JP2024065133A - Gear change device - Google Patents

Abstract

[Problem] To reliably change the gear of a vehicle while suppressing wear of the members constituting the gear change device. [Solution] When an engagement command is issued between an inner peripheral gear 1604 of a sleeve 16 and a first gear 20A or a second gear 20B, the gear change device 10 moves a shift fork 18 from an engagement completion position Px, which is a position on a fixed shaft 2208 where the sleeve 16 abuts against a stopper 2010B of the gear on the engagement command side, to the gear on the engagement command side, and then returns the shift fork 18 to at least the engagement completion position Px and keeps it on standby. [Selected Figure] Fig. 8

Description

The present invention relates to a gear change device that changes the gears of a vehicle.

Conventionally, the gear change device used in two-speed transaxles employs a mesh clutch mechanism that uses an electric actuator to move a shift fork that holds a sleeve, and engages the inner splines of the sleeve with the gear piece splines of the desired gear to change gear.

For example, the following Patent Document 1 discloses a technology for performing accurate reference value testing (so-called "butting learning") for testing the reference value of a signal indicating a shift range in a shift range switching device mounted on a vehicle. In the butting learning of the shift range switching device in Patent Document 1, the driven body is butted against the stopper so as to bend one or both of the driven body and the stopper, and the deflection is reduced by reducing the amount of current while maintaining full-phase current flow in the DC motor, and the value of the position signal from the encoder when it is detected that the deflection has disappeared is set as the reference value. Therefore, since the reference value is determined in a state where the deflection has been eliminated, there is no variation in the reference value due to the influence of the deflection. In other words, since the reference value does not vary even when conditions such as temperature change, it is possible to switch the shift range with high precision.

Patent No. 6443189

In conventional gear-shift devices (meshing clutch mechanisms), after the sleeve has completely engaged with the desired gear piece, in order to ensure reliable engagement, the sleeve is pressed against a stopper in the gear direction with a specified load and then the current supply to the electric actuator is cut off to complete the shift.
Furthermore, the electric actuator of the conventional gear shifting device has a configuration in which a ball screw is inserted into a DC brushless motor. The ball screw has high reverse rotation efficiency, and when the current supply to the electric actuator is cut off, the holding force of the sleeve is lost. Therefore, a sub-lock mechanism (detent) is provided to fix the position of the shift fork after the shift is completed, and the retracting force of the sub-lock mechanism (detent) fixes the shift fork and sleeve at a specified position.
On the other hand, if a mechanism with low reversing efficiency, such as a sliding screw, is used for the electric actuator of the gear shifting device, a holding force remains even when the current supply to the electric motor is cut off, and the shift fork and sleeve positions are maintained even without a sub-lock mechanism (detent). However, as with conventional gear shifting devices, if the current supply to the electric actuator is cut off after the sleeve has completed meshing with the desired gear piece and has been pressed against the stopper with a predetermined load in the gear direction, a pressing force remains due to the deflection of the shift fork, etc. This pressing force may cause problems such as melting the fork pads of the shift fork.

In addition, the above-mentioned Patent Document 1 requires a sensor that detects the amount of deflection of the driven body or the stopper with high accuracy, which increases costs. In addition, the above-mentioned Patent Document 1 operates the driven body while reading the motor current value, which is a problem in that the operation is complicated.

The present invention was developed in consideration of these circumstances, and its purpose is to reduce wear on the components that make up the gear shift device while reliably shifting the vehicle's gears.

In order to achieve the above-mentioned object, one embodiment of the present invention is a gear change device for changing gears of a vehicle, comprising: a drive gear provided on a drive shaft; a sleeve having an inner peripheral spline that meshes with the drive gear; a shift fork that rotatably supports the sleeve; a first gear and a second gear that are rotatably arranged on the drive shaft on both sides of the drive gear and each have an outer peripheral spline that can mesh with the inner peripheral spline; stoppers that are provided on the first gear and the second gear and can abut against the sleeve; and a gear change device that uses an electric motor to move the shift fork on a fixed axis that is aligned with the center line of the drive shaft to move the inner peripheral spline to the first gear. The device includes a moving mechanism that selectively meshes the outer peripheral spline with the outer peripheral spline of the second gear, a stroke sensor that detects the position of the shift fork on the fixed shaft, and a movement control unit that controls the movement state of the shift fork based on the detection value of the stroke sensor, and when a command is issued to mesh the inner peripheral spline with the first gear or the second gear, the movement control unit moves the shift fork from a meshing completion position, which is a position on the fixed shaft where the sleeve abuts against the stopper of the meshing command side gear, to the meshing command side gear side, and then returns the shift fork to at least the meshing completion position and keeps it waiting.

