Power transmission device

Abstract

The power transmission device (1) has a sun gear (7), a ring gear (8), a pinion (9) and a planet carrier (10), wherein the input member (4) is connected to the sun gear (7), the ring gear (8) is fixed to a specified part (11), the output member is connected to the planet carrier (10), a part of the outer circumferential side of the pinion (9) becomes a protruding part protruding to the outer circumferential side of the planet carrier (10), a clamping part (17) is formed in the side surface of the protruding part, a clamping plate (18) moving forward and backward towards the side surface is arranged in a state integrated with the specified fixed part (3) in the rotation direction of the planet carrier (10), and the clamping plate (18) is provided with a clamped part (19) clamped with the clamping part (17) in the rotation direction of the pinion (10).

Description

Technical Field

[0001] This utility model relates to a device for transmitting power via a gear mechanism, and in particular to a power transmission device mainly composed of a planetary gear mechanism with a locking mechanism. Background Technology

[0002] Such power transmission devices are described in Patent Documents 1-3. The devices described in Patent Documents 1 and 2 are devices comprising a planetary gear mechanism disposed between independently driven left and right wheels, and a rotation limiting mechanism for restricting the rotation of the planetary gear mechanism to stop the rotation of the left and right wheels. The planetary gear mechanism consists of a sun gear, a ring gear, and a planetary carrier that holds the pinions disposed between the sun gear and the ring gear. As a rotation limiting mechanism, a mechanism is disclosed that engages with the planetary carrier to restrict its rotation. Furthermore, Patent Document 3 describes a device that transmits the torque of a motor to the planetary gear mechanism of the final reducer via a reduction mechanism, and includes a parking lock mechanism that selectively engages with the ring gear as an output element to prevent the rotation of the ring gear and the wheel connected to it.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2018-054099

[0004] Patent Document 2: Japanese Patent Application Publication No. 2018-054098

[0005] Patent Document 3: Japanese Patent Application Publication No. 2009-040296

[0006] As described in Patent Documents 1-3, the planetary gear mechanism has multiple rotating elements, so by stopping the rotation of any one of them, the rotation of the entire planetary gear mechanism can be stopped, thus achieving a so-called parking lock. In the devices described in Patent Documents 1 and 2, a parking gear is formed on the outer periphery of the planetary carrier, and a parking pawl engages with the parking gear to restrict rotation. However, in the configurations described in Patent Documents 1 and 2, the torque applied to the planetary carrier is large, so the parking mechanism composed of the parking gear, parking pawl, etc., can potentially be made larger. In addition, since the parking mechanism is arranged adjacent to each other in the axial direction of the planetary gear mechanism, the overall axial length (length along the direction of the rotation center axis) of the power transmission device becomes longer. Furthermore, in the configuration described in Patent Document 3, the rotation of the gear ring is restricted by the parking mechanism disposed on its outer periphery, so the number of components arranged in the axial direction of the planetary gear mechanism is reduced, and the shaft length can be shortened. However, in a power transmission device configured with the gear ring as a fixed element, the gear ring is originally fixed, so it cannot be used in such a power transmission device. Utility Model Content

[0007] This utility model was developed in response to the aforementioned technical issues, and its purpose is to provide a power transmission device that can reduce the torque required to limit or stop rotation, thereby simplifying the overall structure.

[0008] To achieve the above objectives, the power transmission device of this utility model comprises: a sun gear, which is an external gear; a ring gear, which is an internal gear arranged concentrically with the sun gear; a pinion, which is disposed between the sun gear and the ring gear in a state of meshing with the sun gear and the ring gear; and a planet carrier, which holds the pinion so that it can rotate on its own axis. The power transmission device is characterized in that the sun gear is connected to an input component, the ring gear is fixed at a predetermined position, the planet carrier is connected to an output component, a portion of the outer periphery of the pinion becomes a protrusion protruding towards the outer periphery of the planet carrier, an engaging portion is formed on the side of the protrusion, a locking plate that moves back and forth toward the side is provided in a state of being integrated with a predetermined fixing portion in the rotation direction of the planet carrier, and the locking plate is provided with an engaging portion that engages with the engaging portion in the rotation direction of the pinion.

[0009] According to this invention, when the locking plate moves towards the pinion, the engaging portion of the locking plate engages with the engaging portion of the pinion. Since the locking plate is fixed to the designated fixed portion in a non-rotatable manner, the rotation of the pinion is stopped. Because the gear ring meshing with the pinion is fixed at a designated position, the rotation of the planet carrier and the sun gear is stopped. That is, it becomes locked. In this case, the torque applied to the pinion to stop the rotation of the sun gear and planet carrier is smaller than the torque required to directly stop the rotation of the sun gear and planet carrier, since the pinion is located on the outer periphery of the sun gear and has a small diameter. Accordingly, the locking plate, the engaging portion, or the engaging portion can be miniaturized. Furthermore, since the locking plate can be located on the outer periphery of the planet carrier, in other words, it does not need to be arranged coaxially with the sun gear. Therefore, an increase in the number of components arranged on the same axis can be avoided, thereby preventing or suppressing an increase in the overall shaft length of the device or a larger device size. Attached Figure Description

[0010] Figure 1 This is a cross-sectional view showing one embodiment of the present invention.

