Shifting device

Abstract

To provide a shift device having a highly reliable shift function in a simple construction.SOLUTION: A shift device S includes a casing in which there are provided a motor M, a speed reduction gear train engaged with a rotary shaft of the motor M, a first sector gear SG1 provided on the final gear shaft of the speed reduction gear train, where a tooth lacking area T0 having driving teeth T1 in part and having no driving teeth T1 is formed as a circular-arc-shaped edge of which the diameter is equal to or longer than the diameter of a pitch circle of the driving teeth T1, a second sector gear SG2 engaged with the driving teeth T1, and having driven teeth T2 of which the number is the same as the number of the tooth bottoms of the driving teeth T1, for enabling the side of the driven teeth T2 to abut on the tooth lacking area T0 with the rotation of the driving teeth T1 in the state that the driven teeth T2 are disengaged from the driving teeth T1, and an output shaft A4 to which the second sector gear SG2 is journaled.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The shift device according to the present invention relates to a device that drives an output shaft by a motor and switches the output shaft to a plurality of shift positions and holds the same. [Background technology]

[0002] Conventionally, an example of such a shift device is shown in Patent Document 1 (see paragraphs

[0009] ,

[0017] to

[0020] and Figures 1, 3 and 4).

[0003] This technology is a device for switching the driving range of an automatic transmission, and includes a switching valve operating means for operating a shift range switching valve, a detent mechanism for holding the switching valve operating means at each shift position, a drive motor for driving the switching valve operating means, a power transmission means having a missing tooth gear provided between the drive motor and the switching valve operating means, a shift range operating means, and a motor control means for controlling the drive motor based on a signal from the shift range operating means.

[0004] In this device, when the motor control means determines that there has been a change in the shift position based on a signal from the shift range operation means, it drives the drive motor to rotate the missing tooth gear toward the shift position selected by the shift range operation means. The missing tooth gear drives the switching valve operation means via the power transmission means only when switching ranges, and switches the switching valve between each shift position. When the switching operation is completed, the area of ​​the missing tooth gear where there is no gear faces the downstream reduction gear, disengaging the two, and the connection between the drive motor and the range switching valve operation means is released. As a result, the switching valve operation means is positioned and held at each shift position only by the action of the detent mechanism, and the connection with the drive motor is cut off.

[0005] In this way, in the conventional device, the missing tooth gear drives the switching valve operating means until the position of the switching valve operating means approaches the vicinity of each shift position. However, when the switching valve operating means is biased and positioned at each shift position by the detent mechanism, the meshing of the missing tooth gear is released.

[0006] This simplifies the configuration of the shift device, and in particular eliminates the need for precise control of the drive motor to position the switching valve operating means at each shift position, and also eliminates the need for complex control routines for the drive motor, resulting in cost benefits. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2000-249223 A Summary of the Invention [Problem to be solved by the invention]

[0008] The partly-toothed gear in the above-mentioned conventional shift device is a normal gear with teeth removed from four circumferential regions. Therefore, when the partly-toothed gear is out of mesh with the downstream reduction gear, the tips of the teeth of the reduction gear are spaced apart from the surface of the partly-toothed gear, allowing the two gears to rotate freely relative to one another.

[0009] If there is backlash between the two gears, or if there is an assembly error, the missing tooth gear will not mesh properly with the reduction gear when the next shift position is changed, causing the shift device to malfunction.

[0010] In this way, while the conventional shift device has a simplified device structure, there are still problems to be solved, such as insufficient reliability of the device, etc. In view of the above circumstances, there has been a demand for a shift device that has a simple structure and a highly reliable shift function. [Means for solving the problem]

[0011] (Features) The characteristic configuration of the shift device according to the present invention is as follows: Casing, A motor; a reduction gear train meshed with a rotary shaft of the motor; a first sector gear provided on a final gear shaft of the reduction gear train, the first sector gear having drive teeth on a portion thereof and a toothless region where the drive teeth are not formed formed as an arc-shaped edge having a diameter equal to or larger than a diameter of a pitch circle of the drive teeth; The driven teeth are engaged with the driving teeth and have the same number of tooth bases as the driving teeth, and when the driven teeth are disengaged from the driving teeth due to rotation of the driving teeth, the side of the driven teeth abuts against the toothless region. and the first sector gear is allowed to rotate freely. A second sector gear; and an output shaft on which the second sector gear is journalled.

