which is displaceable between a first position and a second position; and three contacts (11, 12, 13) whose state is switched between a first state in which a signal line is connected or interrupted, and a second state in which the signal line is reversed to the first state due to the displacement of the actuating element between the first position and the second position; wherein the three contacts include: a first contact (11, 21, 31) which is switched from the first state to the second state during the displacement of the actuating element (10, 20, 30) from the first position to the second position; a second contact (12, 22, 32) which is switched from the first state to the second state during the displacement of the actuating element (10, 20, 30) from the first position to the second position, at a time later than a time of switching of the first contact; and a third contact (13, 23, 33) which is switched from the second state to the first state during the displacement of the actuating element (10, 20, 30) from the first position to the second position, at a time which lies between the time of switching of the first contact (11, 21, 31) and the time of switching of the second contact (12, 22, 32), the method being characterized by; Determining that a fault fixed to the first state occurs in the third contact (13, 23, 33), in a state that all of a first signal output from the first contact (11, 21, 31), a second signal output from the second contact (12, 22, 32), and a third signal output from the third contact (13, 23, 33) are signals corresponding to the first state, and when the first signal and the second signal are switched into signals corresponding to the second state, and only the third signal remains the signal corresponding to the first state.

Description

TECHNICAL FIELD

[0001] An example of the present invention relates to a fault determination method for determining a fault in a switch. BACKGROUND

[0002] As described, for example, in JP 2002-254 950 A, a switch is used in an input device of a vehicle control system, such as a switching device. A switch designed according to the preamble of independent claims 1 and 2 is known from DE 38 41 373 A1.

[0003] Some switches used in a vehicle's control system have multiple signal lines to ensure redundancy. Each signal line is equipped with a contact that is activated by the switch. Each contact is connected or disconnected by the switch's on / off operation.

[0004] A combination of signals received from each signal line detects whether the switch has been turned on or off. Furthermore, the occurrence of an open or short circuit in such a switch is detected based on the combination of signals.

[0005] However, depending on the structure of the switch, especially the structure of the contact, an abnormality or fault may be falsely detected even if no fault has occurred. SUMMARY

[0006] It is an object of the present invention to provide a fault determination method for accurately determining a fault occurring in a switch.

[0007] A switch according to an example of the present invention includes an actuating element movable between a first position and a second position, and three contacts. A state of the three contacts is switched between a first state and a second state by the movement of the actuating element. Each contact connects or disconnects a signal line in the first state and, in the second state, brings the signal line to a state opposite to the first state. A first contact of the three contacts is configured to switch from the first state to the second state upon movement of the actuating element from the first position to the second position.A second contact of the three contacts is configured to switch from the first state to the second state during the movement of the actuating element from the first position to the second position, at a time later than the time at which the first contact is switched. A third contact of the three contacts is configured to switch from the second state to the first state during the movement of the actuating element from the first position to the second position, at a time between the time at which the first contact is switched and the time at which the second contact is switched.

[0008] In a first failure determination method of the switch configured as above according to the present invention, when all of a first signal output from the first contact, a second signal output from the second contact, and a third signal output from the third contact are signals corresponding to the first state, when the first signal and the second signal are switched to signals corresponding to the second state, and when only the third signal remains a signal corresponding to the first state, it is determined that a failure in which the third contact is fixed in the first state occurs.

[0009] In a second method of determining a failure of the switch configured as above according to the present invention, when all of a first signal output from the first contact, a second signal output from the second contact, and a third signal output from the third contact are signals corresponding to the second state, when the first signal and the second signal are switched to signals corresponding to the first state, and when only the third signal remains a signal corresponding to the second state, it is determined that a failure in which the third contact is fixed in the second state occurs.

[0010] In the switch according to the example of the present invention, when no fault occurs at any of the three contacts and when the operating member is in the first position, the first and second contacts are in the first state, while the third contact is in the second state. When no fault occurs at any of the three contacts and when the operating member is in the second position, the first and second contacts are in the second state, while the third contact is in the first state. Therefore, when no fault occurs at any of the three contacts, during the process of shifting the operating member from the first position to the second position, not all of the contacts will enter the first state, nor will all of the contacts enter the second state. Therefore, all of the contacts will be in the same state only when a fault occurs in the switch.As described above, according to the switch of the example in the present invention, it is possible to physically suppress erroneous detection of a fault.

