JP4641293B2 - Overheat protection device for saddle-ride type vehicles - Google Patents

Description

The present invention relates to a thermal protection device for a saddle-type vehicle, in particular saddle-ride that estimates the temperature of the motor and motor peripheral devices, to limit the current in accordance with the estimated temperature to protect the motor and motor devices from overheating The present invention relates to an overheat protection device for a type vehicle .

  2. Description of the Related Art When steering a vehicle by turning a steering shaft, there is known an electric power steering system that applies a turning assisting force to the steering shaft by an electric motor to facilitate steering.

  Japanese Patent Application Laid-Open No. 2005-324796 describes a control device for an electric power steering apparatus that estimates the winding temperature of a motor and performs motor temperature protection control based on the estimated temperature in order to prevent overheating of the electric motor. Has been.

  In general, when estimating the winding temperature of a motor, the current value flowing through the winding and the resistance value of the winding are used according to Joule's law. That is, assuming that the current value is I, the resistance value is R, and the energization time is t, the calorific value Q can be estimated by Q = I × I × R × t (Equation 1).

  Although the calorific value is estimated by this equation 1, in order to estimate the temperature more accurately, the heat radiation amount must also be taken into consideration. The following equation 2 is a calorific value estimation formula including a constant a as a heat dissipation amount correction term. In this equation, the cumulative value T represents temperature.

Cumulative value T = Σ (K × I × I−a) (Formula 2). This expression 2 is an expression for estimating the temperature by integrating the heat generation amount when the power steering is operated and the electric motor is energized for the energization time, and the constant a is subtracted as the heat dissipation amount. The constant a in Equation 2 is estimated so that the accumulated value returns to zero in a longer time than the time until the temperature returns to normal temperature when the current is stopped from the maximum temperature of the winding in order to ensure temperature protection by estimating the temperature higher. Set a smaller value. This is because if the constant a is too large, the cumulative value T tends to be small, and the winding temperature can be easily estimated low. When the energization is not performed for a long time due to the constant a, the accumulated value T returns to zero. In Equation 2, the coefficient K is an integration coefficient, and is a numerical value obtained beforehand through experiments so that the calculated value approaches the actual measurement value.
JP-A-2005-324796

  If Equation 2 is used, the temperature of the electric motor can be estimated without using a temperature sensor, and if the estimated temperature is equal to or higher than a preset temperature, the current supply to the electric motor is stopped to stop the electric motor. Protection is achieved.

  However, in the electronic power steering device, the heat generation part due to energization is not limited to the motor (motor coil or brush), but also extends to peripheral devices such as a motor controller (particularly electronic components such as FET) for controlling the motor. All of these are subject to overheat protection. When all of a plurality of elements or components (hereinafter referred to as “components”) are to be subject to overheat protection, it is necessary to consider the heat generation and heat dissipation characteristics of each component. Since each part has a different heat capacity, some parts generate heat quickly and dissipate quickly, and other parts generate heat slowly and dissipate slowly.

  Therefore, when considering the heat generation and heat dissipation characteristics due to such heat capacity differences, the estimated temperature does not fall below all actual component temperatures, that is, the estimated temperature rises earlier than the temperature rise of all components during heat generation. However, when radiating heat, it must be determined so that it drops more slowly than the temperature drop of all parts.

  However, when the heat capacities of the respective parts are different, it is difficult to appropriately estimate the temperature. For example, a part may be presumed to be overheated and protection measures such as current limiting may be performed early. In this case, it may be delayed to release the protective device and return to normal operation even though the temperature of the component is actually decreasing. Further, since not only the heat capacity but also the heat-resistant temperature is different for each part, the temperature of a plurality of parts cannot be easily estimated with only one calculation formula.

An object of the present invention is to provide an overheat protection device for a saddle-ride type vehicle that can determine an estimated temperature suitable for preventing a plurality of parts from being overheated and appropriately protect them.

  The present invention for solving the above-mentioned problems is an overheat protection device for a device including a motor and a motor controller that controls the supply current of the motor within a predetermined upper limit value, based on the supply current to the motor. First temperature calculating means for calculating the estimated temperature of the motor, second temperature calculating means for calculating the estimated temperature of the motor controller based on the supply current to the motor, and the estimated estimated temperature of the motor First current value calculation means for determining an upper limit value of the supply current to the motor, and second current value calculation means for determining an upper limit value of the supply current to the motor in accordance with the estimated temperature of the estimated motor controller And selecting means for selecting one of the upper limit values of the currents calculated by the first current value calculating means and the second current value calculating means according to a preset reference. There is first characterized in that the Bei.

  Further, the present invention is characterized in that the selection means is configured to select the smaller one of the upper limit values of the currents calculated by the first current value calculation means and the second current value calculation means. There is a second feature.

  Further, the present invention is configured such that the first temperature calculation stage and the second temperature calculation means calculate an estimated temperature using the following equation, and at least a heat generation coefficient among the coefficients in the equation: A third feature is that Kup and heat dissipation coefficient Kdn are individually set for the motor and the motor controller. The calculation formula is as follows. Estimated temperature = Σ ((heat generation coefficient Kup × motor current I × I) − (heat dissipation coefficient Kdn × (previous integrated temperature Td−ambient temperature Tm)) + initial temperature T0.

  Further, according to the present invention, the heat generation coefficient Kup and the heat dissipation coefficient Kdn with the larger heat capacity are set smaller than the heat generation coefficient Kup and the heat dissipation coefficient Kdn with the smaller heat capacity according to the heat capacities of the motor and the motor controller. There is a fourth feature.