[0012] (effect) With this configuration, when the first sector gear rotates a predetermined angle, the second sector gear disengages from the gear, and the driving force of the motor is not transmitted to the output shaft. After this, the first sector gear can rotate further, but the second sector gear remains stationary. Therefore, for example, by setting the rotational position of the second sector gear at which it disengages from the first sector gear as the desired shift position, the second sector gear can be set to the shift position by rotating the first sector gear by more than a predetermined angle during a shift operation. This eliminates the need for highly accurate rotation control of the motor during a shift operation.

[0013] Also, if the shift position is obtained by over-rotating the first sector gear to a certain extent, after the shift operation, the first sector gear can rotate a predetermined angle in either direction without affecting the rotation of the second sector gear. If the direction of rotation can be confirmed by slightly rotating the motor in either direction prior to the next shift operation, there is no need to constantly store the state of the motor. This simplifies the drive control of the motor, and makes it possible to obtain an inexpensive shift device.

[0014] Furthermore, in this configuration, the rotation of the motor is transmitted to the output shaft via a reduction gear train, making it possible to reduce the size of the motor, thereby enabling further cost reduction.

[0015] (Features) The shift device according to the present invention advantageously includes regulating portions disposed on both sides of the swing range of the second sector gear and abutting against a part of the second sector gear to regulate the swing of the second sector gear when the driven teeth are out of mesh with the driving teeth.

[0016] (effect) By providing the regulating unit as in this configuration, the rotational phase of the second sector gear can be determined simply by driving the first sector gear until it disengages from the second sector gear. Therefore, there is no need to precisely grasp the rotational phase of the first sector gear when driving the first sector gear, and it is possible to specify an accurate shift position while simplifying the drive control of the motor.

[0017] (Features) The shift device according to the present invention can be configured such that the regulating portion is made of an elastic member and that when the second sector gear is in contact with the toothless region, the regulating portion elastically deforms upon contact with the second sector gear.

[0018] (effect) With this configuration, when the second sector gear is at the end point of its swing range, it is sandwiched between the toothless region of the first sector gear and the elastically deformed restricting portion, so the rotational phase of the second sector gear is maintained without rattle. Also, when the second sector gear abuts against the restricting portion, the elastic deformation of the restricting portion suppresses the generation of abnormal noise, resulting in a high-quality shift device.

[0019] Furthermore, since the second sector gear fixed in the shift position is constantly subjected to an elastic repulsive force from the restricting portion, the driven teeth can be actively pressed against the driving teeth of the first sector gear during the next shift operation, thereby ensuring re-engagement of the driving teeth and the driven teeth during the shift operation and providing a shift device with good responsiveness.

[0020] (Features) In the shift device according to the present invention, a predetermined play can be provided in a mounting portion of the second sector gear relative to the output shaft in a rotational direction of the output shaft.

[0021] (effect) With this configuration, for example, when there is a misalignment between the shift position of the transmission connected to the shift device and the swing position of the second sector gear when it disengages from the first sector gear, the output shaft can further rotate relative to the second sector gear. Therefore, even if there are manufacturing errors or assembly errors of the components, or even if there are installation errors of the shift device itself, the transmission can be moved to a desired shift position, and a shift device that is easy to install in a vehicle can be obtained. [Brief description of the drawings]

[0022] [Figure 1] FIG. 1 is a schematic diagram showing a configuration of a shift device according to the present invention; [Diagram 2] FIG. 1 is a cross-sectional plan view showing a configuration of a shift device according to the present invention; [Diagram 3] FIG. 1 is a side cross-sectional view showing a configuration of a shift device according to the present invention. [Figure 4] FIG. 13 is an explanatory diagram showing a linked operation mode between the output shaft and the holding mechanism. [Diagram 5] FIG. 1 is an explanatory diagram showing an operation mode of a shift device; [Figure 6] FIG. 1 is an explanatory diagram showing the configuration of a shaft holding member; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] (overview) The shift device S according to the present invention is particularly attached to a vehicle transmission or the like, and aims to realize a shift position switching operation and a holding operation with a simple structure. The shift device S is configured to include a casing C1 and a casing C2 that are combined with each other to form an exterior, a base part C3 that is provided inside these and holds components, a motor M that is provided inside the casings C1 and C2 and drives the shift position switching, a reduction gear train that meshes with a motor gear G1 of the motor M, an output shaft A4 that is located at the final stage of the reduction gear train and applies a driving force to the transmission, etc. These components are mainly provided between the base part C3 and the casing C1.