According to one embodiment of the present invention, when a command to change gear to a specified gear stage is issued, the sleeve abuts against the stopper of the gear on the changeover side (gear on the meshing command side) and the shift fork is moved from the meshing completion position, which is a position on the fixed shaft where no deformation occurs in the shift fork, toward the gear on the changeover side, and after completing meshing between the gears with the shift fork deformed, the shift fork is returned to at least the meshing completion position and made to wait. This releases the shift fork from pressing the sleeve against the stopper, and prevents wear on the fork pad of the shift fork and wear on the contact surface between the sleeve and the stopper.

1 is a cross-sectional perspective view showing an overall configuration of a gear change device according to an embodiment; 2 is a diagram showing the configuration of a shift fork moving mechanism as viewed from the rear side of FIG. 1 . 2 is a cross-sectional view showing a schematic meshing relationship between gears constituting the gear shift device; FIG. 2 is a diagram showing a schematic diagram of the meshing relationship of each gear constituting the gear shifting device; FIG. FIG. 2 is a cross-sectional view illustrating a schematic configuration of an electric actuator. 4 is an explanatory diagram showing a schematic diagram of the movement of the shift fork when the shift fork is in a reference position. FIG. 10 is an explanatory diagram illustrating a schematic diagram of a movement of a shift fork, showing a case where the shift fork is at a movement limit position and deflection occurs. FIG. 4 is an explanatory diagram showing a schematic diagram of the movement of the shift fork when the shift fork is in a meshing complete position. FIG. 4A and 4B are explanatory diagrams illustrating the movement of the shift fork when the shift fork is in a standby position. 4 is a timing chart showing time variations in the position of the shift fork (detection value of the stroke sensor) and the current value of the electric motor. 13 is a flowchart showing a procedure of a process for learning the meshing completion position by a movement control unit.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of a gear change device and a control method for a gear change device according to the present invention will be described in detail with reference to the accompanying drawings.
The configuration of a gear change device 10 according to an embodiment will be described with reference to FIGS.
The gear change device 10 changes the gear of an automatic transmission vehicle between two gears, a high (H) gear and a low (L) gear, and includes a drive shaft 12, a clutch hub 14, a sleeve 16, a shift fork 18, a first gear 20A, a second gear 20B, a movement mechanism 22, a stroke sensor 24, and a movement control unit 300 (see FIG. 6).

The drive shaft 12 is an output shaft that transmits engine power to the drive wheels of the vehicle.

The clutch hub 14 is attached to the drive shaft 12 and has an outer periphery spline 1402 on its outer periphery as shown in FIG. 3. The clutch hub 14 and the drive shaft 12 are splined together, so that the clutch hub 14 rotates integrally with the drive shaft 12.

The sleeve 16 is a cylindrical member having an inner peripheral spline 1604 that meshes with the outer peripheral spline 1402 of the clutch hub 14. More specifically, as shown in FIG. 3, the sleeve 16 has a cylindrical sleeve base 1602 provided with the inner peripheral spline 1604, and an engagement portion 1606 provided on the outer periphery of the sleeve base 1602 with which the shift fork 18 described below can engage. The engagement portion 1606 has an outer periphery surface 1608 of the sleeve base 1602, and protruding strips 1610 on both sides that rise from both sides in a direction perpendicular to the circumferential direction of the outer periphery surface 1608.

