Dog clutch engagement control system

Abstract

To provide a meshing clutch engagement control system which properly performs the sampling of a phase difference sensor signal for detecting an engagement timing.SOLUTION: A meshing clutch 10 is switched between an engaged state and a released state by axial relative movement of a first engagement member 11 having a first gear tooth row 13 formed in a circumferential direction and a second engagement member 12 having a second gear tooth row 14 formed in the circumferential direction. A phase difference sensor 21 detects a total area of the first gear tooth row 13 and the second gear tooth row 14 that pass in a detection range along with rotation, and outputs a phase difference sensor signal in which a rotation phase difference between the first engagement member 11 and the second engagement member 12 appears as an amplitude of a roaring wave. A calculation device 30 determines a timing at which the amplitude of the phase difference sensor signal is equal to a determination threshold or smaller as an engagement timing at which the meshing clutch can be engaged on the basis of a plurality of signal values that are obtained by sampling the phase difference sensor signal at a timing synchronized with the rotation of the first engagement member 11.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a dog clutch engagement control system. [Background technology]

[0002] BACKGROUND ART Conventionally, there is known a dog clutch engagement control system that detects the timing at which a first engagement member and a second engagement member that rotate at different rotational speeds can be engaged.

[0003] For example, Patent Document 1 discloses a phase difference sensor configuration that is provided radially outside the dog clutch at an axial position spanning the gear teeth of the first and second engagement members, and detects the rotational phase difference based on the area of ​​both gear teeth within the detection range. The node of the beat wave output by the phase difference sensor corresponds to the engagement timing at which the dog clutch can be engaged. Patent Document 2 also discloses a technology that predicts future engagement timing from detected past engagement timing and drives a linear actuator taking into account the operation delay time. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-025658 [Patent Document 2] Patent Publication No. 2021-025561 Summary of the Invention [Problem to be solved by the invention]

[0005] To actually detect the node of the beat wave of the phase difference sensor signal, it is necessary to judge the instantaneous value of the A / D converted phase difference sensor signal using multiple signal values ​​sampled at a specified sampling frequency. However, if sampling is performed regardless of the frequency of the phase difference sensor signal, a value close to the vibration center value may be sampled at the antinode of the beat wave, which could result in an erroneous detection of the engagement timing.

[0006] Furthermore, if the sampling frequency is determined in proportion to the frequency of the phase difference sensor signal, the number of samplings per unit time increases when the clutch is rotating at high speed, resulting in a huge amount of processing by the computing device.Patent Documents 1 and 2 do not disclose a sampling method for the phase difference sensor signal that is appropriate for actually detecting the engagement timing.

[0007] SUMMARY OF THE INVENTION An object of the present invention is to provide a dog clutch engagement control system that appropriately samples a phase difference sensor signal to detect engagement timing. [Means for solving the problem]

[0008] The dog clutch engagement control system of the present invention includes a dog clutch (10), a phase difference sensor (21), and a computing device (30).

[0009] The dog clutch has a first engagement member (11) that rotates about its axis and has a first gear tooth row (13) formed in the circumferential direction, and a second engagement member (12) that rotates coaxially and in the same direction as the first engagement member and has a second gear tooth row (14) formed in the circumferential direction and that can mesh with the first gear tooth row. Relative axial movement between the first engagement member and the second engagement member switches between an engaged state and a disengaged state.

[0010] The phase difference sensor has an axial position spanning the first gear tooth row and the second gear tooth row as its detection range, and detects the total area of ​​the first gear tooth row and the second gear tooth row that pass through the detection range as the gear rotates. The phase difference sensor outputs a phase difference sensor signal in which the rotational phase difference between the first engagement member and the second engagement member appears as the amplitude of a beat wave.

[0011] In a first aspect of the present invention, a computing device samples the phase difference sensor signal at timings synchronized with the rotation of the first engagement member, and determines the timing at which the amplitude of the phase difference sensor signal falls below a determination threshold as the engagement timing at which the dog clutch can be engaged, based on multiple signal values ​​obtained by sampling the phase difference sensor signal at timings synchronized with the rotation of the first engagement member. Here, the vibration center value of the beat wave of the phase difference sensor signal is defined as zero. For example, in a system in which the first engagement member is coupled to a motor shaft, the computing device obtains the motor rotation position detected by the motor rotation sensor and performs sampling at "timings synchronized with the rotation of the first engagement member."

[0012] Immediately before the clutch engages, the rotation speed of the first engaging member and the rotation speed of the second engaging member are constant, and the beat frequency obtained by multiplying the differential rotation speed between the rotation speeds of the first engaging member and the second engaging member by the number of gear teeth is also considered to be constant. By sampling the phase difference sensor signal at a timing synchronized with the rotation of the first engaging member, multiple signal values ​​in the beat period can be uniquely obtained, making it possible to appropriately determine the engagement timing that corresponds to the node of the beat wave.

[0013] One type of calculation device in the first aspect sets one or more reference phases for each pitch angle obtained by dividing the angle of one rotation of the first engagement member by the number of teeth of the first gear tooth row, and samples the phase difference sensor signal at timing corresponding to the reference phases.

[0014] For example, the calculation device sets the rotational phase of the first engaging member at which the area of ​​the first gear tooth row within the detection range of the phase difference detection sensor is maximum or minimum as the reference phase. Alternatively, the calculation device sets any rotational phase of the first engaging member for each pitch angle as the main reference phase, and sets a phase that is shifted a predetermined phase from the main reference phase as the sub-reference phase. In this type, the engagement timing can be determined using the same logic even if the rotational speed of the first engaging member changes.

[0015] Another type of the first aspect is based on the premise that the beat period (τb), which is the period of the beat wave based on the difference between the rotational speed of the first engagement member and the rotational speed of the second engagement member, is constant regardless of the rotational speed of the first engagement member, and that the engagement timing is determined only when the rotational speed of the first engagement member is equal to or greater than a predetermined lower limit rotational speed.

[0016] The calculation device sets a regular number (R) of 5 or more, which is a fixed number of samplings per beat cycle, and calculates the interval number (n), which is the integer part of the value obtained by dividing the number of periods (Fp) of the phase difference sensor signal per beat cycle by the regular number. The calculation device samples the phase difference sensor signal a number of times equal to the regular number per beat cycle, at timings synchronized with the rotation of the first engagement member, for each interval number period of the phase difference sensor signal, regardless of the rotation speed of the first engagement member, and determines the timing at which the absolute value of the obtained signal value falls below a determination threshold as the engagement timing. This type of calculation reduces the processing load of the calculation device even when the rotation speed of the first engagement member is high.

