Vehicle control device

Abstract

To provide a vehicle control device that can improve the durability of a parking mechanism that is operated based on a control command signal and is provided on the output side of a transmission mechanism.SOLUTION: When parking selection operation is made by a driver, a parking mechanism is operated so as to switch a shift position to a parking position in the state where a transmission mechanism is put in a high gear stage. As a result, if the transmission mechanism is in a reduction gear stage when the parking selection operation is made, after the transmission mechanism is switched to the high gear stage, the parking mechanism is operated. When the operation of the parking mechanism is performed in the state of the high gear stage, the load that is caused by the inertia of an electric motor and is input to the parking mechanism is reduced as compared with the case where the operation of the parking mechanism is performed in the state of the reduction gear stage. Therefore, it is possible to improve the durability of the parking mechanism provided on the output side of the transmission mechanism, which is operated based on a control command signal.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a vehicle control device that switches a shift position of a power transmission device to a parking position based on a control command signal corresponding to a parking selection operation. [Background technology]

[0002] A control device for a vehicle is well known, which includes an electric motor, a power transmission device that transmits power from the electric motor to drive wheels, a transmission mechanism including a reduction gear that constitutes part of the power transmission device, and a parking mechanism that switches the shift position of the power transmission device between a parking position in which rotation of a rotating member that rotates with the drive wheels is mechanically prevented and a non-parking position in which rotation of the rotating member is permitted. Patent Document 1 discloses an electric vehicle that includes such a control device. Patent Document 1 discloses that the parking mechanism is disposed in a power transmission path between the electric motor and a reducer, which is a transmission mechanism configured with one reduction gear. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 7-285422 Summary of the Invention [Problem to be solved by the invention]

[0004] A well-known transmission mechanism includes a reduction gear and a high gear, which is located at a higher vehicle speed than the reduction gear. A parking mechanism is also known that operates to switch the shift position of a power transmission device between a parking position and a non-parking position based on a control command signal corresponding to a driver's selection. It is conceivable to install a parking mechanism on the output side of a transmission mechanism including a reduction gear and a high gear, i.e., in the power transmission path between the transmission mechanism and the drive wheels. In this case, when the transmission mechanism is in a reduction gear, the torque of the electric motor is amplified and transmitted to the output side of the transmission mechanism. Therefore, when the parking mechanism is operated to switch the shift position to the parking position while the vehicle is in a reduction gear and the vehicle is not stopped (i.e., when the rotation of the electric motor is not stopped), the amplified inertial force of the electric motor is transmitted to the parking mechanism. This may result in a reduction in the durability of the parking mechanism due to the input of a load caused by the inertia of the electric motor.

[0005] The present invention has been made against the background of the above circumstances, and its purpose is to provide a vehicle control device that can improve the durability of a parking mechanism provided on the output side of a transmission mechanism, which is operated based on a control command signal. [Means for solving the problem]

[0006] The gist of the first invention is a control device for a vehicle including: (a) an electric motor; a power transmission device that transmits power from the electric motor to drive wheels; a transmission mechanism that forms part of the power transmission device and includes a reduction gear stage and a high gear stage that is higher in vehicle speed than the reduction gear stage; and a parking mechanism provided on the output side of the transmission mechanism that is operated to switch the shift position of the power transmission device to either a parking position in which rotation of a rotating member that rotates together with the drive wheels is mechanically prevented or a non-parking position in which rotation of the rotating member is permitted based on a control command signal corresponding to a selection operation by the driver; and (b) when a parking selection operation to select the parking position is performed by the driver, the control device operates the parking mechanism to switch the shift position to the parking position with the transmission mechanism in the high gear stage. [Effects of the Invention]

[0007] According to the first aspect of the present invention, when a parking selection operation is performed by the driver, the parking mechanism is operated to switch the shift position to the parking position while the transmission mechanism is in a high gear. As a result, if the transmission mechanism is in a reduction gear when the parking selection operation is performed, the parking mechanism is operated after the transmission mechanism is switched to a high gear. When the parking mechanism is operated in a high gear, the load input to the parking mechanism due to the inertia of the electric motor is reduced compared to when the parking mechanism is operated in a reduction gear. This improves the durability of the parking mechanism, which is provided on the output side of the transmission mechanism and is operated based on a control command signal. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a diagram illustrating a schematic configuration of a vehicle to which the present invention is applied, and is also a diagram illustrating main parts of control functions and control systems for various controls in the vehicle. [Figure 2]1 is a flowchart illustrating a main part of the control operation of the electronic control device, and is a flowchart illustrating the control operation for improving the durability of the parking mechanism. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. [Example]

[0010] Fig. 1 is a diagram illustrating the schematic configuration of a vehicle 10 to which the present invention is applied, and also illustrates the control functions and main parts of the control system for various controls in the vehicle 10. In Fig. 1, the vehicle 10 is equipped with an electric motor 12 that functions as a power source, drive wheels 14, and a power transmission device 16 that transmits the power of the electric motor 12 to the drive wheels 14.

