Control device for mesh type transmission mechanism

Abstract

To prevent or suppress abnormal noise due to ratcheting and placement of an excessive load.SOLUTION: There is provided a controller for a meshing type engagement mechanism that comprises: fixed teeth fixed in an axial direction; movable teeth moving in the axial direction to mesh with the fixed teeth; and an actuator powered to generate a thrust for moving the movable teeth in the axial direction, has axial end parts of the fixed teeth and movable teeth chamfered, and performs engagement control to power the actuator for a predetermined engagement powering time in response to an engagement instruction to engage the movable teeth with the fixed teeth. The controller comprises condition violence determination means for determining the condition for engaging the movable teeth with the fixed teeth after the engagement instruction is not met (step S3), and powering-time shortening means for making the time for which the actuator is powered shorter than the engagement powering time when it is determined that the condition is not met (step S5).SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a meshing type transmission mechanism that transmits torque by meshing meshing teeth such as splines, and more particularly to a device that controls the meshing of the meshing teeth. [Background technology]

[0002] As a transmission mechanism for transmitting and interrupting torque, a meshing transmission mechanism is known in which spline teeth formed on the outer circumferential surface of a specific rotating member are selectively meshed with spline teeth formed on the inner circumferential surface of a sleeve that moves axially around the outer circumferential side of the rotating member. In this type of transmission mechanism, when the sleeve is moved axially to mesh the spline teeth, if the spline teeth are in phase with each other and aligned axially, the ends of the spline teeth may butt against each other and fail to mesh. This state is sometimes called apex contact, and in order to avoid this state, a synchronization mechanism (synchronizer) is provided or a chamfer is formed on the end of the spline teeth.

[0003] If a chamfer is provided, a torque can be generated by the thrust (axial pressing force) that moves the sleeve, which can bring the spline teeth into meshing. On the other hand, if the difference in rotation speed between the spline teeth that should mesh or the torque to be transmitted is large, the chamfer generates a reaction force that pushes back the sleeve, which results in ratcheting, in which the spline teeth repeatedly bounce back and come into contact again, which can cause an abnormal noise known as gear rattle, and can also impose a large load on the shift fork that moves the sleeve, reducing its durability.

[0004] In order to eliminate such inconvenience, the device described in Patent Document 1 eliminates the switching. That is, the device described in Patent Document 1 is configured to return the sub-transmission, which can be switched between a high state with a small gear ratio and a low state with a large gear ratio, to the state at the start of the switching operation when the switching allowance condition is no longer satisfied, for example, when a torque equal to or greater than a predetermined value is applied, after the switching decision is satisfied.

[0005] Meanwhile, a device configured to avoid damage to the shift fork, etc., when a so-called peak hit occurs is described in Patent Document 2. The device described in Patent Document 2 is a transfer device configured to use a single actuator for both pressing the clutch for torque distribution control and for controlling the movement of the sleeve for range switching, and is configured to reduce the output (thrust) of the actuator when a peak hit occurs to switch the sleeve. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2009-041637 A [Patent Document 2] JP 2017-159763 A Summary of the Invention [Problem to be solved by the invention]

[0007] As described above, even if the meshing teeth are provided with chamfers, there are cases where the meshing teeth butt against each other and the meshing does not proceed any further. The device described in Patent Document 1 detects such a state where meshing is not possible and returns to the state before the start of meshing control. However, the state where the meshing teeth butt against each other (the so-called peak hit state) occurs when normal meshing control is being executed, and the peak hit state continues until the detection of the peak hit state and the start of the return control. Therefore, the device described in Patent Document 1 has problems such as abnormal noise such as gear rattle during the peak hit state and a large load being applied to related members such as the shift fork.

[0008] In addition, in the device described in Patent Document 2, when so-called peak contact occurs, the drive current value for moving the sleeve is reduced, but ratcheting may continue until the sleeve passes the chamfer and engages after the peak contact occurs. Therefore, although the device described in Patent Document 2 can avoid or suppress damage to the shift fork, etc., there is room for improvement in terms of preventing or reducing abnormal noise such as gear rattle.