[0024] Also provided are a control board E that drives and controls the motor M, a rotation angle sensor D that detects the rotation angle of the output shaft A4, and the like. The control board E and the like are mainly provided between the base portion C3 and the casing C2. Hereinafter, various embodiments of the shift device S of the present invention will be described with reference to Figs. 1 to 6.

[0025] (Overall composition) The configuration of a shift device S according to the present invention is shown in Fig. 1 to Fig. 3. In the shift device S of this embodiment, a motor M drives a reduction gear train, and the rotational driving force is transmitted to an output shaft A4 of the final stage to determine a shift position. At that time, the connection between the reduction gear train and the output shaft A4 is separated. That is, the driving force of the motor M is utilized to change the shift position, and once the shift position has been determined, the shift position is maintained by the mechanical components excluding the motor M.

[0026] As shown in Figs. 1 to 3, the rotational force generated by the drive of the motor M is transmitted to the third shaft A3 via the first shaft A1 and the second shaft A2, which are the motor shafts. The third shaft A3 is the final gear shaft of the reduction gear train. The rotational force of the third shaft A3 is further transmitted to the fourth shaft A4, i.e., the output shaft A4. In this embodiment, the first sector gear SG1 is provided on the third shaft A3, and the second sector gear SG2 is provided on the output shaft A4. The second shaft A2, the third shaft A3, and the fourth shaft A4 are supported at both ends by the base part C3 and the casing C1, as shown in Fig. 3. In addition, a rotation angle sensor D for measuring the rotation angle of the fourth shaft A4 is provided on the end of the fourth shaft A4.

[0027] (1st sector gear) The first sector gear SG1 has drive teeth T1 in a portion of the circumferential direction, and a toothless region T0 without drive teeth T1 in the other portion. Four drive teeth T1 are shown in FIG. 2. However, the number of teeth is arbitrary. The contour of the toothless region T0 is a simple circle. The diameter of the toothless region T0 can be set to any dimension as long as the teeth of the second sector gear SG2 abut against the outer periphery of the toothless region T0 when the second sector gear SG2 is out of mesh with the driven teeth T2 of the second sector gear SG2, and the rotation of the second sector gear SG2 is restricted. The diameter of the toothless region T0 in this embodiment is set to a dimension slightly larger than the pitch circle of the drive teeth T1, for example.

[0028] (Second sector gear) In this embodiment, the second sector gear SG2 has, for example, five driven teeth T2. That is, the number of driven teeth T2 is set to be the same as the number of tooth bottoms of the drive teeth T1. After the drive teeth T1 rotate and the end teeth of the driven teeth T2 disengage from the drive teeth T1, the side of the driven tooth T2 at the end abuts against the toothless region T0 of the first sector gear SG1, and the posture of the second sector gear SG2 is maintained.

[0029] (Regulations Department) 2, on both sides of the swing range of the second sector gear SG2, there are provided regulating parts B for maintaining the position of the second sector gear SG2 in a predetermined position after it has disengaged from the first sector gear SG1. The regulating parts B are made of, for example, a rubber material or a resin material having elasticity.

[0030] The restriction portion B is installed, for example, so that the second sector gear SG2 receives a rotational force from the first sector gear SG1, rotates in either the left or right direction, and just before disengaging from the first sector gear SG1, the side of the second sector gear SG2 abuts against the restriction portion B. According to this configuration, the second sector gear SG2, which has disengaged from the first sector gear SG1 and is in a restricted state, is clamped between the toothless region T0 of the first sector gear SG1 and the restriction portion B.

