JP7582074B2 - Anomaly detection device - Google Patents

Description

The present invention relates to an abnormality determination device.

Patent document 1 discloses that a vehicle control device uses the results of calculations by a main microcomputer and a sub-microcomputer to determine whether or not the shift range change control is being performed normally when controlling the shift range change.

JP 2013-23859 A

In the configuration described in Patent Document 1, it is determined whether the control shift range calculated by the main microcomputer and the comparison shift range calculated by the sub-microcomputer match. However, the main microcomputer and the sub-microcomputer do not necessarily execute processing at the same calculation cycle. Therefore, due to a difference in the calculation cycle of each microcomputer, it is possible that only the control shift range switches when the comparison shift range does not change, or that only the comparison shift range switches when the control shift range does not change. In other words, although each microcomputer outputs a calculation result that is determined to be normal, if the output timing is shifted due to differences in the calculation cycle and it is determined that the control shift range and the comparison shift range do not match, there is a risk of it being erroneously determined that an abnormality has occurred.

The present invention was made in consideration of the above circumstances, and aims to provide an abnormality determination device that can suppress the occurrence of erroneous abnormality determinations when monitoring control that changes the vehicle's shift range.

The present invention is an abnormality determination device that includes a first microcomputer and a second microcomputer that each execute a control according to the operation of a switch for changing a shift range of a vehicle when the switch is operated, and the first microcomputer executes change control to switch the shift range to the shift range corresponding to the switch based on a signal input from the switch when the switch is operated, and the second microcomputer executes monitoring control to determine whether an abnormality has occurred based on the signal input from the switch and the signal input from the first microcomputer, and is characterized in that the second microcomputer sets an allowed time to allow a change to the shift range corresponding to the switch when the input state of the signal input from the switch changes, and determines that the system is normal when it detects that the first microcomputer has executed change control to switch the shift range to the shift range corresponding to the switch between the time when the input state changed and the time when the allowed time has elapsed, and determines that an abnormality has occurred when it detects that the first microcomputer has executed change control to switch the shift range to the shift range corresponding to the switch after the time when the input state changed.

According to this configuration, if the first microcomputer executes control to change the shift range to the one corresponding to the switch between the time when the input state of the signal input from the switch to the second microcomputer changes and the time when the permission time has elapsed, the second microcomputer can be determined to be normal. By setting the permission time in this way, the change in the shift range executed during that time is determined to be normal, so that even if there is a discrepancy between the calculation timing of the first microcomputer and the calculation timing of the second microcomputer, it is possible to prevent a misjudgment of an abnormality.

The second microcomputer may also provisionally determine that an abnormality has occurred if it detects that the first microcomputer has executed change control to switch to the shift range corresponding to the switch when the input state of the signal input from the switch has not changed.

With this configuration, if the first microcomputer executes control to change the shift range to the one corresponding to the switch before the input state of the signal input from the switch to the second microcomputer changes, the second microcomputer can make a provisional determination that an abnormality has occurred.

The second microcomputer may also set a predetermined grace period when it has provisionally determined that an abnormality has occurred, and if the input state of the signal input from the switch changes between the time when it provisionally determined that an abnormality has occurred and the time when the grace period has elapsed, cancel the provisional determination, and if the input state of the signal input from the switch does not change between the time when it provisionally determined that an abnormality has occurred and the time when the grace period has elapsed, determine that an abnormality has occurred.

According to this configuration, by providing a predetermined grace period after a provisional judgment, it is possible to cancel the provisional judgment before the grace period has elapsed and to determine an abnormality judgment after the grace period has elapsed. This makes it possible to prevent erroneous judgments from occurring.

The present invention is an abnormality determination device that includes a first microcomputer and a second microcomputer that each execute a control according to the operation of a switch for changing a shift range of a vehicle when the switch is operated, and the first microcomputer executes a change control to switch the shift range to the shift range corresponding to the switch based on a signal input from the switch when the switch is operated, and the second microcomputer executes a monitoring control to determine whether an abnormality has occurred based on the signal input from the switch and the signal input from the first microcomputer, and the switch has a normally open contact and a normally closed contact, and a signal output from each contact is The switch is controlled to be turned on and off in response to a signal, and when the second microcomputer detects that all signals input from the contacts of the switch to the first microcomputer are off after the state in which all signals input from the contacts of the switch are off continues for a predetermined time or more, it determines that an abnormality has occurred in the wire harness provided between the switch and each microcomputer or in the switch, and when the second microcomputer detects that all signals input from the switch to the first microcomputer are not off after the state in which all signals input from the switch are off continues for a predetermined time or more, it determines that an abnormality has occurred in the input circuit of the second microcomputer.

With this configuration, in a switch that has multiple contacts with different characteristics, such as normally open contacts and normally closed contacts, the occurrence of an abnormality can be determined by comparing the input state of the signals input from each contact of the switch to each microcomputer. In addition, it is possible to determine the type of abnormality based on the combination of signals input from each contact to each microcomputer.

In addition, if the state in which all signals input from each contact of the switch remain off for a second predetermined time or more before the second microcontroller determines that the abnormality has occurred, the first microcontroller determines that an abnormality has occurred in the input circuit of the first microcontroller, and the second predetermined time may be longer than the predetermined time used in the processing of the second microcontroller.

With this configuration, the first microcontroller can determine that an abnormality has occurred in the input circuit of the first microcontroller.

In addition, after determining that an abnormality has occurred in the input circuit of the second microcomputer, the second microcomputer may execute the monitoring control using a signal input from the switch to the first microcomputer.

With this configuration, after determining that an abnormality has occurred in the input circuit of the second microcontroller, the second microcontroller can continue monitoring and control using the signal input from the switch to the first microcontroller.

In addition, after determining that an abnormality exists in the input circuit of the first microcomputer, the first microcomputer may execute the change control using a signal input from the switch to the second microcomputer.

With this configuration, after determining that an abnormality has occurred in the input circuit of the first microcontroller, the first microcontroller can continue change control using the signal input from the switch to the second microcontroller.

The switch further comprises an operating member that is displaced between a first position and a second position, and three contacts whose states change between an on state in which a signal line is connected and an off state in which the signal line is disconnected by the displacement of the operating member between the first position and the second position, and the three contacts are constituted by the normally open type contacts, a first contact that changes from the off state to the on state during the displacement of the operating member from the first position to the second position, a second contact that changes from the off state to the on state at a timing slower than that of the first contact during the displacement of the operating member from the first position to the second position, and a normally closed type contact, and the operating unit and a third contact that switches from the on state to the off state during the displacement of the material from the first position to the second position, at a timing slower than when the first contact switches from the off state to the on state and earlier than when the second contact switches from the off state to the on state, and the first microcomputer and the second microcomputer receive as signals from the switch 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, and the first microcomputer and the second microcomputer may determine that all signals input from the switch are off when the first signal, the second signal, and the third signal in the switch are all off.

With this configuration, the first microcomputer and the second microcomputer can monitor the occurrence of abnormalities in a switch having a first contact, a second contact, and a third contact with different characteristics.

In the present invention, when monitoring shift range change control based on the input state of the signal input from the switch to each microcomputer, an abnormality determination is not made until a predetermined time has passed since the input state of the signal changed. Also, if it can be determined that the condition is normal before the predetermined time has passed, it can be determined that the condition is normal. This makes it possible to prevent erroneous abnormality determinations from occurring.