  In the present invention, the heat generation coefficient Kup and the heat dissipation coefficient Kdn are determined by the respective heat capacities of the motor current supply brush in the motor for the motor and the motor current switching element in the motor controller for the motor controller. This is the fifth feature.

  Furthermore, the present invention is a power steering apparatus motor in which the motor applies a steering assist force to the steering shaft according to the torque acting on the steering shaft, and the motor controller responds to the magnitude of the torque. A sixth feature is that the steering assist force is controlled by changing the motor supply current.

  According to the present invention having the first to sixth characteristics, the estimated temperature and the upper limit value of the current according to the estimated temperature are calculated individually for both the motor and the motor controller. Accordingly, appropriate current limiting can be performed.

  In particular, according to the second feature, since the motor supply current is controlled by selecting the smaller one of the calculated upper limit values of the current, the control is performed on the basis of the one that is less likely to overheat, and the device is reliably connected. Overheat protection can be done.

  Further, according to the third feature, the temperature can be estimated in consideration of the heat generation coefficient and the heat dissipation coefficient, and at least the heat generation coefficient and the heat dissipation coefficient are set separately for the motor and the motor controller, and the calculation formula itself is common. The configuration is simple.

  Moreover, according to the 4th characteristic, the appropriate overheat protection which considered the heat_generation | fever and heat radiation by the difference in heat capacity is possible.

  Furthermore, according to the fifth feature, among the component parts of the motor and the motor controller, the heat generation coefficient and the heat dissipation coefficient are set based on parts that have a small heat capacity compared to other parts and are likely to overheat. Overheat protection can be performed.

  Furthermore, according to the sixth feature, it is possible to more accurately estimate the temperature of the motor for the power steering device in a traveling state where the power steering frequently operates, and to protect it from overheating.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 2 is a left side view of a saddle-ride type vehicle incorporating an electric power steering device with an overheat protection device according to an embodiment of the present invention. A saddle-ride type vehicle (hereinafter simply referred to as “vehicle”) 1 includes front and rear left and right wheels 2 and 3 that are relatively large-diameter low-pressure balloon tires in front of and behind a compact and lightweight vehicle body. It is an ATV (All Terrain Vehicle) with improved driving performance.

  An engine 5 as a prime mover is mounted at the center of the body frame 4. The engine 5 is a water-cooled single-cylinder engine, and is arranged with the output shaft oriented in the front-rear direction of the vehicle 1. A propeller shaft 8f led forward from the lower part of the engine 5 is connected to the front wheels 2 via the front speed reduction mechanism 11 on the lower side of the front part of the vehicle body frame 4 so that power can be transmitted. Similarly, the propeller shaft 8r is connected to the rear wheel 3 via the rear reduction mechanism 12 at the lower rear side of the vehicle body frame 4 so as to be able to transmit power.

  In the engine 5, a throttle body 17 is connected to the rear portion of the cylinder portion 7 erected on the crankcase 6, and an air cleaner 18 is connected to the rear portion of the throttle body 17. An exhaust pipe 19 is connected to the cylinder portion 7, and a tip portion of the exhaust pipe 19 is connected to a silencer 21 at the rear of the vehicle body.

  A fuel tank 22 is provided at the front center in the vehicle width direction of the upper portion of the vehicle 1, and a passenger seat 23 is disposed behind the fuel tank 22. A battery 94 is disposed below the rear portion of the seat 23. A front portion of the fuel tank 22 is formed with a recess so that the steering shaft 25 can extend up and down. It is fixed. A radiator 26 for cooling the engine is disposed in front of the lower portion of the steering shaft 25, and a radiator fan 29 is provided in front of the radiator 26.

  A vehicle body cover 31 that covers the front portion of the vehicle body, a front fender 32 that covers the front wheel 2, a front protector 33, and a front carrier 34 are attached to the front portion of the vehicle body frame 4. A rear fender 35 and a rear carrier 36 that cover the upper portion of the rear wheel 3 are attached to the rear portion of the vehicle body frame 4.

  FIG. 3 is an enlarged side view of the main part of FIG. 2 showing the electric power steering apparatus. The upper and lower ends of the steering shaft 25 are supported by an upper support bracket 54 and a lower end support bracket 55 that are joined to the vehicle body frame 4, respectively. The electric power steering device 80 includes an actuator unit 81 provided at an intermediate portion of the steering shaft 25, and a control unit 93 as an electronic control unit (ECU) for driving and controlling a power assist motor 82 integrated with the actuator unit 81. Consists of. The power assist motor 82 is controlled based on a detection value of a torque sensor 91 as torque detection means provided in the actuator unit 81.

  The lower end portion of the steering shaft 25 is coaxially connected to the input shaft 83 of the actuator unit 81, and the output shaft 84 that is coaxial with these is supported by the lower support bracket 55 via a bearing 55a. The input shaft 83 and the output shaft 84 are connected to each other via a torsion bar 92 that is a part of the torque sensor 91 in the housing 85 of the actuator unit 81.

  Since the ground resistance acts on the front wheel 2, when the handle 24 is operated clockwise or counterclockwise, an input shaft 83 that is mechanically coupled to the handle 24 and an output shaft that is mechanically coupled to the front wheel 2. 84, relative rotational force is generated. As a result, the torsion bar 92 is twisted, and the steering torque of the handle 24 can be detected based on the twist amount. The detected value of the steering torque is input to the control unit 93, and the power assist motor 82 is driven and controlled according to this detected value.