[0017] In a second aspect of the present invention, the calculation device samples the phase difference sensor signal at a plurality of sampling frequencies including one representative sampling frequency (fsr) and one or more fine-difference sampling frequencies (fsd1, fsd2), and determines the timing at which the amplitudes of the phase difference sensor signals acquired at each sampling frequency are all below a determination threshold as the engagement timing at which the dog clutch can be engaged.

[0018] The calculation device calculates the beat frequency (fb), which is the frequency of the beat wave, on the assumption that the differential rotation speed, which is the difference between the rotation speed of the first engagement member and the rotation speed of the second engagement member, is a predetermined value, or based on the differential rotation speed calculated from the rotation speed detection value. The representative sampling frequency is set to be between four and ten times the beat frequency. The difference between the fine-difference sampling frequency and the representative sampling frequency is set to be one-tenth or less of the beat frequency.

[0019] In the second aspect, even when the rotation speed of the first engagement member is high, the nodes of the beat wave can be detected using a relatively low sampling frequency, thereby reducing the amount of processing by the calculation device. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is a diagram showing a first example of the configuration of a vehicle to which a dog clutch engagement control system is applied; [Figure 2] FIG. 2 is a diagram showing a second example of a vehicle configuration to which the dog clutch engagement control system is applied. [Figure 3] FIG. 2 is a configuration diagram of a dog clutch engagement control system according to the first to third embodiments. [Figure 4] 4 is a diagram illustrating the detection principle of a phase difference sensor as viewed in the direction of an arrow IV in FIG. 3. [Figure 5] 5A and 5B are diagrams illustrating sampling phases synchronized with the rotation of a first engagement member in the first and second embodiments. [Figure 6] 1 is a time chart showing an example (1) of the first embodiment (reference phase=maximum area phase). [Figure 7] 10 is a time chart showing Example (2) of the first embodiment (reference phase=minimum area phase). [Figure 8] 4 is a flowchart of engagement timing determination according to the first embodiment. [Figure 9] 10 is a time chart showing an example (1) of the second embodiment (phase shift=(1 / 16)P). [Figure 10] 10 is a time chart showing an example (2) of the second embodiment (phase shift=(1 / 8)P). [Figure 11] 10 is a timing chart showing an example (3) of the second embodiment (phase shift=(1 / 4)P). [Figure 12] 10 is a timing chart showing an example (4) (phase shift=(1 / 2)P) of the second embodiment. [Figure 13] 10 is a time chart showing an example (5) (three reference phases) of the second embodiment. [Figure 14] 10 is a flowchart of engagement timing determination according to a second embodiment. [Figure 15] 10 is a time chart showing a third embodiment (rotation speed: 1000 rpm). [Figure 16] 10 is a time chart showing a third embodiment (rotation speed: 6000 rpm). [Figure 17] 10 is a time chart showing a third embodiment (rotation speed: 10,000 rpm). [Figure 18] FIG. 11 is a diagram showing the relationship between the number of intervals and the pitch angle in the third embodiment. [Figure 19] 10 is a flowchart of engagement timing determination according to a third embodiment. [Figure 20] 10 is a timing chart showing a modified example of the third embodiment. [Figure 21] FIG. 10 is a configuration diagram of a dog clutch engagement control system according to a fourth embodiment. [Figure 22] 10 is a timing chart showing a fourth embodiment. [Figure 23] Graph showing amplitude changes due to sampling timing shifts at (a) the antinode and (b) the node of a beat wave. [Figure 24] 10 is a flowchart of engagement timing determination according to a fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0021] A dog clutch engagement control system according to multiple embodiments of the present invention will be described with reference to the drawings. Substantially identical components in multiple embodiments are designated by the same reference numerals, and description thereof will be omitted. The following first to fourth embodiments are broadly divided into a group of first to third embodiments and a fourth embodiment. The first to fourth embodiments are collectively referred to as "the present embodiment." The dog clutch engagement control system of the present embodiment is a system that detects the timing at which a first engagement member and a second engagement member, which rotate at different rotational speeds, can be engaged in a dog clutch provided in a vehicle powertrain system.

[0022] [Vehicle, dog clutch engagement control system] An example configuration of a vehicle 90 to which a dog clutch engagement control system is applied will be described with reference to Figures 1 and 2. This vehicle 90 is an electric vehicle powered by a main motor 6. Electric vehicles include electric vehicles and hybrid vehicles. The main motor 6 is configured as an MG (motor generator), and the rotation speed ωM of the main motor 6 is detected by a rotation sensor 56. A resolver is typically used as the rotation sensor 56. In the first to third embodiments, the motor rotation speed ωM detected by the rotation sensor 56 is input to the calculation device 30. In the fourth embodiment, the motor rotation speed ωM does not have to be input to the calculation device 30.

[0023] 1 and 2 show an example configuration of a vehicle 90, which is a front-wheel drive vehicle. The left and right front wheels are drive wheels 91 connected to a drive shaft 95, and the left and right rear wheels are driven wheels 92 connected to a non-drive shaft 96. Hereinafter, reference to the driven wheels 92 will be omitted. The left and right drive wheels 91 are provided with wheel speed sensors 59 that detect, for example, the wheel rotation speed ωT. In this embodiment, it is assumed that the clutch is engaged during straight-ahead driving in principle, and the wheel rotation speeds ωT of the left and right drive wheels 91 are equal. The wheel rotation speed ωT may be used as a value correlated to the rotation speed of the second engagement member 12, for example, in the fourth embodiment.

[0024] The rotation of the motor shaft 81 of the main motor 6 is reduced in speed by the reducer 7 and transmitted to the drive wheels 91 via a differential gear 94 and a drive shaft 95. In vehicle configuration example 1 of FIG. 1, a dog clutch 10 is provided between the main motor 6 and the reducer 7. In vehicle configuration example 2 of FIG. 2, a dog clutch 10 is provided between the reducer 7 and the differential gear 94.

[0025] The dog clutch 10 has a first engagement member 11, a second engagement member 12, and a linear actuator 15. The first engagement member 11 has a first gear tooth row 13 formed in the circumferential direction and rotates about an axis. The second engagement member 12 has a second gear tooth row 14 formed in the circumferential direction that can mesh with the first gear tooth row 13 and rotates coaxially and in the same direction as the first engagement member 11. The first gear tooth row 13 and the second gear tooth row 14 each have, for example, 60 teeth (the pitch angle between adjacent teeth is 6°).

