JP6372231B2 - Torque measurement method for rotating member - Google Patents

Description

  The present invention relates to a method for measuring torque transmitted by rotating members constituting various rotary machine devices such as a gear shaft of a transmission for an automobile.

  The rotational speed of the rotary shaft constituting the automatic transmission for automobiles and the torque transmitted by the rotary shaft are measured, and the measurement results are used as information for performing shift control of the transmission or engine output control. It has been used conventionally. On the other hand, as a device that can be used for measuring the torque, the amount of elastic torsional deformation of the rotating shaft transmitting torque is converted into a phase difference between the output signals of a pair of sensors. An apparatus for measuring the torque based on the above is known (for example, see Patent Document 1). Such a basic structure of the torque measuring device will be described with reference to FIG. 1, which shows an example of a torque measuring device to which the torque measuring method of the present invention is applied.

  The torque measuring device 1 has a pair of encoders 3a and 3b externally fixed at two positions in the axial direction of the rotating member 2 to be measured. The magnetic characteristics of the outer peripheral surfaces of the encoders 3a and 3b, which are detected parts, are alternately changed at equal pitches in the circumferential direction. In addition, the pitches at which the magnetic properties of the outer peripheral surfaces change in the circumferential direction are equal to each other on the outer peripheral surfaces. The two sensors 4a and 4b are supported by a housing (not shown) in a state where the tip portions which are the detection portions of the pair of sensors 4a and 4b are opposed to both the outer peripheral surfaces. These two sensors 4a and 4b change their output signals in response to changes in the magnetic characteristics of the portions where their own detection units are opposed to each other. For this purpose, a magnetic detection element such as a Hall element or a magnetoresistive element is incorporated in the detection part of both sensors 4a and 4b.

  The output signals of the sensors 4a and 4b as described above periodically change as the encoders 3a and 3b rotate together with the rotating member 2. The frequency (and period T) of this change takes a value commensurate with the rotational speed of the rotating member 2. For this reason, the said rotational speed is calculated | required based on this frequency (or period T). When the rotating member 2 is elastically twisted and deformed as torque is transmitted by the rotating member 2, the encoders 3a and 3b are relatively displaced in the rotational direction. As a result, the phase difference ratio ε (= phase difference λ / period T) existing between the output signals (A phase, B phase) of both the sensors 4a and 4b changes. The phase difference ratio ε takes a value commensurate with the torque (the amount of elastic torsional deformation of the rotating member 2). Therefore, the torque can be obtained based on the phase difference ratio ε. That is, the relationship between the phase difference ratio ε and the torque, which have been examined in advance by calculation or experiment, is stored as a map or calculation formula in a memory of a calculator (not shown). Then, the torque corresponding to the phase difference ratio ε at that time is obtained (calculated) by the computing unit using such a map or calculation formula.

A method for measuring torque based on such a phase difference ratio ε will be specifically described with reference to FIG. 6 in addition to FIG. The phase difference (initial phase difference) λ ₀ between the output signals of the sensors 4a and 4b in a state where the rotating member 2 is not transmitting torque (initial state) is represented by a solid line in the upper stage of FIG. As shown by the lower broken line, it is set to 1/2 of one period T (λ ₀ = T / 2, 180 degrees). When the rotating member 2 is elastically twisted and deformed as the torque is transmitted by the rotating member 2 from such an initial state, for example, as shown by a solid line in FIG. The phase of the output signal of the other (B phase) sensor 4b advances with respect to the phase of the output signal of the sensor 4a, and the phase difference λ between the output signals of both the sensors 4a and 4b is the initial phase difference λ _0. Smaller than.

At the time of torque transmission by the rotating member 2 (during the rotational movement of the rotating member 2), the computing unit is included in both the A phase and the B phase that are input from the sensors 4a and 4b. The falling edge input time is measured sequentially. Among the falling edges included in the output signal (A phase) of one of the sensors 4a and 4b, the computing unit includes two falling edges F _A1 that are continuously input from each other. Of the falling edges included in the input time t _A1 and t _{A2 of} F _A2 and the output signal (phase B) of the other sensor 4b, one input is made between these input times t _A1 and t _A2 . falling by using the input time _{t B} of the edge _{F B,} to calculate the phase difference ratio ε ₌ λ _/ T = a _{(t B -t A1) / (} t A2 -t A1). Then, based on the calculated phase difference ratio ε, the torque transmitted by the rotating member 2 is obtained using the map and the calculation formula. The process for obtaining the torque is performed each time the A-phase falling edge is input to the computing unit one by one (the falling edge is referred to as F _A2 each time).