[0011] According to the failure determination method of the switch according to the example of the present invention, when all signals are signals corresponding to the second state, it is possible to correctly determine that a failure occurs in which the third contact is fixed in the first state based on the subsequent combination of the signals. Also, when all signals are signals corresponding to the first state, it is possible to correctly determine that a failure occurs in which the third contact is fixed in the second state based on the subsequent combination of the signals. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a diagram showing a schematic configuration of a switch according to a first embodiment of the present invention; Fig. 2 is a diagram for explaining a method for determining an error occurring in the Fig. 1 shown switch occurs; Fig. 3 is a diagram for explaining a method for determining an error occurring in the Fig. 1 shown switch occurs; Fig. 4 is a diagram illustrating a comparative example of the Fig. 1 shown switch and a problem thereof; Fig. 5 is a diagram showing a comparative example of the Fig. 1 and a problem with the switch; Fig. 6 is a diagram showing a schematic configuration of a switch according to a second embodiment of the present invention; Fig. Figure 7 is a diagram showing the operation of the Fig. 6 shows the switch shown; Fig. Figure 8 is a diagram showing the operation of the Fig. 6 shows the switch shown; Fig. 9 is a diagram showing the operation of the Fig. 6 shows the switch shown; Fig. 10 is a diagram showing a schematic configuration of a switch according to a third embodiment of the present invention; Fig. 11 is a diagram showing the operation of the Fig. 10 shown switch; Fig. 12 is a diagram showing the operation of the Fig. 10 shown switch; Fig. 13 is a diagram showing the operation of the Fig. 10 shown switch; Fig. 14 is a flowchart showing a determination procedure of the fault determination applied to the switch according to each embodiment of the present invention; Fig. 15 is a sub-flowchart showing a process 1 of the Fig. 14 shows the determination process; Fig. 16 is a sub-flowchart showing a process 2 of the Fig. 14 shows the determination process; Fig. 17 is a sub-flowchart showing a process 3 of the Fig. 14 shows the determination process; Fig. 18 is a sub-flowchart showing a process 4 of the Fig. 14 shows the determination process; Fig. 19 is a sub-flowchart showing a process 5 of the Fig. 14 shows the determination process; Fig. 20 is a sub-flowchart showing a process 6 of the Fig. 14 shows the determination process; Fig. 21 is a sub-flowchart showing a process 7 of the Fig. 14 shows the determination process; Fig. 22 is a sub-flowchart showing a process 1 of the Fig. 14 shows the determination process. DESCRIPTION OF EMBODIMENTS

[0012] Embodiments of the present invention will be described with reference to the drawings. Although numerical values ​​of individual elements such as the number, quantity, amount, and range are described in the embodiment, the embodiment of the present invention is not limited to the numerical values ​​unless expressly stated or the numerical values ​​are fundamentally unambiguous. Furthermore, the configurations, steps, and the like described in the embodiments described below are not necessarily essential to the present invention unless expressly stated or fundamentally unambiguous. 1. First embodiment

[0013] A schematic structure of a switch 1 according to a first embodiment of the present invention is shown in Fig. 1. The switch 1 is a sliding contact switch having three fixed terminals or poles 11, 12, 13 and a movable terminal or pole 10 that functions as an actuator. Signal lines 14, 15, 16 are connected to the fixed terminals 11, 12, 13, respectively. A grounding conductor 17 is connected to the movable terminal 10. The fixed terminals 11, 12, 13 are configured to include a first fixed terminal 11, a second fixed terminal 12, and a third fixed terminal 13. The first terminal 11 forms a normally open contact or normally open contact with the movable terminal 10. The second fixed terminal 12 forms a normally open contact or normally open contact with the movable terminal 10. The third fixed terminal 13 forms a normally closed contact or normally closed contact with the movable terminal 10.That is, switch 1 is configured as an inverted triple switch.

[0014] In this specification, normally open or normally closed is referred to as "NO", and normally closed or normally closed is referred to as "NC". When the fixed terminals 11, 12, and 13 are referred to individually, the first fixed terminal 11, which forms the NO contact (hereinafter referred to as the "first NO contact") as the first contact, is referred to as the "first NO terminal". The second fixed terminal 12, which forms the NO contact (hereinafter referred to as the "second NO contact") as the second contact, is referred to as the "second NO terminal". The third fixed terminal 13, which forms the NC contact as the third contact, is referred to as the "NC terminal".

[0015] The movable terminal 10 slides on the fixed terminals 11, 12 and 13 in a range from a first position which is in Fig. 1 is represented by a solid line, to a second position, which is represented by a dashed line. In Fig. 1, black circles indicate a state in which the contacts are closed, while white circles indicate a state in which the contacts are open. In the first position, the movable terminal 10 is in contact only with the NC terminal 13. Therefore, in the first position, the NC contact is closed, and the first NO contact and second NO contact are open. This state is an OFF state, a first state of switch 1.

[0016] When the movable terminal 10 is moved toward the second position, the movable terminal 10 also contacts the first NO terminal 11. Thus, the NC contact and the first NO contact are closed, and only the second NO contact is open. When the movable terminal 10 is further moved toward the second position, the contact of the movable terminal 10 with the NC terminal 13 is released, and the movable terminal 10 contacts only the first NO terminal 11. Thus, the NC contact and the second NO contact are open, and only the first NO contact is closed.

[0017] When the movable terminal 10 is further moved toward the second position and the movable terminal 10 reaches the second position, the movable terminal 10 is in contact with the first NO terminal 11 and the second NO terminal 12. Thus, in the second position, the first NO contact and the second NO contact are closed, and the NC contact is open. This state is an ON state as the second state of switch 1.

