JP4176984B2 - Stepping motor drive device and pointer driving method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a stepping motor drive device, and more particularly to a stepping motor drive device that controls the rotation of a stepping motor.
[0002]
[Prior art]
Conventionally, an indicating device as shown in FIG. 1 is known as a vehicle indicating device using a stepping motor. In the figure, an instruction device includes a stepping motor 1, a pointer 2 that is linked to the rotation of the stepping motor 1, and a stepping motor drive device 3 that rotates the stepping motor 1 forward and backward (hereinafter simply referred to as a drive device 3). .). The stepping motor 1 described above includes two excitation coils 1a1 and 1a2, NS poles alternately magnetized in three poles, a rotor 1b that rotates following the change in the excitation state of the excitation coils 1a1 and 1a2, and a rotation A gear 1c that transmits the driving force of the child 1b to the pointer 2 is provided.
[0003]
Further, the stepping motor 1 is provided on the back side of the gear 1c on the pointer 2 side, and a piece 1d as a driven member interlocked with the rotation operation of the rotor 1b, the excitation coils 1a1 and 1a2, the rotor 1b, and the gear 1c. And a stopper 1e that is provided in a housing case (not shown) that houses the piece 1d and mechanically stops the rotation of the rotor 1b by contact with the piece 1d.
[0004]
Note that rotating the stepping motor 1 so that the piece 1d faces the stopper 1e is reverse rotation, and the rotation direction of the pointer 2 during reverse rotation is the reverse rotation direction Y1. On the other hand, rotating the stepping motor 1 so that the piece 1d is separated from the stopper 1e is forward rotation, and the rotation direction of the pointer 2 during forward rotation is the forward rotation direction Y2. Further, the stopper 1e is provided so that the pointer 2 indicates a scale of 0 km / h on the dial when it comes into contact with the piece 1d.
[0005]
When the indicating device is used as a vehicle speedometer, for example, the driving device 3 moves the rotor 1b in accordance with the movement amount θ−θ ′ that is the difference between the target position θ of the pointer 2 and the current position θ ′. By rotating, the pointer 2 moves by the difference θ−θ ′ to indicate the target position θ. The target position θ is updated to the angle data θi every time the angle data θi calculated based on the speed information that is the output of the vehicle speed sensor (= corresponding to the sensor position in the claims) is input. The angle data θi is data that increases as the speed information increases when the reference angle 0 ° (= corresponding to the reference position in the claims) is calculated when the speed information is 0 km / h.
[0006]
By the way, the pointing device has a movement amount (= difference θ−θ ′) to which the pointer 2 is supposed to move and an actual movement amount due to the input of the angle data θi on which the vibration or noise of the vehicle is superimposed. Sometimes caused a different step-out. If this step-out is repeated, a difference occurs between the speed indicated by the pointer 2 and the speed information measured by the speed sensor, and the instruction device cannot give an accurate instruction.
[0007]
Therefore, in order to solve such a problem, the driving device 3 is caused to perform an initialization operation described later. In the initialization operation, every time the ignition switch is turned on, the driving device 3 rotates the stepping motor 1 in the reverse direction so that the piece 1d faces the stopper 1e. Further, when the piece 1d comes into contact with the stopper 1e and the pointer 2 mechanically stops at the initialization end position on the dial of 0 km / h on the dial plate, the driving device 3 previously turns the excitation coils 1a1 and 1a2 on. The rotation of the stepping motor 1 is electrically stopped while maintaining the determined initial excitation state. By performing the above initialization operation, when the current position θ ′ is recognized as 0 °, the pointer 2 also instructs the scale of 0 km / h, which is the initialization end position. The difference between the speed indicated by the pointer 2 and the speed information measured by the speed sensor could be reset.
[0008]
[Problems to be solved by the invention]
However, the conventional driving device 3 described above has the following problems. That is, as shown in FIG. 8, the pointer 2 stops at the position P1 indicating the scale of 0 km / h on the dial after the initialization operation is completed. However, after the initialization operation is completed, the driving device 3 once rotates the stepping motor 1 in the normal direction, and then the target position θ becomes 0 ° by inputting 0 ° angle data θi or turning off the ignition switch. When the stepping motor 1 is rotated reversely so that 2 indicates a scale of 0 km / h on the dial, an indication error angle α (corresponding to an instruction error amount in the claims) from the scale of 0 km / h. ), Indicating the position P2 on the positive rotation direction Y2 side and stopping.
[0009]
That is, after the end of the initialization operation and before the start of the instruction according to the angle data θi, that is, the speed information, and after the start of the instruction according to the speed information, When the angle data θi is input or the ignition switch is turned off, the indication error angle α is generated although the position indicated by the pointer 2 should be indicated on the scale of 0 km / h. There was a problem. In particular, an instruction of 0 km / h must indicate a scale of 0 km / h, and higher accuracy is required than other instructions of 50 km / h, for example.
[0010]
The cause of the indication error angle α is due to the backlash of the gear 1c. The details of the cause of the indication error angle α will be described below with reference to FIGS. As shown in the figure, when the initialization operation is started and the piece 1d comes into contact with the stopper 1e, the gear 1c2 on the rotor 1b side is shifted to one side with respect to the gear 1c1 on the pointer 2 side. (See FIG. 9A).
[0011]
Thereafter, when the driving device 3 holds the exciting coils 1a1 and 1a2 in the initial excitation state, the rotor 1b rotates forward to a position corresponding to the initial excitation state. At this time, the rotor 1b vibrates by repeating forward rotation and reverse rotation near the position corresponding to the initial excitation state due to the influence of inertia or the like, and the vibration converges to be in a stopped state. After the vibration as described above, the rotor 1b is in a stopped state. After the stop, the gear 1c1 on the rotor 1b side is in a neutral state with respect to the gear 1c2 on the pointer 2 side (see FIG. 9B). At this time, the pointer 2 indicates a scale of 0 km / h, and the driving device 3 recognizes that the current position θ ′ is 0 °.
