Vehicle control device

Abstract

To provide a vehicle control device capable of suppressing abnormal noise generation in a constant velocity joint with an opposed groove structure.SOLUTION: An electronic control unit 90 for a vehicle 10 which includes an engine 12, a drive shaft 36 and a constant velocity joint 22 with an opposed groove structure in a power transmission path PT between the engine 12 and a pair of drive wheels 24, when it is determined that the outside air temperature THair is equal to or less than a predetermined outside air temperature determination value THair_jdg, the cooling water temperature THwat of the engine 12 is equal to or less than a predetermined water temperature determination value THwat_jdg, the longitudinal acceleration Ax is equal to or greater than a predetermined acceleration determination value Ax_jdg, and a steering angle φst exceeds a predetermined steering angle determination value φst_jdg, controls the axial torque Tds of the drive shaft 36 to be lower than the requested axial torque Tdsdem.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a control device for a vehicle equipped with a constant velocity joint having an opposed groove structure. [Background technology]

[0002] Vehicles equipped with constant velocity joints having an opposed groove structure are known, such as that described in Patent Document 1. In a constant velocity joint having an opposed groove structure, the angle of the balls provided in the groove portion consisting of the outer track groove and the inner track groove of the constant velocity joint varies according to the joint angle, and may be within a predetermined range including the zero value and near the zero value. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-84992 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, when the included angle is within a predetermined range around zero, including zero, the ball is locked in the groove of the constant velocity joint, resulting in a ball-locked state, while when the included angle is outside the predetermined range, the ball is released and can move within the groove of the constant velocity joint. As a result, when a predetermined condition is met, the ball changes from the ball-locked state to the ball-released state, which may cause the ball to collide with the cage of the constant velocity joint, generating abnormal noise.

[0005] The present invention has been made in light of the above circumstances, and an object of the present invention is to provide a vehicle control device that can suppress the generation of abnormal noise in a constant velocity joint having an opposed groove structure. [Means for solving the problem]

[0006] The gist of the present invention is to provide a control device for a vehicle having an engine, a drive shaft and a constant velocity joint of an opposed groove structure in a power transmission path between the engine and a pair of drive wheels, which controls the axial torque of the drive shaft to be lower than a target axial torque when it is determined that (a) the outside air temperature is below a predetermined outside air temperature judgment value, (b) the engine cooling water temperature is below a predetermined water temperature judgment value, (c) the vehicle's longitudinal acceleration is above a predetermined acceleration judgment value, and (d) the steering angle exceeds a predetermined steering angle judgment value. Effect of the Invention

[0007] According to the vehicle control device of the present invention, when it is determined that (a) the outside air temperature is equal to or lower than a predetermined outside air temperature judgment value, (b) the engine cooling water temperature is equal to or lower than a predetermined water temperature judgment value, (c) the longitudinal acceleration of the vehicle is equal to or higher than a predetermined acceleration judgment value, and (d) the steering angle exceeds a predetermined steering angle judgment value, the axial torque of the drive shaft is controlled to be lower than a target axial torque. When all of the conditions (a) to (d) for generating abnormal noise in a constant velocity joint having an opposed groove structure are satisfied, the generation of abnormal noise is suppressed by controlling the axial torque of the drive shaft to be lower than the target axial torque. [Brief description of the drawings]

[0008] [Figure 1] 1 is a schematic configuration diagram of a vehicle equipped with an electronic control device according to an embodiment of the present invention, and is also a functional block diagram showing the main control functions of the electronic control device. [Diagram 2] 2A and 2B are explanatory diagrams of a wheel-side constant velocity joint, in which FIG. 2A is an axial cross-sectional view, and FIG. 2B is a side view of FIG. 2A as viewed from the right. [Diagram 3] FIG. 3(a) is an explanatory diagram of a wheel side constant velocity joint, showing the relationship between the included angle and the joint angle in the wheel side constant velocity joint, and FIG. 3(b) is a diagram explaining the mechanism of abnormal noise caused by the pushing out of the ball. [Figure 4] 4 is an example of a flowchart illustrating a control operation of an electronic control device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that in the embodiments, the drawings are appropriately simplified or modified, and the dimensional ratios and shapes of the various parts are not necessarily drawn accurately. EXAMPLES

[0010] Fig. 1 is a schematic diagram of a vehicle 10 equipped with an electronic control device 90 according to an embodiment of the present invention, and is also a functional block diagram showing the main control functions of the electronic control device. In Fig. 1, the longitudinal direction X is the longitudinal direction of the vehicle 10, and the vehicle width direction Y is the width direction (= left-right direction) of the vehicle 10.