[0018] As described above, the fixed terminals 11, 12, 13 are arranged so that one or two of the fixed terminals 11, 12, 13 are in contact with the movable terminal 10 when the movable terminal 10 slides in the range from the first position to the second position. That is, the fixed terminals 11, 12, 13 are arranged so that the movable terminal 10 does not come into contact with all of the fixed terminals 11, 12, 13 at the same time and comes into contact with at least one of the fixed terminals 11, 12, 13 until the switch 1 is switched from the OFF state to the ON state.

[0019] The signal lines 14, 15, and 16 extending from the respective contacts are connected to an ECU 18. The signal line 14 transmits a signal (first signal) from the first NO contact, the signal line 15 transmits a signal (second signal) from the second NO contact, and the signal line 16 transmits a signal (third signal) from the NC contact. An OFF signal is output to the ECU 18 from the contact in the open state, and an ON signal is output to the ECU 18 from the contact in the closed state. The ECU 18 determines the operation of switch 1 based on the combination of the signals from the signal lines 14, 15, and 16. When the combination of the signals from the signal lines 14, 15, and 16 is ON, ON, and OFF, the ECU 18 determines that an ON operation is being performed on switch 1.When the signal combination of the signal lines 14, 15 and 16 is switched to OFF, OFF and ON, the ECU 18 determines that an OFF operation is performed on the switch 1.

[0020] The ECU 18 is, for example, an ECU or control unit of a vehicle's switching device. Inverted triple switches, such as switch 1, are suitable for use in applications requiring reliability, such as a vehicle's manual switch or IG (ignition) switch. When switch 1 is used in the manual switch, switch 1 is designated for each range, such as P, R, N, D, and B. The switching processing for each range is assigned to the turn-on operation of switch 1.

[0021] According to the switch 1 configured as described above, when no fault occurs in any of the three contacts and when the movable terminal 10, which is an operating element, is in the first position, the first NO contact and the second NO contact are in the open state, and the NC contact is in the closed state. When no fault occurs in any of the three contacts and the movable terminal 10 is in the second position, the first NO contact and the second NO contact are in the closed state, and the NC contact is in the open state. Then, when no fault occurs in any of the three contacts, during the movement of the movable terminal 10 from the first position to the second position, not all of the contacts are in the open state, nor are all of the contacts in the closed state.

[0022] That is, according to the configuration of switch 1, all of the first NC contact, the second NC contact, and the NC contact are in the open state only when a fault occurs in switch 1. Likewise, all of these contacts are in the closed state only when a fault occurs in switch 1. As will be described in detail later, when a switch is configured to pass through a state where all contacts are in the same state in the course of on- or off-operation, it is not possible to immediately determine whether the fact that all contacts are in the same state is due to a fault of the contacts or not, such as off-fixation and on-fixation. However, since according to switch 1 configured as described above, not all contacts are in the same state when they are normal, it is possible to physically suppress erroneous detection of a fault.

[0023] A method for determining a fault occurring in switch 1 will be described with reference to the Fig. 2 and Fig. 3. First, a method for determining the interruption of the NC contact is described with reference to Fig. 2. As described in Fig. As shown in Figure 2, it is assumed that all contacts are in the open state when the movable terminal 10 is located at a position indicated by a dot-dash line. In this case, the combination of the signals input to the ECU 18 from the signal lines 14, 15, and 16 is OFF, OFF, OFF. However, such a combination does not exist in the switch 1 in the normal state. Therefore, it is determined that the OFF fixation, that is, the open circuit, occurs at any of the contacts.

[0024] When the movable terminal 10 moves to the state indicated by a solid line, if both the first NO contact and the second NO contact are normal, they are closed. Therefore, the signals input to the ECU 18 from the signal lines 14 and 15 are switched from OFF to ON. The signal input to the ECU 18 from the signal line 16 corresponding to the NC contact is kept OFF. If the change in the signals of the signal lines 14 and 15 indicates that both the first NO contact and the second NO contact are normal, it is determined that the fault is occurring at the NC contact, and that the fault is an open circuit. In other words, it is confirmed that the NC contact is open circuit.

[0025] Next, a method for determining the short circuit of the NC contact will be described with reference to Fig. 3. As described in Fig. As shown in Figure 3, it is assumed that all contacts are in the closed state when the movable terminal 10 is located at a position indicated by a dot-dash line. In this case, the combination of the signals input to the ECU 18 from the signal lines 14, 15, and 16 is ON, ON, ON. However, such a combination does not exist in the switch 1 in the normal state. Therefore, it is determined that the ON fixation, that is, a short circuit, occurs at any of the contacts.

[0026] When the movable terminal 10 moves to the position indicated by the solid line, if both the first NO contact and the second NO contact are normal, they are open. Therefore, the signals input to the ECU 18 from the signal lines 14 and 15 are switched from ON to OFF. On the other hand, the signal input to the ECU 18 from the signal line 16 corresponding to the NC contact is kept ON. If the change in the signal of the signal lines 14 and 15 indicates that both the first NO contact and the second NO contact are normal, it is determined that the fault occurs at the NC contact and that the fault is a short circuit. That is, it is determined that a short circuit has occurred at the NC contact.