[0026] The linear motion actuator 15 moves the first engagement member 11 and the second engagement member 12 relative to each other in the axial direction. The linear motion actuator 15 is not limited to being provided on the first engagement member 11 side, but may also be provided on the second engagement member 12 side. When the first engagement member 11 and the second engagement member 12 move in a direction toward each other, an engaged state is established in which the first gear tooth row 13 and the second gear tooth row 14 mesh with each other. When the first engagement member 11 and the second engagement member 12 move in a direction away from each other, a disengaged state is established in which the meshing is released. In other words, the relative axial movement of the first engagement member 11 and the second engagement member 12 switches between an engaged state and a disengaged state of the first engagement member 11 and the second engagement member 12.

[0027] In vehicle configuration example 1 of Fig. 1, the first engagement member 11 is directly coupled to a motor shaft 81 of the main motor 6. The second engagement member 12 is coupled to a post-clutch motor shaft 82 that is input to the reducer 7. The reducer 7 reduces the rotation of the post-clutch motor shaft 82 to rotate a differential gear input shaft 84.

[0028] In vehicle configuration example 2 of Fig. 2, the first engagement member 11 is connected to the output shaft 83 after reduction by the reducer 7. In other words, the first engagement member 11 is connected to the motor shaft 81 of the main motor 6 via the reducer 7. The second engagement member 12 is connected to the differential gear input shaft 84.

[0029] The dog clutch engagement control system 100 includes a dog clutch 10, a phase difference sensor 21, and a computing device 30. When the dog clutch 10 is in a disengaged state and the first engagement member 11 and the second engagement member 12 are rotating at different rotational speeds, the phase difference sensor 21 detects the rotational phase difference between the first engagement member 11 and the second engagement member 12 and outputs a phase difference sensor signal to the computing device 30.

[0030] The computing device 30 determines the timing at which the dog clutch 10 can be engaged based on the signal output by the phase difference sensor 21. Hereinafter, the "timing at which the dog clutch 10 can be engaged" will be referred to as "engagement timing." The computing device 30 drives the linear actuator 15 to engage the dog clutch 10 based on the determined engagement timing. The computing device 30 may predict future engagement timing from detected past engagement timings using the technology disclosed in Patent Document 2, and drive the linear actuator taking into account an operation delay time.

[0031] (First to third embodiments) The dog clutch engagement control systems of the first to third embodiments will be described with reference to Figures 3 and 4. Figure 3 shows a configuration in which the first engagement member 11 of the dog clutch 10 is coupled to the motor shaft 81 and the second engagement member 12 is coupled to the post-clutch motor shaft 82, similar to vehicle configuration example 1 in Figure 1. The relationship between the motor rotation speed ωM and the rotation speed of the first engagement member 11 in the following embodiments will be described assuming this configuration. However, in other embodiments, a reducer 7 may be provided between the main motor 6 and the dog clutch 10, similar to vehicle configuration example 2 in Figure 2. In that case, the rotation speed of the first engagement member 11 is calculated by multiplying the motor rotation speed ωM by the reduction ratio of the reducer 7.

[0032] The phase difference sensor 21 is similar to those disclosed in Patent Documents 1 and 2, and is composed of a magnet and a magnetic detection element such as a Hall element. The phase difference sensor 21 has a detection range SA (see FIG. 4) in the axial direction that straddles the first gear tooth row 13 and the second gear tooth row 14, and is disposed so as to face the clutch axis Z from the radial outside so as not to interfere with the dog clutch 10. The phase difference sensor 21 detects the total area of ​​the first gear tooth row 13 and the second gear tooth row 14 that pass through the detection range SA as the dog clutch 10 rotates, based on changes in magnetic flux intensity.

[0033] In Figure 4, pitch angle P is the angle obtained by dividing the angle of one rotation of first engagement member 11 (i.e., 360° in degrees) by the number of teeth of first gear tooth row 13. When the number of teeth of first gear tooth row 13 is 60, pitch angle P is 6°. Note that the number of teeth of second gear tooth row 14 that meshes with first gear tooth row 13 is the same as that of first gear tooth row 13, 60, and the pitch angle of 6° is also the same.

[0034] The top diagram in Figure 4 shows the general phase difference Δθ during rotation. The middle diagram shows a state where the rotational phases of the first gear tooth row 13 and the second gear tooth row 14 are the same, i.e., "phase difference Δθ = 0." In this state, the first engagement member 11 and the second engagement member 12 cannot engage with each other. The sensor output is maximized when the detection range SA includes both the teeth of the first gear tooth row 13 and the second gear tooth row 14, and the total area is maximized. The sensor output is minimized when the detection range SA includes both the gaps of the first gear tooth row 13 and the second gear tooth row 14, and the total area is minimized.

[0035] The lower diagram in Fig. 4 shows a state where the rotational phase between the first gear tooth row 13 and the second gear tooth row 14 is shifted by half the pitch angle P, that is, a "phase difference Δθ = (½)P." In this state, the first engagement member 11 and the second engagement member 12 are engageable. The detection range SA includes one tooth portion of the first gear tooth row 13 and the second gear tooth row 14 and the gap portion of the other, and the sensor output becomes an intermediate value when the total area becomes an intermediate value between the maximum and minimum values.

[0036] As shown in Figure 6 and subsequent figures, when the first engagement member 11 and the second engagement member 12 rotate at different rotational speeds, the phase difference sensor signal is a beat wave with a frequency of "clutch rotational speed x number of teeth." For example, when the number of teeth is 60 at 6000 rpm (100 Hz), the frequency of the phase difference sensor signal is also 6000 Hz. The rotational phase difference between the first engagement member 11 and the second engagement member 12 appears as the amplitude of the beat wave.

[0037] Returning to Fig. 3, the arithmetic unit 30 includes a low-pass filter (hereinafter referred to as "LPF") 31, a sampling circuit 32, and an engagement timing determination circuit 33. The phase difference sensor signal output by the phase difference sensor 21 is input to the arithmetic unit 30 as a continuous wave analog signal. The LPF 31 removes disturbance components from the input phase difference sensor signal. The sampling circuit 32 samples the phase difference sensor signal, which is an analog signal, at a predetermined sampling timing and outputs a discrete digital signal value.

[0038] In the first to third embodiments, the motor rotation speed ωM detected by the rotation sensor 56 is input to the sampling circuit 32 of the calculation device 30. The sampling circuit 32 samples the phase difference sensor signal at a timing synchronized with the rotation of the first engagement member 11. Based on a plurality of signal values ​​obtained by sampling, the engagement timing determination circuit 33 determines, as the engagement timing, the timing at which the amplitude of the phase difference sensor signal becomes equal to or smaller than a determination threshold.