[0011] The vehicle 10 includes, in a power transmission path PT between an engine 12, which is a power source for traveling, and a pair of drive wheels 24, in that order from the engine 12 side, a crankshaft 30, a torque converter 14, an AT input shaft 32, an automatic transmission 16, an AT output shaft 34, a differential 18, a pair of drive shafts 36, etc., which are well-known components. The vehicle 10 is, for example, a front-engine, front-drive (FF) vehicle, and the pair of drive wheels 24 are also steered wheels. The vehicle 10 also includes a hydraulic control circuit 38 and an electronic control device 90.

[0012] The drive shaft 36 includes a differential side constant velocity joint 20 (hereinafter simply referred to as "constant velocity joint 20") arranged on the differential 18 side, and a wheel side constant velocity joint 22 (hereinafter simply referred to as "constant velocity joint 22") arranged on the drive wheel 24 side. The axial direction of the drive shaft 36 is variable at two locations, the constant velocity joint 20 and the constant velocity joint 22. The constant velocity joint 22 is a counter groove type constant velocity joint. The constant velocity joint 22 corresponds to the "constant velocity joint" in this invention.

[0013] FIG. 2 is an explanatory diagram of the constant velocity joint 22, where FIG. 2(a) is an axial cross-sectional view, and FIG. 2(b) is a side view seen from the right of FIG. 2(a).

[0014] The constant velocity joint 22 includes an outer joint member 42 and an inner joint member 44. A shaft 46 (on the drive wheel 24 side) is connected to the inner joint member 44 via a spline or the like so as to be capable of transmitting power. Fig. 2 is a diagram showing a reference state where the center line CL1 of the outer joint member 42 and the center line CL2 of the inner joint member 44 are aligned in a straight line and the joint angle φ=0 [deg]. The joint angle φ [deg] is the intersection angle between the center lines CL1 and CL2 (CL1 and CL2), with the reference state where the center lines CL1 and CL2 are aligned in a straight line being 0 [deg].

[0015] A plurality of first outer track grooves 50a and a plurality of second outer track grooves 50b (three in this embodiment) are alternately provided on the inner peripheral surface of the outer joint member 42 at equal angular intervals around the center line CL1. A plurality of first inner track grooves 52a and a plurality of second inner track grooves 52b (three in this embodiment) are alternately provided on the outer peripheral surface of the inner joint member 44 at equal angular intervals around the center line CL2. A ball 54a for torque transmission is interposed between the first inner track groove 52a and the first outer track groove 50a, and a ball 54b for torque transmission is interposed between the second inner track groove 52b and the second outer track groove 50b. A ring-shaped cage 56 is disposed in the annular space between the outer joint member 42 and the inner joint member 44 so as to be rotatable around the joint center O. The cage 56 has six pockets 58 (openings) arranged at equal angular intervals, each of which holds a ball 54a, 54b. The cage 56 has a spherical outer circumferential surface, which is slidably fitted and held on the inner circumferential surface of the outer joint member 42. The first outer track groove 50a and the first inner track groove 52a form a first groove portion 60a, and the second outer track groove 50b and the second inner track groove 52b form a second groove portion 60b. The first groove portion 60a and the second groove portion 60b are alternately provided around the center lines CL1, CL2, and as is clear from FIG. 2(b), the first groove portion 60a and the second groove portion 60b are arranged symmetrically with respect to the center lines CL1, CL2.

[0016] In the reference state shown in Fig. 2, in the first groove portion 60a, the angle α [deg] between the first outer track groove 50a and the first inner track groove 52a and the ball 54a is positive, i.e., the angle is open toward the cup opening side of the outer joint member 42 (to the right in Fig. 2(a)). On the other hand, in the second groove portion 60b, the angle β [deg] between the second outer track groove 50b and the second inner track groove 52b and the ball 54b is negative, i.e., the angle is open toward the back side of the cup of the outer joint member 42 (to the left in Fig. 2(a)).

