Shift control device of meshing clutch type automatic transmission

Abstract

To provide a control device of a meshing clutch type automatic transmission in which meshing teeth easily come off even when a vehicle is rapidly decelerated during downshift.SOLUTION: A shift control device of a meshing clutch type automatic transmission includes a blipping amount calculation unit 72 that calculates a blipping amount ΔTE that decreases as a vehicle deceleration G at the start of a downshift increases, and a blipping control unit 70 executes blipping control with the blipping amount ΔTE calculated by the blipping amount calculation unit 72. Therefore, it is possible for meshing teeth to easily come off even when a vehicle 10 is rapidly decelerated during downshift.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a shift control device for a meshing clutch type automatic transmission in which gear stages are established by alternatively switching the engagement of a meshing clutch.

Background Art

[0002] There is known a shift control device for an automatic transmission that automatically performs blipping control to temporarily increase the output of an engine so as to increase engine torque during downshifting of the automatic transmission. For example, the control device for a meshing clutch type automatic transmission described in Patent Document 1 is such a device. Usually, since downshifting starts from the fully closed throttle position, the meshing teeth of the release side meshing clutch are pressed against the non-driving side by the drag torque of the engine. To solve this, predetermined blipping control is performed to reduce the force holding down the meshing teeth, pull out the meshing teeth, and execute the shift.

[0003] And in such a conventional control device for a meshing clutch type automatic transmission, downshifting is permitted when the current vehicle deceleration is less than a preset determination threshold value (initial value at the time of a downshift request). On the other hand, when the vehicle deceleration exceeds the determination threshold value, an increase process is performed to increase the determination threshold value from the initial value in consideration of the fact that the vehicle will decelerate also during the period from the downshift request to the execution of the downshift. When this determination threshold value increase process is performed, if the current deceleration changes to less than the vehicle deceleration at the time of the downshift request, the blipping amount is changed to a lower side than the normal value, and blipping is executed.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Incidentally, in a vehicle equipped with a meshing clutch type automatic transmission in which a gear shifting stage is established by disengaging the meshing of the release side meshing clutch and engaging the meshing of the engagement side meshing clutch, when the vehicle decelerates rapidly with a large deceleration, the meshing teeth of the release side meshing clutch for executing downshifting are strongly pressed against the driving side. When blipping is performed in this state, the meshing teeth are further pressed against the driving side, making it difficult for the meshing teeth to disengage. For this reason, even when the vehicle deceleration does not change from the time when a downshift is requested, there has been a problem that it is difficult for the meshing teeth to disengage and shifting becomes difficult. When the meshing teeth are strongly pressed against the driving side as in the case of rapid deceleration of the vehicle, even when the vehicle deceleration does not change from the time when a downshift is requested, the blipping amount should be adjusted to facilitate the disengagement of the meshing teeth. However, in the prior art, such rapid deceleration is not considered at all in the adjustment of the blipping amount.

[0006] The present invention has been made against the background of the above circumstances, and an object thereof is to provide a control device for a meshing clutch type automatic transmission in which the meshing teeth can be easily disengaged even in a rapid deceleration state of the vehicle during downshifting.

Means for Solving the Problem

[0007] The gist of the present invention is: (a) a control device for a meshing clutch type automatic transmission having a plurality of meshing clutches respectively actuated by a shift actuator, in which downshifting is performed by disengaging the meshing teeth of one meshing clutch that has established the previous gear shifting stage while engaging the meshing teeth of the other meshing clutch that establishes a new gear shifting stage, and blipping control for temporarily increasing the output torque of the engine is performed during the process of disengaging the meshing teeth of the one meshing clutch, and (b) including a blipping amount calculation unit that calculates a blipping amount that decreases as the deceleration of the vehicle at the start of the downshift increases, and performing the blipping control with the blipping amount calculated by the blipping amount calculation unit.

Effect of the Invention

[0008] According to the control device of the meshing clutch type automatic transmission of the present invention, it includes a blipping amount calculation unit that calculates a blipping amount that decreases as the deceleration of the vehicle at the start of downshifting increases, and the blipping control is performed with the blipping amount calculated by the blipping amount calculation unit. Thereby, even when the vehicle is in a rapid deceleration state during downshifting, it is easy for the meshing teeth to come out.

