Vehicle control device

Abstract

To provide a vehicle control device that suppresses gear noise generated when switching gear stages in an auxiliary transmission.SOLUTION: A vehicle control device detects a violation of the "switchover condition" while switching gear stages of an auxiliary transmission 44. If an energization current value (I) of a switch motor 82, which moves a sleeve 68 in a dog clutch mechanism 58, exceeds a predetermined value (Iz), the device executes control to stop the gear stage switch and return the sleeve 68 to a clutch gear 62 prior to the switch. Since an engagement state between the clutch gear 62 and the sleeve 68 before the switch can be detected including a variation in each auxiliary transmission 44 through the energization current value (I) of the switch motor 82, the control to return the sleeve 68 accurately determines whether gears are still engaged, thereby suppressing gear noise.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a vehicle control device that suppresses the generation of gear rattle in an auxiliary transmission that switches gear stages by means of a meshing clutch mechanism.

Background Art

[0002] A vehicle control device including a power source, a main transmission provided in a power transmission device that transmits power from the power source to wheels, and an auxiliary transmission provided on the output side of the main transmission of the power transmission device is well known. For example, the vehicle power transmission device described in Patent Document 1 is such a device. Patent Document 1 discloses that when the release of the neutral range of the main transmission is detected during gear stage switching in the auxiliary transmission, the gear stage switching is aborted according to the sleeve position of the meshing clutch mechanism of the auxiliary transmission, and control is performed to return the sleeve to the gear stage before switching.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The control in the above-mentioned Patent Document 1 aims to perform control (hereinafter referred to as return control) to stop gear stage switching and return the sleeve to the gear stage before switching when the engagement between the gear stage before switching and the sleeve continues at the time of detecting the release of the neutral range. Whether the engagement continues or not is determined by comparing and judging the sleeve position of the engagement clutch mechanism at the time of detection or the time from the start of gear switching with the preset judgment values respectively. However, since the engagement state between the sleeve and the gear stage before switching depends on the engagement length of each spline, the switching speed of the gear stage, etc., variations in length (position) and time occur for each auxiliary transmission. Therefore, in the comparison judgment with the judgment value (fixed value) of position or time, the control as intended cannot be achieved, and there is a problem that gear rattle occurs.

[0005] The present invention has been made against the background of the above circumstances, and its object is to provide a vehicle control device that suppresses the occurrence of gear rattle by performing detection corresponding to the variations of the auxiliary transmission in the return control.

Means for Solving the Problems

[0006] The gist of the present invention is: (a) a control device for a vehicle including a power source, a main transmission provided in a power transmission device that transmits power from the power source to wheels, and an auxiliary transmission provided on the output side of the main transmission of the power transmission device and switching gear stages by an engagement clutch mechanism, wherein (b) when a violation of the gear stage switching condition is detected during the switching of the gear stage of the auxiliary transmission and the energization current value of an electric drive device that moves the sleeve of the engagement clutch mechanism exceeds a predetermined value, control is performed to stop the gear stage switching and return the sleeve to the gear stage before switching.

Effects of the Invention

[0007] According to the present invention, when a violation of the gear stage switching condition is detected during the switching of the gear stage of the auxiliary transmission, and if the energization current value of the electric drive device that moves the sleeve of the meshing clutch mechanism exceeds a predetermined value, the switching of the gear stage is aborted, and control is performed to return the sleeve to the gear stage before switching. Since the meshing state between the gear stage before switching and the sleeve includes variations for each auxiliary transmission and is detected by the energization current value of the electric drive device, an accurate determination as to whether meshing is continuing can be made in the return control, and a vehicle control device that suppresses gear rattling can be provided.

[0008] Preferably, the predetermined value is set in advance by design or experiment. Also preferably, a suitable predetermined value may be set by learning the energization current value of the electric drive device at the first gear stage switching of the auxiliary transmission.

[0009] Preferably, due to a change in the operating temperature of the electric drive device, the grease viscosity inside the electric drive device changes, and the energization current value of the electric drive device also changes due to a change in sliding resistance, so the predetermined value is set according to the operating temperature. Thereby, the probability of erroneously determining the meshing state due to a change in the operating temperature can be reduced. Also preferably, the operating temperature may be predicted from the outside air temperature.

[0010] Preferably, as the number of operations of the electric drive device, that is, as the cumulative number of gear stage switches of the auxiliary transmission increases, the driving performance inside the electric drive device deteriorates and the energization current value of the electric drive device also decreases, so the predetermined value is set according to the number of switches. Thereby, the probability of erroneously determining the meshing state due to an increase in the number of switches can be reduced.

