JP7563308B2 - Shift Switching Device - Google Patents

Description

The present invention relates to the structure of a shift switching device that switches the shift range of a transmission.

A shift switching device is known that includes a manual shaft whose one end is housed in a transmission case and rotates to switch the shift range of the transmission, an actuator that rotates the manual shaft, and an actuator case that is the housing for the actuator. The automatic transmission control unit described in Patent Document 1 is an example of such a device.

International Publication No. 2009/041679

In Patent Document 1, the manual shaft protrudes from the transmission case and is exposed between the transmission case and the actuator case, so external moisture may adhere to the manual shaft, causing the manual shaft to rust and potentially damaging the oil seal between the transmission case and the manual shaft. To address this issue, a water ingress seal could be provided to prevent water from entering from the outside, but when a leak test is performed on the transmission side at the time of shipment, there is a problem that even if an air leak occurs from the oil seal, the air leak cannot be detected because it is sealed by the water ingress seal.

The present invention was made against the background of the above circumstances, and its purpose is to provide a structure for a shift switching device equipped with a manual shaft rotated by an actuator that can prevent moisture from adhering to the manual shaft from the outside and that can perform a leak test on the transmission.

The gist of the first invention is a shift switching device including: (a) a manual shaft that has one end housed in a transmission case and the other end protruding from the transmission case toward the outside, and that rotates to switch the shift range of the transmission; an actuator that is attached to the outside of the transmission case and rotates the manual shaft; and an actuator case that is a housing for the actuator; (b) a seal member is inserted in a gap formed between the transmission case and the actuator case; and (c) the seal member is configured to come into close contact with the transmission case and the actuator case when a predetermined amount of heat or more is applied to the seal member.

According to the first invention, the seal member inserted in contact with the gap between the transmission case and the actuator case is configured to adhere to the transmission case and the actuator case when a predetermined amount of heat or more is applied, so that application of heat to the seal member brings the seal member into close contact with the transmission case and the actuator case, preventing water from entering from the outside. In addition, when heat is not applied to the seal member, air is permitted to leak from between the seal member and the transmission case and the actuator case, making it possible to carry out a leak test.

1 is an external view of a transmission to which the present invention is applied; FIG. 2 is an enlarged front view of the actuator of FIG. 1 . FIG. 2 is a diagram showing the internal structure of the actuator of FIG. 1 . FIG. 2 is a diagram showing a configuration of a parking mechanism driven by an actuator. 11 is a cross-sectional view showing a fitting portion of a manual shaft connecting a parking mechanism and an actuator. FIG.

Here, preferably, the sealing member is made of a foam whose main component is EPDM rubber (ethylene propylene diene rubber). When heat is applied to this sealing member, it softens and penetrates into the minute irregularities formed on the sealing surfaces of the transmission case and the actuator case that come into contact with the sealing member, thereby bringing the sealing member into close contact with the sealing surfaces of the transmission case and the actuator case.

Preferably, the seal member is subjected to heat generated while the vehicle is running after the transmission is shipped, thereby causing the seal member to adhere closely to the transmission case and the actuator case. As a result, the seal member is caused to adhere closely to the transmission case and the actuator case by applying heat to the seal member as the vehicle is driven after the vehicle is shipped.

The following describes in detail the embodiments of the present invention with reference to the drawings. Note that in the following embodiments, the drawings have been simplified or modified as appropriate, and the dimensional ratios and shapes of the various parts are not necessarily drawn accurately.

Figure 1 is an external view of a transmission 10 to which the present invention is applied. A shift-by-wire actuator 14 (hereinafter, actuator 14) for rotating a manual shaft 58, which will be described later, is provided in a transmission case 12 of the transmission 10. A shift switching device 8 for switching the shift range of the transmission 10 is constituted by the actuator 14, which is attached to the outside of the transmission case 12 of the transmission 10, and a parking mechanism (see Figure 4), which will be described later, housed inside the transmission case 12.

Figure 2 is an enlarged front view of the actuator 14 in Figure 1, and Figure 3 shows the internal structure of the actuator 14.

The actuator 14 includes an ECU board 20, a motor 22, a rotor shaft 24, a drive gear 26, a driven gear 28, and an output shaft 30 within the space formed by the housing 16 and the cover 18.

The housing 16 and the cover 18 are each formed in a tray shape. In addition, flange portions 16a, 18a are formed along the edges of the opening sides of the housing 16 and the cover 18, and the housing 16 and the cover 18 are fastened to each other by fastening bolts 32 with the mating surfaces of the flange portions 16a, 18a abutting against each other. Fastening the housing 16 and the cover 18 to each other forms the actuator case 19, which is the housing of the actuator 14.