The shift fork 18 rotatably supports the sleeve 16. The shift fork 18 is movable in the extension direction of the drive shaft 12 by a moving mechanism 22, which will be described later. When the shift fork 18 moves, the sleeve 16 also moves in the extension direction of the drive shaft 12.
As shown in FIG. 2 , the shift fork 18 includes a retaining portion 1802 that retains the sleeve 16, a cylindrical portion 1804 through which a fixed shaft 2208 of the moving mechanism 22 described later is inserted, and a main body portion 1806 that connects the retaining portion 1802 and the cylindrical portion 1804.
As shown in Fig. 3, the retaining portion 1802 has a contact surface 1808 that rotatably contacts the outer circumferential surface 1608 between the ridges 1610 on both sides provided on the outer periphery of the sleeve 16. In addition, as shown in Fig. 2, a fork pad 1812 is attached to a side wall 1810 of the retaining portion 1802 that faces the ridges 1610 in order to prevent seizure when the shift fork 18 comes into contact with the sleeve 16 due to relative rotation.
3, in the retaining portion 1802, a width W1 (including a thickness of the fork pads 1812) of a contact surface 1808 in a direction perpendicular to the circumferential direction of the outer circumferential surface 1608 of the sleeve 16 is smaller than a dimension W2 between the protrusions 1610 on both sides. In other words, a gap (backlash) of a distance W2-W1 is provided between the retaining portion 1802 of the shift fork 18 and the engaging portion 1606 of the sleeve 16.

As shown in Fig. 1, the first gear 20A and the second gear 20B are rotatably disposed on the drive shaft 12 on either side of the clutch hub 14. The first gear 20A corresponds to a high gear, and an outer peripheral gear 2008A of a large diameter portion 2004A (described later) rotates in mesh with a third gear 34A fixed to the counter shaft 32 shown by a two-dot dashed line in Fig. 1. The second gear 20B corresponds to a low gear, and an outer peripheral gear 2008B of a large diameter portion 2004 (described later) rotates in mesh with a fourth gear 34B fixed to the counter shaft 32.
The first gear 20A and the second gear 20B are connected to the drive shaft 12 via a needle roller bearing (not shown), and the gear corresponding to the desired shift, either the first gear 20A or the second gear 20B, is connected to the drive shaft 12 via a drive gear 14 by a sleeve 16, whereby the rotation of the gear is transmitted to the drive shaft 12. Note that a position restriction member (not shown) is provided to prevent the axial positions of the first gear 20A and the second gear 20B from changing.

As shown in FIG. 3, the first gear 20A and the second gear 20B each have a spline 2002 (2002A, 2002B) arranged adjacent to the clutch hub 14 and a large diameter portion 2004 (2004A, 2004B) arranged on the side away from the drive gear 14.
The splines 2002 of the first gear 20A and the second gear 20B each have an outer circumferential gear 2006 (2006A, 2006B) that can mesh with the inner circumferential splines 1604 of the sleeve 16.
The large diameter portion 2004 has a larger radius than the spline 2002, and the outer periphery of the outer gear 2008 (2008A, 2008B) provided on its outer periphery is constantly meshed with the outer periphery gear 3400A of the third gear 34A or the outer periphery gear 3400B of the fourth gear 34B fixed to the counter shaft 32.

The moving mechanism 22 selectively meshes the inner peripheral spline 1604 of the sleeve 16 with the outer peripheral spline 2006A of the first gear 20A and the outer peripheral spline 2006B of the second gear 20B by using the electric motor 2204A to move the shift fork 18 along the center line O of the drive shaft 12.
2, in the present embodiment, the moving mechanism 22 includes an electric actuator 2204, a moving shaft 2206, a guide portion 2208, and a lever 2212. The guide portion 2208 and the shift fork 18 are provided integrally.
As shown in Fig. 5, the electric actuator 2204 has a sliding screw 2204B inserted into an electric motor (in this embodiment, a DC brush motor) 2204A, and functions as a linear motion mechanism that converts the rotation around the axis output by the electric motor 2204A into linear motion in the axial direction. The electric motor 2204A rotates the female thread side of the sliding screw 2204B, so that the electric actuator 2204 moves in the vertical direction (the direction of the arrow A in Fig. 2). That is, the movement mechanism 22 converts the rotational force output by the electric motor 2204A into a linear motion force by the sliding screw 2204B connected to the output shaft of the electric motor 2204A, thereby moving the shift fork 18.
The moving shaft 2206 is attached to the tip of an output shaft 2204C of the electric actuator 2204, and moves in conjunction with the movement of the electric actuator 2204 in the linear motion direction (the direction of arrow A in FIG. 2).
The guide portion 2210 is integral with the shift fork 18 as described above, and includes a main body portion 2210A, an insertion hole 2210B through which a lever 2212 (described later) is inserted, and a spring 2210C through which the fixed shaft 2208 is inserted.
The lever 2212 is generally L-shaped, with one end 2212A inserted into a connection portion 2206A provided on the moving shaft 2206, and the other end 2212B inserted into an insertion hole 2210B of the guide portion 2210. The lever 2212 is swingable about a support shaft 2212C supported by the vehicle body.
When the electric actuator 2204 is operated and the moving shaft 2206 moves up and down (in the direction of the arrow A), the lever 2212 swings, and the shift fork 18 and the guide portion 2208 perform a reciprocating linear motion (in the direction of the arrow B).