FIG. 1 is a skeleton diagram that illustrates a vehicle according to a first embodiment. FIG. 2 is a functional block diagram for explaining the electronic control device of the first embodiment. FIG. 3 is a flow chart showing the process of monitoring the control shift range. FIG. 4 is a flow chart showing a process for monitoring the control shift range in the modified example of the first embodiment. FIG. 5 is a diagram showing a schematic configuration of a shift switch according to the second embodiment. FIG. 6 is a functional block diagram for explaining the electronic control device of the second embodiment. FIG. 7 is a diagram for explaining a case where the NC contact of the shift switch is broken. FIG. 8 is a diagram for explaining a case where the NC contact of the shift switch is shorted. FIG. 9 is a flow chart showing the shift operation monitoring process in the second embodiment. FIG. 10 is a flow chart showing the process of determining the control shift range in the second embodiment. FIG. 11 is a flow chart showing a shift operation monitoring process in a modified example of the second embodiment. FIG. 12 is a flow chart showing a process for determining the control shift range in a modified example of the second embodiment. FIG. 13 is a diagram showing a schematic configuration of a shift switch in a modified example of the second embodiment. FIG. 14 is a diagram showing the operation of the shift switch shown in FIG. FIG. 15 is a diagram showing the operation of the shift switch shown in FIG. FIG. 16 is a diagram showing the operation of the shift switch shown in FIG. FIG. 17 is a diagram showing a schematic configuration of a shift switch in another modified example of the second embodiment. FIG. 18 is a diagram showing the operation of the shift switch shown in FIG. FIG. 19 is a diagram showing the operation of the shift switch shown in FIG. FIG. 20 is a diagram showing the operation of the shift switch shown in FIG.

The following describes in detail an abnormality determination device according to an embodiment of the present invention with reference to the drawings. Note that the present invention is not limited to the embodiment described below.

First Embodiment
Fig. 1 is a skeleton diagram that shows a vehicle according to a first embodiment. The vehicle 1 includes an engine 2, which is a power source for driving the vehicle, a transmission 3, a differential gear 4, an axle 5, and drive wheels 6. The vehicle 1 is a front-engine, front-drive (FF) vehicle. Power output from the engine 2 is transmitted to left and right drive wheels 6 via the transmission 3, the differential gear 4, and the left and right axles 5 in this order. The transmission 3 is, for example, a multi-speed transmission that includes a plurality of planetary gear devices and engagement devices.

The vehicle 1 is equipped with a shift-by-wire system 20 that electrically switches the shift range of the transmission 3 according to the shift range selected by a shift switch 10 disposed near the driver's seat. The shift-by-wire system 20 includes a shift operation device 30 equipped with the shift switch 10, an electronic control unit (ECU) 40, and a parking lock device 50.

The shift operation device 30 is provided, for example, on an interior panel near the driver's seat, and includes a shift switch 10 for changing the shift range of the transmission 3. The shift switch 10 is operated by the driver to select the shift range, and is configured, for example, as a momentary push button switch. This shift switch 10 is an ON/OFF switch for specifying the shift range, and has multiple contacts for determining ON and OFF with a single switch.

The shift operation device 30 is also provided with multiple shift switches 10 for selecting each shift range. The shift operation device 30 is provided with the following shift switches 10: a P switch 11 for selecting a parking range, an R switch 12 for selecting a reverse driving range, an N switch 13 for selecting a neutral range in which power transmission is cut off, a D switch 14 for selecting a forward driving range, and a B switch 15 for selecting a deceleration forward driving range.

The P switch 11 is a switch for switching the shift range of the transmission 3 to the parking range (P range) and is operated when the driver selects the P range. The P range is a shift range in which the power transmission path in the transmission 3 is interrupted and the parking lock is performed by the parking lock device 50. The parking lock device 50 is a mechanism that mechanically prevents the rotation of the drive wheels 6 when parking. For example, when the parking lock is not performed by the parking lock device 50 (non-parking lock state), if the driver presses the P switch 11 when a certain condition is met, a signal is output from the P switch 11, and the electronic control device 40 that receives the signal switches the shift range of the transmission 3 to the P range. The non-parking lock state is a state in which the rotation of the drive wheels 6 is permitted.

The R switch 12 is a switch for switching the shift range of the transmission 3 to a reverse driving range (R range) and is operated when the driver selects the R range. The R range is a shift range in which the driving force for moving the vehicle 1 backward is transmitted to the drive wheels 6.

The N switch 13 is a switch for switching the shift range of the transmission 3 to the neutral range (N range) and is operated when the driver selects the N range. The N range is a shift range in which the power transmission path within the transmission 3 is cut off and the vehicle is in a neutral state. In this N range, the power transmission path from the engine 2 to the drive wheels 6 is cut off, but the drive wheels 6 are allowed to rotate.

The D switch 14 is a switch for switching the shift range of the transmission 3 to a forward driving range (D range) and is operated when the driver selects the D range. The D range is a shift range in which the driving force for moving the vehicle 1 forward is transmitted to the drive wheels 6.

The B switch 15 is a switch for switching the shift range of the transmission 3 to a decelerated forward driving range (B range) and is operated when the driver selects the B range. The B range is a shift range that exerts an engine braking effect on the vehicle 1 in the D range, slowing down the rotation of the drive wheels 6. In other words, the B range can be selected by pressing the B switch 15 when the D range is selected.

The shift switch 10 outputs a shift signal to the electronic control unit 40 each time the driver presses the shift switch 10. The shift signal is an electrical signal that indicates that the shift switch 10 has been turned ON or OFF. The electronic control unit 40 electrically detects that the shift switch 10 has been operated in response to the shift signal from the shift switch 10.

The electronic control unit 40 includes a microcomputer equipped with a CPU, RAM, ROM, and an input/output interface. This electronic control unit 40 processes signals according to a program prestored in the ROM. For example, the electronic control unit 40 controls the output of the engine 2, the shifting of the transmission 3, and changes the shift range in the shift-by-wire system 20. The electronic control unit 40 outputs a command signal for controlling the engine 2 and a command signal for controlling the transmission 3.

Regarding the shift range change control, when one of the shift ranges is selected with the shift switch 10, the electronic control unit 40 controls the transmission 3, the parking lock device 50, the display device 60, etc. in accordance with the selected shift range. For example, the electronic control unit 40 executes control to switch from a non-forward driving range (non-D range) other than the forward driving range to the forward driving range (D range). In this case, a command signal is output from the electronic control unit 40 to the display device 60. As a result, the D range is displayed on the display device 60, which displays the selected shift range.

The shift range change control also includes control to switch the state of the parking lock device 50. For example, when the parking lock device 50 is in a non-parking lock state and a signal is input from the P switch 11 to the electronic control unit 40, the electronic control unit 40 executes parking lock using the parking lock device 50. When the parking lock device 50 is in a parking lock state and any of the R switch 12, N switch 13, and D switch 14 is pressed, the electronic control unit 40 releases the parking lock, provided that a certain condition, such as the brake pedal being depressed, is met.

The electronic control device 40 also includes a control microcomputer 41 and a monitoring microcomputer 42. As shown in FIG. 2, a signal from the shift switch 10 is input to both the control microcomputer 41 and the monitoring microcomputer 42. The signal input from the shift switch 10 to the control microcomputer 41 is a control shift signal. The signal input from the shift switch 10 to the monitoring microcomputer 42 is a monitoring shift signal. In this electronic control device 40, the control microcomputer 41 is the first microcomputer, and the monitoring microcomputer 42 is the second microcomputer.

The control microcomputer 41 is a main microcomputer that executes change control to switch the shift range to the shift range corresponding to a shift switch 10 based on a signal output from the shift switch 10 when the driver presses the shift switch 10. This control microcomputer 41 has a determination unit 41a.