The housing 16 is formed with multiple fixing parts 34 for fixing the actuator 14 to the transmission case 12, and each fixing part 34 is formed with a bolt hole 34a for inserting a bolt (not shown). The housing 16 is also provided with connectors 36a, 36b for connecting the ECU board 20 to external wiring (not shown). A vibration-damping material 40 is attached to the outer wall of the cover 18 with adhesive tape 38.

In the space formed by the housing 16 and the cover 18, an ECU board 20 is housed on the cover 18 side. The ECU board 20 is provided to control the motor 22 that constitutes the actuator 14. In addition, a cushioning material 42 is inserted between the ECU board 20 and the cover 18.

The motor 22 is driven by a command from the ECU board 20, and rotates the rotor shaft 24 to a predetermined rotation position in response to the command from the ECU board 20. A drive gear 26 is fixed to the rotor shaft 24 so that it cannot rotate relative to the rotor shaft 24. The drive gear 26 is meshed with a driven gear 28. The driven gear 28 is joined to the output shaft 30 by welding or the like. The driven gear 28 is formed in an arc shape when viewed in the axial direction of the output shaft 30. In addition, since the diameter of the driven gear 28 is longer than the diameter of the drive gear 26, the torque output from the motor 22 is amplified and transmitted to the output shaft 30. The output shaft 30 is formed with a spline hole 44 formed with spline teeth into which a manual shaft 58 described later is spline-fitted.

Figure 4 is a diagram showing the overall structure of the shift switching device 8, which includes the actuator 14 and the parking mechanism 46 driven by the actuator 14. Figure 4(a) shows the overall structure of the actuator 14 and the parking mechanism 46, and Figure 4(b) corresponds to a view of the parking mechanism 46 in Figure 4(a) viewed in the direction of the rotation axis CL of a parking lock gear 48, which will be described later. Note that Figure 4(a) corresponds to a view of the parking mechanism 46 in Figure 4(b) viewed in the direction of arrow A. The parking mechanism 46 is housed inside the transmission case 12, which is not shown in Figure 4.

The parking mechanism 46 includes a parking lock gear 48, a parking pole 50, a cam 52, a rod 54, a detent lever 56, a manual shaft 58, and a detent spring 60. The parking lock gear 48 is fixed to an output shaft (not shown) of the transmission 10 so that it cannot rotate relative to the shaft. The parking pole 50 is a longitudinal member that can rotate around a rotation support portion 50a. A lock tooth 50b that can mesh with the outer teeth of the parking lock gear 48 is formed on the portion of the parking pole 50 that faces the parking lock gear 48. The parking pole 50 is rotated by the cam 52.

The cam 52 is formed in a cone shape and abuts against the portion of the parking pole 50 opposite the rotation support portion 50a in the longitudinal direction. The cam 52 is movable in a direction parallel to the rotation axis CL of the parking lock gear 48 in FIG. 4(a) (perpendicular to the paper). When the cam 52 is moved, the portion of the cam 52 that abuts against the parking pole 50 is changed, and the parking pole 50 is rotated. For example, when the cam 52 moves to the front side of the paper in FIG. 4(a), that is, when the cam 52 moves to the right side of the paper in FIG. 4(b), the parking pole 50 is rotated counterclockwise around the rotation support portion 50a. At this time, as shown in FIG. 4(a), the outer teeth of the parking lock gear 48 and the lock teeth 50b of the parking pole 50 are engaged, and the rotation of the parking lock gear 48 is prevented. In other words, the rotation of the output shaft of the transmission 10 is prevented. On the other hand, when the cam 52 moves toward the back of the paper in FIG. 4(a), that is, when the cam 52 moves to the left side of the paper in FIG. 4(b), the parking pawl 50 is rotated clockwise around the rotation support portion 50a. At this time, the meshing between the outer teeth of the parking lock gear 48 and the lock teeth 50b of the parking pawl 50 is released, and the rotation of the parking lock gear 48 is permitted.

The rod 54 connects the cam 52 and the detent lever 56. The detent lever 56 is a fan-shaped member and is fixed integrally to the manual shaft 58. Therefore, when the manual shaft 58 rotates, the detent lever 56 rotates around the manual shaft 58, and the cam 52 is moved via the rod 54. The detent lever 56 has a corrugated surface 56a, which is a corrugated surface, and the end of the detent spring 60 is pressed against the corrugated surface 56a. When the end of the detent spring 60 abuts against each valley formed on the corrugated surface 56a of the detent lever 56, the detent lever 56 is switched to a predetermined shift range defined for each valley. In this way, the end of the detent spring 60 is pressed against the corrugated surface 56a of the detent lever 56, and the detent lever 56 is held in a rotational position corresponding to the predetermined shift range.