[0039] Immediately before the clutch is engaged, the rotation speed of the first engaging member 11 and the rotation speed of the second engaging member 12 are constant, and the beat frequency obtained by multiplying the differential rotation speed between the rotation speeds of the first engaging member 11 and the second engaging member 12 by the number of gear teeth T is also considered to be constant. By sampling the phase difference sensor signal at a timing synchronized with the rotation of the first engaging member 11, multiple signal values ​​in the beat period can be uniquely obtained, making it possible to appropriately determine the engagement timing that corresponds to the node of the beat wave.

[0040] Next, the configurations for determining the engagement timing by the arithmetic device 30 of the first to third embodiments will be described in order.

[0041] (First embodiment) In the first and second embodiments, the calculation device 30 sets one or more reference phases for each pitch angle P of the first engagement member 11 and samples the phase difference sensor signal at timing corresponding to the reference phase. In the first embodiment, the calculation device 30 sets one reference phase for each pitch angle P of the first engagement member 11. In the second embodiment, the calculation device 30 sets multiple reference phases, including one main reference phase and one or more sub-reference phases, for each pitch angle P of the first engagement member 11.

[0042] The first embodiment will be described with reference to Figures 5 to 8. Figure 5 shows an example of a reference phase α used in the first and second embodiments. The rotational phase of the second engagement member 12 is not related to the reference phase α, so the second engagement member 12 is not shown. Of the rotational phases shown in Figure 5, the top row "α = α0" and the bottom row "α = α0 + (1 / 2)P" are used in the first embodiment.

[0043] In the first embodiment, the calculation device 30 sets, as the reference phase, the rotational phase of the first engaging member 11 at which the area of ​​the first gear tooth row 13 in the detection range SA of the phase difference detection sensor 21 is maximum or minimum. α0 is the phase at which the area of ​​the first gear tooth row 13 in the detection range SA of the phase difference detection sensor 21 is maximum, and is hereinafter referred to as the "maximum area phase." α0 + (½)P is the phase at which the area of ​​the first gear tooth row 13 in the detection range SA of the phase difference detection sensor 21 is minimum, and is hereinafter referred to as the "minimum area phase."

[0044] Figure 6 shows a time chart for determining engagement timing, using the maximum area phase as the reference phase, and Figure 7 shows the minimum reference phase. The clutch rotational speed conditions common to both the time charts of the first and second embodiments are that the rotational speed of the first engaging member 11 is 5000 rpm, the rotational speed of the second engaging member 12 is 4800 rpm, and the differential rotational speed is 200 rpm. Because the number of gear teeth T is 60, the area of ​​the first gear tooth row 13 passing through the detection range SA changes at a frequency of 5000 Hz (a period of 0.2 ms), and the area of ​​the second gear tooth row 14 changes at a frequency of 4800 Hz. The beat wave has a frequency of 200 Hz and a period of 5 ms. The beat wave has a loop around 0 ms and 5 ms on the horizontal axis, and a node around 2.5 ms on the horizontal axis.

[0045] The sensor output of the phase difference sensor 21 is offset-adjusted so that the median value of the total area of ​​the gear teeth 13, 14 in the detection range SA is 0 [V]. When the total area of ​​the gear teeth 13, 14 in the detection range SA is greater than the median value, the sensor output is a positive value, and when the total area of ​​the gear teeth 13, 14 in the detection range SA is smaller than the median value, the sensor output is a negative value. In other words, the vibration center value of the beat wave of the phase difference sensor signal is defined as zero. A threshold for determining whether the absolute value of the signal is positive or negative is set across zero for the sensor output.

[0046] FIG. 6 shows an embodiment in which the phase difference sensor signal is sampled using a timing corresponding to the maximum area phase of the first engagement member 11 as a trigger, and FIG. 7 shows an embodiment in which the phase difference sensor signal is sampled using a timing corresponding to the minimum area phase of the first engagement member 11 as a trigger. In the embodiment (1) of FIG. 6, the sampled signal value changes in a concave shape in the positive region. In the embodiment (2) of FIG. 7, the sampled signal value changes in a convex shape in the negative region. The engagement timing determination circuit 33 determines, as the engagement timing, the timing at which the absolute value of the signal value obtained by sampling the phase difference sensor signal becomes equal to or less than a determination threshold.

[0047] The process for determining engagement timing according to the first embodiment is shown in the flowchart of Figure 8. In the following explanation of the flowchart, the symbol "S" denotes a step. In S11, the LPF 31 removes disturbance components from the phase difference sensor signal.

[0048] In S12, the sampling circuit 32 sets the maximum area phase as the reference phase for each pitch angle P, according to the embodiment (1) of Fig. 6. In S13, the sampling circuit 32 samples the phase difference sensor signal, triggered by the timing corresponding to the reference phase, according to the embodiment (2) of Fig. 7.

[0049] In S14, the engagement timing determination circuit 33 determines the timing when the absolute value of the obtained signal value becomes equal to or less than the determination threshold value as the engagement timing. In S15, the calculation device 30 drives the linear motion actuator 15 based on the engagement timing.

[0050] As described above, in the first embodiment, the maximum area phase or minimum area phase of the first engaging member 11 is set as a reference phase, and the phase difference sensor signal is sampled at a timing corresponding to the reference phase based on the motor rotation speed ωM detected by the rotation sensor 56. Since the relationship of the sampling timing with respect to the beat wave nodes remains unchanged even when the rotation speed changes, it is possible to determine the engagement timing under stable conditions. Furthermore, since one reference phase is set for each pitch angle P, a sufficient number of samples can be ensured to detect the beat waveform nodes.

[0051] (Second embodiment) A second embodiment will be described with reference to Figs. 9 to 14. In the second embodiment, the calculation device 30 sets one main reference phase, which is an arbitrary rotational phase, for each pitch angle P, and one or more secondary reference phases that are shifted by a predetermined phase from the main reference phase. With respect to the "reference phases" defined as being set at least once for each pitch angle P, the main reference phase is the "main reference phase" and the secondary reference phase is the "secondary reference phase." Figs. 9 to 12 show an example in which one main reference phase and one secondary reference phase are set, and Fig. 13 shows an example in which one main reference phase and two secondary reference phases are set.

[0052] In the second embodiment, the key point is the relative phase shift between the main reference phase and the secondary reference phase, and the absolute value of the main reference phase is not important. However, for convenience, Fig. 5 shows an example of the phase shift between the main reference phase and the secondary reference phase, assuming that the maximum area phase α0 is selected as the main reference phase. Assuming that α0 shown in the top row is the main reference phase, the secondary reference phases when the phase shifts are (1 / 16)P, (1 / 8)P, (1 / 4)P, and (1 / 2)P are shown in the second to fifth rows from the top, respectively.