The stroke sensor 24 detects the position of the shift fork 18 by reading the movement of the guide portion 2208. In this embodiment, the stroke sensor 24 determines the position of the shift fork 18 when the axial center position of the holding portion 1802 of the shift fork 18 is located at the axial center position S0 (see FIG. 3 ) of the drive gear 14 as a reference position P0, and detects the position of the shift fork 18 by detecting the amount of movement of the shift fork 18 from this reference position P0.
That is, the stroke sensor 24 detects the movement distance of the shift fork 18 from the reference position P0 of the shift fork 18 where the inner peripheral spline 1604 of the sleeve 16 does not mesh with the outer peripheral spline 2006A of the first gear 20A and the outer peripheral spline 2006B of the second gear 20B.

3, when the sleeve 16 is located on the outer periphery of the drive gear 14, the first gear 20A and the second gear 20B are not connected to the drive shaft 12 and rotate independently around the drive shaft 12. In this case, the vehicle is in neutral (N) gear.
4, when the sleeve 16 is moved in the direction of the first gear 20A by the shift fork 18, a portion of the inner peripheral spline 1604 of the sleeve 16 meshes with the outer peripheral spline 2006A of the spline 2002A of the first gear 20A. The remaining portion of the inner peripheral spline 1604 of the sleeve 16 meshes with the drive gear 14, so that the first gear 20A, the sleeve 16, and the drive gear 14 are integrated to transmit the rotational force of the drive shaft 12 to the drive shaft 32 via the sleeve 16, the first gear 20A, and the third gear 34A. When the sleeve 16 meshes with the first gear 20A, the vehicle shifts to high gear.
Furthermore, when the sleeve 16 is moved in the direction of the second gear 20B by the shift fork 18, a portion of the inner peripheral gear 1604 of the sleeve 16 meshes with the outer peripheral gear 2006B of the spline 2002B of the second gear 20B. The remaining portion of the inner peripheral gear 1604 of the sleeve 16 meshes with the drive gear 14, so that the second gear 20B, the sleeve 16, and the drive gear 14 become one unit and transmit the rotational force of the drive shaft 12 to the drive shaft 32 via the sleeve 16, the second gear 20B, and the fourth gear 34B. When the sleeve 16 meshes with the second gear 20B, the vehicle shifts to low gear.

Furthermore, as shown in FIG. 4, when the sleeve 16 moves axially toward the first gear 20A by the shift fork 18, the axial end face 1612 of the sleeve 16 abuts against the side of the large diameter portion 2004 on the clutch hub 14 side, thereby restricting the axial movement of the sleeve 16.
That is, in this embodiment, the side surface of this large diameter portion 2004 functions as a stopper 2010 (2010A, 2010B) that is provided on the first gear 20A and the second gear 20B and can abut against the sleeve 16.

Next, the movement control unit 300 will be described.
As shown in FIG. 6, the movement control unit 300 is realized as one function of a TCU (Transmission Control Unit) 30 that controls the transmission of the vehicle.
The TCU 30 is composed of a CPU, a ROM for storing and remembering control programs, a RAM as the operating area for the control programs, an EEPROM for storing various types of rewritable data, an interface section for interfacing with peripheral circuits, etc., and functions as a movement control section 300 by the CPU executing the control program.

The movement control unit 300 controls the movement state of the shift fork 18 based on the detection value of the stroke sensor 24. For example, when there is a command to change the gear stage from the ECU that controls the entire vehicle (i.e., when there is a command to mesh the sleeve 16 with the first gear 20A or the second gear 20B), the movement control unit 300 operates the electric actuator 2204 to move the shift fork 18 to a position where the gear 20 corresponding to that gear stage meshes with the sleeve 16.