[0009] This invention has been made with attention to the technical problems described above, and aims to provide a control device for a meshing transmission mechanism that can reduce abnormal noise and load caused by the chamfers of the meshing teeth butting against each other and preventing the meshing from progressing. [Means for solving the problem]

[0010] In order to achieve the above-mentioned object, the present invention provides a control device for a meshing engagement mechanism comprising a fixed tooth fixed in an axial direction, a movable tooth that moves in the axial direction to mesh with the fixed tooth, and an actuator that generates a thrust when energized to move the movable tooth in the axial direction, wherein chamfers are formed on the axial ends of the fixed tooth and the movable tooth, and which performs engagement control to energize the actuator for a predetermined engagement current time when an engagement instruction is given to engage the movable tooth with the fixed tooth, the control device being characterized in that it further comprises a condition violation determination means for determining that the condition for engaging the movable tooth with the fixed tooth has become unsatisfied after the engagement instruction, and a current shortening means for shortening the time for which current is applied to the actuator to be shorter than the engagement current time when the condition violation determination means determines that the condition has become unsatisfied. Effect of the Invention

[0011] In this invention, when there is an instruction to move the movable teeth in the axial direction to mesh with the fixed teeth, the actuator is energized so that the actuator moves the movable teeth toward the fixed teeth. If the condition for engaging the movable teeth with the fixed teeth is satisfied, the energization continues for a predetermined engagement energization time, and when the engagement energization time has elapsed, the current is cut off and the load (thrust) pressing the movable teeth in the axial direction is stopped. On the other hand, if it is determined that the above condition is not satisfied after the start of energization of the actuator, that is, if the condition violation is determined, the energization is started but the time for which the energization is continued is made shorter than the normal engagement energization time. Therefore, if the chamfers butt against each other due to the non-satisfaction of the condition and the meshing does not progress any further, the energization is stopped at the point when a time shorter than the normal engagement energization time has elapsed, and the thrust force by the actuator to press the movable teeth toward the fixed teeth is eliminated or reduced. That is, even if so-called ratcheting occurs due to the chamfers butting against each other when a torque equal to or greater than a certain level is applied, the duration of the ratcheting is shortened, so that abnormal noises such as gear noise can be quickly eliminated. In addition, since the state in which the reaction force is large due to the chamfers butting against each other can be quickly eliminated, the load applied to the member for moving the movable teeth in the axial direction can be quickly reduced, and the deterioration of the durability of the member can be avoided or suppressed. [Brief description of the drawings]

[0012] [Figure 1] 1 is a schematic diagram showing an example of a powertrain according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a skeleton diagram showing a schematic example of the meshing type transmission mechanism. [Diagram 3] FIG. 2 is a schematic diagram showing the shapes and relative positions of fixed teeth and movable teeth. [Figure 4] 4 is a flowchart illustrating an example of control in the embodiment of the present invention. [Diagram 5] 5 is a time chart for explaining a change in a current value when control is performed and when control is not performed in the embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Note that the embodiment described below is merely one example of the case where the present invention is implemented, and is not intended to limit the present invention.

[0014] First, an example of a four-wheel drive transfer (hereinafter simply referred to as a transfer) 2 including a meshing type power transmission mechanism 1 to which the present invention can be applied, and a power train 3 including the transfer 2 will be described. In Fig. 1, reference numeral 4 denotes an engine, which is an example of a driving force source, and a transmission 5 is connected to the output side of the engine 4. The transmission 5 may be either a conventionally known general manual transmission or an automatic transmission, and may be either a stepped transmission or a continuously variable transmission. The transfer 2 is connected to the output side of the transmission 5.

[0015] The transfer 2 is equipped with an LH switching mechanism 6 that switches between a low state with a large gear ratio and a high state with a small gear ratio, and a 2-4 switching mechanism 7 that switches between a two-wheel drive state (2WD) in which the rear wheels (not shown) are the drive wheels and a four-wheel drive state (4WD) in which the front and rear four-wheel drive wheels are used. These mechanisms 6 and 7 may be of a conventionally known configuration, and for example, the 2-4 switching mechanism 7 may be configured such that a drive sprocket 9 is rotatably attached to a rear wheel output shaft 8, a meshing engagement mechanism 10 is provided between the rear wheel output shaft 8 and the drive sprocket 9, and a chain 11 as a transmission member wound around the drive sprocket 9 is wound around a driven sprocket 13 attached to a front wheel output shaft 12.

