JP2003289694A - Drive switching device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To protect a motor by suppressing heating of the motor even when a movement of an output member such as a rod or the like is restrained. <P>SOLUTION: A drive switching device 10 comprises a motor side rotary member 35A rotating by a rotation of an output shaft 31A of the motor 31, the rod 33 for switching a drive state by the rotation of the motor 31, a spiral spring 35B for absorbing a rotary force from the motor 31 when the rotation of the rod 33 is restricted, an operation switch 36 for designating switching of the drive state, and a control unit 40 for moving the rod 33 according to the state of the switch 36. The unit 40 detects a motor current I flowing to the motor 31, detects an energizing time T1 from the start of the motor 31, and estimates a heating temperature T of the motor 31 according to the current I and the time T1. The device allows or inhibits the input from the switch 50 based on the estimated heating temperature T to protect the motor 31. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive switching device for switching drive states, and switches drive modes (two-wheel drive state, four-wheel drive state such as center differential free or center differential lock) in a vehicle. It is related to the drive switching device.

[0002]

2. Description of the Related Art In recent years, as the performance of vehicles has improved, drivers have been able to change the form of power transmission of a vehicle, which gives driving force, to a two-wheel drive state according to their own preference or the running state or running state of the vehicle. Alternatively, the configuration is such that it can be switched to a four-wheel drive state such as a center differential free state or a center differential lock state.

For example, in the thrust actuator disclosed in Japanese Unexamined Patent Publication No. 8-223983, the motor is converted into axial thrust by the power transmission mechanism and transmitted to the rod. The rod receives the thrust and moves in the axial direction, and drives the fork shaft of the switching device to switch between two-wheel drive and four-wheel drive. In this case, the load current flowing through the motor is limited so that the rod is locked and the motor is not overloaded.

[0004]

However, in the thrust actuator disclosed in the above publication, when the rod locks during driving of the motor and the load applied to the motor exceeds a predetermined value, the current supplied to the motor is limited. I am trying to do it. For this reason, for example, if some load acts on the rod while the rod is moving, the load applied to the motor is smaller than the load at the time of locking, but the rod moves smoothly in the normal motor drive state. If it is larger than the load, the energization of the motor is not restricted.

Therefore, if the load acting on the rod is smaller than when the rod is locked and larger than when the motor is normally driven, the motor may generate heat and be damaged due to burning or the like.

Therefore, the present invention has been made in view of such a problem, and it is possible to suppress the heat generation of the motor and protect the motor even when the movement of the output member such as the rod is restricted. It is an issue.

[0007]

[Means for Solving the Problems] Means taken for solving the above-mentioned problems include a motor driven in response to energization,
A motor-side rotating member that rotates together with the output shaft of the motor, an output member that switches the driving state of the vehicle to either the first state or the second state by moving with the driving of the motor, and the output member. A rotation absorbing mechanism that is disposed between the motor-side rotating member output shaft and the motor-side rotating member and absorbs rotation of the motor when rotation of the output member is restricted; A drive switching device comprising: an operation member for selecting either one state or the second state; and a control device for controlling the drive of the motor and moving the output member according to a selection operation of the operation member. The control device detects a motor current flowing through the motor, detects an energization time from the start of the motor, and detects the energization time from the motor current and the energization time. By estimating the heat generation temperature of the motor,
The electric power to the motor is regulated based on the heat generation temperature.

According to the above means, the control device detects the motor current flowing through the motor, detects the energization time from the start of the motor, and estimates the heat generation temperature of the motor from the motor current and the energization time. Is possible. Then, by restricting energization to the motor based on the estimated exothermic temperature, the motor is monitored by a simple method for the exothermic state that causes a failure such as burnout according to the motor current and the energization time from startup. Therefore, heat generation of the motor can be surely suppressed and the motor can be protected.

As a result, when the motor is likely to generate heat, the energization of the motor is surely restricted, so that the motor can be miniaturized.