The determination unit 41a determines the control shift range based on the shift signal input from the shift switch 10. The control microcomputer 41, which is the first microcomputer, switches the shift range of the transmission 3 based on the control shift range determined by the determination unit 41a. In addition, a signal is output from the control microcomputer 41 to the display device 60. Therefore, the control shift range determined by the determination unit 41a is displayed on the display device 60, which displays the selected shift range.

The monitoring microcomputer 42 is a sub-microcomputer that monitors the change control by the control microcomputer 41. This second microcomputer, the monitoring microcomputer 42, executes monitoring control to determine whether or not an abnormality has occurred based on the signal input from the shift switch 10 and the signal input from the control microcomputer 41. This monitoring microcomputer 42 has a monitoring unit 42a.

The monitoring unit 42a monitors the shift range change control by the electronic control unit 40. The monitoring unit 42a receives the signal output from the determination unit 41a and the shift signal output from the pressed shift switch 10. The signal input from the determination unit 41a to the monitoring unit 42a is a signal indicating the control shift range determined by the determination unit 41a. Therefore, based on the signal input from the shift switch 10 to the monitoring microcomputer 42 and the signal input from the control microcomputer 41 to the monitoring microcomputer 42, the monitoring unit 42a can determine whether the shift range selected by the operation of the shift switch 10 matches the control shift range determined by the control microcomputer 41.

In this way, the monitoring microcomputer 42 monitors the occurrence of an abnormality in the shift-by-wire system 20 by monitoring the shift signal from the shift switch 10 and the calculation result in the control microcomputer 41. In this case, the signal output from the decision unit 41a of the control microcomputer 41 is input to the monitoring unit 42a, so that the monitoring microcomputer 42 can detect that the control microcomputer 41 has executed change control to switch the control shift range. For example, when the control microcomputer 41 executes control to switch the control shift range to the D range when the signal from the D switch 14 is not input to the monitoring microcomputer 42, the monitoring microcomputer 42 determines that an abnormality has occurred with respect to the change control of the control shift range. In this way, the electronic control unit 40 is a device that monitors malfunctions of the shift-by-wire system 20 and is an abnormality determination device that determines abnormalities in the shift-by-wire system 20.

Figure 3 is a flow chart showing the process of monitoring the control shift range. Note that Figure 3 shows a case where the D range is monitored among multiple shift ranges. The process shown in Figure 3 is repeatedly executed by the monitoring microcomputer 42 at a predetermined calculation cycle.

The monitoring microcomputer 42 determines whether the input state of the signal from the D switch 14 has changed for the monitoring shift signal (step S101). In step S101, it is determined whether the input state of the signal from the D switch 14, among the shift signals input from the shift operation device 30 to the monitoring microcomputer 42, has changed from OFF to ON.

In this step S101, it is possible to determine whether the input state of even one of the signals input from the multiple contacts in the D switch 14 has changed. In short, the signal whose input state changes may be a signal output from any of the contacts with different characteristics. When the input state of even one of the signals input from the multiple contacts in the D switch 14 has changed, it is clear that an operation to select the D range has clearly been performed, rather than a change in the shift signal due to an operation other than the D range.

When the input state of the signal from the D switch 14 for the monitoring shift signal changes (step S101: Yes), the monitoring microcomputer 42 sets the D range permission flag to ON and sets the D range counter to a predetermined value A (step S102). The D range permission flag is a flag that permits the control shift range to be switched to the D range. The D range counter indicates the permission time for permitting a change to the D range. The predetermined value A is a value greater than zero. In other words, by setting the predetermined value A in the D range counter, the predetermined time is set as the permission time for permitting a change to the D range.

If the input state of the signal from the D switch 14 has not changed for the monitoring shift signal (step S101: No), or after performing the processing of step S102, the monitoring microcontroller 42 determines whether the D range counter is greater than zero (step S103).

If the D range counter is greater than zero (step S103: Yes), the monitoring microcomputer 42 decrements the D range counter (step S104). In step S104, for example, the value of the D range counter is decremented by one. If the D range counter before the decrement is "A", the D range counter after the decrement can be expressed as "A-1". In short, in step S104, a countdown is performed from a predetermined time according to the predetermined value A set in the D range counter.

If the D-range counter is not greater than zero (step S103: No), the monitoring microcomputer 42 sets the D-range permission flag to OFF (step S105). In step S105, if the current D-range permission flag is ON, it is switched from ON to OFF, and if the current D-range permission flag is OFF, it is maintained OFF.

After performing the process of step S104 or after performing the process of step S105, the monitoring microcomputer 42 determines whether the control shift range has changed from a range other than the D range to the D range (step S106). In step S106, based on the signal input from the control microcomputer 41 to the monitoring microcomputer 42, it is determined whether the control shift range has switched to the D range.

If the control shift range changes from a range other than the D range to the D range (step S106: Yes), the monitoring microcontroller 42 determines whether the D range permission flag is ON (step S107).

If the D range permission flag is not ON (step S107: No), the monitoring microcomputer 42 performs abnormality processing for the control shift range (step S108). In step S108, the monitoring microcomputer 42 detects that the control shift range has been switched to the D range in a state in which changing to the D range is not permitted, and determines that an abnormality has occurred in the shift-by-wire system 20. The processing of step S108 is performed when the control shift range is switched to the D range when none of the input states of the monitoring shift signals have changed. In other words, this case occurs when the input signal does not change due to all of the signal lines (multiple signal lines provided for each contact) that input the monitoring shift signals are disconnected or shorted (first abnormality), when noise that erroneously determines that a pressing operation has occurred is input only to the input of the control shift signal (second abnormality), or when a bug or malfunction in the control causes a determination that a pressing operation has occurred despite the absence of a shift signal input (third abnormality). Therefore, the electronic control unit 40 performs fail-safe control, such as cutting off the driving force of the vehicle 1, as a countermeasure to the abnormality of the controlled shift range. After performing the process of step S108, this control routine ends.

If the control shift range does not change from a range other than the D range to the D range (step S106: No), or if the D range permission flag is ON (step S107: Yes), this control routine ends. In this case, the monitoring microcomputer 42 determines that the processing related to the D range among the control shift ranges is normal.

Then, since the monitoring microcomputer 42 repeats the process at a predetermined calculation cycle, the process shown in FIG. 3 loops. Therefore, after it is determined that the input state of the signal from the D switch 14 has switched to ON, the process enters a loop in which the result is determined negatively in step S101. When this loop is entered, the D range counter counts down toward 0 each time the process of step S104 is performed. If the D range counter is greater than zero, the D range permission flag is maintained ON, so the process enters a loop in which the result is determined positively in step S107. Then, when the D range counter reaches 0 in a certain number of loops, the result is determined negatively in step S103, and the D range permission flag is switched from ON to OFF in step S105. In other words, after the permission time (a predetermined time according to the predetermined value A) has elapsed since the input state of the signal from the D switch 14 changed, the D range permission flag is OFF, so if the control shift range changes to the D range, it is determined that an abnormality has occurred, and the process of step S108 is performed.

As described above, according to the first embodiment, when the monitoring microcomputer 42 monitors for malfunctions, it permits a change to that shift range from when the state of the monitoring shift signal input from the shift switch 10 to the monitoring microcomputer 42 changes until a predetermined permitted time has elapsed. Then, if the control microcomputer 41 changes the control shift range to that shift range when the monitoring microcomputer 42 does not permit a change to that shift range, the monitoring microcomputer 42 determines that an abnormality has occurred. As a result, since no abnormality determination is made from when the input state of the shift signal changes until the predetermined permitted time has elapsed, even if there is a discrepancy in the calculation timing between the control microcomputer 41 and the monitoring microcomputer 42, it is possible to suppress the occurrence of erroneous abnormality determinations.