[0016] Furthermore, the LH switching mechanism 6 may be any speed change mechanism capable of changing the speed between high and low in two stages, and may be, for example, a mechanism mainly composed of a planetary gear mechanism 14 as shown in Fig. 2. The planetary gear mechanism 14 includes a sun gear S integral with an input shaft 15 connected to the transmission 5, a ring gear R fixed to a casing 16, and a carrier C that is disposed between the sun gear S and the ring gear R and holds pinion gears that mesh with the sun gear S and the ring gear R. The sun gear S and the carrier C are output elements, and the meshing type power transmission mechanism 1 is configured to selectively connect the sun gear S and the carrier C to the rear wheel output shaft 8 described above. Therefore, in the LH switching mechanism 6, when the carrier C is connected to the rear wheel output shaft 8, the carrier C rotates slower than the sun gear S, so a low state (Lo) is set, and when the sun gear S is connected to the rear wheel output shaft 8, the rotation speed of the input shaft 15 and the rotation speed of the rear wheel output shaft 8 become the same, so a high state (Hi) with a gear ratio of "1" is set.

[0017] The transmission mechanism 1 is a mechanism in which splines are used as meshing teeth, and includes low fixed teeth 17 which are internal teeth integrated with the carrier C and high fixed teeth 18 which are external teeth integrated with the sun gear S as fixed teeth that are engagement teeth fixed in the axial direction. The transmission mechanism 1 includes low movable teeth 19 which engage with the low fixed teeth 17 and high movable teeth 20 which engage with the high fixed teeth 18 as movable teeth that move in the axial direction and selectively engage with the fixed teeth 17, 18. These movable teeth 19, 20 are provided on the outer circumferential side and inner circumferential side of a shift sleeve (hereinafter simply referred to as sleeve) 21 which moves back and forth in the axial direction.

[0018] Also provided is an actuator 22 that moves the sleeve 21 back and forth in the axial direction. The actuator 22 is an electrically controlled actuator such as a motor or an electromagnetic solenoid, and is configured to operate when electricity is applied. The actuator 22 and the sleeve 21 may be directly connected to each other, or may be connected to each other via a cam mechanism or a feed screw mechanism that converts rotation into linear motion, or even a shift fork (neither of which are shown).

[0019] Figure 3 shows a schematic diagram of the shapes and relative positions of the fixed teeth 17, 18 and the movable teeth 19, 20. For convenience, Figure 3 shows one movable tooth 19 (or 20) engaging with the low fixed tooth 17 and the high fixed tooth 18, but in the mechanism shown in Figure 2, the low movable tooth 19 engages with and disengages from the low fixed tooth 17, and the high movable tooth 20 engages with and disengages from the high fixed tooth 18.

[0020] As described above, the fixed teeth 17, 18 are spline teeth, and the fixed teeth 17, 18 are provided on the outer circumferential surface of a predetermined cylinder (not shown) in parallel with each other at a predetermined pitch (the interval in the vertical direction in FIG. 3). The low fixed teeth 17 and the high fixed teeth 18 are disposed at a predetermined interval in the axial direction (the horizontal direction in FIG. 3), and the pitches are the same. Furthermore, chamfers Cf are formed on the opposing ends of the fixed teeth 17, 18.

[0021] On the other hand, each of the movable teeth 19, 20 is configured as a relatively short spline tooth that moves in the axial direction, enters between the fixed teeth 17, 18, engages with the fixed teeth 17, 18 in the rotational direction (up and down direction in FIG. 3), and also comes out from between the fixed teeth 17, 18 and disengages from the fixed teeth 17, 18, and a chamfer Cf is formed at each end (both ends) in the axial direction. The distance in the axial direction between the low movable tooth 19 and the high movable tooth 20 is equal to or less than the distance in the axial direction between the fixed teeth 17, 18. In other words, the distance is set so that when one movable tooth 19 (or 20) is engaged with one fixed tooth 17 (or 18), one movable tooth 20 (or 19) disengages from one fixed tooth 18 (or 17), and the low state and the high state are not established simultaneously.