[0011] Figure 2 This is a front view showing the shape of the pinion blade as the engaging part provided on the side of the pinion. (a) shows a rectangular pinion blade, (b) shows a pinion blade in the shape of a round pin, and (c) shows a pinion blade in the shape of an inclined rectangular pinion.

[0012] Figure 3 This is the front view of the parking brake.

[0013] Figure 4 It is a schematic front view showing the state in which the parking vane engages with the pinion vane, stopping the rotation of the pinion.

[0014] Figure 5 This is a cross-sectional view showing examples of chamfers formed on the parking blades and pinion blades.

[0015] Explanation of reference numerals in the attached figures

[0016] 1…Power transmission device; 2…Planetary gear mechanism; 3…Motor housing; 4…Sun gear shaft; 5…Blocking section; 6, 12, 13…Bearings; 7…Sun gear; 8…Ring gear; 9…Pinus gear; 10…Planet carrier; 10a…Side wall section; 10b…Side wall section; 10c…Bridge section; 11…Cover; 14…Pinus gear shaft; 15…Bearing; 16…Locking mechanism; 17…Pinus gear blade; 18…Parking plate; 19…Parking blade; 20…Actuator; 20a…Rod; 20b…Push rod; 21…Elastic element; C…Chamfer. Detailed Implementation

[0017] Next, embodiments of the present invention will be described with reference to the accompanying drawings. Furthermore, the embodiments described below are merely one example of implementing the present invention and do not limit the scope of the invention.

[0018] Figure 1 This is a cross-sectional view illustrating an example of an embodiment of the present invention. The power transmission device 1 shown here is configured as a reduction mechanism primarily consisting of a single pinion-type planetary gear mechanism 2. A sun gear shaft 4 is arranged at the center of the motor housing 3, which houses a motor or electric generator (hereinafter collectively referred to as a motor), which serves as a power source (not shown), so that it can rotate around its central axis. The sun gear shaft 4 corresponds to the input component in the embodiment of the present invention. It is supported by a bearing 6 mounted on a partition 5 located inside the motor housing 3, allowing it to rotate. A sun gear 7, serving as an external gear, is provided at the front end protruding from the bearing 6. The sun gear 7 can be integrally formed with the sun gear shaft 4, or it can be embedded into the sun gear shaft 4 as an integral unit.

[0019] The planetary gear mechanism 2 is a differential gear mechanism, comprising a sun gear 7, a ring gear 8 arranged concentrically with the sun gear 7 as an internal gear, and a planet carrier 10 as a rotating element that holds a pinion 9 disposed between the sun gear 7 and the ring gear 8 and meshes with the sun gear 7 and the ring gear 8. A cover 11 is installed at the open end of the motor housing 3, and the planetary gear mechanism 2 is disposed inside the hollow portion formed by the cover 11 and the aforementioned partition 5. Furthermore, the planet carrier 10 is held rotatably by a bearing 12 embedded in the inner surface of the cover 11. In addition, a bearing 13 is embedded in the center of the planet carrier 10, and the front end of the sun gear shaft 4 is supported by the bearing 13 to be rotatable. Moreover, the ring gear 8 is mounted on the inner surface of the cover 11. Therefore, the planetary gear mechanism 2 constitutes a reduction mechanism that uses the sun gear 7 as an input element, the ring gear 8 as a stationary element (or a reaction force element), and the planet carrier 10 as an output element. An output component (not shown) is connected to the planet carrier 10. In addition, the cover 11 corresponds to the specified part in the embodiments of this utility model.

[0020] like Figure 1 As shown, the planetary carrier 10 is generally cylindrical and includes: a first sidewall portion 10a, in which a bearing 12 is embedded on its outer periphery and a bearing 13 is embedded on its inner periphery; a second sidewall portion 10b, which is opposite to the first sidewall portion 10a in the direction of the rotational central axis (hereinafter sometimes simply referred to as the central axis) of the planetary gear mechanism 2; and a bridging portion 10c, which connects the outer peripheries of these sidewall portions 10a and 10b. Multiple bridging portions 10c are provided at certain intervals in the circumferential direction, thus the planetary carrier 10 has multiple openings that open outwards in the radial direction.

[0021] A pinion 9 is positioned corresponding to the opening. That is, the opening is such that a portion of the outer periphery of the pinion 9 protrudes towards the outer periphery of the planet carrier 10 to allow it to mesh with the ring gear 8. With a portion of its outer periphery protruding towards the outer periphery of the planet carrier 10, the pinion 9 is mounted to the planet carrier 10 via a pinion shaft 14. The pinion shaft 14 is mounted to the planet carrier 10 by engaging its two ends with the aforementioned sidewall portions 10a and 10b. A bearing 15 is fitted into the middle portion along the axial direction of the pinion shaft 14. By engaging the outer periphery of the bearing 15 with the pinion 9, the pinion 9 is held by the planet carrier 10 to rotate and revolve.