[0053] Here, a pair of phase shifts for which the sum of the coefficients for pitch angle P equals 1 are equivalent to each other, with only the main reference phase and the secondary reference phase swapped. For example, the phase shifts of (1 / 8)P and (7 / 8)P, and (1 / 4)P and (3 / 4)P are equivalent to each other. Furthermore, P can be considered as one period, and can be expressed as "-(1 / 8)P = (7 / 8)P" and "-(1 / 4)P = (3 / 4)P."

[0054] Corresponding to Fig. 5, the time charts of Fig. 9, Fig. 10, Fig. 11 and Fig. 12 show examples (1) to (4) in which the engagement timing is determined using the main reference phase and the secondary reference phase when the phase shift is (1 / 16)P, (1 / 8)P, (1 / 4)P and (1 / 2)P, respectively. The conditions in each example, "first engaging member rotation speed = 5000 rpm, second engaging member rotation speed = 4800 rpm, number of gear teeth T = 60", are the same as those in Fig. 6 and Fig. 7 of the first embodiment.

[0055] The signal value obtained by sampling the phase difference sensor signal at a timing (trigger 1) corresponding to the main reference phase is called the main signal value and is indicated by a hatched circle. The signal value obtained by sampling the phase difference sensor signal at a timing (trigger 2) corresponding to the secondary reference phase is called the secondary signal value and is indicated by a hatched square. In each of Examples (1) to (4), the waveforms of the main signal value and the secondary signal value that are discretely drawn are offset from each other, but at the nodes of the beat wave, the absolute values ​​of both the main signal value and the secondary signal value are below the determination threshold. Therefore, this timing is determined as the engagement timing. As in the first embodiment, the oscillation center value of the beat wave of the phase difference sensor signal is defined as zero.

[0056] Here, when the phase shift is (1 / 16)P or (1 / 8)P, the difference between the main signal value and the sub-signal value is relatively small, so there is a risk of being affected by noise. Therefore, by setting the phase shift of the reference phase from the main reference phase to (1 / 4)P or (3 / 4)P, it is possible to ensure a high signal strength (S / N ratio) against noise.

[0057] Furthermore, in Example (5) shown in Figure 13, a first auxiliary reference phase is set to have a phase shift of -(1 / 8)P relative to the main reference phase, and a second auxiliary reference phase is set to have a phase shift of -(1 / 4)P. By determining the engagement timing based on three or more signal values, the reliability of the determination is improved even in a noisy environment. Furthermore, since the phase shift of the second auxiliary reference phase is set to -(1 / 4)P (=(3 / 4)P), a large S / N ratio is ensured.

[0058] 14 shows the process of determining engagement timing according to the second embodiment. In S21, disturbance components of the phase difference sensor signal are removed by the LPF 31. In S22, the sampling circuit 32 sets an arbitrary rotational phase of the first engaging member 11 as the main reference phase for each pitch angle P, and sets a phase shifted by a predetermined phase from the main reference phase as the sub-reference phase.

[0059] In S23, the sampling circuit 32 samples the phase difference sensor signal using timings corresponding to the main reference phase and the sub-reference phase as triggers. In S24, the engagement timing determination circuit 33 determines, as the engagement timing, the timing at which the absolute values ​​of the main signal value and the sub-signal value are both equal to or less than the determination threshold value. In S25, the calculation device 30 drives the linear motion actuator 15 based on the engagement timing.

[0060] Although the diagrams of the examples of the second embodiment illustrate the case where the main reference phase is the maximum area phase α0, the main reference phase may be any rotational phase. In the second embodiment, the sampling circuit 32 does not need to acquire the absolute rotational phase of the first engaging member 11 as known information or by learning, and can determine the engagement timing only by using multiple reference phases.

[0061] (Third embodiment) A third embodiment will be described with reference to Figures 15 to 19. In the first and second embodiments, in which sampling is performed at a reference phase for each pitch angle P of the first engagement member 11, the number of samplings per unit time increases in proportion to the rotation speed of the first engagement member 11, i.e., the rotation speed ωM of the main motor 6 in the vehicle configuration example of Figure 1. Compared to when the motor rotation speed ωM is 1000 rpm, the number of samplings is six times as many at 6000 rpm and ten times as many at 10000 rpm.

[0062] Incidentally, just before the clutch engages, the differential rotation speed between the rotation speeds of the first engaging member 11 and the second engaging member 12 is substantially constant, regardless of the motor rotation speed ωM. Since the value obtained by multiplying the differential rotation speed by the number of teeth is the beat frequency of the phase difference sensor signal, the beat period will be constant if the differential rotation speed is constant. Furthermore, if there are five or more sampled values ​​per beat period, the beat waveform can be detected. Focusing on this point, the third embodiment aims to determine the engagement timing with a minimum number of samplings, regardless of the rotation speed of the first engaging member 11.

[0063] In the third embodiment, it is assumed that (1) the beat period is constant regardless of the rotation speed of the first engagement member 11, and (2) the engagement timing is determined only when the rotation speed of the first engagement member 11 is equal to or greater than a predetermined lower limit rotation speed.

[0064] The calculation device 30 then sets a regular number R, which is a fixed number of samplings per beat cycle, that is, 5 or more. Below, an example will be described in which the regular number R=5, that is, the case in which five samples are taken per beat cycle regardless of the motor rotation speed ωM. In order to efficiently detect the entire beat waveform, it is preferable that the regular number be an odd number greater than or equal to 5, and in particular a prime number such as 7, 11, or 13.

[0065] Figures 15, 16, and 17 show the sampling and engagement timing determination when the motor rotation speed ωM is 1000 rpm, 6000 rpm, and 10,000 rpm, respectively. The rotation speed of the second engagement member 12 is 800 rpm, 5,800 rpm, and 9,800 rpm, respectively, and the difference frequency is constant at 200 rpm. The motor rotation speed ωM = 1000 rpm corresponds to the lower limit rotation speed. The number of gear teeth T is 60, the beat frequency fb is 200 Hz, and the beat period τb is constant at 5 ms. The frequency fp of the phase difference sensor signal obtained by multiplying the motor rotation speed ωM by the number of gear teeth T is 1000 Hz, 6000 Hz, and 10,000 Hz, respectively.

[0066] Furthermore, the number of periods of the phase difference sensor signal per beat period τb (i.e., 5 ms) is represented as Fp. Note that the term "number of periods" is used to distinguish it from "frequency," which is the number of periods per second. If the "number of periods Fp of the phase difference sensor signal per beat period τb" is defined as the "number of unit periods Fp," then the number of unit periods Fp in FIGS. 15, 16, and 17 is 5, 30, and 50, respectively.