The conventional torque measuring method as described above has room for improvement in terms of facilitating the assembly work of the torque measuring device 1 and reducing the manufacturing cost. That is, in the case of the conventional torque measuring method, the initial phase difference λ ₀ is set to ½ of one cycle T (λ ₀ = T / 2). The reason for this is that during the torque measurement, due to the phase change between the A phase and the B phase, the input order of the falling edge to the computing unit is reversed between the A phase and the B phase ( This is because when the overtaking of the pulse edge timing occurs), it is difficult to determine the torque transmitted by the rotating member 2 (the direction of the torque operation cannot be specified). Therefore, in order to prevent such a reverse of the input order, in the case of the conventional structure, the A phase and the B phase are opposite to each other while the rotating member 2 is not transmitting torque. The positioning in the circumferential direction between the encoders 3a, 3b and the sensors 4a, 4b must be precisely and precisely regulated so as to be in phase (the phase difference ratio ε is 0.5). This increases the manufacturing cost of the torque measuring device 1.

Japanese Unexamined Patent Publication No. 63-82330

  In view of the circumstances as described above, the present invention has been invented to realize a torque measuring method for a rotating member that can facilitate the assembly work of the torque measuring device and can reduce the manufacturing cost of the torque measuring device. It is.

The torque measurement method for a rotating member according to the present invention includes a pair of encoders that are supported and fixed at two positions separated in the axial direction of the rotating member, and the characteristics of the respective detection surfaces are alternately changed in the circumferential direction. Each detection part of a pair of sensors supported and fixed to the non-rotating part is opposed to the detection surface. Then, a pulse edge time difference that is a difference between the input time of the reference pulse edge included in the output signal of one of the two sensors and the input time of the pulse edge to be measured included in the output signal of the other sensor Based on this pulse edge time difference, the torque transmitted by the rotating member is calculated.

Especially at the torque measurement method of a rotating member of the present invention, before Symbol rotary member of said pulse edge in the output signal of both sensors in a state that does not transmit the torque, the direction of signal change each other on the basis of the phase difference which is a difference between the input time of the pulse edges the mechanic is the same, the as measured object pulse edge, to determine whether to use either the rising edge and the falling edge.

When implementing the torque measurement method of the rotating member of the present invention as described above, preferably, as both sensors, the jitter (fluctuation) of the rising edge of the output signal expressed in electrical angle is the jitter of the falling edge. That is less than 2 times the
When the present invention is implemented in a torque measuring device in which the rotational speed of the rotating member varies during torque measurement, a pulse that is a value obtained by dividing the pulse edge time difference by the period of the output signals of both sensors. The torque transmitted by the rotating member is calculated based on the edge time difference ratio. An initial phase difference ratio that is a value obtained by dividing the phase difference (initial phase difference) between the output signals of the two sensors when the rotating member is not transmitting torque by the period of the output signals of the two sensors. Based on the above, a combination of pulse edges included in the output signals of the two sensors used to calculate the pulse edge time difference in a state where the rotating member is transmitting torque is determined.

When the torque measuring method for a rotating member of the present invention as described above is carried out, specifically, when the initial phase difference is 0 or in the vicinity of 0, it is included in the output signals of both sensors. The difference between the input times of pulse edges having different signal change directions among the generated pulse edges is defined as the pulse edge time difference. On the other hand, when the initial phase difference is ½ of the cycle of the output signals of the two sensors or in the vicinity of ½ of the cycle, of the pulse edges included in the output signals of the two sensors, A difference (phase difference) between input times of pulse edges having the same signal change direction is defined as the pulse edge time difference.
In this case, preferably, when the initial phase difference is in the vicinity of 1/4 of the cycle of the output signals of the two sensors or 1/4 of the cycle, the initial phase difference is included in the output signal of one of these sensors. The input time of the reference pulse edge (rising edge or falling edge) and, after this reference pulse edge is measured, of the pulse edge included in the output signal of the other sensor, The difference from the input time is defined as the pulse edge time difference.

