seat

Abstract

Considering that a small duty cycle at startup mitigates the startup shock, but still requires time for the electric motor to actually begin rotating, we disclose an example of a "seat capable of oscillation control." [Solution] In the vehicle seat, after the start of the rocking control, for the second and subsequent starts in the rocking control, a duty cycle that allows the electric motor to actually start rotating from the beginning, i.e., a starting duty cycle Sdr, is applied to the electric motor 6. After the starting duty cycle Sdr is applied to the electric motor 6, the duty cycle is controlled to reach a predetermined target speed. Therefore, with the vehicle seat 1, the shock at startup is mitigated, and the time until the electric motor 6 actually starts rotating can be significantly shortened.

Description

Technical Field

[0001] The present disclosure relates to a seat capable of performing swing control for reciprocally swinging a seat body in the front - rear direction of the seat with the rear - end side of a seat cushion as a swing center.

Background Art

[0002] For example, in the electric seat device described in Patent Document 1, by making the duty ratio at startup smaller than the duty ratio after a predetermined time has elapsed after startup, the impact (shock) at startup is mitigated.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, since the static friction coefficient is larger than the dynamic friction coefficient, the frictional force generated in a stationary member is larger than the frictional force generated in an operating member. Moreover, when the duty ratio is small, the torque generated by an electric motor is small.

[0005] Therefore, when the duty ratio at startup is small, although the shock at startup is mitigated, it actually takes time until the electric motor starts to rotate. The present disclosure discloses an example of a "seat capable of performing swing control" in view of this point.

Means for Solving the Problems

[0006] The seat is preferably equipped with at least one of the following components: a seat body (2) having a seat cushion (3) and a seat back (4); an electric motor (6) that exerts a oscillating force to reciprocate the seat body (2) in the front-rear direction, with the rear end of the seat cushion (3) as the pivot point; a rotation detection unit (6A) that detects the rotation of the electric motor (6); a control unit (5) that performs PWM control of the voltage applied to the electric motor (6), wherein the control unit (5) controls the duty cycle so that the electric motor (6) reaches a predetermined target speed and is capable of performing oscillating control to reciprocate the seat body (2); and a duty cycle detection unit (5A) that detects the duty cycle.

[0007] Furthermore, when the electric motor (6), which is in a stopped state, actually starts to rotate in the forward or reverse direction, after the start of the oscillation control, the duty cycle detected at the first start is set as the detected duty cycle (Ddr), and the duty cycle determined based on the detected duty cycle (Ddr) is set as the start duty cycle (Sdr). In such cases, it is desirable that the control unit (5) be able to perform start control in which, after the start of the oscillation control, for the second and subsequent starts in the oscillation control, a voltage of the start duty cycle (Sdr) is applied from the time of the start.

[0008] As a result, after the start of the oscillation control, for the second and subsequent startups in the oscillation control, a duty cycle that allows the electric motor to actually start rotating from the beginning, i.e., the starting duty cycle (Sdr), is applied to the electric motor (6).

[0009] Then, after the starting duty cycle (Sdr) is applied to the electric motor (6), the duty cycle is controlled to reach a predetermined target speed. Therefore, with this seat, the shock at startup is mitigated, and the time until the electric motor (6) actually starts rotating can be significantly reduced.

[0010] The sheet may also have the following configuration, for example. In other words, when the duty cycle determined based on the starting duty cycle (Sdr) is set as the stopping duty cycle (Qdr), it is desirable that the control unit (5) be able to perform stopping control during the deceleration phase when the electric motor (6) is stopped, with the stopping duty cycle (Qdr) set as the lower limit, thereby reducing the duty cycle. This can prevent the electric motor (6) from stopping at an unintended timing.

[0011] Furthermore, it is desirable that the control unit (5) perform startup control at the start of forward rotation and at the start of reverse rotation. Furthermore, it is desirable that the control unit (5) can perform a lock determination prohibition function during the initial startup after the start of oscillation control, which prevents the PWM control from stopping until the detected duty cycle (DDR) is detected. This can prevent the startup control from ending at an unintended time.