[0011] Preferably, if the time from the start of gear stage switching exceeds the maximum value of the time for the sleeve to disengage from the meshing with the gear stage before switching, it is determined as an abnormal value, and the return control is not performed. Thereby, malfunction due to an abnormal value can be prevented.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Figure 4

Embodiments for Carrying Out the Invention

[0013] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

Embodiment

[0014] In FIG. 1, a vehicle 10 is a four-wheel drive vehicle including an engine 12 as a power source, front wheels 14, and rear wheels 16. The vehicle 10 includes a power transmission device 18 that transmits the power from the engine 12 to the front wheels 14 and the rear wheels 16, which are the wheels, respectively.

[0015] The engine 12 is a known internal combustion engine. The power transmission device 18 includes a torque converter 20, an automatic transmission 22, a transfer 24, an F propeller shaft 26, an R propeller shaft 28, an F differential 30, an R differential 32, an F drive shaft 34, and an R drive shaft 36. The automatic transmission 22 is, for example, a known planetary gear type automatic transmission and corresponds to the "main transmission" in the present invention. The transfer 24 is connected to the output side of the automatic transmission 22 and is a power distribution device that distributes the power from the engine 12 to the front wheels 14 and the rear wheels 16. The transfer 24 includes an auxiliary transmission 44, a center differential 50, and the like.

[0016] FIG. 2 is a schematic diagram for explaining the auxiliary transmission 44, showing the upper half of the axis line CL. The auxiliary transmission 44 includes a planetary gear device 56 and an engagement clutch mechanism 58.

[0017] The planetary gear device 56 has a sun gear S1 connected to an input shaft 42 connected to the automatic transmission 22, a ring gear R1 connected to the case 40, and a carrier CA1 that rotatably and revolvably supports a plurality of pinions P1 that mesh with the sun gear S1 and the ring gear R1. A synchronization engagement mechanism 60 that is involved in the establishment of the high gear stage Hg among the engagement clutch mechanisms 58 is connected to the sun gear S1. A clutch gear 62 that is involved in the establishment of the low gear stage Lg among the engagement clutch mechanisms 58 is connected to the carrier CA1.

[0018] The engagement clutch mechanism 58 has an engagement clutch 64 for establishing the low gear stage Lg and a synchronization engagement mechanism 60 for establishing the high gear stage Hg. The engagement clutch 64 includes a clutch gear 62 that meshes with an outer peripheral tooth 70 provided on the outer peripheral portion of a sleeve 68. Further, the engagement clutch 64 includes a cylindrical sleeve 68 that is provided so as not to be relatively rotatable about the axis line CL and to be relatively movable in the axis line CL direction with respect to a differential case 66 provided in the center differential 50. The torque transmitted from the planetary gear device 56 to the differential case 66 via the sleeve 68 is transmitted to the center differential 50.

[0019] In the auxiliary transmission 44, when the sleeve 68 slides rightward in the drawing about the axis line CL and the outer peripheral tooth 70 of the sleeve 68 meshes with the clutch gear 62, the low gear stage Lg is established. Further, when the sleeve 68 slides leftward in the drawing about the axis line CL and the inner peripheral tooth of the sleeve 68 meshes with the synchronization engagement mechanism 60, the high gear stage Hg is established.

[0020] The gear shift of the auxiliary transmission 44 is performed by the operation of the switching motor 82 to move the output member 84 in the axial direction CL of the sleeve 68 when a switching motor control signal Shl is transmitted from an electronic control unit 90 described later. The switching motor 82 corresponds to the "electric drive device" in the present invention. Further, the switching motor 82 may be composed of a linear solenoid or the like. The gear shift of the auxiliary transmission 44 is carried out when the following "switching condition" is satisfied, that is, when power exceeding the allowable amount is not transmitted to the auxiliary transmission 44. The "switching condition" is that the vehicle speed V is less than a predetermined value Va, the engine rotational speed Ne is less than a predetermined value Na, and the shift position of the automatic transmission 22 is in the neutral position.

[0021] Returning to FIG. 1, the vehicle 10 includes an electronic control unit 90 as a controller including a control device for the vehicle 10.

[0022] Various signals (for example, the engine rotational speed Ne, the output rotational speed No corresponding to the vehicle speed V which is the rotational speed of the R propeller shaft 28, the energization current value I of the switching motor 82, the motor temperature Ta of the switching motor 82, the outside air temperature To, the high-low switching operation signal OPhl indicating the shifted gear stage of the gear stage switching switch 118, etc.) based on the detection values by various sensors etc. (for example, the engine rotational speed sensor 100, the output rotational speed sensor 102, the switching motor current sensor 110, the switching motor temperature sensor 112, the outside air temperature sensor 114, the gear stage switching switch 118 of the auxiliary transmission 44, etc.) provided in the vehicle 10 are respectively supplied to the electronic control unit 90.