According to the torque measuring method of the rotating member of the present invention configured as described above, the assembly work of the torque measuring device can be facilitated, and the manufacturing cost of the torque measuring device can be reduced.
In other words, in the case of the present invention, the rotation member transmits torque using a combination of pulse edges included in the output signals of a pair of sensors used for calculation of the pulse edge time difference when the rotation member is transmitting torque. This is determined based on the phase difference between the output signals of these two sensors in a state where they are not. For this reason, it is not always necessary to restrict the phases of the output signals of these sensors to opposite phases in a state where torque is not transmitted, and the positional accuracy between the encoder and the sensor constituting the torque measuring device is excessively high. There is no need to do. Therefore, the assembly work of the torque measuring device can be facilitated, and the manufacturing cost of the torque measuring device can be reduced.
Further, when both sensors are used in which the jitter (fluctuation) of the rising edge of the output signal expressed by the electrical angle is less than twice the jitter of the falling edge, the pulse edge time difference is obtained. Even when the rising edge is used, the measurement accuracy of the torque transmitted by the rotating member can be sufficiently ensured. That is, when a general sensor is used, the rising edge is less responsive than the falling edge (there is a “margin”), so when measuring the rising edge using a general sensor. The torque measurement accuracy is lower than when using a falling edge, but if both sensors have the above-mentioned performance, the measurement accuracy can be sufficiently ensured.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. The diagram showing the output signals of both sensors when the initial phase difference λ ₀ between the output signals (A phase, B phase) of a pair of sensors is zero. Similarly, a diagram showing the output signals of the two sensors when the initial phase difference λ ₀ is ½ of the period T. FIG. Similarly, a diagram representing output signals of both sensors when the initial phase difference λ ₀ is ¼ of the period T. FIG. Similarly, the diagram which shows the relationship between pulse edge time difference ratio (kappa) and torque. The diagram showing the output signal of a pair of sensors by the conventional torque measuring method.

[First example of embodiment]
A first example of the embodiment of the present invention will be described with reference to FIGS. The feature of the present invention, including this example, is that the method for measuring the torque transmitted by the rotating member 2 is devised in order to reduce the manufacturing cost of the torque measuring device 1. The basic structure and operation of the torque measuring device 1 are as described above. That is, in the torque measuring device 1, a pair of encoders 3a and 3b are fitted and fixed to two positions (both ends in the axial direction) spaced apart in the axial direction of the rotating member 2. The two sensors 4a and 4b are not shown in a state in which the outer end surfaces of both the encoders 3a and 3b, which are detected parts, are opposed to the tip portions that are the detection parts of the pair of sensors 4a and 4b. It is supported by the housing. In the case of the present example, as these sensors 4a and 4b, those having the rising edge jitter of the output signal expressed in electrical angle are also less than twice the falling edge jitter.

In order to measure the torque transmitted by the rotating member 2 using such a torque measuring device 1, first, the output signals (2) of the sensors 4a and 4b in a state where the rotating member 2 is not transmitting torque ( The phase difference (initial phase difference) λ ₀ and the period T between the upper solid line and the lower broken line in FIGS. 2 and 3 are measured, and the initial phase difference ratio is obtained by dividing the initial phase difference λ ₀ by this period T. ε ₀ (= λ ₀ / T) is obtained. Then, in accordance with the initial phase difference ratio ε ₀ , the combination of pulse edges of the output signals of the sensors 4a and 4b used to calculate the torque when the rotating member 2 is transmitting torque is determined. To do. In the following description, the initial phase difference ratio ε ₀ is assumed to be in the range of 0 or more and ½ or less (0 ≦ ε ₀ ≦ 1/2). In other words, of the pair of sensors, the sensor on the side where the phase of the output signal is not delayed at least in the state where the rotating member 2 is not transmitting torque is referred to as one sensor 4a (the side where the phase is not delayed at least). In the following description, the sensor on the side where the phase of the output signal is not advanced at least is the other sensor 4b (the output signal on the side where the phase is not advanced at least is the B phase).

First, when the initial phase difference ratio ε ₀ is 0 or more and ¼ or less (0 ≦ ε ₀ ≦ 1/4), the calculator (not shown) shows a case where the initial phase difference ratio ε ₀ is 0. As shown in FIG. 2, among the falling edges included in the output signal (A phase) of the one sensor 4a, the input times of two falling edges F _A1 and F _A2 that are continuously input to each other. Of the rising edges included in t _A1 and t _A2 and the output signal (phase B) of the other sensor 4b, one rising edge R _B input between these input times t _A1 and t _A2 to measure the input time _{t B.} On the other hand, when the initial phase difference ratio ε ₀ is greater than 1/4 and equal to or less than ½ (1/4 <ε ₀ ≦ 1/2), the initial phase difference ratio ε ₀ is 1/2. As shown in FIG. 3 showing a certain case, among the falling edges included in the A phase, the input times t _A1 and t _{A2 of} two falling edges F _A1 and F _A2 that are continuously input to each other. When, among the falling edge included in the B-phase, is input between these two input time t _A1, t _A2, measures the input time t _B of one falling edge F _B.