One end of the manual shaft 58 is housed within the transmission case 12 and the other end protrudes from the transmission case 12 toward the outside, and the manual shaft 58 is rotated to change the shift range of the transmission 10. The manual shaft 58 is rotated by the actuator 14. When the manual shaft 58 rotates, the cam 52 moves via the detent lever 56 and the rod 54, and the parking pole 50 is rotated around the rotation support part 50a.

Figure 5 is a cross-sectional view showing the fitting portion of the manual shaft 58 that connects between the parking mechanism 46 and the actuator 14. The transmission case 12 is formed with a cylindrical first tube portion 62, and a through hole 63 through which the manual shaft 58 passes is formed on the inner periphery side of the first tube portion 62. The manual shaft 58 passes through the through hole 63 and has one end protruding toward the outside of the case. In addition, an oil seal 64 is provided between the inner periphery of the through hole 63 and the outer periphery of the manual shaft 58 to prevent oil leakage from inside the transmission case 12. The housing 16 is formed with a cylindrical second tube portion 66 that fits into the through hole 63 of the transmission case 12, and the outer periphery of the second tube portion 66 is fitted in a state of surface contact with the inner periphery of the through hole 63.

The manual shaft 58 has spline teeth 68 formed on the portion protruding from the transmission case 12, and is spline-fitted into a spline hole 44 formed in the output shaft 30. Therefore, the manual shaft 58 and the output shaft 30 rotate together. The output shaft 30 is fitted so that its outer circumferential surface can slide against the inner circumferential surface of the second cylindrical portion 66. In addition, the driven gear 28 is fixed to the outer periphery of the output shaft 30 by welding or the like.

Here, if water from the outside penetrates into the inside through the gap between the transmission case 12 and the housing 16, there is a risk of rusting the surface of the manual shaft 58. In relation to this, if the oil seal 64 is damaged, there is a risk that the oil inside the transmission 10 will leak out from between the oil seal 64 and the manual shaft 58. To prevent this, a foam sealant 70 is inserted in the gap L formed between the transmission case 12 and the housing 16 in the axial direction of the manual shaft 58 to prevent water from penetrating from the outside. The foam sealant 70 has an annular shape. The foam sealant 70 corresponds to the seal member of the present invention.

A wall portion 72 is formed on the base side of the second cylindrical portion 66 of the housing 16, extending perpendicularly from the base to the second cylindrical portion 66. The foam seal material 70 is inserted into a gap L formed between the end of the first cylindrical portion 62 and the wall portion 72 of the housing 16 in the axial direction of the manual shaft 58. Before assembly, the foam seal material 70 has a square cross section as shown by the dashed line in FIG. 5. On the other hand, when the first cylindrical portion 62 of the transmission case 12 and the second cylindrical portion 66 of the housing 16 are fitted together during assembly, the foam seal material 70 is compressed and deformed, and the foam seal material 70 has an L-shaped cross section as shown by the solid line in FIG. 5. When assembling, an adhesive is applied in advance to the portion of the foam seal material 70 that contacts the second seal surface 76, and the foam seal material 70 is assembled in a state where it is adhered to the second seal surface 76.

When the foam seal material 70 is inserted between the transmission case 12 and the housing 16, it is in contact with the first seal surface 74 formed at the tip of the first cylindrical portion 62 and the second seal surface 76 formed on the wall portion 72 of the housing 16. As described above, the foam seal material 70 and the second seal surface 76 are bonded in advance with an adhesive. The foam seal material 70 inserted between the transmission case 12 and the housing 16 prevents water from entering from the outside. Although the foam seal material 70 is weak against oil, the oil seal 64 inserted between the transmission case 12 and the manual shaft 58 prevents oil from reaching the foam seal material 70.

When the transmission 10 is shipped, a leak test is performed to determine whether oil is leaking from inside the transmission 10. In the leak test, it is determined whether an airtight leak is detected when pressure is applied from inside the transmission 10. If the transmission case 12 and the housing 16 are in a tight contact state due to the foamed seal material 70, it becomes difficult to detect the airtight leak. In contrast, the foamed seal material 70 is configured to be in close contact with the first seal surface 74 of the transmission case 12 when a predetermined amount of heat or more is applied to the foamed seal material 70. The foamed seal material 70 is composed of a foam whose main component is, for example, EPDM rubber (ethylene propylene diene rubber). When heat is applied to the foamed seal material 70, the foamed seal material 70 softens and enters into the minute irregularities formed on the first seal surface 74, so that the foamed seal material 70 and the first seal surface 74 are in close contact with each other. Furthermore, once the foam sealant 70 penetrates into the minute irregularities formed on the first seal surface 74, the tight contact is maintained even when heat is no longer applied.