[0017] 3A and 3B are explanatory diagrams of the constant velocity joint 22, where FIG. 3A shows the relationship between the included angles α, β and the joint angle φ in the constant velocity joint 22, and FIG. 3B is a diagram explaining the mechanism by which abnormal noise is generated due to the pushing out of the ball 54b.

[0018] FIG. 3(a) shows the relationship between the included angles α, β and the joint angle φ in a plane including the center line CL2 of the shaft 46 and the centers of the balls 54a, 54b. That is, the included angles α, β change according to the joint angle φ when the inner joint member 44 is bent up and down in a plane including the balls 54a and 54b. For example, the positive value side of the joint angle φ is the direction in which the shaft 46 of the inner joint member 44 is bent toward the arrow Up shown in FIG. 2(a), and the negative value side of the joint angle φ is the direction in which the shaft 46 of the inner joint member 44 is bent toward the arrow Dn shown in FIG. 2(a). As shown in FIG. 3(a), the included angle α of the ball 54a located above the center line CL1 is a positive value throughout the entire range of the joint angle φ. The included angle β of the ball 54b located below the center line CL1 is a negative value in the range of the joint angle φ<0. The included angle β changes from a negative value to a positive value as the joint angle φ increases from zero.

[0019] Incidentally, as shown in FIG. 3(b), when the angle value β1 (LK2 ≧ β1 ≧ LK1) within a predetermined range near zero including the clamping angle β is in the locking region, the pushing force F1 [N] of the ball 54b based on the clamping angle β becomes smaller than the frictional force R [N] of the ball 54b against the second groove portion 60b, resulting in a ball-locked state. The pushing force F1 is the force that causes the ball 56b to move in the direction of the cage 56, and the frictional force R is the force that acts in the direction opposite to the pushing force F1 to prevent the movement of the ball 56b. In the ball-locked state, the ball 54b is locked without moving within the second groove portion 60b. For example, when the outside air temperature THair [°C] is low and the engine 12 has just started, the temperature of the constant velocity joint 22 is low, and the viscosity of the lubricating oil (grease) between the second groove portion 60b and the ball 54b increases, causing the frictional force R to increase, resulting in the occurrence of the ball-locked state.

[0020] When the angle value β2 (β2 < LK1, LK2 < β2) of the clamping angle β is outside the locking region, the pushing force F2 [N] of the ball 54b based on the clamping angle β becomes larger than the frictional force R of the ball 54b against the second groove portion 60b, resulting in a ball-released state. The pushing force F2 is the force that causes the ball 56b to move in the direction of the cage 56, and the frictional force R is the force that acts in the direction opposite to the pushing force F2 to prevent the movement of the ball 56b. In the ball-released state, the ball 54b is in a state where it can move within the second groove portion 60b. The angle values LK1 and LK2 representing the boundary between the ball-locked state and the ball-released state at the clamping angle β are values determined in advance experimentally or by design.

[0021] Incidentally, when the steering angle φst [deg] of the steering wheel 48 provided in the vehicle 10 is 0 [deg], the joint angle φ is 0 [deg]. When the steering angle φst is not 0 [deg], a predetermined relationship between the steering angle φst and the joint angle φ holds, where the joint angle φ increases according to the magnitude of the absolute value of the steering angle φst.

[0022] Here, the steering angle φst corresponding to the joint angle φ that is the boundary between the ball-locked state and the ball-released state is defined as the "steering angle judgment value φst_jdg," and a case is considered in which the steering angle φst is an angle value φst_x that is greater than the steering angle judgment value φst_jdg.

[0023] When the tires of the steering wheels, i.e., the pair of driving wheels 24, rotate once, the joint angle β becomes a positive value or a negative value. That is, the rotation of the tires of the steering wheels causes the ball 54b to enter a ball-locked state or a ball-released state. When the ball 54b changes from the ball-locked state to the ball-released state, the ball 54b is pushed toward the cage 56 by the backlash G [mm], which is the gap between the cage 56 and the ball 54b, and collides with the cage 56. At this time, a collision sound (abnormal sound) is generated. The larger the vehicle 10 is in a sudden start state, that is, the larger the axial torque Tds [Nm], which is the torque transmitted by the constant velocity joint 22, the louder this abnormal sound becomes. The axial torque Tds is the torque transmitted by the drive shaft 36 to the driving wheels 24, and is also the torque transmitted by the constant velocity joint 22. The shaft torque Tds corresponds to the "shaft torque" in the present invention, and in terms of being the driving amount when the vehicle 10 is running, this "shaft torque" is synonymous with driving force, power, and force.