[0012]
Thereafter, in response to the input of the angle data θi (> 0 °), when the target position θ reaches the angle θi, the driving device 3 rotates the stepping motor 1 forward so that the pointer 2 indicates the target position θi. However, at the beginning of rotation, according to the rotation of the stepping motor 1, the gear 1c2 is shifted from the neutral state to the position where the gear 1c1 is shifted to the other side (see FIG. 9C). The driving force of the stepping motor 1 is not transmitted to the pointer 2 only by rotating.
[0013]
For this reason, the pointer 2 does not move during this period. As shown in FIG. 10, a range during which the pointer 2 does not move is defined as a non-moving range A. However, the drive device 3 rotates the stepping motor 1 by the amount of rotation of the pointer 2 by the angle α even while the pointer 2 does not move to eliminate backlash. For this reason, the driving device 3 recognizes that the pointer 2 indicates the forward rotation direction Y2 by an angle α from the initialization end position P1 even though the pointer 2 does not move while indicating the angle 0 °. To do. Therefore, after that, when the driving device 3 rotates the stepping motor 1 so as to reach the current position θi, the pointer 2 indicates the angle (θi−α).
[0014]
Next, when the target position θ reaches 0 °, the driving device 3 reverses the rotation of the stepping motor 1 so that the pointer 2 indicates 0 ° (= 0 km / h scale). However, at the beginning of reversal, in accordance with the rotation of the stepping motor 1, the gear 1c2 is shifted to the other side from the state where the gear 1c2 is shifted to the other side (FIG. 9 (c)) ( The drive force of the stepping motor 1 is not transmitted to the pointer 2 only by rotating to the position shown in FIG.
[0015]
For this reason, the pointer 2 does not move during this period. As shown in FIG. 10, a range in which the pointer 2 does not move after reversal is defined as a non-moving range B. However, the drive device 3 rotates the stepping motor 1 by the amount that the pointer 2 is rotated by the angle β even while the pointer 2 does not move to eliminate backlash.
[0016]
Therefore, the driving device 3 moves the pointer 2 in the positive rotation direction Y2 side by the angle (θi−β) from the initialization end position even though the pointer 2 is stopped by the angle (θi−α). Recognize that you are instructing. Therefore, after that, when the driving device 3 rotates the stepping motor 1 with 0 ° as the target position θ, the pointer 2 indicates the angle β−α (= (θi−α) − (θi−β)). Stop. As described above, since the backlash generated in response to the inversion is larger than the backlash generated after the initialization operation, the angle β is naturally larger than the angle α. For this reason, the angle β−α ≠ 0 ° is not established, and the positive rotation direction Y2 side is instructed from the scale of 0 km / h and stopped. In FIG. 10, the instruction error angle β−α = α (α2α = β) is given for the sake of simplicity.
[0017]
Therefore, the present invention pays attention to the above-mentioned problems, and the position indicated by the pointer before starting the instruction according to the sensor output and the reference position as the sensor position after starting the instruction according to the sensor output. It is an object of the present invention to provide a stepping motor drive device capable of reducing the amount of instruction error from the position indicated by the pointer when it is calculated or when the ignition switch is turned off.
[0018]
[Means for Solving the Problems]
  In order to solve the above-mentioned problem, the invention according to claim 1 is the initial stage of reversely rotating the stepping motor so that the driven member interlocked with the rotation operation of the stepping motor driving the pointer via the gear faces the stopper. And the driven member abuts against the stopper by the reverse rotation.BeforeAfter the rotation of the stepping motor is mechanically stopped, the excitation coil in the stepping motor is held in the initial excitation state to electrically stop the rotation of the stepping motor.Perform stop processingStop means;The stop process was performedLater, the current position of the pointer stored in the memory is set to a reference position corresponding to sensor output 0.Reference position setting means for performing setting processing, and the setting processing has been performedlaterThe sensor position that is the indicated position of the pointer according to the sensor output is sequentially set as the target position,Current position of the pointer stored in the memoryWhenTarget position of the pointer stored in the memoryWhenA normal rotation means for performing a normal rotation operation for rotating the stepping motor forward and backward according to the difference between the stepping motor, and a stepping motor drive device comprising:The initialization end position, which is the pointer position on the dial when the driven member and the stopper are in contact,Predetermined on the dialCorresponds to sensor output 0From the reference positionOnly the amount of indication errorReverse rotation sideThe indication error amount is determined by the target position of the pointer stored in the memory by the normal rotation means.Once forward rotationAfter the pointer has been rotated forward onceSet to the reference positionThe normal rotation operation was performed asIt is equal to the deviation from the initialization end position of the pointer on the dial that sometimes occursAnd thenNormal rotating meansBy,After the setting processThe pointer movement amount at the current position of the pointer on the memory corresponding to the rotation amount of the stepping motor while the pointer does not move even if the stepping motor is rotated forward, and the initialization end position on the dialFromReference positionFor up toA predetermined position on the positive rotation side from the reference position by the amount of movement of the pointerButSet to the target positionAccording to the difference between the current position of the pointer stored in the memory and the target position of the pointer stored in the memory.Stepping motor rotates forwardIs,continueWhen the indicated position of the pointer according to the sensor output is on the positive rotation side with respect to the predetermined position,The normal rotation operation is startedThe present invention resides in a stepping motor drive device.
[0019]
  According to the invention of claim 1, SuThe initialization rotation means rotates the stepping motor in the reverse direction so that the driven member interlocked with the rotation operation of the tapping motor faces the stopper. This stopper mechanically stops the rotation of the stepping motor by contacting with the driven member and stops the pointer at the initialization end position. After the pointer is stopped at the initialization end position by the initialization rotating means, the stopping means holds the excitation coil of the stepping motor in the initial excitation state and electrically stops the rotation of the stepping motor.
[0020]
  In addition, the guideline will beThe initial position of the pointer on the dial generated when the stepping motor is rotated forward once and then the target position of the pointer stored in the memory is set as the reference position and the stepping motor is rotated. It is a deviation from the end positionIndication error amountJust on the dialThe reverse rotation side from the reference position becomes the initialization end positionA pointer is previously driven into a pointer shaft in the stepping motor.The normal rotation means isThe current position of the pointer on the memory corresponding to the amount of rotation of the stepping motor while the pointer does not move even if the stepping motor is rotated forward.Pointer movement amount andOn the dialThe total amount of the pointer movement between the initialization end position and the reference positionOnlyA predetermined position on the positive rotation side from the reference position is set as a target position after stopping by the stopping means.Rotate the stepping motorThen, when the sensor position, which is the pointing position of the pointer according to the sensor output, is on the positive rotation side with respect to the predetermined position, the stepping motor is rotated with the sensor position as the target position.