[0012] Incidentally, the symbols in each of the parentheses above are just examples showing the correspondence with the specific configurations etc. described in the embodiments described later, and this disclosure is not limited to the specific configurations etc. indicated by the symbols in the parentheses above. [Brief explanation of the drawing]

[0013] [Figure 1] This figure shows a vehicle seat according to the first embodiment. [Figure 2] This is a block diagram showing a seat for a vehicle according to the first embodiment. [Figure 3] This is a graph showing the target speed. [Figure 4] This is a flowchart showing the oscillation control according to the first embodiment. [Figure 5] This is a flowchart showing the oscillation control according to the first embodiment. [Figure 6] This is a flowchart showing the oscillation control according to the first embodiment. [Figure 7] This is a flowchart showing the oscillation control according to the first embodiment. [Modes for carrying out the invention]

[0014] The following "Embodiments of the Invention" show an example of an embodiment belonging to the technical scope of the present disclosure. That is, the invention-specific matters described in the claims are not limited to the specific configurations, structures, etc. shown in the following embodiments.

[0015] This embodiment is an example in which the seat according to the present disclosure is applied to a seat (hereinafter referred to as a vehicle seat) mounted on a vehicle such as a car. Arrows indicating directions attached to each figure are described to facilitate understanding of the relationship between the figures.

[0016] Therefore, the vehicle seat is not limited to the directions attached to each figure. At least the components described with reference numerals are provided with at least one, unless otherwise specified such as "one". The vehicle seat shown in the present disclosure includes at least one of at least the components described with reference numerals.

[0017] (First Embodiment) <1. Overview of Vehicle Seat (see FIGS. 1 and 2)> The vehicle seat 1 includes at least a seat body 2, a control unit 5, an electric motor 6, a rotation sensor 6A, a drive unit 7, etc. As shown in FIG. 1, the seat body 2 has at least a seat cushion 3 and a seat back 4, etc.

[0018] The seat cushion 3 is a part for supporting the buttocks of the seated person. The seat back 4 is a part for supporting the back of the seated person. The electric motor 6 (see FIG. 2) constitutes a part of a rocking device (not shown) and exerts a rocking force.

[0019] The rocking device can alternately execute the case of displacing the seat body 2 from the first state shown by the two-dot chain line in FIG. 1 to the second state shown by the solid line and the case of displacing the seat body 2 from the second state to the first state.

[0020] In other words, the rocking device is a device capable of performing rocking control that causes the seat body 2 in a comfortable posture to reciprocate in the front-to-back direction of the seat, with the rear end of the seat cushion 3 as the pivot point. The comfortable posture refers to a state in which the angle between the seat cushion 3 and the seat back 4 is larger than that of a normal posture such as when driving.

[0021] The drive unit 7 is a drive circuit that applies a voltage to the electric motor 6 to drive the electric motor 6. The drive unit 7 is controlled by the control unit 5. The control unit 5 controls the voltage applied to the electric motor 6 using PWM control.

[0022] Specifically, the control unit 5 controls the duty cycle of the voltage applied to the electric motor 6 and the direction of rotation of the electric motor 6 so that the electric motor 6 reaches a predetermined target speed (see Figure 3).

[0023] In this embodiment, when the electric motor 6 rotates forward, the seat body 2 changes from the first state to the second state. When the electric motor 6 rotates in reverse, the seat body 2 changes from the second state to the first state. Note that a positive speed in Figure 3 indicates forward rotation, and a negative speed in Figure 3 indicates reverse rotation.

[0024] The rotation sensor 6A is an example of a rotation detection unit that detects the rotation of the electric motor 6. The detection signal from the rotation sensor 6A is input to the control unit 5. The control unit 5 uses the detection signal from the rotation sensor 6A to perform feedback control so that the electric motor 6 operates at a target speed.

[0025] Specifically, the control unit 5 (in this embodiment, the duty cycle determination unit 5A) increases the current duty cycle if the speed detected by the rotation sensor 6A is lower than the target speed. The duty cycle determination unit 5A decreases the current duty cycle if the speed detected by the rotation sensor 6A is higher than the target speed.

[0026] The control unit 5 is configured as a computer having a CPU, ROM, RAM, etc. The duty cycle determination unit 5A is implemented by software being executed on the CPU. This software is pre-stored in a non-volatile storage unit such as ROM. In this embodiment, the duty cycle determination unit 5A also serves as the duty cycle detection unit. The duty cycle detection unit performs the function of detecting the duty cycle.