[0027] The method for determining the error described above is possible because the switch 1 is configured in such a way that it does not allow all of the fixed terminals 11, 12, 13 to come into contact with the movable terminal 10 at the same time, and that it allows at least one of the fixed terminals 11, 12, 13 to come into contact with the movable terminal 10. In the case of a Fig. In the comparative example of a switch 101 shown in Fig. 4, during the course of sliding the movable terminal 10, a situation occurs in which none of the fixed terminals 11, 12, 13 comes into contact with the movable terminal 10. Therefore, even if all the signals are OFF, it cannot be immediately determined that a disconnection has occurred. In this case, for example, by determining whether a situation in which all the signals are in the OFF state continues for a predetermined time, it may be possible to determine whether a disconnection actually occurs. However, if a situation in which an operator moves the movable terminal 10 only a little continues, it may be determined that a disconnection occurs in the switch 101 even though no failure actually occurs.

[0028] In a Fig. In the comparative example of a switch 102 shown in Figure 5, during the movement of the movable terminal 10, a situation occurs in which all the fixed terminals 11, 12, 13 come into contact with the movable terminal 10. With such a switch 102, even if all the signals are ON, it cannot be immediately determined that a short circuit has occurred. In this case, if a situation continues in which an operator moves the movable terminal 10 even slightly, it may be determined that a short circuit has occurred in the switch 101, even though no failure has actually occurred. 2. Second embodiment

[0029] Next, a switch according to a second embodiment of the present invention will be described with reference to the Fig. 6 to 9. As described in Fig. As schematically shown in Fig. 6, the switch 2 of the present embodiment is a counter-contact type switch. A first NO terminal 21 and a second NO terminal 22 are arranged to face a ground terminal 26 whose position is fixed. An NC terminal 23 is arranged to face a ground terminal 27 whose position is fixed. However, the direction in which the NC terminal 23 faces the ground terminal 27 is a direction opposite to the direction in which the first NO terminal 21 and the second NO terminal 22 face the ground terminal 26.

[0030] The first NO terminal 21 and the second NO terminal 22 are arranged between an actuator 20 and the ground terminal 26. The first NO terminal 21 is connected to the actuator 20 via a spring 25 with a large spring constant and is connected to the ground terminal 26 via a spring 24 with a small spring constant. Conversely, the second NO terminal 22 is connected to the actuator 20 via a spring 24 with a small spring constant and is connected to the ground terminal 26 via a spring 25 with a large spring constant. The NC terminal 23 is arranged between the actuator 20 and a fixed element 28 whose position is fixed. The NC terminal 23 is connected to the actuator 20 by a spring 24 with a small spring constant and is connected to the fixed element 28 by a spring 25 with a large spring constant.

[0031] When no force acts on the actuator 20, the first NO terminal 21 and the second NO terminal 22 are away from the ground terminal 26, and the NC terminal 23 is in contact with the ground terminal 27. The first NO terminal 21 and the ground terminal 26 configure an NO contact (hereinafter referred to as the "first NO contact") as a first contact, and the second NO terminal 22 and the ground terminal 26 configure an NO contact (hereinafter referred to as the "second NO contact") as a second contact. The NC terminal 23 configures an NC contact as a third contact with the ground terminal 27. That is, the switch 2 is configured as an inverted triple switch, similar to the switch 1 of the first embodiment.

[0032] A signal line (not shown) is connected to each of the first NO terminal 21, the second NO terminal 22, and the NC terminal 23. The signal line is connected to an ECU (not shown). In the open state, an OFF signal is output from the contact to the ECU, and in the closed state, an ON signal is output from the contact to the ECU. The ECU determines the operation performed on the switch 2 from the combination of the signals from each signal line. In a state in which no force is exerted on the actuating element 20, the actuating element 20 is in a first position, as shown in Fig. 6. In this state, the first NO contact and the second NO contact are open, and OFF signals are output from them. The NC contact is closed, and an ON signal is output from it. This state is an OFF state as the first state of switch 2.

[0033] In the switch 2 configured as described above, the actuating element 20 is pushed down. Then, as shown in Fig. 7, the springs 24, which have a small spring constant, and the first NO terminal 21 contact the ground terminal 26. This changes the signal output by the first NO contact to an ON signal. Upon further depression of the actuating element 20, as shown in Fig. As shown in Figure 8, the springs 25 with a large spring constant begin to shrink, and the NC terminal 23 is disconnected from the ground terminal 27. Thus, the signal output from the NC contact becomes an OFF signal.

[0034] If the actuating element 20 is then pressed down even further, the actuating element 20 finally reaches, as in Fig. 9, a second position. In the second position, the second NO terminal 22 contacts the ground terminal 26. This changes the signal output from the second NO contact to an ON signal. At this time, the first NO contact and the second NO contact are closed, and the NC contact is open. This state is an ON state as the second state of the switch 2. To realize the operation of such a switch 2, the strength and length of each spring 24 and 25 and the clearance in each contact are adjusted. The spring is an example of an element; it may also be another elastic element, such as rubber.