[0021]
  As described above, the normal rotating means isThe amount of pointer movement at the current position of the pointer on the memory corresponding to the amount of rotation of the stepping motor while the pointer does not move even if the stepping motor is rotated forward after stopping by the stopping means, and the initialization end position on the dial-the reference position As much as the amount of pointer movement betweenWhen the stepping motor is rotated with the predetermined position on the positive rotation side from the reference position as the target position, the pointer moves from the initialization end position to the reference position on the positive rotation side by the amount of movement of the pointer between the initialization end position and the reference position. Instruct. Thereafter, the normal rotation means rotates the stepping motor with the sensor position as the target position when the sensor position, which is the pointing position of the pointer according to the sensor output, is on the positive rotation side with respect to the predetermined position. When the reference position is calculated as the sensor position or the ignition switch is turned off while the stepping motor is rotated forward and backward with the sensor position as the target position, the normal rotation means sets the stepping motor with the reference position as the target position. Reverse rotation.
[0022]
  However, even if the target position is set as the reference position, the pointer does not return to the initialization end position.Instruction error amount,Specify the positive rotation side. That is, when the reference position is calculated as the sensor position or the ignition switch is turned off after starting the instruction according to the sensor output, the pointer moves from the initialization end position.Instruction error amount,Specify the positive rotation side.
[0023]
  Therefore, the position indicated by the pointer before the start of the instruction according to the sensor output and the position indicated by the pointer when the reference position is calculated as the sensor position after the start of the instruction according to the sensor output or when the ignition switch is turned off. From the initialization end position.Needle error amount,Forward rotation sideReference positionIt can be.
[0024]
  According to a second aspect of the present invention, there is provided an initialization rotating means for reversely rotating the stepping motor so that a driven member interlocked with a rotation operation of a stepping motor for driving a pointer via a gear is directed to a stopper, and by the reverse rotation The driven member contacts the stopper.BeforeAfter the rotation of the stepping motor is mechanically stopped, the excitation coil in the stepping motor is held in the initial excitation state to electrically stop the rotation of the stepping motor.Perform stop processingStop means;The stop process was performedLater, the current position of the pointer stored in the memory is set to a reference position corresponding to sensor output 0.Reference position setting means for performing setting processing, and the setting processing has been performedlaterThe sensor position that is the indicated position of the pointer according to the sensor output is sequentially set as the target position,Current position of the pointer stored in the memoryWhenTarget position of the pointer stored in the memoryWhenA normal rotation means for performing a normal rotation operation for rotating the stepping motor forward and backward according to the difference between the stepping motor, and a stepping motor drive device comprising:The initialization end position, which is the pointer position on the dial when the driven member and the stopper are in contact,Predetermined on the dialCorresponds to sensor output 0From the reference positionOnly larger than the indication error amountReverse rotation sideThe indication error amount is determined by the target position of the pointer stored in the memory by the normal rotation means.Once forward rotationAfter the pointer has been rotated forward onceSet to the reference positionThe normal rotation operation was performed asEqual to the deviation from the initialization end position of the pointer on the dial that sometimes occursAnd,AndNormal rotating meansBy,After the setting processThe pointer movement amount at the current position of the pointer on the memory corresponding to the rotation amount of the stepping motor while the pointer does not move even if the stepping motor is rotated forward, and the initialization end position on the dialFromReference positionFor up toA predetermined position on the positive rotation side from the reference position by the amount of movement of the pointerButSet to the target positionAccording to the difference between the current position of the pointer stored in the memory and the target position of the pointer stored in the memory.Stepping motorButPositive rotationIs,continueWhen the indicated position of the pointer according to the sensor output is on the positive rotation side with respect to the predetermined position,The normal rotation operation is started,The initialization end position on the dial when the reference position is calculated as the sensor position during the normal rotation operation or when the ignition switch is turned offFromReference positionFor up toDifference between the amount of movement of the pointer and the amount of instruction errorOnlyPosition on the positive rotation side from the reference positionButSet to target positionAccording to the difference between the current position of the pointer stored in the memory and the target position of the pointer stored in the memory.Stepping motorButrotationBe doneThe present invention resides in a stepping motor drive device.
[0025]
  According to invention of Claim 2,, SuThe initialization rotation means rotates the stepping motor in the reverse direction so that the driven member interlocked with the rotation operation of the tapping motor faces the stopper. This stopper mechanically stops the rotation of the stepping motor by contacting with the driven member and stops the pointer at the initialization end position. After the pointer is stopped at the initialization end position by the initialization rotating means, the stopping means holds the excitation coil of the stepping motor in the initial excitation state and electrically stops the rotation of the stepping motor.
[0026]
  In addition, the guideline will beThis is the deviation from the initialization end position of the pointer on the dial that occurs when the stepping motor is rotated forward once and then the target position of the pointer stored in the memory is set as the reference position and the stepping motor is rotated. is thereIndication error amountJust on the dialThe reverse rotation side from the reference position becomes the initialization end positionIt has been driven in advance into the pointer shaft in the stepping motor.Normal rotating meansBut,After stopping by stopping meansThe current position of the pointer on the memory corresponding to the amount of rotation of the stepping motor while the pointer does not move even if the stepping motor is rotated forward.Pointer movement amount andOn the dialThe total amount of the pointer movement between the initialization end position and the reference positionOnlyA predetermined position on the positive rotation side from the reference position is set as a target position after stopping by the stopping means.Rotate the stepping motorThen, when the sensor position, which is the pointing position of the pointer according to the sensor output, is on the positive rotation side with respect to the predetermined position, the stepping motor is rotated with the sensor position as the target position.