[0027] <2. Oscillation Control> <2.1 Overview of Oscillating Control> The rocking control is a control mechanism that causes the seat body 2, in a comfortable position, to rock back and forth in the front-to-back direction of the seat, with the rear end of the seat cushion 3 as the pivot point. This rocking control is executed when the seated person operates the rocking start switch (not shown) or the like.

[0028] <Definition of Terms> "Start of oscillation control" refers to the moment when the oscillation start switch is operated and oscillation control is initiated.

[0029] "Detected duty cycle DDR" refers to the duty cycle detected at the first startup after the start of oscillation control, when the electric motor 6, which was in a stopped state, actually begins to rotate in the forward or reverse direction (hereinafter referred to as startup).

[0030] "Startup duty cycle Sdr" refers to the duty cycle determined based on the detection duty cycle DDR. The startup duty cycle Sdr may be either the same value as the detection duty cycle Ddr or a different value from the detection duty cycle Ddr. In other words, the startup duty cycle Sdr is a function of the detection duty cycle Ddr.

[0031] "Stop duty cycle Qdr" refers to the duty cycle determined based on the start duty cycle Sdr. The stop duty cycle Qdr may be the same value as the start duty cycle Sdr or a different value from the start duty cycle Sdr. In other words, the stop duty cycle Qdr is a function of the start duty cycle Sdr or the detection duty cycle Ddr.

[0032] <Start-up control / Shutdown control> Start-up control is a control that is performed during the second and subsequent starts in the oscillation control after the start of the oscillation control (hereinafter referred to as restart). Specifically, when the control unit 5 starts the electric motor 6 during a restart, the voltage initially applied is set to the start-up duty cycle Sdr.

[0033] In other words, the startup control is performed at the time shown in Figure 3A during restart. After the control unit 5 starts the electric motor 6 by applying the startup duty cycle Sdr, it variably controls the duty cycle to achieve the target speed.

[0034] Stop control is a control that is performed after the electric motor 6 has started, when the electric motor 6 is in the deceleration period (as shown in Figure 3B). Specifically, when decelerating to stop the electric motor 6, the control unit 5 reduces the duty cycle, setting the stop duty cycle Qdr as the lower limit. In this embodiment, start control and stop control are performed in both forward and reverse rotation.

[0035] <Lock detection disabling function> The control unit 5 can execute a lock detection prohibition function. The lock detection prohibition function is a function that, after the start of oscillation control, prevents the PWM control from stopping until the detected duty cycle DDR is detected during the initial startup.

[0036] In other words, the control unit 5 is capable of performing a lock detection function. The lock detection function is a function that stops the application of voltage to the electric motor 6 if the rotation of the electric motor 6 is not detected by the rotation sensor 6A within a predetermined time from the time voltage is applied to the electric motor 6.

[0037] Furthermore, the control unit 5 temporarily suspends the execution of the lock determination function during the initial startup after the start of oscillation control. After restarting, the control unit 5 resumes the execution of the lock determination function.

[0038] <2.1 Details of oscillation control (see Figures 4-7)> Figures 4 to 7 are flowcharts illustrating an example of detailed oscillation control. This oscillation control is executed when the oscillation start switch is operated.

[0039] When this control is executed, the control unit 5 first applies a voltage with a low duty cycle (for example, a duty cycle of less than 15%) to the electric motor 6 in order to rotate the electric motor 6 in the forward direction (S1), and then increases the duty cycle to achieve the target speed (S2).

[0040] Then, the control unit 5 continues to increase the duty cycle until it detects from the rotation sensor 6A that the electric motor 6 is actually rotating in the forward direction (S3:NO). When it is detected that the electric motor 6 is actually rotating in the forward direction (S3:YES), the control unit 5 determines the start duty cycle Sdr and the stop duty cycle Qdr based on the detected duty cycle DDR (S4).

[0041] Subsequently, the control unit 5 controls the electric motor 6 to maintain a target speed until the seat body 2 reaches the target position (the position corresponding to point C in Figure 3) (S6: NO). When the seat body 2 reaches the target position (S6: YES), the control unit 5 stops the electric motor 6 for a specified time (S7, S8).

[0042] Furthermore, before reaching the target position, that is, when the deceleration start position is reached, the control unit 5 decelerates the electric motor 6 with the stop duty cycle Qdr determined in S4 as the lower limit, and then stops the electric motor 6.