In this case, the control device detects the power supply stop time after the power supply to the motor is finished, estimates the heat generation temperature from the motor current and the power supply stop time, and operates until the heat generation temperature reaches a predetermined temperature. If you prohibit the selection operation by members,
Even after the driving of the motor is stopped, it is possible to estimate the heat generation temperature from the motor current and the power supply stop time, and monitor the state where the heat generation temperature of the motor decreases. As a result, when the heat generation temperature is higher than the predetermined temperature even after the driving of the motor is stopped, it is possible to protect the motor by prohibiting the driving of the motor according to the selection operation of the operation member. On the other hand, if the heat generation temperature after the driving of the motor is stopped becomes lower than the predetermined temperature, it becomes possible to permit the driving of the motor according to the selection operation of the operation member.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view of a drive switching device 10 whose drive state is switched by an actuator for a switching device in this embodiment. It should be noted that in FIG. 1, hatching is omitted except for a part so that the respective components are not easily seen.

The drive switching device 10 is a transmission (not shown).
Is arranged between the front wheel drive shaft 12 and the rear wheel drive shaft 11 of the vehicle so that the driving force of the input shaft 24, which is the output of the above, is transmitted to the front wheels and the rear wheels. The drive switching device 10 can switch the drive state of the vehicle to any of three states of two-wheel drive, four-wheel drive (center differential lock), and four-wheel drive (center differential free) by operating the actuator 30. It is a device. The drive switching device 1 in this embodiment
In addition to the above three states, 0 is configured such that the reduction gear 23 can switch the final reduction ratio during four-wheel drive between high gear and low gear. The driver can manually switch the shift lever 20 that switches between high gear and low gear to switch between high gear and low gear. Rotational driving force is transmitted to the rear wheel drive shaft 11 provided at substantially the center via an input shaft 24 of a transmission (not shown). Then, the rotational drive force of the rear wheel drive shaft 11 is transmitted to the center differential unit 13 provided in the center, and the rotational drive force is transmitted from the center differential unit 13 to the front wheel drive shaft 12 via the silent chain 19. It is configured to.
The center differential unit 13 shown here is the front wheel drive shaft 1
It is a device that absorbs the difference in rotation speed between the two and the rear wheel drive shaft 11, and is configured by a planetary gear mechanism.

The drive switching device 10 shown in FIG.
A first shaft 14 connected to a rod (output member) 33 of the actuator 30 serving as a drive source shown in FIG. 2, a second shaft 15 provided in parallel with the first shaft 14, and a first shaft 14.
A shift fork 16 for switching between two-wheel drive and four-wheel drive, which is arranged so as to be axially movable within a predetermined range with respect to the shaft 14 and the second shaft 15, a shift fork 17 for performing center differential lock, and a shift fork 16. A sleeve 16A that is provided and moves integrally with the shift fork 16, and
The shift fork 17 is integrally provided with a sleeve 17A that moves integrally with the shift fork 17.

Shift forks 16 and 17 slidably moving on the first shaft 14 and the second shaft 15 are movably fitted to the two first shafts 14 and the second shaft 15. The first shaft 14 has 2 in the axial direction.
Two circumferential flanges 14A, 14B are formed,
The shaft 15 has three flanges 15 in the axial direction.
A, 15B and 15C are formed. The positions at which these flanges 14A, 14B, 15A, 15B, 15C are provided are as follows.

That is, in the state shown in FIG. 1, in the first shaft 14, the flange 14A does not abut on both shift forks 16 and 17, and the flange 14B is on one side of the shift fork 16 (left side in FIG. 1). A).
Further, in the second shaft 15, the flange 15C abuts on one side of the shift fork 17 (on the right side in FIG. 1), but the flange 15A does not contact both shift forks 16, 1.
Don't touch 7. The flange 15B abuts on one side of the shift fork 16 (on the right side in FIG. 1), and
The shaft 14 and the second shaft 5 are independently movable in the axial direction. Thereby, the above-mentioned flanges 14A, 14B, 15A, 15B, 15
By the action of C, the two shift forks 16 and 17 are
Each is pressed or not pressed,
The position can be moved in the axial direction of the shift forks 16 and 17 by sliding on the shaft 14 and the second shaft 15.