[0031] As a result, regardless of the rotation speed of the first sector gear SG1, for example, the disengaged second sector gear SG2 is reliably maintained in its swinging position by the regulating portion B. Therefore, the rotation angle of the motor M may overshoot to some extent, which simplifies the drive control of the motor M.

[0032] In this maintained state, it is desirable that the regulating portion B is slightly elastically deformed. In this case, the second sector gear SG2 is securely clamped without rattle between the toothless region T0 and the regulating portion B, and the maintained posture becomes more stable. In addition, the elastic deformation of the regulating portion B reduces the impact noise when the second sector gear SG2 abuts against the regulating portion B.

[0033] Furthermore, since the restricting portion B holds the second sector gear SG2 while elastically deforming, when the first sector gear SG1 is rotated to change the shift position next time, the driven teeth T2 of the second sector gear SG2 are pressed against the driving teeth T1 of the first sector gear SG1, ensuring re-engagement of both teeth. This makes the operation of the shift device S quick and reliable.

[0034] In addition, since the drive teeth T1 and the driven teeth T2 are disengaged while the shift position is held, the first sector gear SG1 can be rotated a little more to allow the first sector gear SG1 to rotate freely relative to the second sector gear SG2. Therefore, for example, the motor M can be configured as a brushless motor or the like, and this free-rotating state can be actively utilized. In other words, the rotation direction of the motor M can be detected by rotating the motor M alternately in the clockwise and counterclockwise directions prior to driving the motor M. Therefore, it is not necessary to constantly store the state of the shift device S in memory, and a simpler shift device S can be obtained.

[0035] (Shift position retention mechanism) As shown in Fig. 1 and Fig. 4, a shift position retaining mechanism H is provided on one end of the output shaft A4. The retaining mechanism H is mainly composed of a switching plate H1 with a shift position cutout and a pressing member H2 that fits into the switching plate H1, and is configured as a so-called detent mechanism. These retaining mechanisms H are provided on the transmission side, for example. However, the retaining mechanism H may be provided inside the shift device S by appropriately setting the size, etc. of the retaining mechanism H.

[0036] 1, 2, 4 and 5, the second sector gear SG2 and the holding mechanism H are shown in a schematic manner to facilitate understanding of the manner in which they are linked together. An actual shift device S has a configuration as shown in Fig. 3, for example, and the holding mechanism H is provided at the tip of a shaft member A5 extending downward in Fig. 3 from the fourth shaft A4.

[0037] The switching plate H1 is fixed to a shaft member A5 extending from the output shaft A4 and is rotatable together with the output shaft A4. The end of the shaft member A5 is formed with a male part having a track-shaped cross section as shown in Fig. 4, for example, and this end engages with a female part also having a track shape provided on the output shaft A4.

[0038] The switching plate H1 of this embodiment has two notches K on its edge. One notch K1 (for example, the left side in FIG. 4) defines the parking position, and the other notch K2 (for example, the right side in FIG. 4) defines the parking release position.

[0039] For example, a long pressing member H2 is fitted to the switching plate H1. The pressing member H2 is made of a rod-shaped or plate-shaped spring member, and when the pressing member H2 is given a predetermined deflection, the fitting portion H21 at the tip is fitted into the notch K. In this fitted state, no play is generated between the fitting portion H21 and the notch K, and the rotational phase of the switching plate H1, i.e., the output shaft A4, is fixed and held.

[0040] In addition to the notches K1 and K2, other notches K that define the drive position, neutral position, reverse position, etc. may be provided.

[0041] As shown in Fig. 4, the central angles from the bottom of the notch K1 and the bottom of the notch K2 of the switching plate H1 to the boundary part K3 located midway between them are θ1 and θ2, respectively. In this case, the drive angle θ3 at which the second sector gear SG2 rotates due to the drive of the first sector gear SG1 is (θ1 + θ2).

[0042] 3, the rotation angle of the second sector gear SG2 is measured by a rotation angle sensor D provided on the end of the fourth shaft A4 and on the control board E. The rotation angle sensor D is composed of, for example, a magnet D1 provided to rotate integrally with the fourth shaft A4, and a magnetic field detection sensor D2 provided on the control board E to detect the rotation of the magnet D1.