[0043] Next, the control unit 5 applies a voltage with a low duty cycle (for example, a duty cycle of less than 15%) to the electric motor 6 in order to reverse the motor (S9), and increases the duty cycle to achieve the target speed (S10).

[0044] Then, the control unit 5 continues to increase the duty cycle until it detects from the rotation sensor 6A that the electric motor 6 has actually reversed direction (S11: NO). When it is detected that the electric motor 6 has actually reversed direction (S11: YES), the control unit 5 determines the start duty cycle Sdr and the stop duty cycle Qdr based on the detected duty cycle DDR (S12).

[0045] Subsequently, the control unit 5 controls the electric motor 6 to maintain a target speed until the seat body 2 reaches the target position (the position corresponding to point D in Figure 3) (S14: NO). When the seat body 2 reaches the target position (S14: YES), the control unit 5 stops the electric motor 6 for a specified time (S15, S18) and then increases the counter value indicating the number of oscillations by 1 (S17).

[0046] Furthermore, before reaching the target position, that is, when the deceleration start position is reached, the control unit 5 decelerates the electric motor 6 with the stop duty cycle Qdr determined in S12 as the lower limit, and then stops the electric motor 6.

[0047] Next, the control unit 5 starts the forward rotation of the electric motor 6 with the starting duty cycle Sdr determined in S4 (S18), and then increases the duty cycle to reach the target speed (S19). Subsequently, the control unit 5 controls the electric motor 6 to maintain a target speed until the seat body 2 reaches the target position (the position corresponding to point C in Figure 3) (S20: NO). When the seat body 2 reaches the target position (S20: YES), the control unit 5 stops the electric motor 6 for a specified time (S21, S22).

[0048] Furthermore, before reaching the target position, that is, when the deceleration start position is reached, the control unit 5 decelerates the electric motor 6 with the stop duty cycle Qdr determined in S4 as the lower limit, and then stops the electric motor 6.

[0049] Next, the control unit 5 starts the electric motor 6 in reverse with the starting duty cycle Sdr determined in S12 (S23), and then increases the duty cycle to reach the target speed (S24). Subsequently, the control unit 5 controls the electric motor 6 to maintain a target speed until the seat body 2 reaches the target position (the position corresponding to point D in Figure 3) (S25: NO). When the seat body 2 reaches the target position (S25: YES), the control unit 5 stops the electric motor 6 for a specified time (S26, S27).

[0050] Furthermore, before reaching the target position, that is, when the deceleration start position is reached, the control unit 5 decelerates the electric motor 6 with the stop duty cycle Qdr determined in S12 as the lower limit, and then stops the electric motor 6.

[0051] Then, the control unit 5 increases the counter value indicating the number of oscillations by 1 (S28). It then determines whether the number of oscillations has reached a predetermined number (S29). If the number of oscillations has reached the predetermined number (S29: YES), this control ends. If the number of oscillations has not reached the predetermined number (S29: NO), S18 is executed again.

[0052] <3. Features of the vehicle seat according to this embodiment> In the vehicle seat 1 according to this embodiment, after the start of the rocking control, for the second and subsequent starts in the rocking control, a duty cycle that allows the electric motor 6 to actually start rotating from the beginning, i.e., a starting duty cycle Sdr, is applied to the electric motor 6.

[0053] Then, after the starting duty cycle Sdr is applied to the electric motor 6, the duty cycle is controlled to reach a predetermined target speed. Therefore, with this vehicle seat 1, the shock at startup is mitigated, and the time until the electric motor 6 actually starts rotating can be significantly reduced.

[0054] In the above, the starting duty cycle Sdr and stopping duty cycle Qdr used during forward rotation were determined in S4, and the starting duty cycle Sdr and stopping duty cycle Qdr used during reverse rotation were determined in S12.

[0055] Furthermore, the starting duty cycle Sdr and stopping duty cycle Qdr used during forward rotation in S4 do not need to be different values ​​from those used during reverse rotation in S12.

[0056] In other words, the starting duty cycle Sdr and stopping duty cycle Qdr used in forward rotation in S4 and the starting duty cycle Sdr and stopping duty cycle Qdr used in reverse rotation in S12 may be the same value or different values.