[0023] Various control signals (for example, the engine control signal Se, the AT control signal Sat for controlling the automatic transmission 22, the switching motor control signal Shl for switching the gear stage of the auxiliary transmission 44, etc.) are respectively output from the electronic control unit 90 to each device (for example, the engine 12, the automatic transmission 22, the switching motor 82, etc.) provided in the vehicle 10.

[0024] FIG. 3 is a diagram for explaining the operation and determination conditions of the engagement between the clutch gear 62 and the sleeve 68 during gear shift from the low gear stage Lg to the high gear stage Hg of the auxiliary transmission 44.

[0025] In the upper part of the graph in FIG. 3(a), the horizontal axis represents the time T from the start of gear shift, and the vertical axis represents the moving distance L of the sleeve 68 (the outer peripheral teeth 70: hereinafter omitted). For example, from the start of gear shift, the sleeve 68 moves to the distance L1 at the time point T1 and to the distance L2 at the time point T2. Also, since the engagement between the clutch gear 62 and the sleeve 68 depends on the engagement length of the respective splines, the switching speed of the switching motor 82, etc., variations occur for each auxiliary transmission 44. For example, as shown on the right side of the upper part of FIG. 3(a) in the drawing, variations in the engaged state occur from the case of "shortest engagement" where the engagement is disengaged at the time point T1 (distance L1) to the case of "longest engagement" where the engagement is disengaged at the time point T2 (distance L2).

[0026] By the way, in the conventional example, in the return control, whether the engagement between the clutch gear 62 and the sleeve 68 continues or not is determined by comparing and determining the position of the sleeve 68 at the time when the violation of the "switching condition" is detected, that is, the distance L or the time T from the start of gear shift, with the preset determination values for each. Therefore, there is a problem that the control is not as expected and gear noise occurs. For example, if the determination value is set to the value T1 (or the value L1), in the case of "longest engagement", when the violation of the "switching condition" is detected at the time point T (or the L position) where T1 < T < T2 (or L1 < L < L2), the return control is not implemented even though it can be implemented, and the switching to the high gear stage Hg, that is, the engagement in a state where there is a rotational speed difference between the sleeve 68 and the synchronous engagement mechanism 60, occurs, resulting in gear noise. Also, for example, if the determination value is set to the value T2 (or the value L2), in the case of "shortest engagement", when the violation of the "switching condition" is detected at the time point T (or the L position) where T1 < T < T2 (or L1 < L < L2), the sleeve 68 is returned from the state where the engagement between the clutch gear 62 and the sleeve 68 is disengaged, and again, the engagement in a state where there is a rotational speed difference between the sleeve 68 and the clutch gear 62 occurs, resulting in gear noise.

[0027] Therefore, the electronic control device 90 of this embodiment determines whether or not the meshing between the clutch gear 62 and the sleeve 68 continues by comparing the energization current value I of the switching motor 82 with a predetermined value Iz. As shown in FIG. 3(a), when the clutch gear 62 and the sleeve 68 are in the meshed state, the energization current value I of the switching motor 82 is large because the driving load of the switching motor 82 is large, and when they are not in the meshed state, the energization current value I is small because the driving load is small. That is, the meshed state can be detected by the energization current value I. When the energization current value I is greater than the predetermined value Iz, the electronic control device 90 determines that the meshing between the clutch gear 62 and the sleeve 68 continues.

[0028] Preferably, the predetermined value Iz is set in advance by design or experiment. Also preferably, a suitable predetermined value Iz may be set by learning the energization current value I of the switching motor 82 at the first gear shift of the auxiliary transmission 44.

[0029] Also preferably, due to the change in the motor temperature Ta, the grease viscosity inside the switching motor 82 changes, and the energization current value I also changes due to the change in the sliding resistance. Therefore, the predetermined value Iz is set according to the motor temperature Ta. FIG. 3(b) shows an example of setting the predetermined value Iz according to the motor temperature Ta (in the case of "shortest meshing"). For example, by referring to the setting map of the motor temperature Ta and the energization current value I shown at the lower side of FIG. 3(b), when the motor temperature Ta is Ta1, the predetermined value Iz is set to I1, and when the motor temperature Ta is Ta2, the predetermined value Iz is set to I2. Thereby, the probability of erroneously determining the meshed state due to the change in the motor temperature Ta can be reduced. Also, the motor temperature Ta may preferably be predicted from the outside air temperature To.