[0011] The electric motor 12 is a known rotating electric machine, a so-called motor generator. The electric motor 12 is connected to a battery 62 provided in the vehicle 10 via an inverter 60 provided in the vehicle 10. The inverter 60 is controlled by an electronic control device 80 (described later), thereby controlling the electric motor torque Tm of the electric motor 12.

[0012] The power transmission device 16 includes a reduction gear mechanism 18 connected to the electric motor 12, an automatic transmission 20 connected to the reduction gear mechanism 18, a differential gear 24 connected to an output gear 22, and a pair of drive shafts 26 connected to the differential gear 24. The output gear 22 functions as an output rotating member of the automatic transmission 20. The automatic transmission 20 constitutes a part of the power transmission device 16.

[0013] The automatic transmission 20 includes a planetary gear set 20p, a clutch C1, and a brake B1. The planetary gear set 20p is a known single-pinion planetary gear set including a sun gear S, a carrier CA, and a ring gear R. The sun gear S is connected to an electric motor 12 via a reduction gear mechanism 18 so as to be capable of transmitting power. The carrier CA is connected to an output gear 22. The ring gear R is selectively connected to a case 28 via a brake B1. The carrier CA and the sun gear S are selectively connected via a clutch C1. The case 28 is a non-rotating member attached to the vehicle body, and houses the automatic transmission 20 and other components.

[0014] The clutch C1 and the brake B1 are both known friction engagement devices that are actuated by their respective hydraulic actuators. The clutch C1 and the brake B1 each have their control states (which are also synonymous with operating states) switched between an engaged state, a slip state, a released state, and the like, by regulated operating oil pressure supplied from a hydraulic control circuit 64 provided on the vehicle 10.

[0015] In the automatic transmission 20, when the clutch C1 is engaged, a high gear (also synonymous with a high speed) H is established, where the speed ratio (also synonymous with a gear ratio) (= input rotation speed of the automatic transmission 20 / output rotation speed of the automatic transmission 20) is "1." Furthermore, in the automatic transmission 20, when the brake B1 is engaged instead of the clutch C1, a low gear (also synonymous with a low speed) L is established, where the speed ratio is higher than the high gear H. The low gear L is a reduction gear with a speed ratio higher than "1." Thus, the automatic transmission 20 is a transmission mechanism that includes the low gear L and the high gear H, which is located at a higher vehicle speed than the low gear L. When both the clutch C1 and the brake B1 are released, the automatic transmission 20 is placed in a neutral state in which power transmission is disabled. The neutral state of the automatic transmission 20 is synonymous with the neutral state of the power transmission device 16.

[0016] The vehicle 10 further includes a shift operation device 30. The shift operation device 30 is an operation device for manually selecting one of a plurality of shift positions POSsh in the power transmission device 16. The shift operation device 30 is operated by the driver to an operation position POSop corresponding to the shift position POSsh. The operation position POSop includes, for example, a parking operation position, a reverse drive operation position, a neutral operation position, a forward drive operation position, etc. The shift position POSsh includes, for example, a parking position, a reverse drive position, a neutral position, a forward drive position, etc. The shift position POSsh is synonymous with the shift range.

[0017] The parking operating position is an operating position for selecting a parking position of the power transmission device 16 in which the power transmission device 16 is in a neutral state and rotation of the parking lock gear 48 is mechanically prevented.

[0018] The reverse driving operating position is an operating position for selecting a reverse driving position of the power transmission device 16 that enables the vehicle 10 to drive in reverse. The neutral operating position is an operating position for selecting a neutral position of the power transmission device 16 in which the power transmission device 16 is in a neutral state. The forward driving operating position is an operating position for selecting a forward driving position of the power transmission device 16 that enables the vehicle 10 to drive in forward. The reverse driving operating position, neutral operating position, and forward driving operating position are non-parking operating positions. The non-parking operating position is an operating position for selecting a non-parking position of the power transmission device 16, such as a reverse driving position, neutral position, or forward driving position, in which rotation of the parking lock gear 48 is permitted.

[0019] The shift operation device 30 has a shift lever 32 and a parking switch 34 that are selectively operated by the driver to a plurality of operating positions POSop. Both the shift lever 32 and the parking switch 34 are momentary-type operators that return to their original positions when no external force is applied. The shift lever 32 is selectively operated by the driver to a corresponding operating position POSop in order to set the shift position POSsh to a desired shift position POSsh among the non-parking positions. The parking switch 34 is operated by the driver to set the shift position POSsh to the parking position.