Brief Description of the Drawings

[0009] [Figure 1] It is a diagram for explaining an example of a vehicle equipped with a meshing clutch type automatic transmission to which the present invention is applied and its control device. [Diagram 2] It is a time chart for explaining the function of the blipping amount calculation unit provided in the shift control device of FIG. 1. [Diagram 3] It is a diagram for explaining the relationship between the vehicle deceleration and the blipping amount in FIG. 2. [Figure 4] It is a time chart for explaining the main part of the control function of the blipping control unit provided in the shift control device of FIG. 1. [Figure 5] It is a flowchart for explaining the main part of the control operation of the blipping control unit provided in the shift control of FIG. 1. [Figure 6] It is a flowchart for explaining the main part of another example of the control operation of the blipping control unit provided in the shift control of FIG. 1.

Embodiments for Carrying Out the Invention

[0010] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

Examples

[0011] In FIG. 1, in the power transmission path from the engine 12 of the vehicle 10 to the drive wheels 14, an automatic clutch 16, a meshing clutch type automatic transmission (hereinafter referred to as an automatic transmission) 18, and a differential gear device 20 are sequentially provided.

[0012] The vehicle 10 is also provided with an engine control device (EG-ECU) 24 that controls the operation of the engine 12, and a transmission control device (TM-ECU) 26 that controls the operations of the automatic clutch 16 and the automatic transmission 18. These engine control device 24 and transmission control device 26 are electronic control devices including, for example, microcomputers, which are connected to each other by a communication line or a data bus so that signals can be exchanged between them. Also, part or all of these engine control device 24 and transmission control device 26 may be configured as an integrated electronic control device.

[0013] The automatic clutch 16 includes an actuator (not shown) that is operated according to a command from the transmission control device 26, and is a dry single-plate or wet multi-plate friction clutch that is automatically opened and closed by the actuator.

[0014] The automatic transmission 18 is a parallel-axis type constantly meshing type stepped automatic transmission that changes the torque from the engine 12 at the gear ratios of a plurality of gear positions and outputs it to the differential gear device 20. The automatic transmission 18 includes an input shaft 32 and an output shaft 34 that are parallel to each other, and a pair of first-speed drive gears 36 and driven gears 38 that are fixed to one of the input shaft 32 and the output shaft 34 and supported so as to be relatively rotatable with respect to the other and mesh with each other, a pair of second-speed drive gears 40 and driven gears 42, a pair of third-speed drive gears 44 and driven gears 46, a pair of fourth-speed drive gears 48 and driven gears 50, and a pair of fifth-speed drive gears 52 and driven gears 54.

[0015] The automatic transmission 18 includes a first engagement clutch (dog clutch) 56 provided between the driven gear 38 and the driven gear 42 of the output shaft 34, a second engagement clutch (dog clutch) 58 provided between the drive gear 44 and the drive gear 48 of the input shaft 32, and a third engagement clutch (dog clutch) 60 provided between the drive gear 52 of the output shaft 34 and the shaft end of the input shaft 32.

[0016] The first engagement clutch 56 includes a sleeve 56b that is supported by the output shaft 34 so as to be movable in the axial direction of the rotation axis of the output shaft 34 and non-rotatable relative to the output shaft 34 via a clutch hub 56a, and a first shift actuator 56c that drives the sleeve 56b in the axial direction of the rotation axis of the output shaft 34 and selectively engages the inner peripheral teeth (dog teeth) of the sleeve 56b with the outer peripheral teeth (dog teeth) of the gear piece 38a of the driven gear 38 or the outer peripheral teeth (dog teeth) of the gear piece 42a of the driven gear 42 to establish a first-speed gear stage or a second-speed gear stage. The first engagement clutch 56 is composed of a first-speed engagement clutch for establishing a first-speed gear stage and a second-speed engagement clutch for establishing a second-speed gear stage.

[0017] The second engagement clutch 58 includes a sleeve 58b that is supported by the input shaft 32 so as to be movable in the axial direction of the rotation axis of the input shaft 32 and non-rotatable relative to the input shaft 32 via a clutch hub 58a, and a second shift actuator 58c that drives the sleeve 58b in the axial direction of the rotation axis of the input shaft 32 and selectively engages the inner peripheral teeth (dog teeth) of the sleeve 58b with the outer peripheral teeth (dog teeth) of the gear piece 44a of the drive gear 44 or the outer peripheral teeth (dog teeth) of the gear piece 48a of the drive gear 48 to establish a third-speed gear stage or a fourth-speed gear stage. The second engagement clutch 58 is composed of a third-speed engagement clutch for establishing a third-speed gear stage and a fourth-speed engagement clutch for establishing a fourth-speed gear stage.