Next, switching of the drive state in the drive switching device 10 will be described. In the drive switching device 10 according to the present embodiment, the first shaft 14 and the second shaft 15 are driven according to the position of the rod 33, and the rod 33
The first shaft 14 is moved in the axial direction according to the position. As a result, a shift fork 16 for switching between two-wheel drive and four-wheel drive, which is disposed in a slidable manner on both shafts 14 and 15, and a shift fork for performing center differential lock for switching between the center differential free state and the center differential lock state. 17 moves in the axial direction, and each shift fork 1
6 and 17, the sleeves 16A and 17A that move integrally with the shift forks 16 and 17 move in the axial direction, and the sleeves 16A and 17A switch between a gear mechanism (not shown) inside the center differential unit or 2/4 drive Gear 1
8, spline fit or not.

As a result, in this embodiment, the driving state of the vehicle is two-wheel drive, four-wheel drive (center differential free).
And 4 wheel drive (center differential lock) state,
It is possible to switch to three states. In the present embodiment, the first state is a two-wheel drive state and the second state is a four-wheel drive state. However, apart from this, for example, the first state is a two-wheel drive state, a second state. May be set to the center differential free state, and the third state may be set to the center differential lock state. Further, it is not limited to these states,
It is possible to replace the above states or add other states.

A supplementary explanation of the power transmission of the vehicle will be made. In the center-diff free four-wheel drive state, the front wheel drive shaft 12 and the center center diff unit 13 are connected to each other, and a planet provided in the center diff unit is connected. By the action of the planetary gears of the gear mechanism, the rotational driving force of the rear wheel drive shaft 11 is transmitted to the front wheel drive shaft 12 via the silent chain 19 while absorbing the difference in rotational speed generated between the two drive shafts 11 and 12. To be done.

Further, in the four-wheel drive state of the center differential lock, the sleeve 17A that moves integrally with the shift fork 17 meshes with the planetary gear mechanism of the center differential unit 13 and locks. In this way, when the meshing is locked between the two, the front wheel drive shaft 12 and the rear wheel drive shaft 11 are directly connected, and both drive shafts 11 and 12 are rotationally driven at the same rotational speed.

On the other hand, when the drive state is the two-wheel drive state, the front wheel drive shaft 12 and the center differential unit 13 are not connected, and the rotational drive force of the input shaft 24 is transmitted only to the rear wheel drive shaft 11. .

Next, the actuator 30 for driving the drive switching device 10 will be described. 2 shows a cross-sectional view of the actuator 30, and FIG. 3 is a top view shown in FIG.

The actuator 30 includes a motor 31 driven by the control device 40 and an output shaft 31A of the motor 31.
The output mechanism 32 that converts the rotational torque of the motor into the thrust in the axial direction and outputs the thrust, and the thrust corresponding to the rotation torque of the motor 31 are transmitted via the output mechanism 32, and the position is displaced according to the transmitted thrust. The rotation of the output shaft 31A is prohibited by the power transmitted from the rod 33 side to the output shaft 31A side, which is arranged between the rod 33 as the output member, the output shaft 31A of the motor 31, and the output mechanism 32. Cycloid gear 34 as a reverse rotation prohibiting mechanism, and cycloid gear 3
4 and the output mechanism 32, and a rotation absorbing mechanism 35 that absorbs the rotation of the motor 31 when the motor 31 rotates and the rod 33 cannot reciprocate, and a rotation absorbing mechanism 35.
And a limit switch 36 that is disposed between the output shaft 31A and the output shaft 31A and that detects the rotation angle of the output shaft 31A. It is also possible to use a worm gear instead of the cyclic road gear 34.

The rotation absorbing mechanism 35 includes the cycloid gear 3
The motor-side rotating member 35A to which the rotation of the output shaft 31A of the motor 31 is transmitted via the motor 4, and one end fixed to the motor-side rotating member 35A and the motor-side rotating member 35A is rotated by the motor 31 in a rotating direction. A spiral spring 35B as a retractable elastic member, an output side rotating member 35C fixed to the other end of the spiral spring 35B and transmitting the rotational force from the motor side rotating member 35A to the output mechanism 32, and a motor side rotating member. 35A and a plate 35D arranged between the output side rotation member 35C.