[0024] Returning to FIG. 1, the electronic control device 90 is configured to include a so-called microcomputer equipped with, for example, a CPU, RAM, ROM, an input / output interface, etc., and the CPU executes various controls of the vehicle 10 by performing signal processing according to a program previously stored in the ROM while utilizing the temporary storage function of the RAM. The electronic control device 90 corresponds to the "control device" in the present invention. For example, the electronic control device 90 controls the engine torque Te [Nm] which is the torque output from the engine 12. The electronic control device 90 receives various signals based on detection values ​​from various sensors and the like provided on the vehicle 10 (for example, the outside air temperature sensor 70, the water temperature sensor 72, the longitudinal acceleration sensor 74, the steering angle sensor 76, the accelerator opening sensor 78, the vehicle speed sensor 80, etc.) (for example, the outside air temperature THair, the cooling water temperature THwat [°C] which is the temperature of the cooling water for the engine 12, the longitudinal acceleration Ax [m / sec] which is the acceleration in the longitudinal direction X of the vehicle 10, etc.). 2 ], steering angle φst [deg], accelerator opening θacc [%] which is the amount of accelerator operation by the driver, vehicle speed V [km / h], etc. From the electronic control device 90, various command signals (for example, an engine control signal Se for controlling the operation of the engine 12, a shift control signal Sat for controlling the shifting of the automatic transmission 16, an LU connection / disconnection control signal Slu for controlling the connection / disconnection of a lock-up clutch LU (not shown) of the torque converter 14, etc.) are output to each device (for example, the engine 12, the hydraulic control circuit 38, etc.) provided in the vehicle 10.

[0025] The electronic control unit 90 functionally comprises an engine control unit 92, a gear shift control unit 94, an LU control unit 96, and a condition determination unit 98.

[0026] The engine control unit 92 calculates a required driving torque Trdem [Nm], which is a request for a driving torque Tr [Nm] from the driver to the vehicle 10, for example, by applying the accelerator opening θacc and the vehicle speed V to a driving demand map. The driving demand map is a relationship for calculating the required driving torque Trdem, which is obtained experimentally or by design and stored in advance. The engine control unit 92 controls the engine torque Te so as to realize the required driving torque Trdem to the vehicle 10. The shift control unit 94 determines whether to shift the automatic transmission 16 using, for example, a shift map, and executes shift control as necessary. The LU control unit 96 controls the connection / disconnection state of the lock-up clutch LU of the torque converter 14.

[0027] The condition determination unit 98 acquires the outside air temperature THair, the cooling water temperature THwat, the longitudinal acceleration Ax, and the steering angle φst, and determines whether or not a predetermined condition for abnormal noise to occur in the constant velocity joint 22 is satisfied. For example, the predetermined condition for abnormal noise to occur is when all of the following conditions (a) to (d) are satisfied: (a) the outside air temperature THair is equal to or lower than a predetermined outside air temperature determination value THair_jdg, (b) the cooling water temperature THwat of the engine 12 is equal to or lower than a predetermined water temperature determination value THwat_jdg, (c) the longitudinal acceleration Ax is equal to or higher than a predetermined acceleration determination value Ax_jdg, and (d) the steering angle φst exceeds a predetermined steering angle determination value φst_jdg. The outside air temperature determination value THair_jdg and the water temperature determination value THwat_jdg are respectively a predetermined outside air temperature and a predetermined water temperature determined in advance by experiment or design at which the viscosity of the lubricating oil (grease) between the second groove portion 60b and the ball 54b increases, thereby increasing the friction force R and causing a ball-locked state. The acceleration determination value Ax_jdg is a predetermined acceleration value determined in advance by experiment or design at which the abnormal noise generated in the constant velocity joint 22 due to the vehicle 10 being in a sudden acceleration state falls outside the allowable range. The steering angle determination value φst_jdg is the steering angle φst corresponding to the joint angle φ that is the boundary between the ball-locked state and the ball-released state, and is a predetermined angle value determined in advance by experiment or design.