[0035] According to the switch 2 configured as described above, when no fault occurs in any of the three contacts and the operating member 20 is in the first position, the first NO contact and the second NO contact are in the open state, and the NC contact is in the closed state. When no fault occurs in any of the three contacts and the operating member 20 is in the second position, the first NO contact and the second NO contact are in the closed state, and the NC contact is in the open state. Therefore, when no fault occurs in any of the three contacts, when the operating member 20 is moved from the first position to the second position, not all of the contacts are in the open state, nor are all of the contacts in the closed state.

[0036] That is, according to the configuration of switch 2, the first NO contact, the second NO contact, and the NC contact are in the open state only when a fault occurs in switch 2. Likewise, all of these contacts are in the closed state only when a fault occurs in switch 2. According to the switch 2 configured as described above, since not all contacts are in the same state when they are normal, it is possible to physically suppress erroneous detection of a fault. The method for determining a fault of the switch described in the first embodiment can also be applied to switch 2. 3. Third embodiment

[0037] Next, a switch according to a third embodiment of the present invention will be described with reference to FIG. Fig. 10 to 13. As described in Fig. 10, the switch 3 of the present embodiment is a mixed type switch having two sliding contacts and one counter contact.

[0038] The switch 3 is provided with two NO terminals 31 and 32 whose positions are fixed, and a movable terminal 30 connected to ground. Each NO terminal 31 and 32, together with the movable terminal 30, forms a sliding contact. The switch 3 is provided with a ground terminal 37 and an NC terminal 33, whose position is fixed. The NC terminal 33, together with the ground terminal 37, forms a counter contact. The NC terminal 33 is arranged between the movable terminal 30, which is an actuating element, and a fixed element 36. The NC terminal 33 is connected to the movable terminal 30 by a spring 34 having a small spring constant and is connected to the fixed element 36 by a spring 35 having a large spring constant. Each NO terminal 31 and 32, together with the movable terminal 30, configures an NO contact. The NC terminal 33 together with the earth terminal 37 forms an NC contact.That is, switch 3 is configured as an inverted triple switch, similar to switch 1 of the first embodiment and switch 2 of the second embodiment.

[0039] The first NO terminal 31, the second NO terminal 32, and the NC terminal 33 are each connected to a signal line (not shown). The signal line is connected to an ECU (not shown). When the contact is open, an OFF signal is output to the ECU, and when the contact is closed, an ON signal is output to the ECU. The ECU determines the operation performed on switch 3 from the combination of the signals from the individual signal lines. As shown in Fig. As shown in Figure 10, in a state where no force is applied to the movable terminal 30, which is the actuating element, the movable terminal 30 is in a first position. In this state, the first NO contact and the second NO contact are open, and OFF signals are output from them. Fig. The white circles shown in Figure 10 indicate states in which the contacts are open. In the state of Fig. 10, the NC contact is closed, which outputs the ON signal. This state is an OFF state as a first state of switch 3.

[0040] In the switch 3 configured as described above, the movable terminal 30 is moved in one direction to shrink the springs 34 and 35. As shown in Fig. As shown in Figure 11, the movable terminal 30 initially contacts the first NO terminal 31. Thus, the NC contact and the first NO contact are closed and only the second NO contact is open. Fig. The black circle shown in Figure 11 indicates a state in which the contact is open. In this state, the spring 34 has begun to shrink with a small spring constant, and the NC terminal 33 remains in contact with the ground terminal 37. If the movable terminal 30 is further displaced, as shown in Fig. As shown in Figure 12, the spring 35 begins to shrink with a large spring constant, and the NC terminal 33 is disconnected from the ground terminal 37. This causes the signal output from the NC contact to become an OFF signal.

[0041] Then, when the movable terminal 30 is further shifted, the movable terminal 30 finally reaches, as shown in Fig. 13, a second position. In the second position, the movable terminal 30 contacts the second NO terminal 32. This changes the signal output by the second NO contact to an ON signal. At this time, the first NO contact and the second NO contact are closed, and the NC contact is open. This state is an ON state as the second state of switch 3.

[0042] According to the switch 2 configured as described above, when no fault occurs in any of the three contacts and the operating element 30 is in the first position, the first NO contact and the second NO contact are in the open state, and the NC contact is in the closed state. When no fault occurs in any of the three contacts and the operating element 30 is in the second position, the first NO contact and the second NO contact are in the closed state, and the NC contact is in the open state. Therefore, when no fault occurs in any of the three contacts, during the movement of the operating element 30 from the first position to the second position, not all of the contacts are in the open state, nor are all of the contacts in the closed state.