[0018] The third engagement clutch 60 includes a sleeve 60b that is supported by the input shaft 32 so as to be movable in the axial direction of the rotation axis of the input shaft 32 and non-rotatable relative to the input shaft 32 via a clutch hub 60a, and a third shift actuator 60c that drives the sleeve 60b in the axial direction of the rotation axis of the input shaft 32 and engages the inner peripheral teeth (dog teeth) of the sleeve 60b with the outer peripheral teeth (dog teeth) of the gear piece 52a of the drive gear 52 to establish a fifth-speed gear stage.

[0019] Note that the reverse idler gear 62 engages with both the reverse drive gear 64 and the reverse driven gear 66 by a reverse actuator (not shown) to establish a reverse gear stage.

[0020] The engine control device 24 calculates the required output based on the accelerator opening and vehicle speed (rotational speed of the output shaft 34) from a pre-stored relationship, and outputs a command to control the output torque of the engine 12, thereby controlling the throttle opening and fuel injection amount of the engine 12 so that the required output is appropriately obtained.

[0021] The transmission control device 26 determines a target gear position based on the actual vehicle speed (rotational speed of the second shaft 34) and throttle opening from a pre-stored transmission map, and controls any one of the following to achieve the target gear position: a first mesh clutch 56 of the automatic transmission 16; a second mesh clutch 58 provided between the drive gear 44 and the drive gear 48 of the input shaft 32; and a third mesh clutch 60 provided between the drive gear 52 of the output shaft 34 and the shaft end of the input shaft 32. In the case of a 2-to-1 downshift, for example, as shown in FIG. 2, when a power-on 2-to-1 downshift is determined (time t1 in FIG. 2), the transmission control device 26 uses the first shift actuator 56c to disengage the inner peripheral teeth of the sleeve 56b from the outer peripheral teeth of the gear piece 42a of the second-speed driven gear 42. Next, the first shift actuator 56c is used to start moving the sleeve 56b toward the side where it meshes with the gear piece 38a of the first-speed driven gear 38 (time t2 in FIG. 2). Then, the first shift actuator 56c is used to complete the meshing of the sleeve 56b with the gear piece 38a of the first-speed driven gear 38, thereby completing the 2-to-1 downshift (time t3 in FIG. 2).

[0022] The gear shift control device 26 is functionally provided with a blipping control section 70 and a blipping amount calculation section 72.

[0023] When a downshift decision is made, the blipping control unit 70 determines whether the deceleration G of the vehicle 10 calculated based on the change in the vehicle speed V detected by the vehicle speed sensor exceeds a predetermined judgment threshold G1, and if the deceleration G of the vehicle 10 exceeds the judgment threshold G1, automatically performs blipping control to temporarily increase the output torque of the engine 12 by a predetermined blipping amount ΔTE in a predetermined blipping section TB from the time the automatic transmission 18 makes a downshift decision in order to mitigate the shift shock associated with the downshift.

[0024] The blipping amount calculation unit 72 calculates the blipping amount ΔTE of the engine 12 based on the actual deceleration (negative acceleration) G of the vehicle 10 at the time of determining a downshift, from a pre-stored relationship between the deceleration G of the vehicle 10 and the blipping amount ΔTE, which is a temporary increase in output torque from the output torque at the time of determining a downshift of the engine 12, as shown in Fig. 3, for example. The above relationship is determined experimentally in advance, such that the blipping amount ΔTE decreases as the deceleration G of the vehicle 10 at the time of determining a downshift increases.

[0025] Figure 4 shows the relationship between the blipping amount ΔTE1 calculated when the deceleration G of the vehicle 10 is small, the blipping amount ΔTE2 calculated when the deceleration G of the vehicle 10 is medium, and the blipping amount ΔTE3 (=0) calculated when the deceleration G of the vehicle 10 is large, and the torque range A within which the meshing teeth (dog teeth) of the mesh clutch can slide, based on the relationship in Figure 3. The blipping amounts ΔTE1, ΔTE2, and ΔTE3, which are the amounts of temporary increase in output torque from the output torque when a downshift is determined, are all set in advance in the relationship in Figure 3 so that they fall within the torsional torque range A within which the meshing teeth (dog teeth) of the mesh clutch on the release side (release side) can slide.