[0022] The switching between the low state and the high state, which is performed by moving the sleeve 21 in the axial direction, is performed based on the operation of a switch or a lever (not shown) by a passenger of a vehicle equipped with the power train. In this case, since the meshing transmission mechanism 1 does not have a synchronization mechanism (synchronizer) that matches the rotation speeds of the driving side and the driven side (follower side), the chamfers Cf may collide with each other depending on the timing of switching (timing of engagement), which may cause ratcheting, so that different controls are performed depending on whether the switching conditions are satisfied or not. Specifically, an electronic control unit (ECU) 23 is provided that controls the energization of the actuator 22. The ECU 23 is mainly composed of a microcomputer and a memory element, and is configured to perform calculations using input data and pre-stored data, and to output the results of the calculations as control signals. The ECU 23 receives inputs such as a low / high state switching signal (LH switching signal), a range signal indicating the range set in an automatic transmission, or a clutch signal for engaging / disengaging (ON / OFF) the input clutch in the case of a manual transmission, and is configured to determine whether the high / low switching conditions are met or not based on these input signals (input data), and to control the current to the actuator 22 based on the result of this determination. An example of this control is shown in the flow chart of FIG.

[0023] The routine shown in FIG. 4 is executed by the ECU 23 described above. First, it is detected that an operation for switching between the high state and the low state (HL switching) has been performed (step S1). Accordingly, energization of the actuator 22 for HL switching is started (step S2). That is, an engagement instruction is issued and engagement control is started. HL switching is achieved by the sleeve 21 moving (stroking) a distance until one movable tooth 19 (or 20) disengages from one fixed tooth 17 (or 18) and the other movable tooth 20 (or 19) engages with the other fixed tooth 18 (or 17). Therefore, energization of the actuator 22 is continued for the time required for such a stroke. This time is determined by the design depending on the configuration of each fixed tooth 17, 18 and the movable teeth 19, 20 in the transmission mechanism 1 and the moving speed of the sleeve 21, and this time is the engagement energization time in the embodiment of the present invention.

[0024] Following step S2, that is, after the start of energization, a violation of the switching condition is determined (step S3). The functional means for executing this step S3 corresponds to the condition violation determination means in the embodiment of the present invention. As described above, the power transmission mechanism 1 does not have a synchronization mechanism (synchronizer) for automatically matching the rotation speeds of the fixed teeth 17, 18 and the movable teeth 19, 20. Therefore, when the movable teeth 19, 20 are moved in the axial direction to engage with the fixed teeth 17, 18, there is a high possibility that the respective chamfers Cf will butt against each other and the engagement will not proceed further, or that ratcheting will occur. Therefore, when either one of the fixed teeth 17 (or 18) and the movable teeth 19 (or 20) is disengaged (disengaged) and either the other fixed tooth 18 (or 17) and the movable tooth 20 (or 19) are engaged to switch between high and low, a condition for allowing (permitting) the switching is defined. The switching condition is, for example, that no torque is applied to the fixed teeth 17, 18 and the movable teeth 19, 20, and this can be determined, for example, based on the operating state of the transmission 5. That is, if the transmission 5 is a manual transmission, the switching condition can be that the clutch (not shown) is OFF (disengaged) to shift and torque is interrupted, and if the transmission 5 is an automatic transmission, the switching condition can be that the N range (neutral range) is selected and torque is not being transmitted.

[0025] If the switching condition is no longer satisfied after the start of energization, that is, if the state of the switching condition is violated, a positive determination is made in step S3, and conversely, if the switching condition is satisfied as at the start of energization, a negative determination is made in step S3. If a negative determination is made in step S3, energization is continued to complete the switching (step S4), and the routine shown in FIG. 4 is terminated. On the other hand, if a positive determination is made in step S3, a control for shortening the energization time is executed (step S5). In addition, a driver (not shown) is notified that the energization time for switching has been shortened and that the switching has not been completed. The means for this notification may be any of a means that appeals to the auditory sense, such as sounding a buzzer, a means that appeals to the visual sense, such as displaying an indicator, and a means that appeals to the tactile sense, such as vibration. The functional means for executing this step S5 corresponds to the energization shortening means in the embodiment of the present invention.

[0026] The shortened energization time is a time required for the movable teeth 19, 20 to move from a state in which they are separated (separated) from the fixed teeth 17, 18, i.e., a release state, to a position where they slightly engage with the fixed teeth 17, 18, and is a predetermined time. FIG. 3 shows the amount of movement (stroke amount) when one movable tooth (for example, 19) serves both as the high movable tooth 20 and the low movable tooth 19, and when switching from the high state to the low state, a violation of the switching condition occurs after the start of energization, and the energization time is shortened. In this case, if the movable teeth 19 enter between the low fixed teeth 17 without the chamfers Cf hitting each other, the two will be slightly engaged due to the shortened energization time. The shortened engagement time is the time required for the movable teeth 19, 20 to stroke in this way, in other words, it is a time that is shorter than the normal engagement energization time, but is long enough to reach the fixed teeth 17, 18 without stopping before reaching them. Therefore, even if ratcheting occurs due to a violation of the switching conditions, the time during which ratcheting occurs is shortened because the current supply time is shortened, so that abnormal noise such as gear whine can be stopped early, and because the time during which a large load is applied by the actuator 22 is shortened, a decrease in durability of related members such as the shift fork (not shown) can be prevented or suppressed.