In the first embodiment, the shift switch 10 is provided for each shift range, but the present invention is not limited to this. The shift switch 10 may be provided for at least one of the P range, R range, N range, D range, B range, etc. For example, the shift switch 10 may be composed of a P switch 11 and a D switch 14. Furthermore, the process shown in FIG. 3 can be applied to control shift ranges other than the D range. For example, the electronic control unit 40 can execute the process shown in FIG. 3 for the P range. In short, the process shown in FIG. 3 can be applied to the shift range in which the shift switch 10 is provided.

As a modification of the first embodiment, the monitoring microcomputer 42 can be configured to make a provisional determination of an abnormality, and then determine that an abnormality has occurred after a predetermined grace period has elapsed since making this provisional determination. The control of this modification is shown in FIG. 4.

Figure 4 is a flow chart showing the monitoring process of the control shift range in a modified example of the first embodiment. The process shown in Figure 4 is for monitoring the D range among multiple shift ranges, and is repeatedly executed by the monitoring microcomputer 42 at a predetermined calculation cycle. Also, the process of steps S201 to S205 shown in Figure 4 is similar to the process of steps S101 to S105 shown in Figure 3, so a description thereof will be omitted.

After performing the process of step S204 or after performing the process of step S205, the monitoring microcontroller 42 determines whether the D-range permission flag is ON (step S206).

If the D-range permission flag is ON (step S206: Yes), the monitoring microcomputer 42 sets the D-range abnormality counter to zero (step S207). After performing the process of step S207, this control routine ends.

If the D-range permission flag is not ON (step S206: No), the monitoring microcontroller 42 determines whether the D-range abnormality counter is greater than zero (step S208).

If the D-range abnormality counter is not greater than zero (step S208: No), the monitoring microcontroller 42 determines whether the control shift range has changed from a range other than the D range to the D range (step S209).

When the control shift range changes from a range other than the D range to the D range (step S209: Yes), the monitoring microcomputer 42 sets the D range abnormality counter to a predetermined value B (step S210). The D range abnormality counter indicates the grace period until the D range processing is determined to be abnormal. The predetermined value B is a value greater than zero. In other words, by setting the predetermined value B in the D range abnormality counter, the grace period (a predetermined period according to the predetermined value B) until the determination of the abnormality is confirmed is set. In other words, when the monitoring microcomputer 42 detects that the control shift range has been switched to the D range when the D range permission flag is OFF, it provisionally determines that there is an abnormality. Furthermore, the monitoring microcomputer 42 sets a grace period during which this provisional determination remains. In other words, after the provisional determination of an abnormality is made by the processing of step S209, the grace period until the D range permission flag is changed to ON is set in step S210. When the processing of step S210 is performed, this control routine ends.

If the control shift range does not change from a range other than D range to D range (step S209: No), the control routine proceeds to step S207.

If the D-range abnormality counter is greater than zero (step S208: Yes), the monitoring microcomputer 42 decrements the D-range abnormality counter (step S211). In step S211, for example, the value of the D-range abnormality counter is decremented by one. If the D-range abnormality counter before the decrement is "B", the D-range abnormality counter after the decrement can be expressed as "B-1". In short, in step S211, a countdown is performed from a predetermined time according to the predetermined value B set in the D-range abnormality counter.

After performing the processing of step S211, the monitoring microcontroller 42 determines whether the D-range abnormality counter is greater than zero (step S212).

If the D-range abnormality counter is greater than zero (step S212: Yes), this control routine ends. In this case, the system continues to loop while maintaining the state tentatively determined to be abnormal.

If the D-range abnormality counter is not greater than zero (step S212: No), the monitoring microcomputer 42 performs abnormality processing for the controlled shift range (step S213). A negative determination in step S212 means that the grace period has elapsed. In other words, the state has moved from a state in which an abnormality has been provisionally determined to a state in which an abnormality has been confirmed. Therefore, the electronic control unit 40 performs fail-safe control, such as cutting off the driving force of the vehicle 1, as an abnormality processing for the controlled shift range. After performing the processing in step S213, this control routine ends.

Then, since the monitoring microcomputer 42 repeats the process at a predetermined calculation cycle, the process shown in FIG. 4 loops. Therefore, after the control shift range is switched to the D range while the input state of the signal from the D switch 14 has not changed, a loop is entered in which a positive judgment is made in step S208. When this loop is entered, the D range abnormality counter counts down toward 0 each time the process of step S211 is performed. If the D range abnormality counter is greater than zero, a positive judgment is made in step S212, and the state in which a provisional judgment of an abnormality is made is maintained. Then, when the D range abnormality counter reaches 0 in a certain number of loops, a negative judgment is made in step S212, and the judgment of an abnormality is confirmed. In other words, after the grace time has elapsed since the control shift range was switched to the D range while the input state of the signal from the D switch 14 has not changed, the judgment of an abnormality is confirmed, and the process of step S213 is performed.

According to this modification, when the input state of the monitoring shift signal has not changed and the control shift range has switched to the shift range corresponding to that shift switch 10, a provisional abnormality determination can be made. Then, if the input state of the monitoring shift signal has changed for the corresponding shift switch 10 before a predetermined grace period has elapsed in the provisional determination state, the provisional abnormality determination can be cancelled. This makes it possible to prevent erroneous abnormality determinations from occurring even if there is a difference in the calculation timing between the control microcomputer 41 and the monitoring microcomputer 42. In other words, because the calculation cycles of the microcomputers are asynchronous and there is a time lag for exchanging shift control information by communication between the microcomputers, there is a risk that the control side will change the shift range before the monitoring side determines permission. Taking this into consideration, this can be prevented by waiting a predetermined grace period before determining abnormality.

Second Embodiment
Next, a second embodiment will be described. In the second embodiment, a shift switch having a normally open contact and a normally closed contact is configured to monitor occurrence of an abnormality using signals output from each contact of the shift switch. In the description of the second embodiment, description of the same configuration as the first embodiment will be omitted and the same reference numerals will be used.

Figure 5 is a diagram showing the schematic configuration of a shift switch in the second embodiment. The shift switch 100 in the second embodiment has one movable terminal 110 that functions as an operating member, and three fixed terminals, a first fixed terminal 111, a second fixed terminal 112, and a third fixed terminal 113. This shift switch 100 is a sliding contact type switch. Signal lines 114, 115, and 116 are connected to the fixed terminals 111, 112, and 113, respectively. A ground line 117 is connected to the movable terminal 110. In this description, normally open may be written as NO, and normally closed may be written as NC. The shift switch 100 may be installed in the vehicle 1 in place of the shift switch 10 in the first embodiment.

The first fixed terminal 111 forms a normally open contact with the movable terminal 110, and is a terminal that forms the first of the three contacts. This first fixed terminal 111 is a first NO terminal that forms the first NO contact. The second fixed terminal 112 forms a normally open contact with the movable terminal 110, and is a terminal that forms the second of the three contacts. This second fixed terminal 112 is a second NO terminal that forms the second NO contact. The third fixed terminal 113 forms a normally closed contact with the movable terminal 110, and is a terminal that forms the third of the three contacts. This third fixed terminal 113 is an NC terminal that forms an NC contact.

The movable terminal 110 slides over the fixed terminals 111, 112, and 113 in a range from a first position indicated by a solid line in FIG. 5 to a second position indicated by a dashed line. The black circles in FIG. 5 indicate a state in which the contacts are closed, and the white circles in FIG. 5 indicate a state in which the contacts are open. In the first position, the movable terminal 110 is in contact only with the third fixed terminal 113. That is, in the first position, the NC contact is closed and the first NO contact and the second NO contact are open. This state is the off state of the shift switch 100.