[0043] That is, according to the configuration of switch 3, the first NO contact, the second NO contact, and the NC contact are in the open state only when a fault occurs in switch 3. Likewise, only when a fault occurs in switch 3 are all these contacts in the closed state. According to the switch 3 configured as described above, since not all contacts are in the same state when normal, it is possible to physically suppress erroneous detection of a fault. The method for determining a fault of the switch described in the first embodiment can also be applied to switch 3. 4. Determination process for error determination

[0044] Hereinafter, a determination procedure of the fault determination applied to the switch according to each of the above embodiments will be described with reference to the flowcharts of Fig. 14 to 22. It is assumed that the switch is a vehicle's manual switch.

[0045] In step S100 of the Fig. In the determination flow shown in Fig. 14, NO1, which is a signal from the first NO contact, NO2, which is a signal from the second NO contact, and NC, which is a signal from the NC contact, are input to the ECU as determination values. It is determined whether NO1, NO2, and NC are ON or OFF. Process 1 is executed when a state in which NO1, NO2, and NC are OFF continues for a predetermined time. When a state in which NO1, NO2, and NC are respectively OFF, OFF, and ON continues for the predetermined time, Process 2 is executed. When a state in which NO1, NO2, and NC are respectively OFF, ON, and OFF continues for the predetermined time, Process 3 is executed. When a state in which NO1, NO2, and NC are respectively OFF, ON, and ON continues for the predetermined time, Process 4 is executed. When a state in which NO1, NO2 and NC are ON, OFF and OFF respectively continues for the specified time, process 5 is executed.When a state in which NO1, NO2, and NC are respectively ON, OFF, and ON continues for the predetermined time, process 6 is executed. When a state in which NO1, NO2, and NC are respectively ON, ON, and OFF continues for a predetermined time, process 7 is executed. When a state in which NO1, NO2, and NC are respectively ON, ON, and ON continues for the predetermined time, process 8 is executed. Until any of the above states continues for the predetermined time, the process returns to the start of the determination flow, and the determination in step S100 is repeated.

[0046] In the Fig. In process 1 shown in Figure 15, in step S110, a short-circuit suspicion flag is cleared for each of NO1 and NO2, and an open-circuit definite flag is turned on for NC. The suspicion flag is a flag set at the contact that outputs a signal that does not match the other two signals of NO1, NO2, and NC. That is, the suspicion flag is set at the contact where a fault is suspected. If an open circuit is suspected, an open-circuit suspicion flag is set. If a short circuit is suspected, the short-circuit suspicion flag is set. The definite flag is a flag set at the contact where a fault is certain to occur. If it is certain that the open circuit has occurred, the open-circuit definite flag is set. If it is certain that a short circuit has occurred, the short-circuit definite flag is set.According to the configuration of the switches according to the embodiments described above, it is ensured that when all of NO1, NO2, and NC are OFF, the open circuit occurs at one of the contacts, and therefore the open circuit flag is clearly set. On the other hand, since both NO1 and NO2 are OFF, they are at least not short-circuited. Therefore, the short-circuit suspicion flags for NO1 and NO2 are cleared.

[0047] In the Fig. In process 2 shown in Figure 16, the suspected short-circuit flags for NO1 and NO2 are cleared in step S120. Furthermore, the provisional short-circuit error counters for NO1 and NO2 are cleared. When NO1, NO2, and NC are OFF, OFF, and ON, respectively, the relationships between the outputs are consistent. Therefore, at least NO1 and NO2 are not short-circuited.

[0048] Next, in step S121, it is determined whether the short-circuit definite flag is set or not. If the short-circuit definite flag is off, in step S122, it is determined whether the open-circuit suspicion flag for NO1 is set. If NO1, NO2, and NC are currently OFF, OFF, and ON, respectively, and if the open-circuit suspicion flag for NO1 was set last time, it is likely that the first NO contact is disconnected. That is, it is likely that only NO1 is inconsistent with the other outputs because the first NO contact is open. In this case, in step S123, the provisional open-circuit error counter for NO1 is incremented, and the open-circuit suspicion flag for NO1 is cleared.

[0049] Next, in step S124, it is determined whether the provisional interruption error counter for NO1 is a predetermined number or more. The predetermined number is, for example, 2 times. If the provisional interruption error counter for NO1 reaches the predetermined number or more, it is determined in step S125 that an interruption has occurred at the first NO contact corresponding to NO1.

[0050] If it is determined in step S122 that the disconnection suspicion flag for NO1 is off, then in step S126, it is determined whether or not the disconnection suspicion flag for NO2 is on. If NO1, NO2, and NC are currently OFF, OFF, and ON, respectively, and if the disconnection suspicion flag for NO2 was set last time, it is likely that the second NO contact is disconnected. That is, it is likely that only NO2 was inconsistent with the other outputs because the second NO contact was disconnected. In this case, in step S127, the provisional disconnection error counter for NO2 is incremented, and the disconnection suspicion flag for NO2 is cleared.

[0051] Next, in step S128, it is determined whether the provisional NO2 interruption failure count is a predetermined number or more. The predetermined number is, for example, 2 times. If the provisional NO2 interruption failure count becomes the predetermined number or more, it is determined in step S129 that an interruption has occurred at the second NO contact corresponding to NO2.