  As a result, when the handle 24 is rotated, the steering mechanism including the steering shaft 25 (output shaft 84) is given a rotation assist force from the power assist motor 82 in addition to the operation force from the handle 24. Therefore, the operation amount of the handle 24 is relatively reduced.

  FIG. 4 is an enlarged sectional view around the output shaft 84. In FIG. 4, the pair of left and right tie rods 75 extend in the vehicle body width direction of the vehicle 1 and are connected to the left and right front wheels 2, respectively. Ends of these tie rods 75 (ends opposite to the side to which the front wheels 2 are connected) are connected to the pitman arm 84a at the center in the vehicle body width direction. The pitman arm 84a is splined to the output shaft 84.

  The pitman arm 84a is located immediately below the lower support bracket 55, and the pitman arm 84a and the bearing 55a constitute a handle stopper that defines the maximum turning position around the steering shaft 25, that is, the steering wheel 24. is doing. That is, a stopper main body 55b projects from the lower side of the bearing 55a, and contact portions 84b are formed on the left and right front surfaces of the pitman arm 84a, respectively. When the predetermined angle θ1 is rotated clockwise or counterclockwise from the straight traveling state, the contact portion 84b contacts the side portion of the stopper main body 55b, and the maximum steering state in which further steering operation is restricted is achieved. A maximum steering switch 10 serving as a maximum steering detection means is provided on each side of the stopper main body 55b.

  FIG. 5 is a side sectional view of a main part of the power assist motor 82, and FIG. 6 is a front sectional view of the same. The power assist motor 82 is held by a housing 82a, a motor shaft 82c rotatably supported by a bearing 82b fitted in the housing 82a, a commutator 82d attached to the motor shaft 82c, and a brush holder 82e. A brush 82g biased by a spring 82f so as to abut on the outer periphery of the commutator 82d. The brush holder 82e is attached to the housing 82a via an insulating plate 82h.

  FIG. 7 is a cross-sectional view of the electric power steering control device (motor controller), and FIG. 8 is a plan view of the control unit 93 with the lid removed. The control unit 93 conforms to the case 95 made of aluminum die-casting, four FETs 97 as switching elements disposed in the case 95 via an insulating sheet 96, a substrate 98 attached with the FET 97, and the case 95. It consists of a resin lid 99. The FET 97 is bonded to an aluminum case 95 having good thermal conductivity so that the heat capacity is increased.

  FIG. 9 is a block diagram showing the main functions of the control unit 93. The control unit 93 detects and detects the steering angle of the steering shaft 25 based on the maximum steering detection signal input from the maximum steering switch 10 and the voltage and current values supplied to the power assist motor 82. The steering assist force to the steering shaft 25 is controlled based on the steered angle.

  The control unit 93 calculates a relative turning angle (steering angle from an arbitrary position) of the steering shaft 25 and a turning reference position of the steering shaft 25 based on the maximum turning detection signal. A reference position estimation unit 93e for estimating a steering reference state for the vehicle body).

  The target base current calculation unit 93f detects the torque detected by the torque sensor 91, the absolute turning angle of the steering shaft 25 (relative turning angle from the turning reference position) that can be known from the relative turning angle and the turning reference position. Based on the above, a target base current value that is a motor current value serving as a reference for the steering assist force is calculated. It is desirable to add the vehicle speed to the parameter to determine the target base current value.

  The target base current value is input to the target current limiter 93b. A current sensor 93a for detecting the current supplied to the power assist motor 82 is provided, and the current value detected by the current sensor 93a is input to the target current limiting unit 93b and the current feedback control unit 93c.

  In order to protect the power assist motor 82 and the motor output unit 93h from overheating, the target current limiting unit 93b determines a limit ratio (ratio) of the current supplied to the power assist motor 82, and the ratio and the target base current value. Based on the above, a limited target current value is calculated. Specifically, based on the supply current to the power assist motor 82, the brush temperature of the power assist motor 82 and the temperature of the FET constituting the switching circuit of the motor output section 93h are calculated, and the target is determined according to those temperatures. Calculate the current value. The target current limiting unit 93b and calculation formulas used for temperature estimation will be further described later.

  The target current calculation unit 93g adds inertia correction and damper correction to the target current value output from the target current limiting unit 93. Inertia correction corrects the target current value using the amount of change in torque as a parameter. Considering the motor inertia, the weight felt by the driver via the handle 24 at the start of turning can be improved, and the steering feeling can be improved. The damper correction corrects the target current value using the rotation speed of the power assist motor 82 as a parameter. The correction value is set in a direction to decrease the target current value as the rotational speed increases. The steering feel can be improved by optimizing the response of the handle 24.

  The current from the battery 94 is supplied to the power assist motor 82 via the motor output unit 93h. The motor output section 93h is a switching circuit in which the FET 97 is configured as a bridge, and changes a current value supplied to the power assist motor 82 by the on-duty of the FET 97. The current feedback control unit 93c determines the duty instruction value so that the current value detected by the current sensor 93a converges to the target current value, and inputs the duty instruction value to the motor output unit 93h.

  As described above, the power assist motor 82 is driven and controlled in consideration of not only the steering torque detection signal from the torque sensor 91 but also the absolute steering angle of the steering shaft 25. For example, the power assist motor 82 cuts the handle 24 from the straight traveling position of the vehicle. Fine control is possible, for example, the steering assist force can be changed depending on the time and when the steering wheel 24 is returned to the vehicle straight position. In addition, the current supplied to the power assist motor 82 is limited by the estimated temperature of the power assist motor 82 and the motor controller 93, and when the estimated temperature exceeds the planned overheat protection temperature, the steering assist force is reduced or made zero. The power assist motor 82 and its peripheral components, the motor controller (particularly the FET 97) are protected from overheating.