[0043] With this configuration, by alternately rotating the second sector gear SG2 by the drive angle θ3, the shift position can be reliably switched and the shift position of the second sector gear SG2 can be mechanically held. In other words, if the second sector gear SG2 is rotated by the drive angle θ3 by driving the first sector gear SG1 and then the first sector gear SG1 is further rotated to release the meshing with the second sector gear SG2, the shift position is held only by the function of the holding mechanism H. With this configuration, the shift position can be determined without controlling the rotational drive of the motor M with high precision, and a shift device S with a simple configuration and low cost can be obtained.

[0044] However, the drive angle θ3 does not necessarily match the sum of the central angles (θ1+θ2) of the notches K1 and K2 due to manufacturing errors, assembly errors, etc. of the first sector gear SG1 and the second sector gear SG2. In addition, by utilizing the biasing function of the switching plate H1 by the pressing member H2, the drive angle θ3 of the second sector gear SG2 can also be set to be less than the sum of the central angles (θ1+θ2).

[0045] Therefore, in order to determine each shift position more rationally, in this embodiment, as shown in FIG. 4, a play is provided between the second sector gear SG2 and the output shaft A4 in the rotational direction, and the output shaft A4 is configured to rotate with play by an angle θ4.

[0046] Since the output shaft A4 has the play angle θ4 in this way, the drive angle θ3 of the second sector gear SG2 is set as follows. That is, θ3>θ1+θ4 and θ3>θ2+θ4 Condition 1 Let us assume that.

[0047] In order to change the fitting position of the fitting portion H21 from the notch K1 to the notch K2, the switching plate H1 must rotate so that the fitting portion H21 passes over the boundary portion K3. For this purpose, for example, the following driving mode is conceivable. That is, the second sector gear SG2 rotates and first absorbs the play angle θ4, and from this point, the driving rotation of the switching plate H1 begins. After this, if the switching plate H1 is further rotated by θ1 and the fitting portion H21 passes over the boundary portion K3, the biasing state of the fitting portion H21 relative to the switching plate H1 changes, and the switching plate H1 can further rotate by the play angle θ4. As a result, it is sufficient if the fitting position of the fitting portion H21 settles on the notch K2. Therefore, the angle condition of θ3 is specified as in conditional formula 1. This is also true when changing from the notch K2 to the notch K1.

[0048] Another condition is stipulated for the fitting portion H21, which has overcome the boundary portion K3, to settle into the destination notch K1 or notch K2. That is, the second sector gear SG2 must first rotate by the drive angle θ3, and then the switching plate H1 must rotate by the play angle θ4 to reach the sum of the central angles of the notches K1 and K2 (θ1+θ2). Therefore, θ3+θ4>θ1+θ2 Conditional expression 2 must be met.

[0049] If the configuration satisfies conditional expressions 1 and 2, the controllable range of the rotation angle of the first sector gear SG1 by the motor M becomes wider, and drive control becomes even simpler. Moreover, the shift position is determined entirely by the holding mechanism H and is not affected by rotation error of the motor M, so the holding position of the output shaft A4 is always the same.

[0050] Fig. 5 shows an operation mode of the shift device S of this embodiment. Fig. 5(a) shows a state in which the drive tooth T1 of the first sector gear SG1 and the driven tooth T2 of the second sector gear SG2 are disengaged, and the second sector gear SG2 is in contact with one of the restricting portions B. In this state, the fitting portion H21 fits into the notch K2 of the switching plate H1, and the shift position is set to the parking release position.

[0051] After the first sector gear SG1 disengages from the second sector gear SG2, it rotates another 90 degrees clockwise in the figure and remains stationary. The restricting portion B is slightly elastically deformed, and the second sector gear SG2 is held in position by contacting the restricting portion B and the toothless region T0 of the first sector gear SG1. At this time, there is play between the second sector gear SG2 and the output shaft A4 as shown in Figure 4, and the repulsive force from the restricting portion B is not input to the output shaft A4.