[0057] When the control unit 5 is executing oscillation control, during deceleration to stop the electric motor 6, it performs stop control by lowering the duty cycle, with the stop duty cycle Qdr being the lower limit. This helps to prevent the electric motor 6 from stopping at an unintended timing.

[0058] The control unit 5, after the start of oscillation control, executes a lock determination prohibition function during the initial startup, which prevents the PWM control from stopping until the detected duty cycle DDR is detected. This helps to prevent the startup control from ending at an unintended time.

[0059] (Other embodiments) In the above-described embodiment, the starting duty cycle Sdr and stopping duty cycle Qdr used during forward rotation and the starting duty cycle Sdr and stopping duty cycle Qdr used during reverse rotation were determined, respectively. However, this disclosure is not limited thereto.

[0060] In other words, the disclosure may, for example, use the starting duty cycle Sdr and stopping duty cycle Qdr used during forward rotation as the starting duty cycle Sdr and stopping duty cycle Qdr used during reverse rotation.

[0061] The above-described embodiment was configured to perform stop control and lock determination prohibition functions. However, this disclosure is not limited thereto. That is, the disclosure may also include, for example, a configuration in which at least one of the stop control and lock determination prohibition functions is eliminated.

[0062] In the embodiments described above, the system was configured to perform start-up control and stop-down control during forward rotation and reverse rotation. However, the disclosure is not limited thereto. That is, the disclosure may also provide a configuration in which, for example, at least one of the start-up control and stop-down control is performed during forward rotation or reverse rotation.

[0063] In the embodiments described above, the stop duty cycle Qdr was determined based on the start duty cycle Sdr. However, the disclosure is not limited thereto. That is, the disclosure may, for example, be configured such that the stop duty cycle Qdr is determined based on the detection duty cycle Ddr, because the start duty cycle Sdr is determined based on the detection duty cycle Ddr.

[0064] In the embodiments described above, the vehicle seat according to this disclosure was applied to a vehicle. However, the application of the invention disclosed herein is not limited to this. That is, the disclosure can be applied, for example, to seats used in vehicles such as railway cars, ships and aircraft, as well as to stationary seats used in theaters, homes, etc.

[0065] Furthermore, this disclosure is not limited to the embodiments described above, but is sufficient to be consistent with the intent of the disclosures described in the embodiments described above. Therefore, it may be a configuration in which at least two of the embodiments described above are combined, or a configuration in which any of the illustrated components or components described with reference numerals in the embodiments described above are omitted. [Explanation of symbols]

[0066] 1… Vehicle seats 2… Seat body 3… Seat cushion 4… Seat back 5… Control Unit 5A… Duty cycle determination unit 6… Electric motor 6A… Rotation sensor 7… Drive unit

Claims

1. A seat body having a seat cushion and a seat back, An electric motor that generates a swinging force to swing the seat body back and forth in the seat-forward direction, with the rear end of the seat cushion as the pivot point, A rotation detection unit for detecting the rotation of the electric motor, A control unit that performs PWM control of the voltage applied to the electric motor, the control unit that controls the duty cycle so that the electric motor reaches a predetermined target speed, and is capable of performing oscillation control to cause the seat body to reciprocate, It includes a duty cycle detection unit that detects the duty cycle, When the electric motor, which is in a stopped state, actually starts to rotate in the forward or reverse direction, the duty cycle detected at the first start after the start of the oscillation control is defined as the detected duty cycle, and the duty cycle determined based on the detected duty cycle is defined as the start duty cycle, The control unit is capable of performing a startup control that applies a voltage equal to the startup duty cycle from the time of startup, for the second and subsequent startups in the oscillation control after the start of the oscillation control.

2. When the duty cycle determined based on the aforementioned start duty cycle is taken as the stop duty cycle, The control unit, in the case of deceleration that stops the electric motor during the execution of the oscillation control, is capable of performing stop control that reduces the duty cycle, with the stop duty cycle set to a lower limit, as described in claim 1.

3. The control unit performs the startup control during forward rotation and reverse rotation, as described in claim 2.

4. The control unit is capable of executing a lock determination prohibition function that prevents the PWM control from stopping until the detected duty cycle is detected, after the start of the oscillation control, during the first startup. (Sheet according to any one of claims 1 to 3.)

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