[0027]
  As described above, the normal rotating means isThe amount of pointer movement at the current position of the pointer on the memory corresponding to the amount of rotation of the stepping motor while the pointer does not move even if the stepping motor is rotated forward after stopping by the stopping means, and the initialization end position on the dial-the reference position When the stepping motor is rotated with the predetermined position on the positive rotation side from the reference position as the target position by the amount of the movement of the pointer in between, the pointer moves between the initialization end position and the reference position rather than the initialization end position. The reference position on the forward rotation side is indicated by the designated movement amount.Thereafter, the normal rotation means rotates the stepping motor with the sensor position as the target position when the sensor position, which is the pointing position of the pointer according to the sensor output, is on the positive rotation side with respect to the predetermined position. When the reference position is calculated as the sensor position or the ignition switch is turned off while the stepping motor is rotating forward and backward with the sensor position as the target position, the normal rotation meansOn the dialThe difference between the pointer movement amount between the initialization end position and the reference position and the instruction error amount, and the stepping motor reversely rotate so as to return the pointer to the initialization end position with the forward rotation side as the target position from the reference position.
[0028]
  As described above, when the target position is the difference between the movement amount of the pointer between the initialization end position and the reference position and the instruction error amount, and the reference position is set to the positive rotation side, the pointer indicates the reference position. That is, when the reference position is calculated as the sensor position after the instruction corresponding to the sensor output is started or the ignition switch is turned off, the pointer indicates the reference position.
[0029]
  Therefore, the position indicated by the pointer before the start of the instruction according to the sensor output and the position indicated by the pointer when the reference position is calculated as the sensor position after the start of the instruction according to the sensor output or when the ignition switch is turned off. Any of the positions can be used as a reference position.
[0031]
  The invention according to claim 3 is an adding means for adding the first movement amount and the second movement amount stored in advance in the predetermined position storage medium.ButMoreAnd thenNormal rotating meansBut,Movement amount added by the adding meansOnlyThe position on the positive rotation side with respect to the reference position is set as the predetermined position.Claim 2It exists in the drive device for stepping motors.
[0032]
  Claim3According to the described invention, the adding means adds the first movement amount and the second movement amount stored in advance in the predetermined position storage medium. The amount of movement added by the adding means by the normal rotating meansMinute, position on the forward rotation side of the reference positionIs a predetermined position.
[0033]
  According to the above configuration, zero is stored as the second movement amount before driving the pointer onto the pointer shaft that rotates in conjunction with the stepping motor. The first movement amount isBased on the sum of the movement amount of the current position of the pointer on the memory corresponding to the rotation amount of the stepping motor while the pointer does not move and the indication error amountIt is set to be large. At this time, the positive rotation side from the reference position is the predetermined position by the first movement amount. Thereafter, the normal rotation means drives the pointer into the pointer shaft so that the pointer indicates the reference position in a state after rotating the stepping motor with the predetermined position as the target position.
[0034]
  After driving in,Reference positionIf the amount of error in driving the needle with respect to is stored as the second movement amount,Reference positionEven if an error in driving the pointer with respect to either forward or reverse rotation occurs, the position indicated by the pointer before starting the instruction according to the sensor output, and after the start of the instruction according to the sensor output, the sensor position As the reference position is calculated or the position indicated by the pointer when the ignition switch is turned off,Reference positionCan be.
[0035]
  According to a fourth aspect of the present invention, there is provided a pointer driving method for driving a pointer into a pointer shaft in a stepping motor whose rotation is controlled by the stepping motor drive device according to the third aspect, wherein the pointer is applied to the pointer shaft. The first movement amount is larger than the sum of the pointer movement amount at the current position of the pointer on the memory and the pointer error amount corresponding to the rotation amount of the stepping motor while the pointer does not move before driving. And store zero as the second movement amount.Process,After the setting operation, the normal rotation meansMovement amount added by the adding meansOnlyA position on the positive rotation side with respect to the reference position is set as the target position.According to the difference between the current position of the pointer stored in the memory and the target position of the pointer stored in the memoryAfter rotating the stepping motor, the pointer is driven into the pointer shaftMu process and,againAfter the setting operation, the normal rotation meansThe amount of movement added by the adding meansOnlyA position on the positive rotation side with respect to the reference position is set as the target position.According to the difference between the current position of the pointer stored in the memory and the target position of the pointer stored in the memoryThe amount of movement from the pointer position on the dial plate after the stepping motor is rotated to the reference position on the dial plate is stored as the second movement amount.Step by stepThere is a guide driving method characterized by this.
[0036]
  According to the invention of claim 4, before driving the pointer into the pointer shaft,A value larger than the sum of the pointer movement amount at the current position of the pointer on the memory and the instruction error amount corresponding to the rotation amount of the stepping motor while the pointer is not moving is stored as the first movement amount.At the same time, zero is stored as the second movement amount. The normal rotation means sets the position on the positive rotation side of the reference position as the target position by the amount of movement added by the addition means after stopping by the stop means, and after rotating the stepping motor, the pointer indicates the reference position Insert the pointer into the pointer shaft. After that, the normal rotation means again sets the position on the positive rotation side from the reference position as the target position by the amount of movement added by the addition means after stopping by the stop means, and then rotates the stepping motor.On the dialFrom the pointer positionOn the dialA driving error, which is a movement amount to the reference position, is stored as a second movement amount. As a result, even if an error in driving the pointer with respect to the reference position occurs in either the forward or reverse rotation, before the instruction corresponding to the sensor output is started, the position indicated by the pointer and after the instruction corresponding to the sensor output is started. Thus, any of the positions indicated by the hands when the reference position is calculated as the sensor position or when the ignition switch is turned off can be used as the reference position.
[0037]
DETAILED DESCRIPTION OF THE INVENTION
First embodiment
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a view showing an indicating device incorporating a stepping motor driving device. As described above with reference to the related art, the pointing device includes the stepping motor 1, the hands 2, and the driving device 3. The stepping motor 1 also has exciting coils 1a1 and 1a2, a rotor 1b, a gear 1c, a piece 1d (corresponding to a driven member in the claims) and a stopper 1e, as in the prior art.