  A temperature estimation method for the power assist motor 82 and the motor controller 93 executed by the target current limiting unit 93b will be described in comparison with the prior art. In the past, overheat protection was performed based on the temperature of the power assist motor. In the present embodiment, the temperature is also estimated for a motor controller in which the same current as that flowing in the assist motor flows, the motor current is limited according to the higher estimated temperature of the two, and the power assist motor and the motor controller are protected from overheating. Configured to do.

  Conventionally, the temperature of the power assist motor 82 is estimated based on the accumulated value of the difference between the heat generation amount and the heat dissipation amount. As described in relation to Equation 2 in the section “Background Art”, conventionally, the heat dissipation amount is set as a constant a, and a certain amount of heat is dissipated regardless of whether or not power is being supplied. Since the constant a is an extremely small value, the cumulative value T corresponding to the temperature tends to continue to increase without decreasing in a running state where energization continues. Therefore, the target current value is limited in a short time, and the steering assist force may not be generated.

  However, in actuality, for example, in off-road traveling in which the operation of returning the handle 24 is frequent, the temperature is almost balanced by repetition of heat generation and heat dissipation. FIG. 10 is a diagram showing a cumulative value T calculated based on the above-described equation 2 under off-road driving conditions, and an actually measured temperature TB at the brush portion of the power assist motor 82. As shown in this figure, the cumulative value T continues to rise, but the measured temperature TB is balanced at about 140 ° C. If the accumulated value T continues to rise, the temperature represented by the accumulated value T exceeds the threshold temperature (heat resistant temperature) that limits the target current value, even though the measured temperature TB is in equilibrium. Therefore, the target current value is limited, and the application of the steering assist force is stopped or reduced.

  Therefore, it was examined to correct Equation 2 so that the actual temperature of the power assist motor 82 can be represented by the calculated value. First, heat generation / heat radiation characteristics of the power assist motor 82 and the motor controller 93 will be described. FIG. 11 is a heat / heat dissipation characteristic diagram of the power assist motor 82 and the motor controller 93. The temperature of the power assist motor 82 is represented by the temperature of the brush of the motor, and the temperature of the motor controller 93 is represented by the temperature of the FET 97.

  In FIG. 11A, when energization of the power assist motor 82 is started at time t0, the temperature Tpm suddenly increases because the brush has a small heat capacity, and reaches the heat resistant temperature Ty at time t1. When the energization is stopped at time t1 when the brush temperature Tpm reaches the heat-resistant temperature Ty, the brush temperature Tpm rapidly decreases.

  On the other hand, since the FET bridge circuit attached to the heat sink member such as the aluminum die-cast case 95 has a large heat capacity, as shown in FIG. 11B, when the energization is started at time t0, the brush of the power assist motor 82 and The temperature Tdv rises slowly and reaches the heat-resistant temperature at time t2. Therefore, the energization is stopped at time t2 for overheat protection, but due to the large heat capacity, the temperature Tdv continues to rise beyond the heat-resistant temperature Ty, and finally falls at time t3 and slowly falls.

  Since the power assist motor 82 and the FET 97 of the motor controller 93 are started and stopped at the same timing, the temperature changes as follows. FIG. 12 is a diagram showing temperature changes of the power assist motor 82 and the motor controller 93 when energization is started and stopped at the same timing. In FIG. 12A, the energization is stopped when the temperature Tpm of the power assist motor 82 reaches the heat-resistant temperature Ty at time t1, and the energization is started when the temperature Tpm falls to the initial temperature T0 at time t4.

  When the motor controller 93 is energized at the same timing as this energization timing, the temperature Tdv of the motor controller 93 changes as shown in FIG. As shown in FIG. 12 (b), at the same timing as the energization timing of the power assist motor 82 having a small heat capacity, the motor controller 93 having a large heat capacity has a smaller temperature drop during energization stop than the temperature rise during energization. Therefore, the temperature cannot be properly controlled unlike the power assist motor 82. Therefore, the temperature Tdv eventually exceeds the heat-resistant temperature at time t5, and energization is stopped at this time t5 for overheat protection.

  In view of this characteristic, an example in which the temperature is estimated by combining a fast temperature rise and a slow temperature drop is shown in FIG. In FIG. 13, when the estimated temperature Te is superimposed on the temperature Tpm of the power assist motor 82 and the temperature Tdv of the motor controller 93, the estimated temperature Te exceeds both the measured temperature Tpm and the temperature Tdv, and the estimated temperature Te is estimated according to the estimated temperature Te. Control for stopping or reducing the current supply may be performed so that Te does not exceed the heat resistant temperature Ty. However, the estimated temperature Te returns to the initial temperature T0 considerably later than the time when the actual temperatures Tpm and Tdv of the power assist motor 82 and the motor controller 93 drop to the initial temperature T0. Therefore, there are cases where it is not possible to cope with the situation where the power steering operation is frequently performed.