[0026] FIG. 5 is a flowchart for explaining the main part of the control operation of the shift control device 26. In step S1 of FIG. 5 (hereinafter, steps are omitted), it is determined whether or not downshifting is determined based on the actual vehicle speed and throttle opening from a pre-stored shift diagram. If the determination in S1 is negative, this routine is terminated, but if it is positive, in S2, it is determined whether or not the deceleration G of the vehicle 10 is large, that is, whether or not the vehicle 10 is in a rapid deceleration state. If the determination in S2 is positive, S5 and subsequent steps are executed, but if the determination in S2 is negative, after S3 and S4 are executed, S5 and subsequent steps are executed.

[0027] In S3, blipping control is started by increasing the throttle opening or releasing the fuel cut. In S4, the torque of the engine 12 is temporarily increased according to the blipping amount determined according to the deceleration G of the vehicle 10 from the relationship in FIG. 3 in the blipping section TB. In S5, when the torsional torque of the meshing tooth part is within the torsional torque range A where the meshing tooth part can slide, in S6, the meshing teeth of the disengaging side (release side) clutch are disengaged from the outer peripheral teeth of the gear piece of the current gear stage. Next, in S7, the meshing teeth of the engaging side clutch slide so as to engage with the outer peripheral teeth of the gear piece of the target gear stage of downshifting. Then, in S8, the blipping control is terminated.

[0028] FIG. 6 is a flowchart for explaining the main part of another control operation example of the shift control device 26, which corresponds to S2 - S4 in FIG. 5. When the determination in S1 is affirmative, in S12, based on the relationship of FIG. 3 stored in advance between the deceleration G of the vehicle 10 and the blipping amount ΔTE which is the increase amount of the temporary output torque from the output torque at the time of downshift determination of the engine 12, the blipping amount ΔTE of the engine 12 is calculated based on the actual deceleration (negative acceleration) G of the vehicle 10 at the time of downshift determination.. Next, in S13, blipping control using the above blipping amount ΔTE is started by increasing the throttle opening or releasing the fuel cut, and in S14, the torque of the engine 12 is temporarily increased according to the blipping amount determined according to the deceleration G of the vehicle 10 from the relationship of FIG. 3 in the blipping section TB. Thereafter, S5 and below are executed.

[0029] As described above, according to the shift control device 26 of the meshing clutch type automatic transmission 18 of the present embodiment, it includes a blipping amount calculation unit 72 that calculates a blipping amount ΔTE that decreases as the deceleration G of the vehicle at the start of downshift increases, and the blipping control unit 70 executes blipping control with the blipping amount ΔTE calculated by the blipping amount calculation unit 72. Thereby, even in the rapid deceleration state of the vehicle 10 during downshift, the disengagement of the meshing teeth becomes easy.

[0030] As mentioned above, the embodiments of the present invention have been described in detail with reference to the drawings, but the present invention is also applicable in other aspects.

[0031] For example, in the foregoing embodiment, the first meshing clutch 56, the second meshing clutch 58, and the third meshing clutch 60 do not include a synchronizer (synchronization mechanism), but they may include a synchronizer (synchronization mechanism).

[0032] Furthermore, the blipping amount calculation unit 72 in the above-described embodiment calculates the blipping amount ΔTE from the relationship shown in FIG. 3 in which the blipping amount ΔTE changes continuously in accordance with changes in the deceleration G. However, a relationship in which the blipping amount ΔTE changes stepwise, in which the blipping amount ΔTE suddenly decreases when the deceleration G exceeds a predetermined value, may also be used.

[0033] It should be noted that the above is merely one embodiment, and the present invention can be embodied in various modified and improved forms based on the knowledge of those skilled in the art. [Explanation of symbols]

[0034] 10: vehicle, 18: automatic transmission, 26: shift control device (control device), 42: second-speed driven gear, 42a: gear piece, 56: first mesh clutch, 56b: sleeve, 56c: first shift actuator, 58: second mesh clutch, 60: third mesh clutch, 70: blipping control unit, 72: blipping amount control unit

Claims

【Claim 1】 A control device for a meshing clutch type automatic transmission having a plurality of meshing clutches each actuated by a shift actuator, in which downshifting is performed by disengaging the meshing teeth of one meshing clutch that has established the previous gear stage while engaging the meshing teeth of the other meshing clutch that establishes a new gear stage, and performing blipping control to temporarily increase the output torque of the engine during the process of disengaging the meshing teeth of the one meshing clutch, including a blipping amount calculation unit that calculates a blipping amount that decreases as the deceleration of the vehicle at the start of downshifting increases, and performing the blipping control with the blipping amount calculated by the blipping amount calculation unit A control device for a meshing clutch type automatic transmission, characterized by the above.

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