In any case, using the input times t _A1 , t _A2 , t _B measured by the calculator, the pulse edges F _A1 , R _B (or included in the output signals of the sensors 4a, 4b) A pulse edge time difference δ (= t _B −t _A1 ) that is a difference between the input times t _A1 and t _{B of} F _B ) is obtained. Then, by dividing the pulse edge time difference δ by the period T (= t _A2 −t _A1 ), the pulse edge time difference ratio κ = δ / T = (t _B −t _A1 ) / (t _A2 −t _A1 ). Ask. Furthermore, based on this pulse edge time difference ratio κ, using a map or a calculation formula representing the relationship between the pulse edge time difference ratio κ and the torque transmitted by the rotating member 2, which has been obtained in advance by calculation or experiment, The torque transmitted by the rotating member 2 at that time is obtained. The process for obtaining the torque is performed each time the A-phase falling edge is input to the computing unit one by one (the falling edge is referred to as F _A2 each time).

According to the present example as described above, it is possible to reduce the manufacturing cost of the torque measuring device 1 and, in turn, the rotating machine device incorporating the torque measuring device 1.
That is, in the case of this example, the pulses included in the output signals of the two sensors 4a and 4b used for calculating the pulse edge time difference δ (pulse edge time difference ratio κ) when the rotating member 2 is transmitting torque. The combination of edges is determined based on the initial phase difference λ ₀ (initial phase difference ratio ε ₀ ) between the output signals of both the sensors 4a and 4b. Specifically, the input time t _A1 of this early when the phase difference ratio epsilon ₀ is 0 or more than 1/4, the fall of the A-phase as a reference edge F _A1, pulse edges included in Phase B Among these, the pulse edge time difference ratio κ is obtained from the falling edge F _A1 of the A phase and the input time t _B of the rising edge R _{B in which} the direction of change of the output signal is different. On the other hand, when the initial phase difference ratio ε ₀ is greater than ¼ and less than or equal to ½, the input time t _A1 of the reference A-phase falling edge F _A1 is included in the B-phase. Among the pulse edges, the pulse edge time difference ratio κ is obtained from the falling edge F _A1 of the A phase and the input time t _B of the falling edge F _{B in which} the direction of change of the output signal is the same. Then, the torque transmitted by the rotating member 2 is obtained from the pulse edge time difference ratio κ. For this reason, the phases of the output signals of the two sensors 4a and 4b do not necessarily have to be restricted to opposite phases when torque is not transmitted, and the circles of the two encoders 3a and 3b and the two sensors 4a and 4b are not necessary. There is no need to excessively increase the positioning accuracy in the circumferential direction. As a result, the assembly operation of the torque measuring device 1 can be facilitated, and the manufacturing cost of the torque measuring device 1 can be reduced .

In the case of this example, as the sensors 4a and 4b, the jitter of the rising edge of the output signal expressed in electrical angle is similarly less than twice that of the falling edge. Therefore, even when the pulse edge time difference δ (pulse edge time difference ratio κ) is calculated using the rising edge R _B of the B phase, sufficient measurement accuracy of the torque transmitted by the rotating member 2 is ensured. I can do things.

In the case of this example as described above, the falling edge F _A1 of the reference A phase due to the phase change between the A phase and the B phase during the measurement of the torque transmitted by the rotating member 2; Among the B-phase pulse edges, the pulse edge to be measured (when the initial phase difference ratio ε ₀ is 0 or more and 1/4 or less, the rising edge R _B is also larger than 1/4 and smaller than 1/2. In some cases, the rigidity of the rotating member 2 in the torsional direction and the characteristics of the encoders 3a and 3b are set so that the input order with respect to the falling edge F _B ) does not reverse (no pulse edge overtaking occurs). It is necessary to regulate the pitch.

[Second Example of Embodiment]
A second example of the embodiment of the present invention will be described with reference to FIGS. 4 to 5 in addition to FIGS. In the case of this example, when the initial phase difference ratio ε ₀ is 0 or more and 1/8 or less (0 ≦ ε ₀ ≦ 1/8) or less, the computing unit shows the case where the initial phase difference ratio ε ₀ is satisfied. As shown in FIG. 2, among the falling edges included in the output signal (A phase) of one sensor 4a, the input times t _{A1 of} two falling edges F _A1 and F _A2 that are continuously input to each other. T _A2 and the rising edge included in the output signal (B phase) of the other sensor 4b, the input time t of one rising edge R _B input between these input times t _A1 and t _{A2. B} is measured.