[0067] Next, the "interval number n" is calculated, which is the integer part of the value obtained by dividing the unit period number Fp by the regular number R. The interval number n is a natural number and is expressed by equation (3.1). Note that when the motor rotation speed ωM is less than the lower limit frequency, the calculation result of n becomes 0, which does not satisfy the premise. n≦(Fp / R)<(n+1) (3.1)

[0068] Also, using the Gaussian symbol [ ], the interval number is expressed by equation (3.2), where [x] means the largest integer not exceeding x. n=[Fp / R] (3.2)

[0069] The number of intervals n in Figures 15, 16, and 17 are 1, 6, and 10, respectively. As shown in Figure 18, the number of intervals n indicates the number of gear teeth in the first gear tooth row 13 for which one phase difference sensor value is sampled. When the motor rotation speed ωM is 1000 rpm, the number of intervals n = 1, and the phase difference sensor values ​​of all gear teeth are sampled. When the motor rotation speed ωM is 6000 rpm, the number of intervals n = 6, and the phase difference sensor values ​​of one in six gear teeth are sampled. When the motor rotation speed ωM is 10000 rpm, the number of intervals n = 10, and the phase difference sensor values ​​of one in ten gear teeth are sampled. The number of intervals n may be interpreted as indicating how many times the rotation angle serving as the sampling interval is relative to the pitch angle P.

[0070] The same applies when the unit period number Fp is not divisible by the regular number R and a remainder is left. For example, if the motor rotation speed ωM is 6400 rpm and the unit period number Fp is 32 periods, then (Fp / R) = 6.4, so the interval number n is 6 and 2 periods of the unit period number Fp are left as a remainder. In this case, sampling is performed 5 times in the beat period τb with the interval number n = 6, and the phase difference sensor signal for the remainder 2 periods is not sampled.

[0071] The sampling circuit 32 samples the phase difference sensor signal a regular number R of times per beat period at timing synchronized with the rotation of the first engaging member 11, at intervals of n periods of the phase difference sensor signal, regardless of the rotation speed of the first engaging member 11. The engagement timing determination circuit 33 determines the timing at which the absolute value of the obtained signal value becomes equal to or less than a determination threshold as the engagement timing. As in the first and second embodiments, the oscillation center value of the beat wave of the phase difference sensor signal is defined as zero.

[0072] The flowchart in Figure 19 shows the process of determining engagement timing according to the third embodiment. In S31, disturbance components of the phase difference sensor signal are removed by LPF 31. In S32, a regular number R (≧5), which is a fixed number of samplings per beat period τb, is set. In S33, the number of periods of the phase difference sensor signal per beat period τb (i.e., the number of unit periods) Fp is calculated. In S34, the number of intervals n, which is the integer part of the value obtained by dividing the number of unit periods Fp by the regular number R, is calculated.

[0073] In S35, the sampling circuit 32 samples the phase difference sensor signal a number of times equal to the regular number R per beat period at timings corresponding to every interval number n cycles of the phase difference sensor signal, regardless of the rotation speed of the first engagement member 11. Since the sampling phase at each pitch angle P every interval number n cycles is the same, each sampling timing is synchronized with the rotation of the first engagement member 11.

[0074] In S36, the engagement timing determination circuit 33 determines the timing when the absolute value of the obtained signal value becomes equal to or less than the determination threshold value as the engagement timing. In S37, the calculation device 30 drives the linear motion actuator 15 based on the engagement timing.

[0075] As described above, in the third embodiment, sampling is performed a fixed regular number of times for the beat period τb, on the premise that the beat period τb is constant regardless of the rotation speed of the first engaging member 11. Therefore, even when the rotation speed of the first engaging member 11 is high, it is possible to determine the engagement timing without increasing the calculation load.

[0076] FIG. 20 shows engagement timing determination according to a modified example similar to the third embodiment. In this modified example, multiple monitoring intervals are set corresponding to the rotation phase range of the first engagement member 11. In each monitoring interval, the interval maximum value of the phase difference sensor signal is peak-held, A / D converted, and output. The engagement timing determination circuit 33 determines the timing at which the extracted interval maximum value becomes equal to or less than the determination threshold value as the engagement timing. Note that in each monitoring interval, the interval minimum value may be peak-held instead of the interval maximum value. Even in this modified example, the engagement timing can be determined based on the signal value synchronized with the rotation of the first engagement member 11, regardless of the frequency of the phase difference sensor signal.

[0077] (Fourth embodiment) A fourth embodiment will be described with reference to Figures 21 to 24. In the dog clutch engagement control system of the fourth embodiment shown in Figure 21, description of the same configuration as in Figure 3 will be omitted. In addition to the LPF 31 and the engagement timing determination circuit 33, the arithmetic device 30 of the fourth embodiment includes a plurality of sampling circuits made up of a representative sampling circuit 321, a first minute difference sampling circuit 322, and a second minute difference sampling circuit 323.

[0078] The sampling circuits 321, 322, and 323 sample the phase difference sensor signals using a plurality of sampling frequencies with slight frequency differences between them. The engagement timing determination circuit 33 determines the timing at which the dog clutch can be engaged when the amplitudes of the phase difference sensor signals acquired at each sampling frequency are all equal to or less than a determination threshold. In Fig. 22 and Fig. 23, the area inside the positive and negative determination thresholds is referred to as the "engageable range."

[0079] The one sampling frequency used by the representative sampling circuit 321 is represented as the representative sampling frequency fsr. The sampling frequencies used by the first fine-difference sampling circuit 322 and the second fine-difference sampling circuit 323 are represented as fine-difference sampling frequencies fsd1 and fsd2. The fourth embodiment is not limited to using two fine-difference sampling frequencies fsd1 and fsd2, and it is sufficient if one or more fine-difference sampling frequencies fsd* (*=1, 2, etc.) are used.

[0080] The differential rotation speed, which is the difference between the rotation speed of the first engagement member 11 and the rotation speed of the second engagement member 12, may be assumed to be a predetermined value (for example, 100 rpm). In this case, as indicated by the dashed arrow, the motor rotation speed ωM and the wheel rotation speed ωT do not need to be input to the calculation device 30. Alternatively, the calculation device 30 may obtain the rotation speed of the first engagement member 11 from the motor rotation speed ωM detected by the motor rotation sensor 56, for example, and obtain the rotation speed of the second engagement member 12 by converting the wheel rotation speed ωT detected by the wheel speed sensor 59, for example, using the reduction ratio, and calculate the differential rotation speed.