[0052] Fig. 5(b) shows the state in which the first sector gear SG1 is driven to rotate counterclockwise to switch the shift position, and the drive teeth T1 begin to mesh with the driven teeth T2. At this time, the second sector gear SG2 is urged downward in the figure by the elastic force of the regulating portion B, and actively meshes with the drive teeth T1 of the first sector gear SG1. This starts the rotation of the output shaft A4. The play between the second sector gear SG2 and the output shaft A4 is eliminated to the state in which the switching plate H1 is urged counterclockwise by the fitting portion H21.

[0053] In addition, Fig. 5(b) shows a state where the repulsive force of the regulating portion B is completely released and there is a gap between the regulating portion B and the second sector gear SG2. However, it is sufficient that the repulsive force is released, and it is acceptable for the two to be in slight contact. Also, the repulsive force of the regulating portion B may remain to an extent that does not affect the strength of the meshed teeth, and there may be no gap. In this case, re-engagement between the first sector gear SG1 and the second sector gear SG2 is more reliable.

[0054] 5(c) shows the state in which the second sector gear SG2 is driven by the first sector gear SG1. In this state or in a subsequent state, the fitting portion H21 climbs over the boundary portion K3 of the switching plate H1. When climbing over, the contact surface of the switching plate H1 by the fitting portion H21 is shifted to the side of the notch K1, so that the output shaft A4 rotates clockwise relative to the second sector gear SG2, thereby reversing the direction of the play blockage.

[0055] 5(d) shows the state after the second sector gear SG2 is driven to rotate by the first sector gear SG1 and the fitting portion H21 moves to the notch K1. The fitting portion H21 is forced to move toward the valley of the notch K1 by the biasing force of the pressing member H2, but the fitting portion H21 has not yet reached the bottom of the notch K1 because the first sector gear SG1 and the second sector gear SG2 remain in mesh with each other.

[0056] In Fig. 5(d), the second sector gear SG2 is not yet in contact with the regulating portion B. However, as in Fig. 5(b), the two may be in slight contact. The regulating portion B may start to generate a repulsive force to an extent that does not affect the strength of the meshed teeth, and there may be no gap between the two. In this case, re-meshing between the first sector gear SG1 and the second sector gear SG2 is more reliable.

[0057] 5(e) shows the state where the driven teeth T2 of the second sector gear SG2 are disengaged from the driving teeth T1 of the first sector gear SG1, and the side surface of the second sector gear SG2 is pressed against the other regulating part B. At the moment where the second sector gear SG2 is disengaged from the first sector gear SG1, the fitting part H21 moves toward the bottom of the notch K1, and the output shaft A4 and the switching plate H1 settle at the bottom of the notch K1 by making use of the play angle θ4. In this state, the output shaft A4 is held in the parking position, that is, the notch K1, by only mechanical elements.

[0058] (Shaft holding member for rotating shaft) FIG. 6 shows a holding structure for the second shaft A2 and the third shaft A3, which are connected to the first shaft A1 of the motor M, in the reduction gear train.

[0059] In this embodiment, in order to simplify the structure, the second shaft A2 and the third shaft A3 are assumed to be cantilevered on the base part C3. Therefore, when transmitting the driving force of the motor M, these shafts may be slightly tilted, which may reduce the efficiency of transmitting the driving force. As shown in Fig. 6, the respective shaft ends of the second shaft A2 and the third shaft A3 are connected to each other by a stiffening plate P, and the stiffening plate P is fixed in position by the casing C1.

[0060] The stiffening plate P is a long, flat member having an axial hole P1 into which the axial ends of the second shaft A2 and the third shaft A3 are inserted. The second shaft A2 and the third shaft A3 are rotatable within the axial hole P1. Providing such a stiffening plate P makes it possible to prevent the axial distance between the second shaft A2 and the third shaft A3 from increasing.

[0061] In addition, since the second and third shafts A2 and A3 and the first and output shafts A1 and A4 of the motor M are arranged in a substantially straight line as shown in FIG. 2, there is a possibility that the second and third shafts A2 and A3 may tilt in the same direction at the same time when the motor M is driven. For example, tilt in a direction perpendicular to the line segment connecting the two shafts is a concern. Therefore, as shown in FIG. 6, a recess C11 into which the stiffening plate P fits is provided on the inner surface of the casing C1. The shape of the recess C11 corresponds to the outline of the stiffening plate P, and in particular, the distance from the long side edge of the stiffening plate P is set narrow.