  Therefore, it is conceivable that energization is resumed when the estimated temperature Te falls to the reference temperature set higher than the initial temperature T0, thereby enabling frequent power steering operation. However, there are the following problems in that case. FIG. 14 is a diagram illustrating the estimated temperature Te assuming that energization is resumed when the estimated temperature Te decreases to the reference temperature Tr higher than the initial temperature T0. As shown in FIG. 14, since energization is resumed from the reference temperature Tr set higher than the initial temperature T0, the power steering operation can be restored in a short time, while the estimated temperature Te becomes the heat resistant temperature Ty in a short time. The current limit is performed again. That is, the power steering operation is restored in a short time after the current limiting operation, but the time until the current is limited again is shortened.

  Thus, a defect is expected at a single estimated temperature. Therefore, in the embodiment shown below, an estimated temperature is calculated for each of a plurality of parts (here, the power assist motor 82 and the motor controller 93), and the target current value determined according to the estimated temperature is small. The current to be supplied to the power assist motor 82 and the motor controller 93 is determined.

  In the temperature simulation result according to Formula 2, the estimated temperature Te decreases linearly because the constant a is only subtracted for each calculation regardless of the difference between the temperature of the power assist motor 82 and the ambient temperature.

  Therefore, in this embodiment, an estimation formula is set in consideration of the difference between the temperature of the power assist motor 82 and the motor controller 93 and the ambient temperature. In setting the estimation formula, the heat generation coefficient and the heat dissipation coefficient were set so that the estimated temperature Te exceeded the actually measured temperature. The estimation formula is as follows.

  Cumulative value TS = Σ ((heat generation coefficient Kup × current I × I) − (heat dissipation coefficient Kdn × (previously accumulated temperature Td−ambient temperature Tm))) + initial temperature T0 (Equation 3). The initial temperature T0 and the ambient temperature Tm are default values, and both are preferably set to be higher than expected maximum values of the ambient temperature of the power assist motor 82 and the motor controller 93.

  FIG. 1 is a block diagram showing the main functions of the target current limiting unit 93b. The first coefficient storage unit 15 stores in advance a heat generation coefficient Kup of the power assist motor 82, a heat dissipation coefficient Kdn, an initial temperature T0, and a motor ambient temperature Tm as correction coefficients. In the second coefficient storage unit 16, a heat generation coefficient Kup2 of the motor controller 93, a heat dissipation coefficient Kdn2, an initial temperature T02, and a motor controller ambient temperature Tm2 are stored in advance as correction coefficients.

  The first estimated temperature calculation unit 13 calculates the estimated temperature TS1 of the power assist motor 82 using the estimation formula 3 based on the motor current I and the correction coefficient input from the first coefficient storage unit 15. The second estimated temperature calculation unit 14 calculates the estimated temperature TS2 of the motor controller 93 using the estimation formula 3 based on the motor current and the correction coefficient input from the second coefficient storage unit 15. However, the coefficients Kup and Kdn and the temperatures T0 and Tm in the estimation formula 3 are read as Kup2, Kdn2 and temperatures T02 and Tm2, respectively.

  The first target current value calculation unit 27 determines the first temporary target value of the motor current based on the estimated temperature TS1 of the power assist motor 82 input from the first estimated temperature calculation unit 13. The second current limit value calculation unit 28 determines a second temporary target value of the motor current based on the estimated temperature TS2 of the motor controller 93 input from the second estimated temperature calculation unit 14.

  The target current value selection unit 30 selects the smaller one of the first temporary target value and the second temporary target value as the target current value. If the motor current is limited according to a small value, both the power assist motor 82 and the motor controller 93 can be protected from overheating. The selected target current value is subjected to inertia and damper correction by the target current calculation unit 93g and output.

  The target current limiting unit 93b will be described in more detail. FIG. 15 is a detailed block diagram (part 1) of the target current limiting unit. The first estimated temperature calculation unit 13 includes a motor heat generation amount calculation unit 131, a motor heat generation amount integrated value buffer 132, addition units 133 and 134, and a multiplication unit 135. The first target current value calculation unit 27 includes a current value ratio map 271 and a multiplication unit 272.

  The current value (motor current value) I detected by the current sensor 93 a is squared by the multiplication unit 135. The squared value of the motor current value I is input to the motor heat generation amount calculation unit 131 together with the heat generation coefficient Kup and the heat dissipation coefficient Kdn. The motor heat generation amount calculation unit 131 also receives the ambient temperature Tm of the power assist motor 82 and calculates the motor heat generation amount Qpm according to the following equation 4. Motor heat generation amount Qpm = Kup × I × I−Kdn × (Td−Tm) (Formula 4). The motor heat generation amount Qpm is accumulated by the addition unit 133 and input to the motor heat generation amount integrated value buffer 132. The accumulated value Td of the motor heat generation amount Qpm is fed back to the motor heat generation amount calculation unit 131 as the integrated temperature Td. Further, the integrated temperature Td is input to the adding unit 134, and added to the initial temperature T0 to output a cumulative value TS1. A target current value supplied to the power assist motor 82 is determined according to the cumulative value TS1.

  The cumulative value TS1 is input to a ratio map 271 provided in the first target current value calculation unit 27, and a current ratio, that is, a current limiting ratio is determined. The ratio set in the ratio map 271 is “1.0” until the cumulative value TS1 reaches the planned value, and is “0” in an area exceeding the planned value. In the multiplier 272, the target base current value Ib is multiplied by the ratio. Therefore, when the ratio is “1.0” or less, the target base current value Ib is limited. The target current value output from the multiplier 272, that is, the limited target base current value is input to the target current value selector 30.