[0038]
The difference from the above-mentioned conventional is the position where the stopper 1e and the piece 1d are provided. Conventionally, when the piece 1d and the stopper 1e are in contact with each other, the pointer 2 is provided so as to indicate a scale of 0 km / h on the dial. However, in the first embodiment of the present invention, when the stopper 1e and the piece 1d are brought into contact with each other, as shown in FIG. It is provided to stop at the initialization end position P3 on the reverse rotation direction Y1 side by the error angle α.
[0039]
Further, the driving device 3 is composed of, for example, μCOM and the like, and includes a central processing unit (CPU) 3a that performs various processes according to a program, a ROM 3b that is a read-only memory storing a processing program performed by the CPU 3a, and the like. The CPU 3a incorporates a RAM 3c, which is a readable / writable memory having a work area used in various processes in the CPU 3a and a data storage area for storing various data, and these are interconnected by a bus line (not shown). .
[0040]
The driving device 3 is connected to an ignition switch SW1 (hereinafter abbreviated as IG switch SW1). When the IG switch SW1 is turned on, an H level on signal Son is supplied. The drive device 3 is also supplied with angle data θi. The angle data θi is the same value as the angle data θi described above in the related art.
[0041]
The operation of the pointing device incorporating the stepping motor drive device having the above-described configuration will be described below with reference to the flowchart of FIG. 3 showing the processing procedure of the CPU 3a. For example, the CPU 3a starts operation by turning on battery power (not shown), and performs initial setting of various areas formed in the RAM 3c in the driving device 3 in an initial step (not shown).
[0042]
After that, when the IG switch SW1 is turned on by the driver (Y in Step S1), the CPU 3a functions as initialization rotation means and starts initialization rotation processing (Step S2). In the initialization rotation process, the CPU 3a intermittently changes the excitation state of the excitation coils 1a1 and 1a2, and reversely rotates the stepping motor 1 so that the piece 1d moves toward the stopper 1e. By this initialization rotation process, the pointer 2 moves from the scale of 0 km / h toward the initialization end position P3 (see FIG. 2) on the reverse rotation direction Y1 side by an instruction error angle α. At this time, 0 ° is stored as the current position θ ′ of the pointer 2 stored in the RAM 3c.
[0043]
Thereafter, when it is determined that the piece 1d comes into contact with the stopper 1e and the rotation of the stepping motor 1 has been mechanically stopped, the CPU 3a functions as a stopping means and holds the exciting coils 1a1 and 1a2 in a predetermined initial excitation state. Stop processing is performed (step S3). By this stop processing, the rotation of the stepping motor 1 is electrically stopped while the pointer 2 is stopped at the initialization end position P3.
[0044]
By the way, the contact determination is performed based on, for example, the presence or absence of an induced voltage generated in a detection coil provided near the rotor 1b. That is, when an induced voltage is generated in the detection coil, it can be determined that the rotor 1b is rotating and the piece 1d is not in contact with the stopper 1e. On the other hand, when no induced voltage is generated in the detection coil, it can be determined that the rotor 1b is mechanically stopped by the contact between the piece 1d and the stopper 1e.
[0045]
In the embodiment of the present invention, the induction coils 1a1 and 1a2 controlled to be in the non-excited state are used as the detection coils in the initialization rotation process, and induction is generated in the non-excited excitation coils 1a1 and 1a2. A position detection circuit (not shown) for detecting contact based on the presence or absence of voltage is provided.
[0046]
Thereafter, the CPU 3a updates the target position θ stored in the RAM 3c to an angle α ′ stored in advance in the first movement angle area in the RAM 3c (step S4). As shown in FIG. 4, the angle α ′ is after the stop process is completed and when the current position θ ′ is 0 °, the stepping motor 1 is rotated with the target position θ as the angle α ′. At this time, the pointer 2 corresponds to an angle necessary for actually indicating the scale of 0 km / h, which is the position P4 on the positive rotation direction Y2 side, from the initialization end position P3 by the instruction error angle α.
[0047]
That is, the angle α ′ needs to be determined in consideration of the immovable range A in which the pointer 2 does not move even when the stepping motor 1 is rotated, and is set to a value larger than the instruction error angle α. From the above, it can be seen that the angle α ′ corresponds to a predetermined position in the claims, and the angle α corresponds to an instruction error amount and an actual movement amount in the claims.
[0048]
Then, the CPU 3a functions as normal rotation means, and rotates the stepping motor 1 in accordance with the difference between the updated target position θ and the current position of the pointer 2 (set to 0 ° after the stop process). The rotation process is started (step S5).
[0049]
When the normal rotation process is performed immediately after the target position θ is updated to the angle α ′ in step S4, the pointer 2 moves to the position P4 on the positive rotation direction Y2 side by the instruction error angle α from the initialization end position P3. Is indicated on the scale of 0 km / h.
[0050]
Next, the CPU 3a determines whether or not the IG switch SW1 is turned off (step S6). If the IG switch SW1 is off (Y in step S6), the current position θ ′ is forcibly set to 0 ° (step S7), and the process returns to step S1 again. On the other hand, if the IG switch SW1 is not turned off (N in step S6), the CPU 3a determines whether or not the angle data θi is larger than the angle α ′ (step S8).
[0051]
If the angle data θi ≦ angle α ′ (N in step S8), the process returns to step S6 again. Therefore, during the angle data θi ≦ angle α ′, the pointer 2 still indicates the scale of 0 km / h, which is the position P4 on the positive rotation direction Y2 side, by the instruction error angle α from the initialization end position P3. .
[0052]
On the other hand, if the angle data θi> the angle α ′ (Y in step S8), the target position θ is updated to the angle data θi (step S9). Thereafter, the CPU 3a performs a normal rotation process similar to step S5 (step S10). Through the processes in steps S9 and S10, the pointer 2 gives an instruction according to the angle data θi, that is, the vehicle speed information. The operations in steps S9 and S10 are repeated until the IG switch SW1 is turned off (step S11).
[0053]
In step S9, when the target position θ is updated to the angle data θi larger than the angle α ′ and then the normal rotation process in step S10 is performed, the pointer 2 moves from the initialization end position P5 to the angle (θi−α ) For the forward rotation direction Y2 (see FIG. 4). After that, when the target position θ is updated to the angle data θi of 0 ° in step S9 and the normal rotation processing in step S10 is performed, the pointer 2 is caused by backlash as described above in the related art. Thus, the return to the initialization end position P3 is not performed, but the instruction end point P3 is used to indicate the scale of 0 km / h, which is the position P4 on the positive rotation direction Y2 side, by the instruction error angle α.