Here, heat is applied to the foamed sealant 70 after the transmission 10 is shipped. Specifically, the heat generated while the vehicle is running after the shipment of the transmission 10 causes the foamed sealant 70 to adhere to the first seal surface 74. In other words, since no heat is applied to the foamed sealant 70 at the time the leak test is performed, the foamed sealant 70 and the first seal surface 74 are not in close contact and are not airtight between them. Note that the foamed sealant 70 and the second seal surface 76 are previously bonded together with an adhesive to create an airtight seal.

As a result, when the transmission 10 is shipped, the foam seal material 70 and the first seal surface 74 are in contact with each other but are not in tight contact with each other, allowing air to pass through a small gap formed between the foam seal material 70 and the first seal surface 74. Therefore, if there is an air leak in the transmission 10 during a leak test, the air leaking from inside the transmission 10 will leak out from between the foam seal material 70 and the first seal surface 74, and the occurrence of the air leak will be detected. This allows the leak test to be carried out optimally.

After the transmission 10 is shipped, a predetermined amount of heat or more is applied to the foam seal material 70 as the vehicle travels, so that the foam seal material 70 and the first seal surface 74 are brought into close contact with each other, preventing the intrusion of water from the outside. In this way, the heat generated during the vehicle travel is applied to the foam seal material 70, so that the foam seal material 70 and the first seal surface 74 are brought into close contact with each other, so that even if the surface of the first seal surface 74 is uneven, the contact surfaces of the two can be brought into close contact with each other without any gaps by applying heat. Even if the distance between the transmission case 12 and the housing 16 of the actuator 14 is not accurate, the foam seal material 70 is softened by applying heat to the foam seal material 70, and the foam seal material 70 penetrates into the unevenness formed on the surface of the first seal surface 74, so that the foam seal material 70 and the first seal surface 74 can be reliably brought into close contact with each other.

As described above, according to this embodiment, the foam sealant 70 inserted in the gap between the transmission case 12 and the actuator case 19 is configured to seal the transmission case 12 and the actuator case 19 when a predetermined amount of heat or more is applied, so that the foam sealant 70 is sealed to the transmission case 12 and the actuator case 19 by applying heat to the foam sealant 70, preventing water from entering from the outside. In addition, when heat is not applied to the foam sealant 70, air is allowed to leak from between the foam sealant 70 and the transmission case 12 and the actuator case 19, making it possible to perform a leak test.

The above describes an embodiment of the present invention in detail with reference to the drawings, but the present invention can also be applied in other aspects.

For example, in the above embodiment, the foam sealant 70 is a foam whose main component is EPDM rubber, but the present invention is not necessarily limited to this. Specifically, any sealant that has the property of being softened by heat applied during driving and being able to adhere closely to the sealing surface may be used.

In the above embodiment, the foamed seal material 70 is fitted into the minute irregularities formed on each seal surface 74 of the first tubular portion 62 without any special processing on the first seal surface 74, and is thereby brought into close contact with each seal surface 74. However, each seal surface 74 may be processed to actively form irregularities, and the foamed seal material 70 may be brought into close contact with the first seal surface 74. For example, each seal surface 74 may be processed to form irregularities large enough to be visible to the naked eye.

In the above embodiment, the foam seal material 70 and the second seal surface 76 are bonded in advance with an adhesive, but it is not necessary to bond the foam seal material 70 and the second seal surface 76 with an adhesive. The foam seal material 70 and the second seal surface 76 may be bonded together by applying a predetermined amount of heat or more between them. In this case, air will leak from between the foam seal material 70 and the second seal surface 76 during the leak test. Alternatively, the foam seal material 70 and the first seal surface 74 may be bonded in advance with an adhesive, and the foam seal material 70 and the second seal surface 76 may be bonded together by applying a predetermined amount of heat or more between them.

Note that the above is merely one embodiment, and the present invention can be implemented in various forms with various modifications and improvements based on the knowledge of those skilled in the art.

8: Shift switching device 10: Transmission 12: Transmission case 14: Actuator 19: Actuator case 58: Manual shaft 63: Through hole 70: Foam seal material (sealing member)

Claims (1)

A shift switching device including: a manual shaft having one end accommodated in a transmission case and the other end protruding from the transmission case toward the outside, the manual shaft rotating to switch a shift range of a transmission; an actuator attached to the outside of the transmission case for rotating the manual shaft; and an actuator case which is a housing for the actuator,
A seal member is inserted in a gap formed between the transmission case and the actuator case,
The seal member is configured to come into close contact with the transmission case and the actuator case when a predetermined amount of heat or more is applied to the seal member.

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