  FIG. 16 is a detailed block diagram of the second estimated temperature calculation unit 14. The second estimated temperature calculation unit 14 includes a motor controller heat generation amount calculation unit 141, a motor controller heat generation amount integrated value buffer 142, addition units 143 and 144, and a multiplication unit 145. The second target current value calculation unit 28 includes a current value ratio map 281 and a multiplication unit 282.

  The current value (motor current value) I detected by the current sensor 93 a is squared by the multiplier 145. The squared value of the motor current value I is input to the motor controller heat generation amount calculation unit 141 together with the heat generation coefficient Kup2 and the heat dissipation coefficient Kdn2. An ambient temperature Tm2 of the motor controller 93 is also input to the motor controller heat generation amount calculation unit 141, and a motor controller heat generation amount Qdv is calculated according to the following equation 5. Motor heating value Qdv = Kup2 * I * I-Kdn2 * (Td2-Tm2) (Formula 5). The motor controller heat generation amount Qdv is accumulated by the adding unit 143 and input to the motor controller heat generation amount integrated value buffer 142. The accumulated value of the motor controller heat generation amount Qdv, that is, the integrated temperature Td2, is fed back to the motor controller heat generation amount calculation unit 141. Further, the integrated temperature Td2 is input to the adding unit 144, added with the initial temperature T0, and the accumulated value TS2 is output.

  Since the configuration and operation of the second target current value calculation unit 28 are the same as those of the first target current value calculation unit 27, description thereof will be omitted.

  In the above embodiment, the ambient temperatures Tm and Tm2 are fixed values. However, assuming a space where heat is likely to be trapped, it is inconvenient if the ambient temperatures Tm and Tm2 are fixed values. Therefore, the ambient temperatures Tm and Tm2 are calculated in consideration of heat accumulation. The calculation formula of the ambient temperature Tm is the following formula 6.

  Ambient temperature Tm = Σ ((heat generation coefficient Kmup × current I × current I) − (heat dissipation coefficient Kmdn × (previous ambient temperature Tm−ambient temperature Tm0))) + initial temperature T0 (Expression 6). Equation 6 has a different coefficient, and is configured in the same manner as Equation 3. Also, the ambient temperature Tm2 is calculated using this equation in the same manner as the ambient temperature Tm. The heat generation coefficient Kmup and the heat dissipation coefficient Kmdn may be common to the heat generation coefficient Kup and the heat dissipation coefficient Kdn.

  Further, when the heat capacity is small, that is, when the periphery of the power assist motor 82 is a relatively open space, the ambient temperature Tm can be approximately calculated by Expression 7. Ambient temperature Tm = Σ ((heat generation coefficient Kmup × current I × current I−a) (Expression 7). Expression 7 is a simple expression in which the heat dissipation amount is a constant a.

  Whether to use Equation 6 or Equation 7 as the calculation formula for the ambient temperature Tm depends on the situation of the space surrounding the power assist motor 82 and the motor controller 93 (whether it is wide or narrow, or there are many heating parts in the surroundings, etc.) It may be determined according to.

  Further, the heat generation coefficient Kmup and the heat radiation coefficient Kmdn may be fixed values, and the ambient temperatures Tm and Tm2 may be corrected as a function of the motor current I. FIG. 17 is a block diagram showing a main function for calculating the ambient temperatures Tm and Tm2 as a function of the motor current I with the heat generation coefficient Kmup and the heat dissipation coefficient Kmdn as fixed values. In FIG. 17, the integration coefficient calculation unit 37 outputs the integration coefficient RTO as a function of the motor current I × I and can be configured by a map. When the motor current I is input, the integration coefficient calculation unit 37 calculates a corresponding integration coefficient RTO from the map and inputs it to the addition unit 38. The adder 38 adds the latest integration coefficient RTO inputted from the integration coefficient calculator 37 to the accumulated integration coefficient ΣRTO accumulated in the integration value buffer 39. The added integration coefficient RTO is input to the integration value buffer 39 as a new accumulation integration coefficient ΣRTO.

  The accumulated integration coefficient ΣRTO accumulated in the accumulated value buffer 39 is input to the multiplication unit 40, and the multiplication unit 40 multiplies the default motor ambient temperature Tm by the accumulated integration coefficient ΣRTO to correct the motor ambient temperature Tm. The corrected motor ambient temperature Tm is supplied to the motor heat generation amount calculation unit 131.

  The motor controller ambient temperature Tm2 is also corrected by the same configuration as in FIG. 17 and supplied to the motor controller heat generation amount calculation unit 141.

  According to the above-described embodiment, it is possible to estimate the temperatures of the power assist motor 82 and the motor controller 93 without using a temperature sensor, and to prevent these overheatings. That is, the current is limited by the target current value determined based on the ratio read from the ratio map 271 or 281. However, when the current is limited, the accumulated values TS1 and TS2 calculated on the basis of the current value are reduced, so that the ratio is increased according to the ratio map 271 and 281 and the current limit is relaxed. Then, since the current increases, the accumulated values TS1, TS2 increase again, the ratio decreases and the current decreases, and the ratio increases again. Thus, after the ratio is reduced from 1.0 in accordance with the cumulative values TS1 and TS2, the limit current fluctuates little by little in the vicinity of a certain current value and becomes an equilibrium state, and the current cannot be limited to the current value or less.