[0052] If it is determined in step S122 that the open-circuit suspicion flag for NO1 is off, and in step S126 that the open-circuit suspicion flag for NO2 is off, it is determined whether all flags indicating the possibility of failures are off. If all flags are off, it can be determined that no failure has occurred in any of the contacts. In this case, the determination flow proceeds to step S131, and it is determined that the turn-off operation has been performed on the switching switch.

[0053] If the short-circuit definite flag is set in step S121, it is determined in step S132 that a short circuit has occurred at the NC contact corresponding to NC. Specifically, it is determined that a short-circuit fault has occurred only at the NC contact among the three contacts. If both the first NO contact and the second NO contact are found to be normal in situations where it is certain that a short circuit will occur, the contact where the short circuit occurs is obviously the NC contact.

[0054] In the Fig. In process 3 shown in Figure 17, the flag is set in step S140 when NO1, NO2, and NC are currently OFF, ON, and OFF, respectively. In this case, there is no inconsistency between NO2 and NC, but NO1 is inconsistent with the other two outputs. Since NO1 is OFF, it is suspected that the signal line corresponding to NO1 is open. Therefore, the open-circuit suspicion flag for NO1 is set. Since NO2 is ON, the signal line corresponding to NO2 is at least not open. Therefore, the open-circuit suspicion flag for NO2 is cleared.

[0055] In the Fig. In process 4 shown in Figure 18, in step S150, the flag is set when NO1, NO2, and NC are currently OFF, ON, and ON, respectively. There is no inconsistency between NO1 and NC, but NO2 is inconsistent with the other two outputs. Since NO2 is ON, it is suspected that the signal line corresponding to NO2 is short-circuited. Therefore, the short-circuit suspicion flag for NO2 is turned on. Since NO1 is OFF, the signal line corresponding to NO1 is at least not short-circuited. Therefore, the short-circuit suspicion flag for NO1 is cleared.

[0056] In the Fig. In process 5 shown in Figure 19, the flag is set in step S160 when NO1, NO2, and NC are currently ON, OFF, and OFF, respectively. There is no inconsistency between NO1 and NC, but NO2 is inconsistent with the other two outputs. Since NO2 is OFF, it is suspected that the signal line corresponding to NO2 is open. Therefore, the open-circuit suspicion flag for NO2 is set. Since NO1 is ON, no open-circuit occurs at least on the signal line corresponding to NO1. Therefore, the open-circuit suspicion flag for NO1 is cleared.

[0057] In the Fig. In process 6 shown in Figure 20, the flag is set in step S170 when NO1, NO2, and NC are currently ON, OFF, and ON, respectively. In this case, there is no inconsistency between NO2 and NC, but NO1 is inconsistent with the other two outputs. Since NO1 is ON, it is suspected that the signal line corresponding to NO1 is short-circuited. Therefore, the short-circuit suspicion flag for NO1 is set. Since NO1 is OFF, the signal line corresponding to NO1 is at least not short-circuited. Therefore, the short-circuit suspicion flag for NO2 is cleared.

[0058] In the Fig. In process 7 shown in Figure 21, in step S180, the disconnection suspicion flags for NO1 and NO2 are cleared accordingly. Furthermore, each of the provisional interruption error counters for NO1 and NO2 is cleared. When NO1, NO2, and NC are ON, ON, and OFF, respectively, the relationships between the outputs are consistent. Therefore, at least there is no doubt regarding the disconnection or disconnection of NO1 and NO2.

[0059] Next, in step S181, it is determined whether the open-circuit definite flag is set or not. If the open-circuit definite flag is off, in step S182, it is determined whether the short-circuit suspicion flag for NO1 is set or not. If NO1, NO2, and NC are currently ON, ON, and OFF, respectively, and if the short-circuit suspicion flag for NO1 was set last time, it is likely that the first NO contact is short-circuited. That is, it is likely that only NO1 is inconsistent with the other outputs because the first NO contact is short-circuited. In this case, in step S183, the provisional short-circuit error counters for NO1 are incremented, and the short-circuit suspicion flag for NO1 is cleared.

[0060] Next, in step S184, it is determined whether the provisional short-circuit error counters for NO1 are equal to or greater than a predetermined number. The predetermined number is, for example, 2 times. If the provisional short-circuit error counters for NO1 become a predetermined number or more, it is determined in step S185 that a short circuit has occurred in the signal line corresponding to NO1.

[0061] If it is determined in step S182 that the short-circuit suspicion flag for NO1 is off, it is determined in step S186 whether the short-circuit suspicion flag for NO2 is on or not. If NO1, NO2, and NC are currently ON, ON, and OFF, respectively, and if the short-circuit suspicion flag for NO2 was set last time, it is likely that the second NO contact is short-circuited. That is, it is likely that only NO2 is inconsistent with other outputs because the second NO contact is short-circuited. In this case, in step S187, the provisional short-circuit error counters for NO2 are incremented, and the short-circuit suspicion flag for NO2 is cleared.