In this embodiment, as shown in FIG. 8, the position where the end face 1612 of the sleeve 16 contacts the side face (stopper 2010) of the large diameter portion 2004 of the gear 20 and where no deformation (deflection) occurs in the shift fork 18 is defined as the meshing completion position (stopper position) Px.
When there is a command to change gear stages (a command to mesh the sleeve 16 with a specified gear 20), the shift fork 18 is first moved from the meshing completion position Px to the gear side of the meshing command side (for example, a movement limit position Pl (see FIG. 7 ) described later) to press the sleeve 16 against the gear 20, thereby ensuring that the sleeve 16 and the gear 20 mesh together, and then the shift fork 18 is returned at least to the meshing completion position Px and waits until the next command to change gear stages.
In other words, when a command is issued to engage the inner gear 1604 of the sleeve 16 with the first gear 20A or the second gear 20B, the movement control unit 300 moves the shift fork 18 from the meshing completion position Px, which is a position on the fixed shaft 2208 where the sleeve 16 abuts against the stopper 2010 of the gear on the meshing command side and where no deformation occurs in the shift fork 18, to the meshing command side gear side, and after deforming the shift fork, returns the shift fork 18 to at least the meshing completion position Px and keeps it waiting.

The meshing completion position Px is not specified in advance, but is determined by the movement control unit 300 through learning.
The reason for setting the meshing completion position Px in the gear shifting device 10 according to the embodiment will be described below.
As described above, the electric actuator of the conventional gear shifting device has a configuration in which a ball screw is inserted into a DC brushless motor. The ball screw has high reverse rotation efficiency, and when the current supply to the electric actuator is cut off, the holding force of the sleeve is lost. Therefore, a sub-lock mechanism (detent) is provided to fix the position of the shift fork after the shift is completed, and the retracting force of the sub-lock mechanism (detent) fixes the shift fork and sleeve at a specified position.

On the other hand, if a mechanism with low reverse efficiency, such as a sliding screw 2204B, is used for the electric actuator 2204 of the gear shifting device 10 of the embodiment, the holding force remains even when the current supply to the electric motor 2204A is cut off, and the shift fork 18 and sleeve positions are maintained even without a sub-lock mechanism (detent).
However, similar to conventional switching devices, after the sleeve has completed meshing with the desired gear piece and has been pressed against the stopper in the gear direction with a predetermined load, if the current supply to the electric actuator 2204 is cut off, a pressing force remains due to the deflection of the shift fork 18. This pressing force may cause problems such as melting the fork pads 1812 of the shift fork 18.

For this reason, the gear change device 10 does not complete the shifting with the sleeve pressed against the gear (turning off the electric actuator) as in the conventional case, but instead learns the position (engagement completion position) where the end face 1612 of the sleeve 16 contacts the side (stopper 2010) of the large diameter portion 2004 of the gear 20, and completes the shifting by returning the shift fork 18 at least to the engagement completion position.

The dimensions of the drive gear 14, sleeve 16, first gear 20A, second gear 20B, etc. are constant, and a method of determining the meshing completion position based on these dimensions (design values) is conceivable. However, there is a possibility of mechanical errors in the dimensions of each component and variations in the characteristics of the stroke sensor 24. It is therefore considered that a uniform value would be insufficient to solve the above problems, and therefore it was decided to perform learning in each gear change device 10.

The details of learning performed by the movement control unit 300 will be described using the flowchart of FIG. 11 with reference to FIGS.
6 to 9, the drive gear 14, the stroke sensor 24, etc. are omitted from the drawings for the sake of visibility.
In the initial state, the shift fork 18 is in a reference position P0 as shown in FIG.
When the movement control unit 300 receives an instruction to learn the movement amount (step S900: Yes), it operates the electric actuator 2204 at a constant speed to move the shift fork 18 and the sleeve 16 held by the shift fork 18 in one gear direction (toward the first gear 20A in the figure) at a constant speed (step S902, which corresponds to times T0 to T1 in FIG. 10). The stroke sensor 24 detects the movement amount (movement distance) of the shift fork 18 from the reference position P0.