[0081] The calculation device 30 calculates the beat frequency fb, which is the frequency of the beat wave of the phase difference sensor signal, based on the differential rotation speed, which is a preset value, or the differential rotation speed calculated from the detected rotation speed value. When the differential rotation speed is 100 rpm and the number of gear teeth T is 60, the beat frequency fb is 0.1 kHz and the beat period τb is 10 ms.

[0082] As expressed in equation (4.1), the representative sampling frequency fsr is set to be between four and ten times the beat frequency fb. Also, as expressed in equation (4.2), the difference between the fine-difference sampling frequency fsd* and the representative sampling frequency fsr is set to be one-tenth or less of the beat frequency. fb×4≦fsr≦fb×10 (4.1) |fsd*-fsr|≦fb / 10 ···(4.2)

[0083] Specifically, when the beat frequency is 0.1 kHz, equation (4.1) can be replaced by equation (4.3), and equation (4.2) can be replaced by equation (4.4). 0.4kHz≦fsr≦1kHz (4.3) |fsd*-fsr|≦0.01kHz ···(4.4)

[0084] In the examples of FIGS. 21 and 22, fsr=0.4 kHz, fsd1=0.401 kHz, and fsd2=0.402 kHz are set to satisfy equations (4.3) and (4.4).

[0085] Next, with reference to Figure 22 and Figures 23(a) and (b), determination of engagement timing according to the fourth embodiment will be described. To determine the engagement timing, it is not necessary to detect the entire beat waveform; it is sufficient to detect only the nodes of the beat wave. In the fourth embodiment, attention is focused on the fact that it is possible to distinguish between antinodes and nodes of the beat wave based on the difference in amplitude change that accompanies a slight shift in sampling timing.

[0086] As shown in Figure 23(a), at the antinodes of the beat wave, the change in amplitude due to a slight deviation in the sampling timing is large, and the sampled signal values ​​A1, A2, and A3 fall within or fall outside the engageable range. As shown in Figure 23(b), at the nodes of the beat wave, the change in amplitude due to a slight deviation in the sampling timing is small, and the signal values ​​B1, B2, and B3 sampled at any timing fall within the engageable range.

[0087] FIG. 22 shows signal values ​​obtained by sampling a phase difference sensor signal with a beat frequency of 0.1 kHz at three sampling frequencies: a representative sampling frequency of 0.4 kHz, a first fine difference sampling frequency of 0.401 kHz, and a second fine difference sampling frequency of 0.402 kHz.

[0088] Because the representative sampling frequency of 0.4 kHz is four times the beat frequency of 0.1 kHz, signal values ​​are obtained at four points: the node, the midpoint between the node and the abdomen, the abdomen, and the midpoint between the abdomen and the next node. If the frequency of the phase difference sensor signal is an integer multiple of the beat frequency, the amplitude will be 0 at the sampling timing of the abdomen. In other words, even though this is a timing that is actually not possible to engage, the signal value of the abdomen at the representative sampling frequency of 0.4 kHz falls within the range where engagement is possible.

[0089] On the other hand, the signal values ​​sampled at the first fine-difference sampling frequency of 0.401 kHz and the second fine-difference sampling frequency of 0.402 kHz are both outside the engagement range at the antinode of the beat wave. Therefore, at the antinode of the beat wave, the condition that "the amplitudes of the phase difference sensor signals acquired at each sampling frequency are all equal to or less than the determination threshold" is denied, preventing an erroneous determination of engagement timing. Similarly, even if the signal value at one sampling frequency falls within the engagement range midway between a node and an antinode, or midway between an antinode and the next node, the signal value at the other sampling frequency falls outside the engagement range, preventing an erroneous determination of engagement timing.

[0090] In contrast, at the nodes of the beat wave, the amplitudes of the phase difference sensor signals sampled at the representative sampling frequency of 0.4 kHz, the first fine-difference sampling frequency of 0.401 kHz, and the second fine-difference sampling frequency of 0.402 kHz are all below the determination threshold and fall within the engagement range, thereby enabling appropriate determination of the engagement timing.

[0091] The process for determining engagement timing according to the fourth embodiment is shown in the flowchart of Figure 24. In S41, disturbance components of the phase difference sensor signal are removed by the LPF 31. In S42, the calculation device 30 calculates the beat frequency fb from the differential rotation speed.

[0092] In S43, each of the sampling circuits 321, 322, and 323 samples the phase difference sensor signal at one representative sampling frequency fsr and one or more fine-difference sampling frequencies fsd*, where the representative sampling frequency fsr and the fine-difference sampling frequencies fsd* are defined by the above equations (4.1) and (4.2).

[0093] In S44, the engagement timing determination circuit 33 determines the timing at which the amplitudes of the phase difference sensor signals acquired at each sampling frequency become equal to or smaller than the determination threshold as the node of the beat wave, i.e., the engagement timing. In S45, the computing device 30 drives the linear motion actuator 15 based on the engagement timing.

[0094] In the fourth embodiment, even when the rotation speed of the first engagement member 11 is high, the nodes of the beat wave can be detected using a sampling frequency with a relatively low frequency, so that the amount of processing by the arithmetic device 30 can be reduced.

[0095] Here, when starting engagement determination, it is preferable to synchronize the initial sampling timings of the representative sampling frequency fsr, the first fine-difference sampling frequency fsd1, and the second fine-difference sampling frequency fsd2, thereby obtaining signal values ​​with a favorable relationship as shown in Fig. 22 immediately after starting engagement determination.

[0096] Furthermore, if the representative sampling frequency fsr is set to four times the beat wave frequency, there may be cases where the sampling timing exactly crosses a node. On the other hand, if the representative sampling frequency fsr is set to about eight to ten times the beat wave frequency, one sampling timing in the beat cycle will always fall within a node, improving the accuracy of the determination.

[0097] (Other embodiments) (a) The dog clutch engagement control system of the present invention is not limited to dog clutches provided in the powertrain systems of electric vehicles, but can be applied to dog clutches provided on rotating shafts for various applications, such as the powertrains of engine vehicles and power transmission mechanisms of general machinery. The present invention is particularly effective in systems in which the rotational speed of the first engagement member 11 varies widely from low to high rotational speeds.

[0098] (b) The vehicle 90 may be a four-wheel drive vehicle in which both the front and rear wheels are driven wheels, in addition to the FF vehicle exemplified in Figures 1 and 2. Furthermore, in the first to third embodiments, the timing synchronized with the rotation of the first engagement member 11 is not limited to the signal from the rotation sensor 56 (resolver, etc.) of the main motor 6, and may be determined based on other rotation signals.

[0099] (c) The first to fourth embodiments described above are not mutually exclusive and may be combined as appropriate. The embodiment to be adopted may be switched depending on the conditions.