[0062] Next, in step S188, it is determined whether the provisional short-circuit error counters for NO2 are equal to or greater than a predetermined number. The predetermined number is, for example, 2 times. If the provisional short-circuit error counters for NO2 become a predetermined number or more, it is determined in step S189 that a short circuit has occurred in the signal line corresponding to NO2.

[0063] If it is determined in step S182 that the short-circuit suspicion flag for NO1 is off, and further if it is determined in step S186 that the short-circuit suspicion flag for NO2 is off, it is determined in step S190 whether or not all flags indicating the possibility of failures are off. If all flags are off, it can be determined that no failure has occurred in any of the contacts. In this case, the determination flow proceeds to step S191, and it is determined that the switching switch's turn-on operation has been performed.

[0064] In step S181, if the disconnection flag is set, it is determined in step S192 that a disconnection has occurred at the NC contact corresponding to NC. More specifically, it is determined that a disconnection fault has occurred only at the NC contact of the three contacts. If both the first NO contact and the second NO contact are found to be normal in situations where a disconnection is certain, the contact where the disconnection occurs is obviously the NC contact.

[0065] In the Fig.In process 8 shown in Figure 22, the flag is set in step S200 if NO1, NO2, and NC are currently ON. According to the configuration of the switches according to the above-described embodiments, if all NO1, NO2, and NC are turned on, it is confirmed that a short circuit has occurred at one of the contacts, and therefore the short-circuit definite flag is set. Since both NO1 and NO2 are set, the signal lines corresponding to NO1 and NO2 are not open. Therefore, the open-circuit suspicion flags for NO1 and NO2 are cleared. 5. Miscellaneous

[0066] The switch according to each embodiment is an inverted triple switch with two NO contacts and one NC contact. However, the respective embodiment is also applicable to an inverted triple switch with one NO contact and two NC contacts. In the third embodiment, the mixed-type switch has two sliding contacts and one counter contact, but the embodiment is also applicable to a mixed-type switch with one sliding contact and two counter contacts. List of reference symbols 1, 2, 3 switches 10 movable connection (actuating element) 11 first NO connection 12 second NO connection 13 NC connection 14, 15, 16 Signal line 17 Earthing conductors 18 ECU 20 Actuating element 21 first NO connection 22 second NO connection 23 NC connection 24, 25 spring 26, 27 Earth connection 30 movable connection (actuating element) 31 first NO connection 32 second NO connection 33 NC connection 34, 35 spring 37 Earth connection

Claims

[1] Fault determination method for determining a fault occurring in a switch having: an actuating element (10, 20, 30) which is displaceable between a first position and a second position; and three contacts (11, 12, 13) whose state is switched between a first state in which a signal line is connected or interrupted, and a second state in which the signal line is reversed to the first state due to the displacement of the actuating element between the first position and the second position; wherein the three contacts include: a first contact (11, 21, 31) which is switched from the first state to the second state during the displacement of the actuating element (10, 20, 30) from the first position to the second position; a second contact (12, 22, 32) which is switched from the first state to the second state during the displacement of the actuating element (10, 20, 30) from the first position to the second position, at a time later than a time of switching of the first contact; and a third contact (13, 23, 33) which is switched from the second state to the first state during the displacement of the actuating element (10, 20, 30) from the first position to the second position, at a time which lies between the time of switching of the first contact (11, 21, 31) and the time of switching of the second contact (12, 22, 32), the method being characterized by; Determining that a fault fixed to the first state occurs in the third contact (13, 23, 33), in a state that all of a first signal output from the first contact (11, 21, 31), a second signal output from the second contact (12, 22, 32), and a third signal output from the third contact (13, 23, 33) are signals corresponding to the first state, and when the first signal and the second signal are switched into signals corresponding to the second state, and only the third signal remains the signal corresponding to the first state. [2] Fault determination method for determining a fault occurring in a switch having: an actuating element (10, 20, 30) which is displaceable between a first position and a second position; and three contacts (11, 12, 13) whose state is switched between a first state in which a signal line is connected or interrupted, and a second state in which the signal line is reversed to the first state due to the displacement of the actuating element between the first position and the second position; wherein the three contacts include: a first contact (11, 21, 31) which is switched from the first state to the second state during the displacement of the actuating element (10, 20, 30) from the first position to the second position; a second contact (12, 22, 32) which is switched from the first state to the second state during the displacement of the actuating element (10, 20, 30) from the first position to the second position, at a time later than a time of switching of the first contact; and a third contact (13, 23, 33) which is switched from the second state to the first state during the displacement of the actuating element (10, 20, 30) from the first position to the second position, at a time which lies between the time of switching of the first contact (11, 21, 31) and the time of switching of the second contact (12, 22, 32), the method being characterized by; Determining that a fault fixed to the second state occurs in the third contact (13, 23, 33), in a state that all of a first signal output from the first contact (11, 21, 31), a second signal output from the second contact (12, 22, 32), and a third signal output from the third contact (13, 23, 33) are signals corresponding to the second state, when the first signal and the second signal are switched into a signal corresponding to the first state, and only the third signal remains the signal corresponding to the second state.

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