When the inner peripheral spline 1604 of the sleeve 16 meshes with the outer peripheral gear 2006 of the spline 2002 of the first gear 20A and the axial end face 1612 of the sleeve 16 reaches a position (stopper position) where it abuts against 2010A of the large diameter portion 2004, the moving speed of the shift fork 18 decreases. The moving speed of the shift fork 18 can be calculated, for example, from the amount of change per unit time in the detection value of the stroke sensor 24.
When the movement speed of the shift fork 18 decreases (step S904: Yes, corresponding to times T1 to T2 in Figure 10), that is, when the movement control unit 300 detects that the sleeve 16 has reached the stopper position, it temporarily cuts off the power supply to the electric actuator 2204 (step S906, corresponding to times T2 to T3 in Figure 10).

Next, the movement control unit 300 applies a constant voltage to the electric actuator 2204 to further move the shift fork 18 and the sleeve 16 held by the shift fork 18 toward the first gear 20A (step S908, which corresponds to times T3 to T4 in FIG. 10). That is, as shown in FIG. 7, the shift fork 18 is further moved so as to press the sleeve 16 toward the large diameter portion 2004 (toward the stopper). At this time, a deflection D occurs in the shift fork 18 due to the pressing force toward the stopper. Note that FIG. 7 shows the deflection of the shift fork 18 diagrammatically.

The movement control unit 300 continues to apply pressure at a constant voltage until the detection value of the stroke sensor 24 (denoted as "stroke" in the figure) stabilizes (step S910: No). When the detection value of the stroke sensor 24 stabilizes (step S910: Yes), the movement control unit 300 determines that the position is the movement limit position of the shift fork 18, and reads the detection value of the stroke sensor 24 at that time and the value of the current flowing through the electric actuator 2204 (step S912, corresponding to time T4 in FIG. 10).

Next, the movement control unit 300 estimates the axial load that the shift fork 18 receives from the movement mechanism 22 based on the current value of the electric actuator 2204 obtained in step S912 (step S914). In general, the current value of the electric actuator 2204 is proportional to the load received from the shift fork 18, and the movement control unit 300 reads the load value corresponding to the current value from a map that has been created in advance based on actual measurements.

Furthermore, the movement control unit 300 estimates the amount of axial strain (corresponding to symbol D in FIG. 7) occurring in the shift fork 18 based on the load obtained in step S914 (step S916). In general, the load received by a member and the amount of strain of the member are proportional to each other, and the movement control unit 300 reads the value of the amount of strain corresponding to the load from a map created in advance by actual measurements.
The map prepared in advance may be such that the amount of distortion of the shift fork 18 can be obtained directly from the current value in step S912.

The movement control unit 300 determines the value obtained by subtracting the strain value obtained in step S916 from the detection value of the stroke sensor 24 when the stroke is stable read in step S912 as the meshing completion position Px (step S918), and ends the processing according to this flowchart.
Thereafter, the meshing completion position Px for the other gear direction (the direction of the second gear 20B in the above example) is similarly learned.

That is, the movement control unit 300 drives the electric motor 2204A with a constant voltage to move the sleeve 16 to the movement limit position Pl where the movement of the shift fork 18 is restricted by contacting the stopper 2010 (the side surface of the large diameter portion 2004 of the gear 20), estimates the deflection amount D of the shift fork 18 at the movement limit position Pl based on the current flowing through the electric motor 2204A when the shift fork 18 reaches the movement limit position, and learns the position obtained by subtracting the deflection amount D from the detection value of the stroke sensor 24 when the shift fork 18 reaches the movement limit position Pl as the meshing completion position Px.

The movement control unit 300 learns the meshing completion position at least once, for example, before the vehicle is shipped. The movement control unit 300 may also learn the meshing completion position at predetermined intervals after the vehicle has started to be used. This is because, for example, wear of the fork pads 1812 and changes in the motion characteristics of each member of the movement mechanism 22 may occur due to long-term use.
The predetermined period may be set, for example, at a predetermined time interval (every three months, every year, etc.), or at a predetermined mileage (every 10,000 km, etc.).

As described above, when there is a gear change command (a command to mesh the sleeve 16 with a specified gear 20), the movement control unit 300 first moves the shift fork 18 to approximately the movement limit position Pl (see FIG. 7) and presses the sleeve 16 against the gear 20 to ensure that the sleeve 16 and the gear 20 mesh securely, then returns the shift fork 18 to at least the mesh completion position Px, cuts off the power supply to the electric actuator 2204, and waits until the next gear change command. This makes it possible to reduce the pressing force applied to the sleeve 16 toward the gear 20 (stopper) to almost zero, preventing wear on the fork pad 1812 and deterioration of the shift fork 18.