[0100] The present invention is not limited to the above-described embodiment, and can be embodied in various forms without departing from the spirit of the invention.

[0101] The computing device and methods described herein may be implemented by a special-purpose computer configured with a processor and memory programmed to perform one or more functions embodied in a computer program. Alternatively, the computing device and methods described herein may be implemented by a special-purpose computer configured with a processor comprising one or more dedicated hardware logic circuits. Alternatively, the computing device and methods described herein may be implemented by one or more special-purpose computers configured with a processor and memory programmed to perform one or more functions in combination with a processor configured with one or more hardware logic circuits. Furthermore, the computer program may be stored as instructions executed by a computer on a computer-readable non-transitory storage medium. [Explanation of symbols]

[0102] 100... Dog clutch engagement control system, 10. Dog clutch, 11: First engaging member; 13: First gear tooth row; 12: Second engagement member; 14: Second gear tooth row; 21 Phase difference sensor, 30...Arithmetic device.

Claims

1. a dog clutch (10) including a first engagement member (11) having a first gear tooth row (13) formed in the circumferential direction and rotating about an axis, and a second engagement member (12) having a second gear tooth row (14) formed in the circumferential direction and capable of meshing with the first gear tooth row and rotating coaxially and in the same direction as the first engagement member, wherein the first engagement member and the second engagement member are switched between an engaged state and a released state by relative axial movement of the first engagement member and the second engagement member; a phase difference sensor (21) that detects the total area of ​​the first gear tooth row and the second gear tooth row that pass through the detection range in an axial direction as the first gear tooth row and the second gear tooth row rotate, and outputs a phase difference sensor signal in which the rotational phase difference between the first engaging member and the second engaging member appears as the amplitude of a beat wave; a computing device (30) that determines, based on a plurality of signal values ​​obtained by sampling the phase difference sensor signal at timings synchronized with rotation of the first engagement member, a timing at which the amplitude of the phase difference sensor signal becomes equal to or smaller than a determination threshold value as an engagement timing at which the dog clutch can be engaged; 1. A dog clutch engagement control system comprising:

2. the calculation device sets one or more reference phases for each pitch angle obtained by dividing an angle of one rotation of the first engagement member by the number of teeth of the first gear tooth row, 2. The dog clutch engagement control system according to claim 1, wherein the phase difference sensor signal is sampled at a timing corresponding to the reference phase.

3. The computing device a rotational phase of the first engaging member at which an area of ​​the first gear tooth row within a detection range of the phase difference detection sensor is maximized or minimized is set as the reference phase; 3. The dog clutch engagement control system according to claim 2, wherein, when a vibration center value of a beat wave of the phase difference sensor signal is defined as zero, the engagement timing is determined to be a timing when an absolute value of a signal value obtained by sampling the phase difference sensor signal at a timing corresponding to the reference phase becomes equal to or less than the determination threshold value.

4. The computing device For each pitch angle, an arbitrary rotational phase of the first engagement member is set as one main reference phase, which is the main reference phase, and phases shifted by a predetermined phase from the main reference phase are set as one or more sub-reference phases, which are sub-reference phases; based on a main signal value, which is a signal value obtained by sampling the phase difference sensor signal at a timing corresponding to the main reference phase, and a sub-signal value, which is a signal value obtained by sampling the phase difference sensor signal at a timing corresponding to the sub-reference phase, 3. The dog clutch engagement control system according to claim 2, wherein, when a vibration center value of a beat wave of the phase difference sensor signal is defined as zero, the timing at which the absolute values ​​of the main signal value and the sub-signal value are both equal to or less than the determination threshold value is determined as the engagement timing.

5. 5. The dog clutch engagement control system according to claim 4, wherein a phase shift of at least one of said secondary reference phases relative to said primary reference phase is set to one-fourth or three-fourths of said pitch angle.

6. a beat period (τb), which is a period of the beat wave based on the difference between the rotational speed of the first engaging member and the rotational speed of the second engaging member, is constant regardless of the rotational speed of the first engaging member, and the engagement timing is determined only when the rotational speed of the first engaging member is equal to or higher than a predetermined lower limit rotational speed, The computing device a fixed number of samplings per beat period, R, of 5 or more; Calculating the number of intervals (n) which is the integer part of the value obtained by dividing the number of periods (Fp) of the phase difference sensor signal per beat period by the number of regular periods; sampling the phase difference sensor signal a number of times equal to the regular number per beat period at timing synchronized with the rotation of the first engagement member for each interval number period of the phase difference sensor signal, regardless of the rotation number of the first engagement member; 2. The dog clutch engagement control system according to claim 1, wherein, when a vibration center value of a beat wave of the phase difference sensor signal is defined as zero, the timing when the absolute value of the obtained signal value becomes equal to or less than the determination threshold value is determined as the engagement timing.

7. a dog clutch (10) including a first engagement member (11) having a first gear tooth row (13) formed in the circumferential direction and rotating about an axis, and a second engagement member (12) having a second gear tooth row (14) formed in the circumferential direction and capable of meshing with the first gear tooth row and rotating coaxially and in the same direction as the first engagement member, wherein the first engagement member and the second engagement member are switched between an engaged state and a released state by relative axial movement of the first engagement member and the second engagement member; a phase difference sensor (21) that detects the total area of ​​the first gear tooth row and the second gear tooth row that pass through the detection range in an axial direction as the first gear tooth row and the second gear tooth row rotate, and outputs a phase difference sensor signal in which the rotational phase difference between the first engaging member and the second engaging member appears as the amplitude of a beat wave; a computing device (30) that samples the phase difference sensor signal at a plurality of sampling frequencies including one representative sampling frequency (fsr) and one or more fine difference sampling frequencies (fsd1, fsd2), and determines a timing when the amplitudes of the phase difference sensor signals acquired at each sampling frequency become equal to or smaller than a determination threshold as an engagement timing at which the dog clutch can be engaged; Equipped with The computing device calculating a beat frequency (fb) that is the frequency of the beat wave on the assumption that a differential rotation speed that is a difference between the rotation speed of the first engaging member and the rotation speed of the second engaging member is a predetermined value, or based on the differential rotation speed calculated from a rotation speed detection value; the representative sampling frequency is set to be 4 times or more and 10 times or less the beat frequency, A dog clutch engagement control system in which the difference between the fine-difference sampling frequency and the representative sampling frequency is set to be equal to or less than one-tenth of the beat frequency.

8. The dog clutch engagement control system according to any one of claims 1 to 7, which is applied to an electric vehicle (90) that uses a main motor (6) as a power source and in which the first engagement member is coupled to a motor shaft (81) of the main motor directly or via a reducer (7).

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