[0028] When the condition determination unit 98 determines that the predetermined condition for generating abnormal noise is not satisfied, the engine control unit 92 causes the engine 12 to output an engine torque Te that realizes the required drive torque Trdem. In this case, the shaft torque Tds becomes a required shaft torque Tdsdem [Nm] that realizes the required drive torque Trdem on the drive shaft 36. The required shaft torque Tdsdem corresponds to the "target shaft torque" in the present invention. When the condition determination unit 98 determines that the predetermined condition for generating abnormal noise is satisfied, the engine control unit 92 causes the engine 12 to output an engine torque Te that is lower than that which realizes the required drive torque Trdem. In this case, the shaft torque Tds becomes a value lower than the required shaft torque Tdsdem that realizes the required drive torque Trdem on the drive shaft 36.

[0029] 4 is an example of a flowchart for explaining the control operation of the electronic control device 90. First, in step S10 (hereinafter, "step" will be omitted), which corresponds to the function of the condition determination unit 98, the outside air temperature THair, the cooling water temperature THwat, the longitudinal acceleration Ax, and the steering angle φst are acquired, and in S20, which corresponds to the function of the condition determination unit 98, it is determined whether or not all of the conditions (a) to (d) are satisfied. If the determination in S20 is YES, in S30, which corresponds to the function of the engine control unit 92, the shaft torque Tds is controlled to be lower than the required shaft torque Tdsdem. If the determination in S20 is NO, in S40, which corresponds to the function of the engine control unit 92, the shaft torque Tds is controlled to be equal to the required shaft torque Tdsdem. After the execution of S30 and S40, the process returns.

[0030] According to the electronic control device 90 of this embodiment, when it is determined that (a) the outside air temperature THair is equal to or lower than a predetermined outside air temperature judgment value THair_jdg, (b) the engine 12 cooling water temperature THwat is equal to or lower than a predetermined water temperature judgment value THwat_jdg, (c) the longitudinal acceleration Ax is equal to or higher than a predetermined acceleration judgment value Ax_jdg, and (d) the steering angle φst exceeds a predetermined steering angle judgment value φst_jdg, the axial torque Tds is controlled to be lower than the required axial torque Tdsdem. When the conditions (a) to (d) under which abnormal noise occurs in the constant velocity joint 22 having the opposed groove structure are satisfied, the generation of abnormal noise is suppressed by controlling the axial torque Tds to be lower than the required axial torque Tdsdem.

[0031] It should be noted that the above is an embodiment of the present invention, 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 without departing from the spirit of the present invention.

[0032] In the above embodiment, the vehicle 10 is of the FF type, but is not limited to this. For example, the present invention can also be applied to a RR (rear engine, rear drive) type vehicle. [Explanation of symbols]

[0033] 10: vehicle, 12: engine, 22: wheel side constant velocity joint (constant velocity joint), 24: drive wheel, 36: drive shaft, 90: electronic control unit (control unit), PT: power transmission path, THair: outside air temperature, THair_jdg: outside air temperature judgment value, THwat: cooling water temperature, THwat_jdg: water temperature judgment value, Ax: longitudinal acceleration, Ax_jdg: acceleration judgment value, φst: steering angle, φst_jdg: steering angle judgment value, Tds: shaft torque, Tdsdem: required shaft torque (target shaft torque)

Claims

[Claim 1] A control device for a vehicle including an engine, and a drive shaft and a constant velocity joint having an opposed groove structure in a power transmission path between the engine and a pair of drive wheels, comprising: When it is determined that the outside air temperature is equal to or lower than a predetermined outside air temperature judgment value, the engine cooling water temperature is equal to or lower than a predetermined water temperature judgment value, the longitudinal acceleration of the vehicle is equal to or higher than a predetermined acceleration judgment value, and the steering angle exceeds a predetermined steering angle judgment value, the axial torque of the drive shaft is controlled to be lower than a target axial torque. A vehicle control device comprising:

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