In addition, when the movable terminal 110 moves from the first position to the second position, the movable terminal 110 also comes into contact with the first fixed terminal 111. As a result, the NC contact and the first NO contact are closed, and only the second NO contact is open.

When the movable terminal 110 moves further toward the second position, the movable terminal 110 loses contact with the third fixed terminal 113 and comes into contact only with the first fixed terminal 111. This causes the NC contact and the second NO contact to open, and only the first NO contact to close.

When the movable terminal 110 moves further toward the second position, it reaches the second position. In the second position, the movable terminal 110 contacts the first fixed terminal 111 and the second fixed terminal 112. That is, in the second position, the first NO contact and the second NO contact are closed and the NC contact is open. This state is the ON state of the shift switch 100.

In this way, the three fixed terminals 111, 112, 113 are arranged so that one or two of them come into contact with the movable terminal 110 when the movable terminal 110 slides in the range from the first position to the second position. In other words, the three fixed terminals 111, 112, 113 are arranged so that a state in which all of the fixed terminals 111, 112, 113 are in contact with the movable terminal 110 does not occur, and a state in which none of the fixed terminals 111, 112, 113 are not in contact with the movable terminal 110 occurs, during the time period from the OFF state to the ON state of the shift switch 100.

Furthermore, signal lines 114, 115, and 116 extending from each contact are connected to the electronic control device 40. As shown in FIG. 6, each signal line 114, 115, and 116 is connected to the control microcomputer 41 and the monitoring microcomputer 42. Signal line 114 transmits a first signal which is a signal from the first NO contact. Signal line 115 transmits a second signal which is a signal from the second NO contact. Signal line 116 transmits a third signal which is a signal from the NC contact. An OFF signal is output from an open contact. An ON signal is output from a closed contact.

The electronic control unit 40 judges the operation performed on the shift switch 100 based on the combination of signals input from each signal line 114, 115, 116. For example, when the combination of the signals of the signal lines 114, 115, 116 is ON, ON, OFF, the electronic control unit 40 judges that the shift switch 100 has been turned on. When the combination of the signals of the signal lines 114, 115, 116 is OFF, OFF, ON, the electronic control unit 40 judges that the shift switch 100 has been turned off. This shift switch 100 is provided for each range such as P, R, N, D, B. Then, the on operation of the shift switch 100 is assigned to a switching process to each range. In the second embodiment, at least the D switch 14 is provided as the shift switch 100. Therefore, when explaining the D range, the shift switch 100 may be described as the D switch 14.

The electronic control unit 40 judges whether an abnormality has occurred based on a combination of signals input from each signal line 114, 115, 116. The control microcomputer 41 has an abnormality judgment unit 41b that judges whether an abnormality has occurred using signals from each signal line 114, 115, 116. The abnormality judgment unit 41b judges whether an abnormality has occurred on the control microcomputer 41 side based on signals input from each contact of the shift switch 100 and information indicating the judgment result input from the monitoring microcomputer 42. The monitoring microcomputer 42 has an abnormality judgment unit 42b that judges whether an abnormality has occurred using signals from each signal line 114, 115, 116. The abnormality judgment unit 42b judges whether an abnormality has occurred on the monitoring microcomputer 42 side based on signals input from each contact of the shift switch 100 to the monitoring microcomputer 42 and signals input from each contact of the shift switch 100 to the control microcomputer 41. The result of this determination by the abnormality determination unit 42b is input to the abnormality determination unit 41b on the control side.

According to the shift switch 100, if no abnormality occurs in any of the three contacts, when the movable terminal 110 is in the first position, the first NO contact and the second NO contact are in an open state, and the NC contact is in a closed state. Also, if no abnormality occurs in any of the three contacts, when the movable terminal 110 is in the second position, the first NO contact and the second NO contact are in a closed state, and the NC contact is in an open state. And, if no abnormality occurs in any of the three contacts, in the process of displacing the movable terminal 110 from the first position to the second position, not all of the contacts are in an open state, and not all of the contacts are in a closed state.

In other words, with the shift switch 100, the first NO contact, the second NO contact, and the NC contact are all open only when an abnormality occurs in the shift switch 100. Similarly, all of these contacts are closed only when an abnormality occurs in the shift switch 100. If the switch is configured so that all of the contacts go through a state in which they are in the same state during the on or off operation, it is not possible to immediately determine whether the fact that all of the contacts are in the same state is due to an abnormality in the contacts, such as being stuck off or stuck on. In contrast, with the shift switch 100, if the switch is normal, all of the contacts will not be in the same state, so it is possible to suppress erroneous determination of an abnormality.

Here, we will explain the types of abnormalities that can occur in the shift switch 100.

First, referring to FIG. 7, a disconnection of the NC contacts will be described. As shown in FIG. 7, when the movable terminal 110 is in the position shown by the dashed line, all of the contacts are in an open state. In this case, the combination of signals input to the electronic control device 40 from each of the signal lines 114, 115, and 116 is OFF-OFF-OFF, but such a combination of signals does not exist in a normal shift switch 100. Therefore, it is determined that one of the contacts is stuck OFF, that is, a disconnection has occurred.

When the movable terminal 110 moves to the position shown by the solid line in FIG. 7, the first fixed terminal 111 and the second fixed terminal 112 are closed if both are normal. Therefore, the signal input from the signal lines 114 and 115 to the electronic control unit 40 switches from OFF to ON. Meanwhile, the signal input from the signal line 116 corresponding to the third fixed terminal 113 to the electronic control unit 40 is maintained OFF. When it is determined from the change in the signal on the signal lines 114 and 115 that both the first NO contact and the second NO contact are normal, it is determined that the contact where the abnormality is occurring is the NC contact, and that the abnormality is an open circuit. In other words, it is confirmed that an open circuit has occurred in the NC contact.

Next, referring to Figure 8, a short circuit of the NC contacts will be described. As shown in Figure 8, when the movable terminal 110 is in the position shown by the dashed line, all of the contacts are in a closed state. In this case, the combination of signals input to the electronic control unit 40 from each of the signal lines 114, 115, and 116 is ON-ON-ON. However, such a combination of signals does not exist in a normal shift switch 100. Therefore, it is determined that one of the contacts is stuck on, in other words, a short circuit has occurred.

When the movable terminal 110 moves to the position shown by the solid line in Figure 8, if the first fixed terminal 111 and the second fixed terminal 112 are both normal, they will be in an open state. Therefore, the signal input from signal lines 114 and 115 to the electronic control unit 40 switches from ON to OFF. Meanwhile, the signal input from signal line 116 corresponding to the third fixed terminal 113 to the electronic control unit 40 is maintained ON. When it is determined from the change in the signal on signal lines 114 and 115 that both the first NO contact and the second NO contact are normal, it is determined that the contact where the abnormality is occurring is the NC contact, and that the abnormality is a short circuit. In other words, it is confirmed that a short circuit has occurred in the NC contact.

These abnormality determination methods are possible because the shift switch 100 is configured so that the movable terminal 110 is not in contact with all the fixed terminals 111, 112, and 113, and is not in contact with any of the fixed terminals 111, 112, and 113. If the movable terminal is configured so that it does not contact any of the fixed terminals in the process of sliding, it cannot be immediately determined that a break has occurred on the basis that all signals are OFF. In this case, in order to determine whether a break has actually occurred, for example, it can be considered to determine whether all signals remain OFF for a predetermined period of time. However, in this case, when the driver continues to move the movable terminal slightly, there is a risk that it will be erroneously determined that a break has occurred in the shift switch, even though no abnormality actually occurs. Alternatively, if the movable terminal is configured so that it contacts all the fixed terminals in the process of sliding, it cannot be immediately determined that a short has occurred on the basis that all signals are ON. In this case, too, if the driver continues to move the movable terminal slightly, there is a risk that the system will mistakenly determine that a short has occurred in the shift switch, even though no abnormality is actually occurring.