  In order to solve this, the above-described embodiment can be modified as follows. FIG. 18 is a principal functional block diagram of the target current limiting unit according to the second embodiment, and the same reference numerals as those in FIG. 1 denote the same or equivalent parts. The motor heat generation amount calculation unit 42 is the same as the motor heat generation amount calculation unit 131 except that the heat generation amount Qpm of the power assist motor 82 is calculated using the following equation 8 instead of the calculation equation 5. Motor heat generation amount Qpm = Kup × (I / Rc) × (I / Rc) −Kdn × (Td−Tm) (Equation 8) That is, the motor heat generation amount calculation unit 42 includes a calculation formula (Formula 8) in which “I” in Formula 4 is replaced with “I / Rc”.

  The non-limit current calculation unit 43 calculates the current when the target current is not limited by the current ratio by dividing the current motor current I by the current ratio Rc. The multiplying unit 44 squares the output (I / Rc) of the non-limit current calculating unit 43 and inputs it to the motor heat generation amount calculating unit 42.

  The motor heat generation amount calculation unit 42 is the value (I / Rc) × (I / Rc) input from the multiplication unit 44, the heat generation coefficient Kup, the heat dissipation coefficient Kdn, the ambient temperature Tm, the current value I / Rc, and the integrated value. The integrated temperature Td fed back from the buffer 142 is input to calculate the calorific value Qm and output to the adder 143. The output of the integrated value buffer 142, that is, the integrated temperature Td is input to the adding unit 144, and is added to the initial temperature T0 to output the accumulated value TSm. Thus, the cumulative value TSm calculated on the basis of the current I / Rc when not limited does not decrease even if the ratio decreases, and continues to increase. Accordingly, the ratio decreases correspondingly, and the target current is limited.

  The ratio determination unit 45 determines whether or not the current ratio has decreased below a predetermined value (zero or a planned lower limit ratio). If the current ratio has not decreased below the predetermined value, the current ratio Rc is input to the non-limit current calculation unit 43. When the current ratio has decreased to a predetermined value, the ratio resetting unit 46 is activated. The ratio resetting unit 46 inputs “1.0” as the ratio Rc to the non-limit current calculating unit 43. This resetting or resetting of the ratio can prevent the problem of dividing the current I with the ratio Rc = 0, and can prevent the cumulative value TS1 from increasing in a state where the current is sufficiently limited.

  If the current limit state is continued for a long time, the accumulated value TS1 increases excessively, and it takes time for the accumulated value to decrease after the steering operation is stopped, and the current limit state returns to the normal state. The problem of delaying can occur. By resetting the ratio Rc to “1”, it is possible to return from the current limit state to the normal state in an appropriate time.

  The unrestricted current calculation unit 43 divides the current motor current by the current ratio to calculate the current value for calculating the heat generation amount. The value can be modified so as to be corrected to a higher value using the ratio.

  The motor controller heat generation amount calculation unit 141 can also be modified as if the motor heat generation amount calculation unit 131 is changed to the motor heat generation amount calculation unit 42, but the configuration can be made in the same manner, and thus the description thereof is omitted.

  As described above, the target current value is calculated by estimating the temperature using different calculation formulas for the power assist motor 82 and the motor controller 93, and the current is limited to the smaller one of the target current values. did. Therefore, each estimated temperature obtained by calculation can be approximated to the actual temperature shown in FIG. 12, and the current limitation is not applied too early, and the restart of energization is not delayed, and the power assist is properly performed. The motor 82 and the motor controller 93 can be protected from overheating.

  In each of the above embodiments, different heat generation coefficients, heat dissipation coefficients, ambient temperatures, initial temperatures, and the like are set in advance for the power assist motor 82 and the motor controller 93. However, among these, the heat assist coefficient and the heat dissipation coefficient of the power assist motor 82 and the motor controller 93 that are directly affected by the heat capacity are set at least exclusively for each other, and the others may be common coefficients. Further, regarding the ratio map, different ones may be provided exclusively for estimating the temperatures of the power assist motor 82 and the motor controller 93, but a single ratio map may be used in common.

  Although the above-mentioned embodiment showed the example which applied the present invention to the electric power steering device, the protection device of the present invention is not limited to the power steering device, and accumulates the difference between the calorific value and the heat radiation amount to the motor. The present invention can be widely applied to a system that includes means for estimating the temperature and the temperature of the motor controller and protects the motor and the motor controller from overheating based on the estimated temperature. Furthermore, it is possible to estimate individual temperatures including not only the motor controller but also peripheral devices of the motor and determine an estimated temperature common to them.

It is a block diagram which shows the principal part function of the target current limiting part in the control apparatus for electric power steering which concerns on one Embodiment of this invention. 1 is a left side view of a saddle-ride type vehicle incorporating an electric power steering control device of the present invention. It is a principal part enlarged side view of FIG. It is AA sectional drawing in FIG. It is side surface sectional drawing of a power assist motor. It is front sectional drawing of a power assist motor. It is sectional drawing of a motor controller. It is an internal front view of a motor controller. It is a block diagram which shows the principal part function of the control apparatus for electric power steering. It is a figure which shows the accumulated value T which is a motor temperature simulation result on off-road driving conditions, and the actual measurement temperature TB in the brush part of a power assist motor. It is a figure which shows the heat_generation | fever and heat dissipation characteristic of the components contained in a power steering apparatus. It is a figure which shows the heat_generation | fever and heat dissipation characteristic of components at the time of intermittent electricity supply. It is a figure which shows the change of the estimated temperature calculated by the common calculation formula. It is a figure which shows the change of the estimated temperature at the time of carrying out intermittent electricity supply. It is a detailed block diagram (the 1) of a target current limiting part. It is a detailed block diagram (the 2) of a target current limiting part. It is a block diagram which shows the function of the means to correct | amend ambient temperature. It is a detailed block diagram of the target current limiting unit according to the second embodiment of the present invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Saddle-ride type vehicle, 10 ... Maximum steering switch, 13 ... 1st estimated temperature calculation part, 14 ... 2nd estimated temperature calculation part, 25 ... Steering shaft, 27 ... 1st target electric current value calculation part, 28 ... 2nd Target current value calculation unit 30 ... Target current value selection unit 43 ... Non-limit current calculation unit 46 ... Ratio resetting unit 80 ... Electric power steering device 82 ... Power assist motor 91 ... Torque sensor 92 ... Torsion Bar, 93 ... Motor controller, 93a ... Current sensor, 93b ... Target current limiting unit, 131 ... Motor heat generation amount calculation unit, 141 ... Motor controller heat generation amount calculation unit, 271, 281 ... Ratio map