As shown in FIG. 3, the motor side rotating member 35A
The shift forks 16, 1 which are arranged in proximity to the output mechanism 32 and operate by the movement of the rod 33 from the rotating state of the output mechanism 32.
The limit switch 36 that switches the switch state at a predetermined position of 7 has four terminals a, b, c, d. The limit switch 36 changes the contact / non-contact combination of the contacts at each terminal according to the rotation angle of the output shaft 31A, detects the rotation angle of the output shaft 31A, and detects the rotation angle of the output shaft 31A, and the rod 33 corresponding to the above three drive states. The position and the intermediate position of each position can be detected.

[0026]

[Table 1] Table 1 shows each terminal a, b, c, d of the limit switch 36.
3 shows the relationship between the contact state of the vehicle and the set position of the vehicle driving state. In Table 1, “◯” indicates when the contacts were in contact, and blank columns indicate when the contacts were not in contact. As described above, in the limit switch 36, the terminal a serves as the ground terminal, and the contact states of the four terminals a, b, c, and d for detecting the state change, so that the set positions I to V of the limit switch 36 are detected. Further, the set positions A to C of the driving state of the vehicle and their intermediate positions are detected depending on the set position I to V. In the present embodiment, as an example, the setting position A
Indicates a two-wheel drive state. Further, the set position B indicates a four-wheel drive (center differential free) state. Further, the set position C indicates a four-wheel drive (center differential lock) state.

Further, the actuator 30 for switching the driving state inputs an external signal such as a vehicle speed signal for detecting the traveling vehicle speed of the vehicle or a shift position signal indicating the position of the transmission to select the driving state of the vehicle, A control device 40 that outputs electric power to the motor 31 so as to achieve the selected driving state is provided outside the housing 37.

Therefore, the internal configuration of the control device 40 will be briefly described with reference to the whole of FIG. The control device 40 includes a microcomputer 41, a power supply circuit 42, an energization switching circuit 43, and a current detection circuit 47 inside. This controller 4
0 is supplied with power (for example, 12 V) from the battery 51 mounted on the vehicle, and the voltage from the battery 51 fluctuates depending on the load state of the vehicle, and thus is temporarily taken into the power supply circuit 42. With this power supply circuit 42,
A stable voltage (for example, 5
V) is generated and the stable voltage is input to the microcomputer 41. Further, the control device 40 has a switching signal of a manual operation switch (operation means) 50 for switching the above-mentioned three driving states in a rotary switch format, and contact / non-contact of each terminal b, c, d of the limit switch 36. State signal is input, and further, the current flowing in the motor 31 is detected by the current detection circuit 4 using a shunt resistor or the like connected to one terminal of the motor 31, and the motor current is input to the microcomputer 41. . These signals input to the microcomputer 41 are input via an interface circuit (not shown) provided inside or outside the microcomputer 41.
Based on these input signals, the microcomputer 41 sends a motor drive signal for driving the motor 31 to the energization switching circuit 43.
Output to. Then, the energization switching circuit 43 energizes according to the motor drive signal (energization for rotating the motor 31 forward or backward) to drive the motor 31.

Next, the operation of the actuator 30 will be described. In the present embodiment, as an example, the operation of each configuration when switching from the center differential free state to the center differential lock state will be described. Figure 5
FIG. 6 shows the relationship between the motor current flowing through the motor 31 (motor current value) and time. Further, FIG. 6 shows the temperature rise due to heat generation of the motor 31 (specifically, the product sum Σ of the motor current I and the motor energization time T1). 7 is a time chart showing the relationship between (I · T1) and time.

First, an outline of motor control will be described with reference to FIGS. 5 and 6. Here, as an example,
A case where the driver operates the operation switch 50 to shift the drive state from the center differential free state to the center differential lock state will be described. However, the present invention is not limited to this, and the three drive states described above are used. The present invention can also be applied to the case where a transition is made from any state to a different drive state.