[0030] Also preferably, as the number of operations of the switching motor 82, that is, the cumulative number of gear stage switches N of the subtransmission 44 increases, the driving performance inside the switching motor 82 deteriorates, and the energization current value I also decreases. Therefore, the predetermined value Iz is set according to the number of switching times N. FIG. 3(c) shows an example of setting the predetermined value Iz according to the number of switching times N (in the case of "shortest engagement"). For example, by referring to the setting map of the number of switching times N and the energization current value I shown on the lower side of FIG. 3(c), when the number of switching times N is N1, the predetermined value Iz is set to I3, and when the number of switching times N is N2, the predetermined value Iz is set to I4. Thereby, the probability of erroneously determining the meshing state can be reduced as the number of switching times N increases.

[0031] FIG. 4 is a flowchart for explaining the main part of the control operation of the electronic control device 90, and is a flowchart for explaining the operation of the return control when switching the gear stage from the low gear stage Lg to the high gear stage Hg of the subtransmission 44, and is repeatedly executed, for example.

[0032] In FIG. 4, first, in step (hereinafter, steps are omitted) S10, it is determined whether there is a gear stage switching request from the low gear stage Lg to the high gear stage Hg. In S20 where the determination in S10 is affirmed, a predetermined value Iz corresponding to the motor temperature Ta is set. Next, in S30, it is determined whether the "switching condition" of the auxiliary transmission 44 is satisfied. If the determination in this S30 is affirmed, then in S40, the switching motor 82 starts to be driven, and the gear stage switching to the high gear stage Hg is started. Next, in S50, it is determined whether the gear stage switching is completed. If the determination in S50 is affirmed, then in S60, the switching motor 82 is stopped from being driven, the gear stage switching is completed, and this routine is terminated. Also, when the determination in the above S10 and the determination in the above S30 are negated, this routine is also terminated. When the determination in S50 is negated, in S70, it is determined whether a violation of the "switching condition" is detected. If the determination in S70 is affirmed, then in S80, it is determined whether the energization current value I is greater than the predetermined value Iz set in S20. When the determination in the above S70 and the determination in the above S80 are negated, a transition is made to S50. When the determination in S80 is affirmed, that is, when it is determined that the meshing between the sleeve 68 and the clutch gear 62 continues, a transition is made to S90. Next, in S90, it is determined whether the time T from the start of the gear stage switching exceeds the maximum value T2 (see FIG. 3(a)) of the time for the sleeve 68 to disengage from the meshing with the clutch gear 62. When the determination in S90 is affirmed, that is, when the sleeve 68 does not disengage from the meshing even if it exceeds T2, it is determined as an abnormal value, and a transition is made to S50 so as not to perform the return control due to malfunction. When the determination in S90 is negated, in S100, control is performed to return the sleeve 68 to the clutch gear 62 before switching (to cancel the gear stage switching), and this routine is terminated.

[0033] This embodiment is an example of gear stage switching from the low gear stage Lg to the high gear stage Hg of the auxiliary transmission 44, but the gear stage switching from the high gear stage Hg to the low gear stage Lg can also be implemented with the same control operation.

[0034] As described above, according to the electronic control device 90 of the present embodiment, when a violation of the "switching condition" is detected during the gear stage switching of the auxiliary transmission 44 and the energization current value I of the switching motor 82 that moves the sleeve 68 of the meshing clutch mechanism 58 exceeds the predetermined value Iz, the gear stage switching is aborted and control is performed to return the sleeve 68 to the clutch gear 62 before switching. The meshing state between the clutch gear 62 before switching and the sleeve 68 includes variations for each auxiliary transmission 44 and is detected by the energization current value I of the switching motor 82. Therefore, in the return control, an accurate determination is made as to whether or not the meshing is continuing, and gear rattle generation is suppressed.

[0035] Note that the above is merely one embodiment, and the present invention can be implemented in various modified and improved forms based on the knowledge of those skilled in the art.

Explanation of Reference Numerals

[0036] 10: Vehicle 12: Engine (power source) 14: Front wheels 16: Rear wheels 18: Power transmission device 22: Automatic transmission (main transmission) 44: Auxiliary transmission 58: Meshing clutch mechanism 68: Sleeve 82: Switching motor (electric drive device) 90: Electronic control device (control device)

Claims

【Claim 1】 A control device for a vehicle, comprising: a power source; a main transmission provided in a power transmission device that transmits power from the power source to wheels; and an auxiliary transmission provided on an output side of the main transmission of the power transmission device and switching gear stages by a meshing clutch mechanism, the control device is configured to detect a violation of a gear stage switching condition during switching of the gear stage of the auxiliary transmission, and if an energization current value of an electric drive device that moves a sleeve of the meshing clutch mechanism exceeds a predetermined value, stop the switching of the gear stage and perform control to return the sleeve to the gear stage before switching.

Images