[0054]
On the other hand, when the IG switch SW1 is turned off (Y in step S11), the CPU 3a updates the target position θ to 0 ° (step S12), and then performs normal rotation processing similar to steps S5 and S10 (step S12). S13), the process returns to step S1. As a result of performing the normal rotation process in step S13, the pointer 2 also instructs the scale of 0 km / h, which is the position P4 on the positive rotation direction Y2 side, from the initialization end position P3 by the instruction error angle α. Stop.
[0055]
According to the above instruction device, the position indicated by the pointer 2 before the start of the instruction according to the vehicle speed information and after the start of the instruction according to the vehicle speed information, 0 ° is calculated as the angle data θi, or the IG switch The position indicated by the pointer 2 when SW1 is turned off is set on the scale of 0 km / h, which is the position P4 on the positive rotation direction Y2 side, from the initialization end position P3 by the instruction error angle α. Can do. Therefore, the indication error between the position indicated by the pointer 2 before starting the instruction according to the vehicle speed information and the position indicated by the pointer 2 when 0 ° is calculated as the angle data θi or the IG switch SW1 is turned off. It can be completely eliminated.
[0056]
Second embodiment
Next, a second embodiment of the present invention will be described. A detailed description of the same configuration as that of the first embodiment described above with reference to FIG. 1 is omitted. The difference from the first embodiment is the position where the piece 1d and the stopper 1e are provided. In the first embodiment, when the stopper 1e and the piece 1d come into contact with each other, as shown in FIG. 2, the pointer 2 rotates backward from the scale of 0 km / h by the instruction error angle α described above in the related art. It was provided to stop at the initialization end position P3 on the direction Y1 side.
[0057]
By the way, in the stepping motor 1, the operation | work which drives the pointer 2 in the pointer shaft (not shown) rotated with the gear 1c is required. In the first embodiment described above, it is necessary to drive the pointer 2 in the reverse rotation direction Y1 side from the scale of 0 km / h by the indicated error angle α with the piece 1d in contact with the stopper 1e. However, if the driving of the pointer 2 with respect to the pointer shaft is deviated, even if the normal rotation process (step S5) is performed immediately after the above-described target position θ is updated to the angle α ′, the pointer 2 has a scale of 0 km / h. Without indicating the top, the position shifted by the displacement of the driving is indicated.
[0058]
Therefore, in the second embodiment described below, as shown in FIG. 5, the reverse rotation direction Y1 side is an angle larger than the indication error angle α from the scale of 0 km / h with the piece 1d in contact with the stopper 1e. With the target position P6 as the target, the pointer 2 is driven. Thereafter, the angle difference (α + γ) between the position P6 where the pointer 2 is actually driven and the position P5 on the scale of 0 km / h is measured, and the angle obtained by subtracting the instruction error angle α from the measured angle difference (α + γ). γ is recorded in the second movement angle area in the RAM 3c. As can be seen from the above, the angle γ varies depending on the displacement of the pointer 2.
[0059]
Hereinafter, the operation of the pointing device in the second embodiment will be described with reference to the flowchart showing the processing procedure of the CPU 3a in FIG. Note that steps that perform the same operations as in the first embodiment are denoted by the same reference numerals, and will be described with emphasis on portions that are different from the first embodiment.
First, the CPU 3a performs the same operation as steps S1 to S3 described with reference to FIG. Thereafter, the CPU 3a functions as an adding means, and adds the angle α ′ stored in advance in the first movement angle area in the RAM 3c and the angle γ stored in the second movement angle area in the RAM 3c after the above-described pointer 2 is driven. The target position θ is updated to the value obtained (step S20).
[0060]
The angle α ′ is the same value as in the first embodiment described above. As shown in FIG. 7, after the stop process is completed and the current position θ ′ is 0 °, the target position θ is changed to the angle α. ′, When the stepping motor 1 is rotated, the pointer 2 corresponds to an angle necessary for actually instructing the position P7 on the positive rotation direction Y2 side from the initialization end position P6 by the pointer error angle α. To do.
[0061]
Accordingly, when the normal rotation process of step S5 is performed immediately after the target position θ is updated to the angle α ′ + γ in step S20, the pointer 2 is moved by the angle α + γ from the initialization end position P6 by the positive rotation direction Y2 side. Point on the scale of 0 km / h, which is position P5. From the above, in the second embodiment, it can be seen that the angle (α ′ + γ) corresponds to a predetermined position in the claims, and the angle (α + γ) corresponds to the actual movement amount in the claims.
[0062]
Next, the CPU 3a determines whether or not the IG switch SW1 is turned off (step S6). If the IG switch SW1 is turned off (Y in step S6), the current position θ ′ is forcibly set to 0 ° (step S7) and the process returns to step S1 as in the first embodiment. On the other hand, if the IG switch SW1 is not turned off (N in step S6), the CPU 3a determines whether or not the angle data θi is larger than the angle α ′ + γ (step S21). If the angle data θi ≦ angle α ′ + γ (N in step S21), the process returns to step S6 again. Therefore, during the angle data θi ≦ angle α ′ + γ, the pointer 2 remains instructed to be on the scale of 0 km / h, which is the position P5 on the positive rotation direction Y2 side, by the angle (α + γ) from the initialization end position P6. is there.
[0063]
On the other hand, if angle data θi> angle α ′ + γ (Y in step S21), CPU 3a then determines whether or not angle data θi = 0 ° (step S22). If it is immediately after performing the process of step S21, the CPU 3a naturally determines that the angle data θi is not 0 ° (N in step S22), and updates the target position θ to the angle data θi (step S23). Thereafter, after performing the normal rotation process (step S10), the CPU 3a returns to step S22 again if the IG switch SW1 is not OFF (N in step S11). When the normal rotation process is performed in step S10 after updating in step S23, as shown in FIG. 7, the pointer 2 moves by an angle (θi−α) from the initialization end position P6 on the positive rotation direction Y2 side. Instruct.