Therefore, when operating the vehicle from the center differential free state to the center differential lock state, the driver operates the operation switch 50. Then, the motor 31 is continuously energized, the motor 31 is driven, and the motor 31 settles down after the starting current flows. As described above, when the starting current flows at the time of starting the motor, the motor current rapidly increases and then decreases. The rod 33 moves along with the rotation of the motor from time t1 to time t2 when the motor current has dropped and settled down. During this period, a stable motor current flows to the motor 31 and the motor 3
The output shaft 31A of No. 1 rotates, and the rod 33 is axially displaced via the output mechanism 32. Rod 33 until time t2
The axial displacement of the rod 33 is not restricted, and the rod 33 strokes in proportion to time. In this period, the load acting on the spiral spring 35B is only the sliding resistance of each member.

At time t2, the axial end of the sleeve 17A provided on the shift fork 17 is moved by the movement of the rod 33, which has been moving smoothly until now.
It contacts the planetary gear mechanism inside the center differential unit 13. In this case, even if the sleeve 17A is displaced in the axial direction, since the planetary gear mechanism operates in the center differential free state, the spline formed on the inner and outer circumferences of the sleeve 17A and the spline formed on the center differential unit 13 Does not immediately engage. Until the spline of the sleeve 17A meshes with the spline of the center differential unit 13 and the movement of the rod 33 is completed, the spiral spring 35B is in a waiting state in which it is elastically contracted. In this waiting state, there are two states: a state in which the rod 33 cannot be displaced in the axial direction and a state in which the rod 33 is displaced in the axial direction while receiving a predetermined load. Under these states, the current flows to the motor 31. The current value gradually increases.

As described above, when the spline fittings are not in mesh with each other, a state similar to a motor lock in which movement of the rod 33 is restricted is generated. When this state occurs,
The spiral spring 35B is elastically contracted to start a waiting operation for winding up the spiral ring 35B. In this case, the movement of the rod 33 is restricted, and the motor current rapidly increases as in the state where the rotation of the motor 31 is locked. After that, when the motor current reaches a preset motor current at a time t3 when a predetermined current is set to protect the motor, the motor 31 is held for a predetermined time from time t3 to t4. The motor 31 is energized with a duty ratio of%. That is, the microcomputer 41 of the control device 40 performs PWM (Pulse Width Modulation) control of the motor 31 in order to ensure sufficient engagement by spline fitting. When the motor current does not decrease even at time t4, the energization by the duty control of the motor 31 is stopped in order to protect the motor 31 from heat generation when the engagement of the spline fitting is insufficient. Start intermittent energization. The intermittent energization performed here is performed by the sleeve 17A and the center differential unit 13.
This is performed when the spline fitting with the planetary gear mechanism is not sufficient, and a time for passing a low current while suppressing the energization amount to the motor 31 and a time for applying a somewhat high current to the motor 31 are set to a predetermined cycle. (For example, 20 msec) is performed intermittently. By performing such intermittent energization, when the sleeve 17A and the planetary gear mechanism of the center differential unit 13 are spline-fitted to each other, the load on the rod 33 is prevented from being released under the condition where the two are not synchronized. , With the prescribed load applied to the rod 33, gradually increase the rod 3
Axial movement force is applied to 3 and the points are searched for for synchronization between the two while shifting.

Then, at the time t5, when the synchronization is achieved by performing the intermittent energization, the rod 33 is axially moved by the urging force of the spiral spring 35B stored when the axial movement of the rod 33 is restricted. Start moving to. Then, the state of motor lock is released,
The motor current drops until time t6. In this state, at time t6, the energization method is switched from intermittent energization to continuous energization. When the energization method is switched, a starting current flows through the motor 31, and the motor current rapidly increases and then decreases. When the rod 33 moves to some extent, the load acting on the rod 33 gradually increases, and the motor current gradually increases. After that, when the rod 33 reaches the final reaching point (the final set position C where the center differential lock state is set), the limit switch 36 indicates the center differential lock state (only the terminals a and d of the four terminals are in contact with each other). State), continuous energization is time t8
Then, the motor control is once ended.