Figure 9 is a flow chart showing the shift operation monitoring process in the second embodiment. Note that the process shown in Figure 9 is for monitoring the shift operation in the D range among the multiple shift ranges, and is repeatedly executed by the monitoring microcomputer 42 at a predetermined calculation cycle.

The monitoring microcomputer 42 receives a control shift signal from the control microcomputer 41 (step S301). In the electronic control device 40, the control shift signal input from the shift switch 10 to the control microcomputer 41 is output from the control microcomputer 41 to the monitoring microcomputer 42. In step S301, the signal input from the shift switch 10 to the control microcomputer 41 is input to the monitoring microcomputer 42. In other words, the control shift signal used for control by the control microcomputer 41 is input to the monitoring microcomputer 42.

The monitoring microcomputer 42 detects that a signal from the D switch 14 has been input as a monitoring shift signal (step S302). In step S302, the signals output from each contact of the shift switch 10 are input to the monitoring microcomputer 42.

The monitoring microcomputer 42 determines whether all of the monitoring shift signals input from the contacts of the D switch 14 are OFF (step S303). In step S303, it is determined whether the combination of signals input to the monitoring microcomputer 42 from the signal lines 114, 115, and 116 is OFF-OFF-OFF.

If the monitoring shift signals input from each contact of the D switch 14 are not all OFF (step S303: No), the monitoring microcomputer 42 clears the duration (step S304). The duration indicates the time during which the state in which all signals input from each contact of the D switch 14 to the monitoring microcomputer 42 are OFF continues.

After performing the process of step S304, the monitoring microcomputer 42 determines that there is no abnormality on the monitoring side (step S305). In step S305, a determination result indicating that there is no abnormality on the monitoring side is output to the control microcomputer 41.

After performing the process of step S305, the monitoring microcomputer 42 performs monitoring control of the D range (step S306). In step S306, monitoring control of processing related to the D range of the control shift ranges is performed. In other words, monitoring control under normal conditions is performed. After performing the process of step S306, this control routine ends.

If all of the monitoring shift signals input from the contacts of the D switch 14 are OFF (step S303: Yes), the monitoring microcomputer 42 counts up the duration (step S307). In step S307, the duration during which all of the signals input from the contacts of the D switch 14 to the monitoring microcomputer 42 are OFF is added.

After performing the process of step S307, the monitoring microcontroller 42 determines whether or not a predetermined time C has elapsed (step S308). In step S308, it is determined whether or not the duration counted up in step S307 exceeds the predetermined time C. The predetermined time C is a preset value. If the duration exceeds the predetermined time C, it is determined that the predetermined time C has elapsed.

If it is not determined that the predetermined time C has elapsed (step S308: No), the control routine proceeds to step S305.

If it is determined that the predetermined time C has elapsed (step S308: Yes), the monitoring microcomputer 42 determines whether or not all of the control shift signals input from each contact of the D switch 14 are OFF (step S309). In step S309, using the control shift signals acquired in step S301, it is determined whether or not all of the signals input from each contact of the D switch 14 to the control microcomputer 41 are OFF. In other words, in step S309, the monitoring microcomputer 42 determines whether or not the signal input from the shift switch 100 to the control microcomputer 41 and the signal input from the shift switch 100 to the monitoring microcomputer 42 match.

When all the control shift signals input from the contacts of the D switch 14 are OFF (step S309: Yes), the monitoring microcomputer 42 judges that there is an abnormality in the wire harness or the shift switch 100 in the shift-by-wire system 20 (step S310). In step S310, it is judged that there is an abnormality in the wire harness (W/H) provided between the shift switch 100 and the monitoring microcomputer 42, or in the module of the shift switch 100. This abnormality includes a break or short in the wire harness, or a break or short in the shift switch 100. In other words, it is judged that there is an abnormality in the signal lines 114, 115, 116 connected to the D switch 14, or in the shift switch 100 itself. In addition, in step S310, a judgment result indicating an abnormality in the wire harness or the shift switch 100 is output to the control microcomputer 41. When the process of step S310 is performed, this control routine ends.

If the control shift signals input from the contacts of the D switch 14 are not all OFF (step S309: No), the monitoring microcomputer 42 determines that an abnormality has occurred in the input circuit on the monitoring side (step S311). In step S311, it is determined that an abnormality has occurred in the input circuit of the monitoring microcomputer 42. Also, in step S311, a determination result indicating an abnormality in the input circuit of the monitoring microcomputer 42 is output to the control microcomputer 41. When the process of step S311 is performed, this control routine ends.

Then, the monitoring microcomputer 42 repeats the process at a predetermined calculation cycle, so the process shown in FIG. 9 loops. Therefore, after it is determined that all monitoring shift signals input from each contact of the D switch 14 are OFF, the process enters a loop in which the process of step S307 is carried out. Once in this loop, the duration is counted up each time the process of step S307 is carried out. If the duration is shorter than the predetermined time C, a negative determination is made in step S308, so it is determined that there is no abnormality on the monitoring side. Then, if the duration exceeds the predetermined time C in a certain number of loops, a positive determination is made in step S308, so it is determined that there is an abnormality.

In addition, in the process flow shown in FIG. 9, the monitoring microcomputer 42 outputs the determination result regarding the presence or absence of an abnormality to the control microcomputer 41, so that the control microcomputer 41 can monitor the control of the monitoring microcomputer 42.

Figure 10 is a flow chart showing the process for determining the control shift range in the second embodiment. Note that the process shown in Figure 10 is for the case where the control shift range is determined to be the D range, and is repeatedly executed by the control microcomputer 41 at a predetermined calculation cycle.

The control microcomputer 41 detects that a control shift signal is being input from the D switch 14 (step S401). In step S401, the signals output from each contact of the shift switch 10 are input to the control microcomputer 41.

The control microcomputer 41 receives the result of the determination made by the monitoring side from the monitoring microcomputer 42 (step S402). In step S402, information indicating that the processing of step S305 shown in FIG. 9 has been performed, that the processing of step S310 has been performed, or that step S3111 has been performed is input to the control microcomputer 41 as the result of the determination made by the monitoring side.

The control microcomputer 41 determines whether all of the control shift signals input from the contacts of the D switch 14 are OFF (step S403). In step S403, it is determined whether the combination of signals input to the control microcomputer 41 from the signal lines 114, 115, and 116 connected to the D switch 14 is OFF-OFF-OFF.

If the control shift signals input from each contact of the D switch 14 are not all OFF (step S403: No), the control microcomputer 41 clears the duration (step S404). This duration indicates the time during which the state in which all signals input from each contact of the D switch 14 to the control microcomputer 41 are OFF continues.

After performing the processing of step S403, the control microcontroller 41 determines that there is no abnormality on the control side (step S405).

After performing the process of step S405, the control microcomputer 41 performs decision control to switch the control shift range to the D range (step S406). In step S406, control to change the shift range during normal operation is performed. That is, in step S406, the electronic control unit 40 determines whether the D range has been selected based on the shift signal input from the D switch 14 to the control microcomputer 41, and makes a decision to switch the control shift range to the D range. After performing the process of step S406, this control routine ends.