On the other hand, when the shift fork 18 is in the complete engagement position Px, the fork pad 1812 on the gear 20 side is in contact with the protrusion 1610 of the sleeve 16, and even a slight error in the amount of movement may result in a pressing force being applied to the sleeve 16.
Therefore, in this embodiment, the standby position of the fork pad 1812 after the shift is completed may be a position (standby position Py) where the fork pad 1812 contacts the protrusion 1610 of the sleeve 16 on the opposite side to the gear 20, as shown in FIG.
9, in the retaining portion 1802, a width W1 (including a thickness of the fork pads 1812) of a contact surface 1808 in a direction perpendicular to the circumferential direction of the outer circumferential surface 1608 of the sleeve 16 is smaller than a dimension W2 between the protrusions 1610 on both sides. In other words, a gap (backlash) of a distance W2-W1 is provided between the retaining portion 1802 of the shift fork 18 and the engaging portion 1606 of the sleeve 16.
The standby position Py is located at a distance of the gap distance W2-W1 from the meshing completion position Px on the opposite side to the meshed gear 20 (the drive gear 14 side).
In other words, the movement control unit 300 may store the gap distance W2-W1 obtained by subtracting the width of the contact surface 1808 including the fork pad 1812 from the dimension W2 between the convex ribs 1610 on both sides of the sleeve 16, and upon receiving an engagement command, may move the shift fork 18 to the movement limit position Pl, and then make the shift fork 18 wait at a position (waiting position Py) that is away from the engagement completion position Px in the opposite direction to the gear 20 by the gap distance W2-W1.
In this way, the gear 20 and the sleeve 16 can be reliably engaged (shifted) while wear on the members constituting the gear change device 10 can be more reliably prevented.

As described above, the gear change device 10 according to the embodiment moves the shift fork 18 toward the gear 20 on the switching side from the meshing completion position Px, which is a position on the fixed shaft 2208 where the sleeve 16 abuts against the stopper 2010 of the gear 20 on the switching side (gear on the meshing command side) when a shift change command is issued to a predetermined shift, and completes meshing between the gears in a state where the shift fork 18 is deformed, and then returns the shift fork 18 to at least the meshing completion position and waits. This releases the sleeve 16 from being pressed against the stopper 2010 by the shift fork 18, and prevents wear of the fork pad 1812 of the shift fork 18 and wear of the contact surface between the sleeve 16 and the stopper 2010. In addition, by moving the shift fork 18 toward the gear 20 on the switching side from the meshing completion position Px, the inner peripheral gear 1604 of the sleeve 16 and the gear 20 on the switching side are meshed, and the shift can be completed reliably.
Furthermore, in the gear shifting device 10 of the embodiment, if the standby position until the next shift change is set to a position (standby position Py) that is away from the meshing completion position Px in the opposite direction to the gear 20 by the gap distance W2-W1, wear of each component that constitutes the gear shifting device 10 can be more reliably prevented.
Furthermore, in the gear shifting device 10 of the embodiment, the shift fork 18 is moved to the movement limit position Pl, and when the shift fork 18 reaches the movement limit position Pl, the amount of deflection D of the shift fork 18 at the movement limit position Pl is estimated based on the current flowing through the electric motor 2204A. The position obtained by subtracting the amount of deflection from the detection value of the stroke sensor when the shift fork 18 reaches the movement limit position Pl is learned as the engagement completion position Px. This makes it possible to estimate the amount of deflection without providing a sensor to detect the amount of deflection of the shift fork 18, and reduces the cost of the gear shifting device 10.
Furthermore, in the gear shifting device 10 according to the embodiment, if the sliding screw 2204B is employed in the rotary-linear motion conversion mechanism of the electric actuator 2204, the component costs of the rotary-linear motion conversion mechanism can be reduced compared to a conventional configuration using a ball screw, etc. In addition, by utilizing the low reverse rotation efficiency of the sliding screw, the sub-lock mechanism for holding the position of the shift fork can be eliminated, thereby achieving further cost reduction.
Furthermore, in the gear shifting device 10 of the embodiment, if the meshing completion position is learned at predetermined intervals after the vehicle begins to be used, it is possible to set the meshing completion position that reflects changes in each part of the gear shifting device 10 due to long-term use, and wear of each component that constitutes the gear shifting device 10 can be more reliably prevented.