In the motor control for performing such operation,
In the present embodiment, in order to prevent heat generation of the motor 31 and protect the motor 31, the motor current I flowing through the motor 31 and the elapsed time T from the start of the motor 31 during motor control are set. The heat generation temperature T of the motor is estimated based on the detected motor current I and the elapsed time T from the start. The estimated motor heat generation temperature T regulates the amount of electricity supplied to the motor 31.

Specifically, the motor current I and the energization time T1 of the motor 31 are detected at a predetermined cycle, and the product sum Σ (I · T1) of the motor current I and the energization time T1 of the motor 31 is calculated. A temperature rise (called heat generation temperature) associated with heat generation of the motor 31 is estimated. This heat generation temperature estimation is such that, when the motor 31 is intermittently energized, the product of the motor current I and the energization time T1 is not added to the temperature estimated value. However, when the motor 31 is continuously energized, the product of the motor current I and the energization time T1 is added to the temperature estimation value to estimate the heat generation temperature of the motor 31. For the estimation of the heat generation temperature, how much the motor temperature rises when a predetermined current is applied to the motor 31 is experimentally obtained in advance, and the rise coefficient or the fall coefficient is set according to the function of the motor current and the energization time. To do. When the motor 31 is being controlled, the coefficient of increase is added to the heat generation temperature T,
When the control is not performed, the lowering coefficient is subtracted from the heat generation temperature T to estimate the heat generation temperature T of the motor 31. Based on this, a decrease in the heat generation temperature of the motor 31 is estimated after the control is completed from the motor heat generation temperature obtained during the motor control in which the motor 31 generates heat, and the operation switch 50 is selected by the heat generation temperature after the motor is stopped. The driving of the motor 31 according to the above is permitted or prohibited. In this case, when the selection operation by the operation switch 50 is performed and the estimated heat generation temperature T of the motor 31 is higher than the predetermined temperature TM, in order to protect the motor 31 from burning or the like, The drive of the motor 31 according to the selection operation of the operation switch 50 is prohibited. On the other hand, when the estimated heat generation temperature T of the motor 31 is lower than the predetermined temperature TM, the heat generation of the motor 31 is sufficiently suppressed.
Alternatively, the motor 31 is assumed to be cold, and the driving of the motor 31 according to the selection operation of the operation switch 50 is permitted.

Therefore, the motor control processing in the microcomputer 41 will be described with reference to the flowchart shown in FIG.

In the motor control shown in FIG. 7, the ignition switch 52 to which power is supplied from the battery 51 shown in FIG. 4 is switched from the off state (open state) to the on state (closed state).
When the above condition occurs, a predetermined voltage (5V) is supplied to the microcomputer 41 and the microcomputer 41 is executed. Therefore, explaining the flowchart of FIG. 7, in step S1,
It is checked whether or not the selection operation by the operation switch 50 is performed. Here, if the selection operation by the operation switch 50 is not performed, the motor control process described below is not performed, but if the selection operation by the operation switch 50 is performed, the operation switch 50 is performed in step S2.
The operation permission flag of is established. Next, in step S3, it is checked whether the operation switch 50 is in the operation permission state. Here, when the operation permission flag of the switch operation 50 is not established (when the operation prohibition flag is established), the process proceeds to step S13 and the motor 31 is de-energized. When the operation permission flag of the switch operation 50 is satisfied in step S3, the process proceeds to step S4, the PWM control of the motor 31 described above is performed, and the process proceeds to step S5.

In step S5, the motor current flowing through the motor 31 is detected by the current detection circuit 47, and the detected motor current I is stored in a predetermined memory in the microcomputer. Further, in the motor control, when the motor 31 is energized (state during motor control), the motor 3
The energization time T1 after 1 is started is detected. Furthermore, when the motor 31 is not energized (when the motor is not being controlled), the energization of the motor 31 is terminated,
The energization stop time (hereinafter simply referred to as stop time) T2 after the motor 31 is stopped is detected and stored in a predetermined memory. Then, in step S6, it is determined whether the movement of the rod 33 is completed. When the movement of the rod 33 is completed, the rod 33 reaches a predetermined state (see the above 3
Limit switch 3 automatically
6 is activated so that the position of the rod 33 can be detected. For example, when the drive state shifts from the center differential free state to the center differential lock state, the movement completion state of the rod 33 means that the limit switch 36 is
As shown in Table 1, this means a state in which only the terminals a and d among the four terminals are in conduction (indicating a center differential lock state). In this state, the splines and the center differential formed on the inner and outer circumferences of the sleeve 17A are indicated. The sleeve 17A integrally rotates the planetary gear mechanism so that the planetary gear mechanism of the center diff unit 13 does not operate, meshing with the spline formed in the unit 13, and the center diff lock state is established, and the movement of the rod 33 is completed.