When all of the control shift signals input from the contacts of the D switch 14 are OFF (step S403: Yes), the control microcomputer 41 counts up the duration (step S407). In step S407, the duration during which all of the signals input from the contacts of the D switch 14 to the control microcomputer 41 are OFF is added.

After performing the process of step S407, the control microcomputer 41 determines whether or not the predetermined time D has elapsed (step S408). In step S408, it is determined whether or not the duration added in step S407 exceeds the predetermined time D. If the duration exceeds the predetermined time D, it is determined that the predetermined time D has elapsed. In addition, the predetermined time D is a second predetermined time that is longer than the predetermined time C.

If it is not determined that the predetermined time D has elapsed (step S408: No), the control routine proceeds to step S405.

If it is determined that the predetermined time D has elapsed (step S408: Yes), the control microcomputer 41 determines whether the monitoring side determination result indicates an abnormality in the wire harness or the shift switch 100 (step S409). In step S409, it is determined whether the monitoring side determination result acquired in step S402 indicates an abnormality in the wire harness or the shift switch 100. In other words, it is determined whether step S310 shown in FIG. 9 has been performed.

If the monitoring determination result indicates an abnormality in the wire harness or the shift switch 100 (step S409: Yes), the control microcomputer 41 determines that there is an abnormality in the wire harness or the shift switch 100 in the shift-by-wire system 20 (step S410). The process of step S410 is the same as the process of step S310 on the monitoring side. After the process of step S410 is performed, this control routine ends.

If the monitoring determination result does not indicate an abnormality in the wire harness or the shift switch 100 (step S409: No), the control microcomputer 41 determines that an abnormality has occurred in the input circuit on the control side (step S411). In step S411, it is determined that an abnormality has occurred in the input circuit of the control microcomputer 41. After the processing of step S411 is performed, this control routine ends.

Then, the control microcomputer 41 repeats the process at a predetermined calculation cycle, so the process shown in FIG. 10 loops. Therefore, after it is determined that all control shift signals input from each contact of the D switch 14 are OFF, the process enters a loop in which the process of step S407 is executed. Once in this loop, the duration is counted up each time the process of step S407 is executed. If the duration is shorter than the predetermined time D, a negative determination is made in step S408, so it is determined that there is no abnormality on the control side. Then, if the duration exceeds the predetermined time D in a certain number of loops, a positive determination is made in step S408, so it is determined that there is an abnormality.

As described above, according to the second embodiment, the signals input from each contact of the shift switch 10 to the control microcomputer 41 and the monitoring microcomputer 42 are compared to determine whether an abnormality has occurred. Using information acquired from the other microcomputer, the control microcomputer 41 and the monitoring microcomputer 42 can determine that an abnormality has occurred after a predetermined period of time has passed during which all signals input from each contact of the shift switch 10 remain OFF. This makes it possible to prevent erroneous determinations of an abnormality from occurring even if there is a discrepancy in the calculation timing between the control microcomputer 41 and the monitoring microcomputer 42.

As a modified example of the second embodiment, when the monitoring microcomputer 42 determines that an abnormality has occurred in its own input circuit, the monitoring control can be performed using a control shift signal in the control microcomputer 41. Furthermore, when the control microcomputer 41 determines that an abnormality has occurred in its own input circuit, the monitoring shift signal in the monitoring microcomputer 42 can be used to perform shift range change control. The control of this modified example is shown in Figures 11 and 12.

Figure 11 is a flow chart showing the shift operation monitoring process in a modified example of the second embodiment. Note that the process shown in Figure 11 is a modified example of the process shown in Figure 9. The processes of steps S501 to S511 shown in Figure 11 are similar to the processes of steps S301 to S311 shown in Figure 9, so a description thereof will be omitted.

After performing the process of step S511, the monitoring microcomputer 42 transitions to a control state in which the control shift signal is substituted for the monitoring shift signal (step S512). In step S512, the control state is switched to one in which the control shift signal acquired in step S501 is used instead of the monitoring shift signal.

After performing the process of step S512, the control routine proceeds to step S506. In this case, the monitoring microcomputer 42 continues to monitor and control the shift operation of the D range using the control shift signal.

Figure 12 is a flow chart showing the process for determining the control shift range in a modified example of the second embodiment. The process shown in Figure 12 is a modified example of the process shown in Figure 10. The processes of steps S601 and S603 to S612 shown in Figure 12 are similar to the processes of steps S401 to S411 shown in Figure 10, and therefore will not be described.

After performing the process of step S601, the control microcomputer 41 receives a monitoring shift signal from the monitoring microcomputer 42 (step S602). In the electronic control device 40, the monitoring shift signal input from the shift switch 10 to the monitoring microcomputer 42 is output from the monitoring microcomputer 42 to the control microcomputer 41. The monitoring shift signal used for monitoring control by the monitoring microcomputer 42 is input to the control microcomputer 41. After performing the process of step S602, this control routine proceeds to step S603.

After performing the process of step S612, the control microcomputer 41 transitions to a control state in which the monitoring shift signal is substituted for the control shift signal (step S613). In step S613, the control state is switched to one in which the monitoring shift signal acquired in step S602 is used instead of the control shift signal.

After performing the process of step S613, the control routine proceeds to step S607. In this case, the control microcomputer 41 performs control to determine whether to switch to D range using the monitoring shift signal.

Modifications of the shift switch 100 are also possible. Modifications of the shift switch are shown in Figures 13 to 20.

As shown in FIG. 13, the shift switch 200 in the modified example is an opposed contact type switch. The first NO terminal 211 and the second NO terminal 212 are arranged opposite to an earth terminal 216 whose position is fixed. The NC terminal 213 is installed opposite to an earth terminal 217 whose position is fixed. However, the direction in which the NC terminal 213 faces the earth terminal 217 is opposite to the direction in which the first NO terminal 211 and the second NO terminal 212 face the earth terminal 216.

The first NO terminal 211 and the second NO terminal 212 are disposed between the operating member 210 and the earth terminal 216. The first NO terminal 211 is connected to the operating member 210 by a spring 214 with a small spring constant, and is connected to the earth terminal 216 by a spring 215 with a large spring constant. Conversely, the second NO terminal 212 is connected to the operating member 210 by a spring 215, and is connected to the earth terminal 216 by a spring 214. The NC terminal 213 is disposed between the operating member 210 and a fixed member 218 whose position is fixed. The NC terminal 213 is connected to the operating member 210 by a spring 214, and is connected to the fixed member 218 by a spring 215.

When no force is applied to the operating member 210, the first NO terminal 211 and the second NO terminal 212 are away from the earth terminal 216, and the NC terminal 213 is in contact with the earth terminal 217. The first NO terminal 211 and the earth terminal 216 form a first NO contact as a first contact, and the second NO terminal 212 and the earth terminal 216 form a second NO contact as a second contact. The NC terminal 213 and the earth terminal 217 form an NC contact as a third contact.

A signal line is connected to each of the first NO terminal 211, the second NO terminal 212, and the NC terminal 213. When no force is being applied to the operating member 210, as shown in FIG. 13, the operating member 210 is located in the first position. In this state, the first NO contact and the second NO contact are open, and an OFF signal is output from them. On the other hand, the NC contact is closed, and an ON signal is output from it. This state is the OFF state of the shift switch 200.

In this shift switch 200, when the operating member 210 is pressed down, the spring 214 with the small spring constant contracts, and the first NO terminal 211 comes into contact with the ground terminal 216, as shown in FIG. 14. This causes the signal output from the first NO contact to become an ON signal. When the operating member 210 is pressed down further, the spring 215 with the large spring constant begins to contract, and the NC terminal 213 moves away from the ground terminal 217, as shown in FIG. 15. This causes the signal output from the NC contact to become an OFF signal.