[0020] The shift operation device 30 is equipped with a lever position sensor 36 that outputs a lever position signal Splev corresponding to the non-parking operation position to an electronic control device 80 (described later). The parking switch 34 is, for example, a push button switch, and outputs a parking switch signal Spsw to the electronic control device 80 (described later) each time it is pushed to the parking operation position. Pushing the parking switch to the parking operation position is a parking selection operation that selects the parking position, and is also referred to as a P switch operation. The lever position signal Splev and the parking switch signal Spsw are signals that indicate the operation position POSop.

[0021] The vehicle 10 further includes a switching device 40. The switching device 40 includes an electric actuator 42, an encoder 44, a parking mechanism 46, and the like. The electric actuator 42 is an actuator that operates the parking mechanism 46. The encoder 44 is a sensor that counts the amount of operation of the electric actuator 42. The parking mechanism 46 includes a parking lock gear 48, a parking lock pole 50, a cam 52, a parking rod 54, and the like. The parking lock gear 48 is a member provided in the power transmission device 16 so as to rotate integrally with the output gear 22, and is a rotating member that rotates together with the drive wheels 14. The parking mechanism 46 is provided on the output side of the automatic transmission 20. The parking lock pole 50 has a claw portion that meshes with the gear teeth of the parking lock gear 48, and is a member that can mesh with the parking lock gear 48. The cam 52 is provided at the tip of the parking rod 54 on the parking lock pole 50 side. The cam 52 is a tapered member that is moved toward the parking lock pole 50 to cause the parking lock pole 50 to mesh with the parking lock gear 48. The parking rod 54 is a member that supports the cam 52 at one end, and is mechanically connected at the other end to the electric actuator 42 via a member (not shown).

[0022] The electric actuator 42 is driven based on a parking switch control command signal Shp from an electronic control device 80, which will be described later. In the switching device 40, the parking mechanism 46 is operated by driving the electric actuator 42, and the switching device 40 switches the shift position POSsh of the power transmission device 16 between a parking position and a non-parking position. In the vehicle 10, the shift position POSsh is switched using a shift-by-wire (SBW) system. In this way, the parking mechanism 46 is operated to switch the shift position POSsh of the power transmission device 16 between a parking position and a non-parking position based on a control command signal from the electronic control device 80 that corresponds to a selection operation by the driver.

[0023] The vehicle 10 further includes an electronic control device 80 as a controller including a control device of the vehicle 10 related to the control of the switching device 40, etc. The electronic control device 80 includes a so-called microcomputer equipped with, for example, a CPU, RAM, ROM, an input / output interface, etc. The CPU executes various controls of the vehicle 10 by performing signal processing according to a program stored in advance in the ROM while utilizing the temporary storage function of the RAM.

[0024] The electronic control device 80 is supplied with various signals based on detection values ​​from various sensors provided in the vehicle 10. The various sensors include, for example, the parking switch 34, the lever position sensor 36, the encoder 44, the vehicle speed sensor 70, and the accelerator opening sensor 72. The various signals include, for example, the parking switch signal Spsw, the lever position signal Splev, the pulse signal Senc, the vehicle speed V, and the accelerator opening θacc.

[0025] The electronic control device 80 outputs various command signals to each device provided in the vehicle 10. The devices are, for example, the electric actuator 42, the inverter 60, and the hydraulic control circuit 64. The various control command signals include, for example, an electric motor control command signal Sm for controlling the electric motor 12, a hydraulic control command signal Scb for controlling the clutch C1 and the brake B1, and a parking switch control command signal Shp for controlling the driving of the electric actuator 42.

[0026] The electronic control unit 80 includes a motor control unit 82, a transmission control unit 84, and a shift control unit 86 in order to realize various controls in the vehicle 10.

[0027] The electric motor control unit 82 calculates a drive demand amount for the vehicle 10 from the driver, for example, by applying the accelerator opening θacc and the vehicle speed V to a predetermined drive demand amount map. This drive demand amount is, for example, a required drive torque at the drive wheels 14. The electric motor control unit 82 outputs an electric motor control command signal Sm to the inverter 60 to control the electric motor 12 so as to realize the drive demand amount, taking into consideration transmission loss, auxiliary load, the gear ratio of the automatic transmission 20, etc.

[0028] The transmission control unit 84 determines whether the automatic transmission 20 should be shifted, for example, by applying the accelerator opening θacc and the vehicle speed V to a predetermined shift map, and outputs a hydraulic control command signal Scb to the hydraulic control circuit 64 as necessary to switch the gear stage of the automatic transmission 20.

[0029] The shift control unit 86 switches the shift position POSsh of the power transmission device 16 based on the operating position POSop of the shift operating device 30. For example, the shift control unit 86 sets a requested position, which is the shift position POSsh desired by the driver, based on the lever position signal Splev or the parking switch signal Spsw. The shift control unit 86 switches to the shift position POSsh corresponding to the requested position.