[0064]
On the other hand, if the angle data θi becomes 0 ° as a result of repeating step S22 (Y in step S22), the CPU 3a forcibly sets the target position θ between the angle α + γ and the instruction error angle α. The angle γ which is the difference is updated (step S24). When the normal rotation process is performed in step S10 after updating in step S24, as shown in FIG. 7, the pointer 2 is positioned at the position P5 on the positive rotation direction Y2 side by an angle α + γ from the initialization end position P6. A certain scale of 0 km / h is indicated.
[0065]
If the IG switch SW1 is turned off (Y in step S11), the CPU 3a updates the target position θ to the angle γ (step S25), and then proceeds to step S13 to perform normal rotation processing. As a result of performing the normal rotation processing in step S13, the pointer 2 also stops on the scale of 0 km / h, which is the position P4 on the positive rotation direction Y2 side by the angle α + γ from the initialization end position P3. . From the above, it can be seen that the angle γ corresponds to the difference between the actual movement amount and the instruction error amount in the claims.
[0066]
According to the above instruction device, the position indicated by the pointer 2 after the start of the instruction according to the vehicle speed information and after the start of the instruction according to the vehicle speed information, 0 ° is calculated as the angle data θi, or the IG switch SW1 When the is turned off, the position indicated by the pointer 2 can be set to the positive rotation direction Y2 side by an angle (α + γ) (> indicated error angle α) from the initialization end position P6. Therefore, the driving error of the pointer 2 is eliminated, and the position indicated by the pointer before starting the instruction according to the vehicle speed information and the angle data θi is calculated as 0 ° or when the IG switch SW1 is turned off. The indication error from the position indicated by 2 can be completely eliminated.
[0067]
Third embodiment
Next, a pointer driving method for driving the pointer 2 into the stepping motor 1 whose rotation is controlled by the driving device 3 in the second embodiment will be described. In the second embodiment described above, the angle α ′ is in the first movement angle area, and the angle between the initialization end position P6 and the position P5 on the scale of 0 km / h in the second movement angle area. The angle γ obtained by subtracting the instruction error angle α from the difference α + γ was stored.
In the third embodiment, first, before driving the pointer 2 with respect to the pointer shaft, the first movement angle area stores the angle α ′ (> α ′) on the positive rotation direction Y2 side from the angle α ′. 0 ° is stored in the second movement angle area. In this state, driving is performed so that the pointer 2 indicates a scale of 0 km / h in a state where the process proceeds from step S1 to step S5.
[0068]
If the second movement angle area is left at 0 ° after the pointer 2 is driven and the process proceeds from step S1 to step S5, the pointer 2 is positioned at a position where the driving error is shifted by ± x ° from the scale of 0 km / h. Instruct. Accordingly, if this driving error ± x ° is stored in the second movement angle area, it is added to the angle α ″ in step S10, and the pointer 2 indicates a scale of 0 km / h.
[0069]
According to the pointer driving method described above, the pointer 2 can be driven with respect to a scale of 0 km / h which is a desired position. In addition, even if the driving error of the pointer 2 with respect to the scale of 0 km / h occurs in either of the forward and reverse rotation directions, the position indicated by the pointer 2 and the vehicle speed information according to the vehicle speed information before starting the instruction according to the vehicle speed information. After the start of the instruction, the position indicated by the pointer 2 when the angle data θi is calculated as 0 ° or the IG switch SW1 is turned off is set to a scale of 0 km / h. it can.
[0070]
【The invention's effect】
  As described above, according to the first aspect of the present invention, the position indicated by the pointer before the start of the instruction corresponding to the sensor output and the reference position is calculated as the sensor position after the start of the instruction corresponding to the sensor output. The position indicated by the pointer when the ignition switch is turned off or the ignition switch is turned off from the initialization end position.Needle error amount,Forward rotation sideReference positionThe indication error between the position indicated by the pointer before the start of the instruction according to the sensor output and the position indicated by the pointer when the reference position is calculated as the sensor position or when the ignition switch is turned offCan be completely eliminatedA driving device for a stepping motor can be obtained.
[0072]
  Claim2According to the described invention,The position indicated by the pointer before starting the instruction according to the sensor output, and the position indicated by the pointer when the reference position is calculated as the sensor position after the instruction corresponding to the sensor output is started or when the ignition switch is turned off. Can be used as the reference position, eliminating the driving error, calculating the position indicated by the pointer before starting the instruction according to the sensor output, and calculating the reference position as the sensor position, or turning off the ignition switch. Thus, it is possible to obtain a stepping motor drive device that can completely eliminate the indication error from the position indicated by the pointer when it is done.
[0073]
  Claim3 and 4According to the described invention,Reference positionEven if an error in driving the pointer with respect to either forward or reverse rotation occurs, the position indicated by the pointer before starting the instruction according to the sensor output, and after the start of the instruction according to the sensor output, the sensor position As the reference position is calculated or the position indicated by the pointer when the ignition switch is turned off,StandardSince the position can be set, it is possible to obtain a stepping motor drive device and a pointer driving method capable of easily driving the pointer.
[Brief description of the drawings]
FIG. 1 is a diagram showing an embodiment of an indicating device incorporating a stepping motor driving device of the present invention.
FIG. 2 is a diagram showing a positional relationship between an initialization end position P3 and a scale of 0 km / h in the first embodiment.
FIG. 3 is a flowchart showing a processing procedure of a CPU 3a in the first embodiment.
FIG. 4 is a graph showing a relationship between a target position θ of the pointer 2 and an actual designated position of the pointer 2 in the first embodiment.
FIG. 5 is a diagram showing a positional relationship between an initialization end position P3 and a scale of 0 km / h in the second embodiment.
FIG. 6 is a flowchart showing a processing procedure of a CPU 3a in the second embodiment.
FIG. 7 is a graph showing the relationship between the target position θ of the pointer 2 and the actual indicated position of the pointer 2 in the second embodiment.
FIG. 8 is a diagram for explaining a conventional problem.
FIG. 9 is a diagram for explaining a conventional problem.