When the operating member 210 is further pressed down, it reaches the second position as shown in FIG. 16. In the second position, the second NO terminal 212 comes into contact with the ground terminal 216. This causes the signal output from the second NO contact to be 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 the ON state of the shift switch 200.

As shown in FIG. 17, a shift switch 300 in another modified example is a mixed switch having two sliding contacts and one opposing contact. This shift switch 300 has two NO terminals 311, 312 whose positions are fixed, and one movable terminal 310 connected to earth. Each NO terminal 311, 312 forms a sliding contact between the movable terminal 310. The shift switch 300 also has an NC terminal 313 and an earth terminal 317 whose position is fixed. The NC terminal 313 forms an opposing contact between the earth terminal 317. The NC terminal 313 is disposed between the movable terminal 310 as an operating member and the fixed member 316. The NC terminal 313 is connected to the movable terminal 310 by a spring 314 with a small spring constant, and is connected to the fixed member 316 by a spring 315 with a large spring constant. Each NO terminal 311, 312 forms a NO contact between the movable terminal 310. The NC terminal 313 forms an NC contact with the earth terminal 317.

When no force is being applied to the movable terminal 310, as shown in FIG. 17, the movable terminal 310 is in the first position. In this state, the first NO contact and the second NO contact are open, and an OFF signal is output from them. The white circles in FIG. 17 indicate the open contact state. On the other hand, the NC contact is closed, and an ON signal is output from it. This state is the OFF state of the shift switch 300.

In this shift switch 300, when the movable terminal 310 is slid in a direction that contracts the springs 314 and 315, the movable terminal 310 comes into contact with the first NO terminal 311, as shown in FIG. 18. This closes the NC contact and the first NO contact, and only the second NO contact is open. The black circles in FIG. 18 indicate the open contact state. At this time, the spring 314 with the large spring constant begins to contract, but the NC terminal 313 remains in contact with the earth terminal 317. When the movable terminal 310 is slid further, the spring 315 with the large spring constant begins to contract, as shown in FIG. 19, and the NC terminal 313 separates from the earth terminal 317. This causes the signal output from the NC contact to become an OFF signal.

Then, when the movable terminal 310 is further slid, it reaches the second position as shown in FIG. 20. In the second position, the movable terminal 310 comes into contact with the second NO terminal 312. As a result, the signal output from the second NO contact becomes 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 the ON state of the shift switch 300.

The shift switches 100, 200, and 300 described in the second embodiment and each of the modified examples can all be applied to the first embodiment. In other words, the shift switch 10 of the first embodiment can be configured like the shift switch 200 of the second embodiment.

1 Vehicle 3 Transmission 10 Shift switch (switch)
11 P switch 14 D switch 20 Shift-by-wire system 30 Shift operation device 40 Electronic control device (abnormality determination device)
41 Control microcomputer (first microcomputer)
42 Monitoring microcomputer (second microcomputer)
100 Shift switch 110 Movable terminal 111 First fixed terminal (first NO terminal)
112 Second fixed terminal (second NO terminal)
113 Third fixed terminal (NC terminal)

Claims (8)

a first microcomputer and a second microcomputer each executing a control in response to an operation of a switch for changing a shift range of a vehicle, when the switch is operated;
the first microcomputer executes a change control for switching the shift range to a shift range corresponding to the switch based on a signal input from the switch when the switch is operated;
The second microcomputer is an abnormality determination device that executes a monitoring control to determine whether or not an abnormality has occurred based on a signal input from the switch and a signal input from the first microcomputer,
The second microcomputer is
When an input state of a signal input from the switch is changed, an allowance time for allowing a change to the shift range corresponding to the switch is set;
When it is detected that the first microcomputer has executed a change control to switch the shift range to the shift range corresponding to the switch during the period from when the input state has changed to when the permitted time has elapsed, the determination is made that the switch is normal;
an abnormality determination device that determines that an abnormality has occurred when it is detected that the first microcomputer has executed a change control to switch the shift range to the shift range corresponding to the switch after the permitted time has elapsed since the input state changed. The abnormality determination device according to claim 1, characterized in that the second microcomputer provisionally determines that an abnormality has occurred when it detects that the first microcomputer has executed a change control to switch to the shift range corresponding to the switch while the input state of the signal input from the switch has not changed. The second microcomputer is
If the abnormality is provisionally determined, a predetermined grace period is set,
If an input state of a signal input from the switch changes during the period from when the provisional abnormality is determined to have occurred until the grace period has elapsed, the provisional abnormality is cancelled;
3. The abnormality determination device according to claim 2, further comprising: a step of determining that an abnormality has occurred if an input state of a signal input from the switch does not change during a period from when the abnormality has been provisionally determined until the grace period has elapsed. a first microcomputer and a second microcomputer each executing a control in response to an operation of a switch for changing a shift range of a vehicle,
the first microcomputer executes a change control for switching the shift range to a shift range corresponding to the switch based on a signal input from the switch when the switch is operated;
The second microcomputer is an abnormality determination device that executes a monitoring control to determine whether or not an abnormality has occurred based on a signal input from the switch and a signal input from the first microcomputer,
the switch has a normally open contact and a normally closed contact, and controls the on/off of the switch in response to a signal output from each contact;
The second microcomputer is
when it is detected that all signals input from the contacts of the switches to the first microcomputer are off when the state in which all signals input from the contacts of the switches are off continues for a predetermined time or more, it is determined that an abnormality has occurred in the wire harness provided between the switch and each microcomputer or in the switch,
An abnormality determination device characterized by determining that an abnormality has occurred in the input circuit of the second microcomputer when it detects that all signals input from the switch to the first microcomputer are not off when a state in which all signals input from the switch are off continues for a predetermined period of time or more. the first microcomputer determines that an abnormality has occurred in an input circuit of the first microcomputer when a state in which all signals input from each contact of the switch are off continues for a second predetermined time or more before the second microcomputer determines that the abnormality has occurred;
5. The abnormality determination device according to claim 4, wherein the second predetermined time is longer than the predetermined time used in the process of the second microcomputer. The abnormality determination device according to claim 4 or 5, characterized in that after the second microcomputer determines that an abnormality has occurred in the input circuit of the second microcomputer, the second microcomputer executes the monitoring control using a signal input from the switch to the first microcomputer. 6. The abnormality determination device according to claim 5, wherein after determining that an abnormality exists in the input circuit of the first microcomputer, the first microcomputer executes the change control using a signal input from the switch to the second microcomputer. The switch is
an operating member displaceable between a first position and a second position;
three contacts whose states are switched between an ON state in which a signal line is connected and an OFF state in which the signal line is disconnected in response to a displacement of the operation member between the first position and the second position,
The three contacts are:
a first contact configured by the normally open type contact and switching from the off state to the on state during the displacement of the operating member from the first position to the second position;
a second contact configured by the normally open type contact and switching from the off state to the on state at a timing slower than that of the first contact during the displacement of the operating member from the first position to the second position;
a third contact that is configured by the normally closed type contact and that switches from the on state to the off state at a timing slower than the first contact switching from the off state to the on state and earlier than the second contact switching from the off state to the on state during the displacement of the operating member from the first position to the second position,
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 input to the first microcomputer and the second microcomputer as signals from the switch;
The abnormality determination device according to any one of claims 4 to 7, characterized in that the first microcontroller and the second microcontroller determine that all signals input from the switch are off when the first signal, the second signal, and the third signal in the switch are all off.

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