Claims (7)

In the overheat protection device for a saddle-ride type vehicle of a device including a motor (82) and a motor controller (93) for controlling a supply current of the motor within a predetermined upper limit value,
First temperature calculating means (13) for calculating an estimated temperature (TS1) of the motor based on a supply current to the motor;
Second temperature calculating means (14) for calculating an estimated temperature (TS2) of the motor controller based on a supply current to the motor;
First current value calculating means (27) for determining an upper limit value of a current supplied to the motor according to the estimated temperature (TS1) of the estimated motor;
A second current value calculating means (28) for determining an upper limit value of a current supplied to the motor according to the estimated temperature (TS2) of the estimated motor controller;
Selecting means (30) configured to select the smaller one of the upper limit values of the currents calculated by the first current value calculating means (27) and the second current value calculating means (28); and,
The first temperature calculating stage (13) and the second temperature calculating means (14) are configured to calculate an estimated temperature using the following equation, and at least heat is generated among the coefficients in the equation. The coefficient Kup and the heat dissipation coefficient Kdn are individually set for the motor and the motor controller,
In accordance with the respective heat capacities of the motor and the motor controller, the heat generation coefficient Kup and the heat dissipation coefficient Kdn with the larger heat capacity are set smaller than the heat generation coefficient Kup and the heat dissipation coefficient Kdn with the smaller heat capacity,
The motor (82) is provided in front of the engine (5) below the rear portion of the steering shaft (25), and the motor controller (93) is provided in an upper front portion of the steering shaft (25). An overheat protection device for saddle riding type vehicles .
Estimated temperature = Σ ((heat generation coefficient Kup × motor current I × I) − (heat dissipation coefficient Kdn × (previously accumulated temperature Td−ambient temperature Tm)) + initial temperature T0 (formula) Regarding the motor (82), the heat generation coefficient depends on the heat capacity of the motor current supply brush (82g) in the motor and on the motor controller (93) depending on the heat capacity of the motor current switching element (97) in the motor controller. The overheat protection device for a saddle-ride type vehicle according to claim 1, wherein Kup and a heat radiation coefficient Kdn are determined . Current ratios provided as current limiting ratios, which are provided in the first current value calculating means (27) and the second current value calculating means (28), respectively, and the estimated temperatures (TS1, TS2) calculated by the above formulas are respectively input. Two ratio maps (271, 281) for outputting (Rc);
The current ratio (Rc) output from each of the two ratio maps (271, 281) is multiplied by the target base current value (Ib), and each multiplication result is used as the upper limit value of the supply current to the motor. 30) and a multiplication unit (272, 282) for input to
2. The current ratio set in the ratio map is set to “1.0” until the estimated temperature reaches a predetermined value, and is set to “0” in a region exceeding the predetermined value. Or an overheat protection device for a saddle-ride type vehicle according to 2 . An unrestricted current calculation unit (43) that calculates a current when the base target current (Ib) is not limited by the current ratio by dividing the current motor current (I) by the current current ratio (Rc) is provided. ,
Wherein said motor current (I) the motor current (I) / current ratio (Rc) by replacing with overheat protection device for a saddle-type vehicle according to claim 3, wherein that you input to the formula. A ratio determination unit (45) for determining whether or not the current current ratio (Rc) is reduced to zero or a predetermined value that is a predetermined lower limit ratio;
If the current ratio (Rc) has not decreased below the predetermined value, the ratio determining unit (45) inputs the current ratio (Rc) to the non-limit current calculating unit (43), Current ratio (Rc) is reduced to the predetermined value, current limit ratio resetting means (46) for inputting “1.0” as the current ratio (Rc) to the non-limit current calculation section (43). ) overheat protection device for a saddle-type vehicle according to claim 4, wherein the biasing to Rukoto a. The saddle riding type vehicle is an uneven terrain vehicle,
Said motor (82), and a steering assist force corresponding to the torque acting on the steering shaft (25) a power steering system for a motor for applying to said steering shaft (25),
The said motor controller (93) is comprised so that a motor supply current may be changed according to the magnitude | size of the said torque, and the said steering assist force may be controlled. The overheat protection device for saddle-ride type vehicles according to 1 . The rough terrain vehicle is
An engine (5) mounted in the center of the body frame (4);
An engine cooling radiator (26) disposed in front of a lower portion of the steering shaft (25);
A vehicle body cover (31) covering the front of the vehicle body;
An upper support bracket (54) and a lower end support bracket (55) which are joined to the vehicle body frame (4) and support the upper and lower ends of the steering shaft (25) to the vehicle body frame (4) are provided. The overheat protection device for a saddle-ride type vehicle according to claim 6.

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