[0030] If the shift control unit 86 detects input of the parking switch signal Spsw when the shift position POSsh is in a non-parking position, that is, if the P switch operation is performed by the driver, the shift control unit 86 sets the parking position as the requested position. Then, the shift control unit 86 outputs a parking switch control command signal Shp to the electric actuator 42 to operate the parking mechanism 46 to switch the shift position POSsh to the parking position and to bring the parking lock pole 50 into mesh with the parking lock gear 48.

[0031] On the other hand, if the shift control unit 86 detects input of the lever position signal Splev when the shift position POSsh is in the parking position, it sets a non-parking position corresponding to the lever position signal Splev as the requested position. Then, the shift control unit 86 operates the parking mechanism 46 to switch the shift position POSsh to the non-parking position and outputs a parking switch control command signal Shp to the electric actuator 42 to release the engagement of the parking lock pole 50 with the parking lock gear 48. In addition, the shift control unit 86 switches to the shift position POSsh corresponding to the requested position among the non-parking positions.

[0032] In the vehicle 10, the automatic transmission 20 is disposed in the power transmission path between the electric motor 12 and the parking mechanism 46. Therefore, if the parking mechanism 46 is operated in low gear L and before the vehicle 10 is stopped, the durability of the parking mechanism 46 may be reduced due to the load input caused by the inertia of the electric motor, which is increased by the gear ratio.

[0033] Therefore, when the P switch is operated by the driver, the shift control unit 86 operates the parking mechanism 46 to switch the shift position POSsh to the parking position while the automatic transmission 20 is in high gear H.

[0034] FIG. 2 is a flowchart illustrating the main control operations of the electronic control device 80, which are performed to improve the durability of the parking mechanism 46 and are executed repeatedly, for example.

[0035] 2, first, in step S10 (hereinafter, the term "step" will be omitted) corresponding to the function of the shift control unit 86, it is determined whether the driver has operated the P switch. If the determination in S10 is negative, the routine is terminated. If the determination in S10 is positive, it is determined in S20, corresponding to the function of the transmission control unit 84, whether the gear position of the automatic transmission 20 is high gear H or low gear L. If the determination in S20 is low gear L, the automatic transmission 20 is shifted to high gear H in S30, corresponding to the function of the transmission control unit 84. If the determination in S20 is high gear H, or following S30, the parking mechanism 46 is operated in S40, corresponding to the function of the shift control unit 86, to switch the shift position POSsh to the parking position.

[0036] As described above, according to this embodiment, when the P switch is operated by the driver, the parking mechanism 46 is activated to switch the shift position POSsh to the parking position with the automatic transmission 20 in high gear H. As a result, if the automatic transmission 20 is in low gear L when the P switch is operated, the parking mechanism 46 is activated after the automatic transmission 20 is shifted to high gear H. When the parking mechanism 46 is activated in high gear H, the load caused by the inertia of the electric motor 12 and input to the parking mechanism 46 is reduced compared to when the parking mechanism 46 is activated in low gear L. This makes it possible to improve the durability of the parking mechanism 46, which is provided on the output side of the automatic transmission 20 and which is activated based on the parking switch control command signal Shp.

[0037] Although the embodiments of the present invention have been described in detail above with reference to the drawings, the present invention can also be applied to other embodiments.

[0038] For example, the present invention can be applied to any vehicle that has an electric motor, a parking mechanism that is operated based on a control command signal, and a transmission mechanism that includes a reduction gear stage and a high gear stage and is arranged in the power transmission path between the electric motor and the parking mechanism.

[0039] It should be noted that the above is merely one embodiment, and the present invention can be embodied in various forms with various modifications and improvements based on the knowledge of those skilled in the art. [Explanation of symbols]

[0040] 10: Vehicle 12: Electric motor 14: Drive wheels 16: Power transmission device 20: Automatic transmission (transmission mechanism) 46: Parking mechanism 48: Parking lock gear (rotating member) 80: Electronic control device (control device)

Claims

[Claim 1] A control device for a vehicle including: an electric motor; a power transmission device that transmits power of the electric motor to drive wheels; a speed change mechanism that constitutes part of the power transmission device and includes a reduction gear stage and a high gear stage that is on the higher vehicle speed side than the reduction gear stage; and a parking mechanism that is provided on an output side of the speed change mechanism and is operated to switch a shift position of the power transmission device between a parking position in which rotation of a rotating member that rotates together with the drive wheels is mechanically prevented and a non-parking position in which rotation of the rotating member is permitted, based on a control command signal that corresponds to a selection operation by a driver, When a parking selection operation to select the parking position is performed by the driver, the vehicle control device operates the parking mechanism so as to switch the shift position to the parking position while the transmission mechanism is in the high gear stage.

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