On the other hand, when the initial phase difference ratio ε ₀ is larger than 1/8 and smaller than 3/8 (1/8 <ε ₀ <3/8), the calculator calculates the initial phase difference ratio. As shown in FIG. 4 showing the case where ε ₀ is ¼, among the falling edges included in the A phase, two falling edges F _A1 and F _A2 that are continuously input to each other. Among the input edges t _A1 and t _A2 and the pulse edge included in the B phase, the first (whether it is a falling edge or a rising edge) input between these input times t _A1 and t _A2 Regardless of), the pulse edge input time t _B is measured. That is, after the falling edge F _A1 of the phase A as a reference is input, as shown in the middle of FIG. 4, when the falling edge F _B of the B-phase is inputted, falling the trailing edge F the input time of the _B and the input time t _B. Meanwhile, after the falling edge F _A1 of the A-phase is entered, as shown in the lower part of FIG. 4, if the rising edge R _B of the B-phase is input, the input time of the rising edge R _B and the input time _{t B.}

Further, when the initial phase difference ratio ε ₀ is 3/8 or more and ½ or less (3/8 ≦ ε ₀ ≦ 1/2), the initial phase difference ratio ε ₀ is 1/2. As shown in FIG. 3, among the falling edges included in the A phase, input times t _A1 and t _{A2 of} two falling edges F _A1 and F _A2 that are continuously input to each other, Among the falling edges included in the B phase, the input time t _{B of} one falling edge F _B input between these input times t _A1 and t _A2 is measured.

In any case, the pulse edge time difference ratio κ is then determined from the input times t _A1 , t _A2 , and t _B , and based on the pulse edge time difference ratio κ, a map or calculation formula that has been obtained in advance is used. Then, the torque transmitted by the rotating member 2 at that time is obtained. Here, FIG. 5 shows the time difference ratio when the initial phase difference ratio ε ₀ is larger than 1/8 and smaller than 3/8 (in the example shown, ε ₀ = ¼). The relationship between κ and the torque is shown. In FIG. 5, a solid line a is a broken line b when the first B-phase pulse edge inputted after the input of the A-phase falling edge F _A1 as a reference is the falling edge F _B. Shows the relationship between the pulse edge time difference ratio κ and the torque when the first input B-phase pulse edge is the rising edge R _B after the input of the A-phase falling edge F _A1. ing. FIG. 5 shows a case where the B phase advances with respect to the A phase as the torque transmitted by the rotating member 2 increases. On the other hand, as the torque transmitted by the rotating member 2 increases, the relationship between the pulse edge time difference ratio κ and the torque when the B phase is delayed with respect to the A phase is the relationship shown in FIG. , The line is symmetrical about a straight line having a pulse edge time difference ratio κ = 1/4.

In the case of this example, the resolution of torque measurement can be improved and the maximum value of torque that can be measured can be increased as compared with the case of the first example of the embodiment described above.
About the structure and effect | action of another part, it is the same as that of the 1st example of embodiment mentioned above.

The present invention can be implemented for various rotating machine devices such as a transmission for an automobile, a spindle device of a machine tool, or a rolling bearing unit for supporting a wheel of an automobile.
When the present invention is carried out, for example, the encoder is made of a permanent magnet, and a portion magnetized to the S pole and a portion magnetized to the N pole are alternately provided in the circumferential direction on the detected surface of the encoder. In addition to the configuration, it is possible to employ a configuration in which the encoder is made of a simple magnetic metal, and through holes (or concave portions) and column portions (or convex portions) are alternately provided in the circumferential direction on the detection surface of the encoder. Also, if the encoder is made of magnetic metal and has a structure in which a through hole (or recess) and a column (or protrusion) are provided on the surface to be detected, a permanent magnet is installed on the sensor side combined with such an encoder. Include.

DESCRIPTION OF SYMBOLS 1 Torque measuring device 2 Rotating member 3a, 3b Encoder 4a, 4b Sensor

Claims (1)

The detection surface of the pair of encoders, which are supported and fixed at two positions separated in the axial direction of the rotating member and whose characteristics of the detection surfaces are alternately changed in the circumferential direction, are supported and fixed to the non-rotating portion. Each detection part of a pair of sensors facing each other,
Find the pulse edge time difference that is the difference between the input time of the reference pulse edge included in the output signal of one of these sensors and the input time of the target pulse edge included in the output signal of the other sensor. ,
In the torque measurement method of the rotating member that calculates the torque transmitted by the rotating member based on the pulse edge time difference,
Among the pulse edges in the output signals of both sensors in a state in which front Symbol rotating member does not transmit torque, the phase difference is the difference between the input time of the pulse edges between the same the direction of signal change from one another And determining which of the falling edge and the rising edge should be used as the measurement target pulse edge .

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