Here, when the limit switch 36 is operated to the position designated by the operation switch 50 (here, the center differential free state) and the movement of the rod 33 is completed, the process proceeds to step S12. But the rod 33
When the movement is not yet reached to the completion position, the energization state of the motor 31 is determined in step S7.

Whether or not the motor 31 is continuously energized (time t4 and time t6 to t8 from start-up) is intermittently energized (time t).
It is determined from the state of the motor 31 whether or not 4 to t6) are performed. In step S8, when the continuous energization is not performed (intermittent energization state), the process proceeds to step S16. If the continuous energization is performed in step S8, the process proceeds to step S9 to clear the stop time T2 for counting the time after the motor control is stopped, and the continuous energization is started in step S10. The energization time T1 from the beginning is counted. In this case, since the motor control is executed in a predetermined cycle, the elapsed time after continuous energization can be found by multiplying the predetermined cycle by the value of the energization time counter. In this way, steps S9 and S8
At, when the motor current I and the elapsed time T are detected, the heat generation temperature T in the increasing direction is estimated in step S11.

The heat generation temperature T of the motor 31 increases due to heat generation during motor control. The heat generation temperature T is estimated by multiplying the product of the motor current I and the energization time T1 by integrating Σ (I · T1).
That is, in the estimation of the heat generation temperature, the amount of heat generated by the motor 31 during the control and the temperature of the motor 31 during the control are determined in advance by experiments or the like based on the integrated value Σ (I · T1).
The rising temperature of the motor 31 is set. Based on this, the heat generation temperature of the motor 31 can be estimated. In this case, during motor control, at the time of continuous energization, the integration Σ (I · T
1) will increase. Thereafter, the processing proceeds to step S16.

On the other hand, when the movement of the rod 33 is completed, in step S12, the energization time counter which was being counted during motor control is cleared, and step S13 is performed.
The motor 31 is de-energized. And step S1
4, the stop time counter that counts the stop time T2 after the motor control is finished is counted in a predetermined cycle. After that, the heat generation temperature of the motor 31 is estimated this time from the motor current I and the stop time T2. Even in this case, the descending temperature of the motor 31 is set in advance by experiments and the like to determine how much the motor 31 is cooled from the heat generation state by the product I · T2 of the energizing current I and the stop time T2. The heat generation temperature of 31 can be estimated. In this case, when the motor control is stopped, the heat generation temperature, which has once increased with heat generation, gradually decreases.

When the motor control is completed and the motor 31 is not energized as in this case,
Since the output shaft 31A is connected to the rotation absorbing mechanism 35 via the cycloid gear 34, the output shaft 31A does not rotate in the reverse direction.

After the step S15, the process proceeds to the step S1.
6. Here, the heat generation temperature T of the motor 31 obtained by the estimation during the motor control or after the motor control is finished is
In the motor control by the next switch operation, it is checked whether the temperature has fallen to a temperature (predetermined temperature TM) that can be endured. Here, if the estimated heat generation temperature T has dropped to the predetermined temperature TM, the switch operation permission flag of the operation switch 50 is established in step S17. If the temperature has not fallen to the predetermined temperature TM in step S17, the switch operation prohibition flag is established in step S18, the process returns to step S3, and the process from step S3 is repeated in a predetermined cycle.