[0027] Thereafter, when it is detected that the switching condition is satisfied again (step S6), energization of the actuator 22 is resumed to perform switching control (step S7). In this case, since the switching condition is satisfied, energization of the actuator 22 is continued for the above-mentioned engagement energization time, and as a result, any one of the movable teeth 19 (or 20) enters between any one of the fixed teeth 17 (or 18), and the movable teeth 19 (or 20) and the fixed teeth 17 (or 18) engage with each other, completing the switching (step S4).

[0028] Figure 5 shows a schematic diagram of the change in current value when the switching condition is not satisfied and the current flow time is shortened and when it is not shortened. When the changeover switch (changeover SW) that switches from a high state to a low state or vice versa is turned ON (time t1), a current sufficient to move the movable teeth in the released state in the axial direction is applied to the actuator. The current flow is maintained until the tip of the movable teeth reaches the end of the fixed teeth (time t2). After that, the current value is gradually increased so that the phase (relative rotation angle) between the movable teeth and the fixed teeth is changed by the guide of the chamfer, and the thrust is sufficient to move the movable teeth in the axial direction against the frictional force between the movable teeth and the fixed teeth.

[0029] At time t3 before the state at time t2 is reached, for example, when the range of the automatic transmission is switched from N range (neutral range) to D range (drive range) (i.e., the D range signal is turned ON) and the switching condition is not satisfied, gear noise (abnormal noise) due to ratcheting or the like occurs at time t2 when the movable teeth reach the end of the fixed teeth. In the embodiment of the present invention, since the current supply time is shortened due to the switching condition being not satisfied, current supply is stopped at time t4 immediately after time t2 as shown by the solid line in FIG. 5. Therefore, abnormal noise such as gear noise is limited to the short time from time t2 to time t4, and a load is prevented from being applied to the shift fork or the like for a longer period of time. In contrast, if the current supply time is not shortened, current is continued to be supplied to the actuator during the normal engagement current supply time (until time t5 in FIG. 5), as shown by the dashed line in FIG. 5. Therefore, abnormal noise such as gear noise continues during that time, and a large load continues to be applied to members such as the shift fork.

[0030] It should be noted that, when the switching condition is not satisfied, the current value can be maintained at a low value without being increased, as shown by the dashed line in Figure 5. By controlling in this way, the load that generates abnormal noise such as gear whine is reduced, so the volume of the abnormal noise is reduced and the load applied to the shift fork, etc. can be reduced. [Explanation of symbols]

[0031] 1. Meshing transmission mechanism 2 Transfer 6 LH switching mechanism 7 2-4 switching mechanism 8 Rear wheel output shaft 9 Drive sprocket 11 Chain 12 Front wheel output shaft 13 Driven sprocket 17 Low fixed teeth 18 Fixed teeth for high 19 Movable teeth for low 20 High Movable Teeth 21 Sleeve 22 Actuator 23 Electronic Control Unit (ECU) Cf Chanfa

Claims

[Claim 1] A control device for a meshing type engagement mechanism includes a fixed tooth fixed in an axial direction, a movable tooth that moves in the axial direction and meshes with the fixed tooth, and an actuator that generates a thrust for moving the movable tooth in the axial direction when energized, wherein chamfers are formed on ends of the fixed tooth and the movable tooth in the axial direction, and when an engagement command is received to engage the movable tooth with the fixed tooth, the control device performs engagement control by energizing the actuator for a predetermined engagement energization time, a condition violation determination means for determining whether a condition for engaging the movable teeth with the fixed teeth after the engagement instruction is satisfied is no longer satisfied; a current supply shortening means for shortening a time for which current is supplied to the actuator, when the condition violation determination means determines that the condition is no longer satisfied, to be shorter than the engagement current supply time; A control device for a mesh type transmission mechanism comprising:

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