REFERENCE SIGNS LIST 10 gear shift device 12 drive shaft 14 clutch hub 16 sleeve 1602 sleeve base 1604 inner peripheral spline 1606 engagement portion 1608 outer peripheral surface 1610 convex strip 1612 end surface 18 shift fork 20A first gear 20B second gear 2002 (2002A, 2002B) spline 2004 (2004A, 2004B) large diameter portion 2006 (2006A, 2006B) outer peripheral spline 2008 (2008A, 2008B) outer peripheral gear 2010 (2010A, 2010B) stopper 22 movement mechanism 2204 electric actuator 2204A electric motor 2204B sliding screw 2204C output shaft 2206 Moving shaft 2208 Guide portion 2212 Lever 24 Stroke sensor 300 Moving control portion P0 Reference position Pl Movement limit position Px Meshing completion position Py Standby position

Claims (5)

A gear shifting device for shifting a gear of a vehicle,
A clutch hub provided on the drive shaft;
a sleeve having an inner peripheral spline that meshes with the clutch hub;
a shift fork that rotatably supports the sleeve;
a first gear and a second gear rotatably disposed on the drive shaft on either side of the clutch hub, the first gear and the second gear each having an outer circumferential spline meshable with the inner circumferential spline;
a stopper provided on the first gear and the second gear and capable of contacting the sleeve;
a moving mechanism that uses an electric motor to move the shift fork on a fixed shaft that is aligned along a center line of the drive shaft, thereby selectively meshing the inner peripheral spline with the outer peripheral spline of the first gear and the outer peripheral spline of the second gear;
a stroke sensor for detecting a position of the shift fork on the fixed shaft;
a movement control unit that controls a movement state of the shift fork based on a detection value of the stroke sensor,
When a mesh command is issued between the inner peripheral spline and the first gear or the second gear, the movement control unit moves the shift fork from a mesh completion position, which is a position on the fixed shaft where the sleeve abuts against the stopper of the gear on the mesh command side, to the gear on the mesh command side, and then returns the shift fork to at least the mesh completion position and makes the shift fork wait.
A gear shifting device comprising: the sleeve has a cylindrical sleeve base portion on which the inner peripheral spline is provided, and an engagement portion that is provided on an outer periphery of the sleeve base portion and with which the shift fork can be engaged,
the engaging portion includes an outer circumferential surface of the sleeve base portion and protruding stripes on both sides rising from both side portions of the outer circumferential surface in a direction perpendicular to the circumferential direction,
the shift fork has a retaining portion having a contact surface that rotatably contacts the outer circumferential surface between the protruding strips on both sides, and a width of the contact surface in a direction perpendicular to a circumferential direction of the outer circumferential surface is smaller than a dimension between the protruding strips on both sides,
the movement control unit stores a gap distance obtained by subtracting the width of the contact surface from the dimension between the convex strips on both sides, and when the meshing command is issued, moves the shift fork from the meshing completion position to the meshing command side gear side, and then makes the shift fork wait at a position away from the meshing completion position by the gap distance in the opposite direction to the meshing command side gear.
2. The gear shift device according to claim 1. the movement control unit drives the electric motor with a constant voltage to move the sleeve to a movement limit position where the movement of the shift fork is restricted by being pressed against the stopper, estimates an amount of deflection of the shift fork at the movement limit position based on a current flowing through the electric motor when the shift fork reaches the movement limit position, and learns a position obtained by subtracting the amount of deflection from a detection value of the stroke sensor when the shift fork reaches the movement limit position as the meshing completion position.
3. The gear shift device according to claim 1 or 2. The moving mechanism converts a rotational force output by the electric motor into a linear moving force by a sliding screw connected to an output shaft of the electric motor to move the shift fork.
4. The gear shift device according to claim 1, wherein the gear shift device is a gear shift mechanism. the movement control unit executes learning of the meshing completion position at predetermined intervals after starting use of the vehicle.
5. The gear shift device according to claim 1, wherein the gear shift device is a gear shift gear.

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