By performing such control, the motor 3
The heat generation amount of No. 1 is estimated from the motor current I and the energization time T1 or the stop time T2 from the end of energization, and when the heat generation temperature T of the motor 31 is higher than the predetermined temperature TM, the motor 31
If the temperature is lower than the predetermined temperature TM (time t10) without controlling the energization of the motor 31, the next switch operation by the operation switch 50 is permitted and the motor 31 is energized. It is possible to switch the drive state of the drive switching device 1 while suppressing the amount of heat generated by the motor and protecting the motor 31.

[0047]

According to the present invention, the control device detects the motor current flowing in the motor, detects the energization time from the start of the motor, and estimates the heat generation temperature of the motor from the motor current and the energization time. Thus, it is possible to regulate the energization of the motor based on the estimated heat generation temperature. As a result, the motor can be protected by a simple method for monitoring the heat generation state that causes a failure such as burnout, based on the motor current and the energization time from startup. With this, when there is a risk of heat generation in the motor, the energization of the motor can be surely limited by the motor temperature, and the motor can be downsized.

In this case, the control device detects the energization stop time after the completion of energization of the motor, estimates the heat generation temperature from the motor current and the current stop time, and operates until the heat generation temperature reaches a predetermined temperature. If you prohibit the selection operation by members,
Even after the driving of the motor is stopped, it is possible to estimate the heat generation temperature from the motor current and the power supply stop time, and monitor the state where the heat generation temperature of the motor decreases. As a result, when the heat generation temperature is higher than the predetermined temperature even after the driving of the motor is stopped, it is possible to protect the motor by prohibiting the driving of the motor according to the selection operation of the operation member. On the other hand, if the heat generation temperature after the driving of the motor is stopped becomes lower than the predetermined temperature, it becomes possible to permit the driving of the motor according to the selection operation of the operation member.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a drive switching device according to an embodiment of the present invention.

FIG. 2 is a sectional view of the drive switching actuator shown in FIG.

FIG. 3 is a view from A shown in FIG.

FIG. 4 is a configuration diagram of a drive switching device according to an embodiment of the present invention.

FIG. 5 is a time chart showing the relationship between time and current flowing through the motor of the drive switching device according to the embodiment of the present invention.

FIG. 6 is a time chart showing a relationship between heat generation temperature and time of the motor of the drive switching device according to the embodiment of the present invention.

FIG. 7 is a flowchart showing a process of a control device of the drive switching device according to the embodiment of the present invention.

[Explanation of symbols]

10 Drive switching device 31 motor 32 output mechanism 33 Rod (output member) 35 Rotational absorption mechanism 36 Limit switch 40 control device 50 Manual switch (operation member) TM predetermined temperature

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 3D036 GA14 GA22 GA32 GA46 GB05                       GB06 GB13 GD09 GG32 GG61                       GH13 GH15 GJ18                 3D043 AA07 AA10 AB17 EA02 EA17                       EA23 EA25 EB12 EB14 EE03                       EE18 EF11 EF12                 5H571 AA02 BB10 CC04 DD00 EE06                       GG04 JJ03 LL34 MM02 MM06

Claims (2)

[Claims] 1. A motor driven in response to energization, a motor-side rotating member that rotates together with an output shaft of the motor, and a drive state of the vehicle that moves with the drive of the motor so that the vehicle is driven in a first state or a first state. An output member that switches between one of two states and a rotation that is disposed between the output member and the motor-side rotating member output shaft and that absorbs the rotation of the motor when the rotation of the output member is restricted. An absorption mechanism, an operation member for selecting the drive state of the vehicle to either the first state or the second state by a selection operation, and controlling the drive of the motor according to the selection operation of the operation member to output the output. In a drive switching device including a control device that moves a member, the control device detects a motor current flowing in the motor and detects an energization time from the start of the motor. The drive switching device is characterized in that the heat generation temperature of the motor is estimated based on the motor current and the energization time, and energization to the motor is regulated based on the heat generation temperature. 2. The control device detects an energization stop time after ending energization of the motor, estimates the heat generation temperature from the motor current and the power supply stop time, and the heat generation temperature is a predetermined temperature. The drive switching device according to claim 1, wherein the operation by the operation member is prohibited until the following condition is satisfied.