10 is a graph showing a relationship between a target position θ of a conventional pointer 2 and an actual designated position of the pointer 2. FIG.
[Explanation of symbols]
1 Stepping motor
1c gear
1d piece (driven member)
1e Stopper
2 Guidelines
3a CPU (initialization rotation means, stop means, normal rotation means)

Claims (4)

Initialization rotating means for reversely rotating the stepping motor so that the driven member linked to the rotation operation of the stepping motor driving the pointer via the gear faces the stopper, and the driven member becomes the stopper by the reverse rotation. a stop means for contact with the rotation of the front Symbol stepping motor stop processing is carried out to electrically stop the rotation of the stepping motor an excitation coil of said stepping motor and held in the initial excitation state after stopping mechanically, a reference position setting means for performing setting processing for setting a reference position of the current position of the pointer stored in the memory corresponding to the sensor output 0 after the stop process is performed, the sensor after the setting process has been performed sequentially sensor position is indicated position of the pointer corresponding to the output, by setting the target position, stored in the memory pointer A stepping motor driving apparatus and a normal rotation means for performing a normal rotation operation for forward and reverse rotation of the stepping motor according to a difference between the target position of the pointer stored in the current position said memory,
(B) The initialization end position, which is the pointer position on the dial plate when the driven member and the stopper contact each other, is instructed from a reference position corresponding to a sensor output 0 predetermined on the dial plate. It is provided to be on the reverse rotation side by the amount ,
(B) The indication error amount is set so that the target position of the pointer stored in the memory by the normal rotation means rotates the pointer once in the positive direction, and the reference is once rotated in the positive direction once. A displacement from the initialization end position of the pointer on the dial generated when the normal rotation operation as set to the position is performed , and
(C) The current position of the pointer on the memory corresponding to the rotation amount of the stepping motor while the pointer does not move even if the stepping motor is rotated forward after the setting process is performed by the normal rotation means setting a pointer movement amount to the pointer movement and the predetermined position is the target position from the combined amount corresponding to the reference position serving as the forward rotation side from the initialization end position on the dial to the reference position of the is, the stepping motor according to a difference between the target position of the pointer stored in the the current position of the pointer stored in the memory the memory is forward rotation, followed by the pointer in response to the sensor output The stepping motor drive device according to claim 1, wherein the normal rotation operation is started when the indicated position is on the positive rotation side with respect to the predetermined position. Initialization rotating means for reversely rotating the stepping motor so that the driven member linked to the rotation operation of the stepping motor driving the pointer via the gear faces the stopper, and the driven member becomes the stopper by the reverse rotation. a stop means for contact with the rotation of the front Symbol stepping motor stop processing is carried out to electrically stop the rotation of the stepping motor an excitation coil of said stepping motor and held in the initial excitation state after stopping mechanically, a reference position setting means for performing setting processing for setting a reference position of the current position of the pointer stored in the memory corresponding to the sensor output 0 after the stop process is performed, the sensor after the setting process has been performed sequentially sensor position is indicated position of the pointer corresponding to the output, by setting the target position, stored in the memory pointer A stepping motor driving apparatus and a normal rotation means for performing a normal rotation operation for forward and reverse rotation of the stepping motor according to a difference between the target position of the pointer stored in the current position said memory,
(B) The initialization end position, which is the pointer position on the dial plate when the driven member and the stopper contact each other, is instructed from a reference position corresponding to a sensor output 0 predetermined on the dial plate. It is provided to be on the reverse rotation side by an amount larger than the amount ,
(B) The reference error amount is set so that the target position of the pointer stored in the memory by the normal rotation means rotates the pointer once in the positive direction, and the reference position after the pointer once rotates in the positive direction. It is assumed equal to the deviation from the initialization end position of the pointer on the dial that occurs when the normal rotation as selection was made, and,
(C) The current position of the pointer on the memory corresponding to the rotation amount of the stepping motor while the pointer does not move even if the stepping motor is rotated forward after the setting process is performed by the normal rotation means setting a pointer movement amount to the pointer movement and the predetermined position is the target position from the combined amount corresponding to the reference position serving as the forward rotation side from the initialization end position on the dial to the reference position of the is, the stepping motor according to a difference between the target position of the pointer stored in the the current position of the pointer stored in the memory the memory is forward rotation, followed by the pointer in response to the sensor output when the indicated position is a positive rotation side than the predetermined position, the normal rotation operation is started, when the reference position as the sensor position in the normal rotation is calculated or Lee The positive rotation side and a position is the target position from only the reference position difference between the pointer movement amount and the indication error amount from the initialization end position on the dial to the reference position when Stevenage Deployment switch is turned off And the stepping motor is rotated in accordance with a difference between the current position of the pointer stored in the memory and the target position of the pointer stored in the memory. . First movement amount and the adding means for adding the second moving amount further Bei Erare which is previously stored in a predetermined position storage medium, and,
The normal rotation means, a stepping motor driving apparatus according to the position of the forward rotation side from the reference position by the movement amount that has been added by the adding means to claim 2, characterized in that the said predetermined position. A pointer driving method for driving a pointer into a pointer shaft in a stepping motor whose rotation is controlled by the stepping motor drive device according to claim 3,
(A) The amount of movement of the pointer at the current position of the pointer on the memory corresponding to the rotation amount of the stepping motor while the pointer does not move before driving the pointer onto the pointer shaft and the amount of pointer error a step of Ru is stored zero as the second movement amount stores a larger value as the first amount of movement,
(B) present the guidelines set stored in the memory the position of the forward rotation side from only the reference position movement amount that has been added by the adding means by the normal rotation means after the setting operation as the target position after according to the difference between the target position of the pointer stored position and in said memory by rotating the stepping motor, and write no step out of the pointer on the pointer shaft,
(C) guidelines are again stored the position of the forward rotation side from the reference position by the movement amount that has been added by the adding means by the normal rotation means after the setting operation in the memory is set as the target position The amount of movement from the pointer position on the dial plate to the reference position on the dial plate after rotating the stepping motor in accordance with the difference between the current position of the pointer and the target position of the pointer stored in the memory step of Ru is stored as the second movement amount
A guide driving method characterized by sequentially performing steps.

Images