[0062] By preventing tilting of the second shaft A2 and the third shaft A3 in this manner, the meshing state between the second gear G2 of the second shaft A2 and the motor gear G1 of the first shaft A1 (motor shaft), or the meshing state between the first sector gear SG1 of the third shaft A3 and the second sector gear SG2 of the fourth shaft A4 (output shaft A4) is maintained appropriately, thereby maintaining the efficiency of transmission of driving force.

[0063] The attachment of the stiffening plate P is also effective from the viewpoint of durability of the shift device S. The shift device S is installed in, for example, an automatic transmission (AT), and when switching the shift state of the AT, an impact may act on the shift device S as a reverse input from the AT. At that time, if the stiffening plate P maintains the meshing state of each gear G in a healthy state, collisions between the gears G are avoided, and the strength reduction and fatigue of the gears G are less likely to occur. This improves the durability of the shift device S.

[0064] In addition, by using the stiffening plate P, the durability of the bearing can be improved. If the casing C1 is made of aluminum or the like and the ends of the shafts are held by shaft holes C12 individually formed in the casing C1 as shown in FIG. 3, the shaft holes C12 will expand in diameter early due to friction with the rotating shafts. However, by forming the stiffening plate P from a relatively hard material such as steel, the expansion of the shaft holes C12 can be prevented. Even if the casing C1 is made of aluminum or the like, the wall of the recess C11 can abut against a region of a predetermined length of the edge of the stiffening plate P. Therefore, even if the casing C1 frequently abuts against the stiffening plate P, wear of the casing C1 will be less likely to occur.

[0065] Furthermore, by using the stiffening plate P, the assembly work of the shift device S is made more efficient. For example, when the ends of the shafts are held by shaft holes C12 individually formed in the casing C1 as shown in FIG. 3, the posture of each shaft is likely to change when the casing C1 is attached to the base part C3, making the alignment of each shaft complicated. In this regard, by fixing the relative positions of the multiple shafts in advance using the stiffening plate P, the distance between the shaft ends is adjusted and the arrangement posture of each shaft relative to the base part C3 is stabilized. Therefore, the subsequent attachment of the casing C1 becomes extremely easy, improving the efficiency of the assembly work. [Industrial Applicability]

[0066] The shift device of the present invention can be widely used, for example, in devices that drive an output shaft by a motor and switch and hold the output shaft at a number of shift positions. [Explanation of symbols]

[0067] A4 Output shaft B Regulatory Department C1 Casing Medium motor S shift device SG1 1st sector gear SG2 Second sector gear T0 Missing tooth area T1 Driving Teeth T2 driven tooth

Claims

1. Casing, A motor; a reduction gear train meshed with a rotary shaft of the motor; a first sector gear provided on a final gear shaft of the reduction gear train, the first sector gear having drive teeth on a portion thereof and a toothless region where the drive teeth are not formed being formed as an arc-shaped edge portion having a diameter equal to or larger than a diameter of a pitch circle of the drive teeth; a second sector gear that meshes with the drive teeth, has driven teeth in the same number as the number of tooth bases of the drive teeth, and when the drive teeth rotate and the driven teeth are disengaged from the drive teeth, a side portion of the driven tooth abuts against the toothless region, allowing the first sector gear to rotate freely; an output shaft on which the second sector gear is journalled; and

2. 2. The shift device according to claim 1, further comprising a restricting portion disposed on each side of the swing range of the second sector gear, the restricting portion contacting a portion of the second sector gear to restrict the swing of the second sector gear when the driven teeth are not engaged with the driving teeth.

3. 3. The shift device according to claim 2, wherein the restricting portion is an elastic member, and is configured to be elastically deformed by contact with the second sector gear when the second sector gear is in contact with the toothless region.

4. 4. The shift device according to claim 1, wherein a predetermined play is provided in a mounting portion of the second sector gear relative to the output shaft in a rotational direction of the output shaft.

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