[0022] Next, the locking mechanism 16, which maintains the planetary gear mechanism 2 in a fixed state, will be described. For the power transmission device 1 mounted on the vehicle, the locking mechanism 16 functions as a parking mechanism, stopping the rotation of the output component (not shown) by restricting the rotation of the entire planetary gear mechanism 2. Figure 1In the embodiment of this invention shown, the configuration is to stop the rotation of the pinion 9. That is, as described above, a portion of the outer periphery of each pinion 9 protrudes towards the outer periphery of the planet carrier 10, and on the side of this protruding portion, a plurality of pinion blades 17, serving as engaging portions, are arranged at certain intervals along the circumferential direction of the pinion 9. Figure 1 In the example shown, the pinion blade 17 is, in summary, a protrusion whose shape can be adapted to suit different needs. For example, as... Figure 2 As shown in (a), it can also be a protrusion with a longer rectangular cross-sectional shape in the circumferential direction of the pinion 9. Or, as... Figure 2 As shown in (b), it can also be a so-called pin-shaped protrusion with a circular cross-section. Furthermore, as... Figure 2 As shown in (c), it can also be a rectangular cross-sectional shape, with a protrusion whose length direction is inclined at a predetermined angle relative to the circumferential direction (tangential direction) of the pinion 9. The pinion blade 17 is inclined in this way so that the rotation and revolution of the pinion 9 can scrape up the lubricating oil accumulated inside the motor housing 3, thereby improving the lubrication of bearings 6, 12, 13, etc. Therefore, the orientation and angle of the inclination of the pinion blade 17 can be appropriately determined based on the direction of the rotation and revolution of the pinion 9 when the planetary gear mechanism 2 rotates stably.

[0023] A parking plate 18, which is equivalent to a locking plate, is provided at a position opposite to the side of the pinion 9 on which the pinion blade 17 is provided. Figure 3 An example of a parking plate 18 is shown. The parking plate 18 is an arc-shaped plate with an inner diameter approximately equal to the outer diameter of the planetary carrier 10. It is disposed on the outer periphery of the planetary carrier 10 and splines into the inner surface of the motor housing 3, which corresponds to a designated fixed part. Therefore, the parking plate 18 serves as a guide surface on the outer periphery of the planetary carrier 10, moves back and forth toward the pinion 9 in the direction of the central axis, and is fixed relative to the direction of rotation.

[0024] A parking blade 19, serving as an engaging portion, is provided on the front side of the parking plate 18 facing the pinion 9. The parking blade 19 is used to hook onto the aforementioned pinion blade 17 in the rotational direction to limit the rotation of the pinion 9. Figure 3 As shown in one example, the shape is formed as a rectangular cross-section protrusion extending outward from the inner end of the parking plate 18 in the radial direction. That is, at least a portion of the parking blade 19 is opposite to the pinion blade 17 in the rotational direction. In addition, when multiple parking blades 19 are provided, the spacing between the parking blades 19 is such that when any pinion blade 17 is engaged with any parking blade 19, the other pinion blades 17 do not interfere with the other parking blades 19.

[0025] An actuator 20 is provided to move the parking plate 18 back and forth. The actuator 20 is a so-called linear actuator that moves a rod 20a back and forth using electromagnetic force, fluid pressure, or the like, and is mounted on the motor housing 3 on the back side of the parking plate 18. A push rod 20b is mounted on the rod 20a, facing the back of the parking plate 18. This push rod 20b is connected to the parking plate 18 via an elastic element 21, such as a coil spring. By providing this elastic element 21, the parking plate 18 can be retracted in the direction that compresses the elastic element 21.

[0026] The function of the locking mechanism 16 described above will be explained. Figure 1 This indicates that the pinion 9 has been released from its fixed state, and the parking plate 18 is moved backward away from the pinion 9 by the actuator 20. Therefore, the parking blade 19 provided on the parking plate 18 separates from the pinion blade 17 provided on the pinion 9, and their engagement is released, allowing the pinion 9 to rotate freely. If, in this state, the motor (not shown) rotates and inputs torque to the sun gear 7, causing it to rotate, the ring gear 8 is fixed, thereby causing the planet carrier 10 to rotate at a lower speed than the sun gear 7, and torque is output from the planet carrier 10. When the planetary gear mechanism 2 rotates, if the aforementioned pinion blade 17 is... Figure 2 As shown in (c), the pinion blade 17 scrapes up the lubricating oil, thus promoting the lubrication of bearings 6, 12, 13, etc.

[0027] On the other hand, for example, if the actuator 20 is activated according to a parking command to keep the vehicle in a stopped state, the lever 20a extends, and the push rod 20b and parking plate 18 move toward the pinion 9. As a result, if the parking blade 19 located on the front of the parking plate 18 enters between the pinion blades 17 located on the side of the pinion 9, the parking blades 19 and pinion blades 17 are opposite each other in the rotational direction. If the pinion 9 rotates, then... Figure 4 As shown, the two are in contact. That is, as Figure 4 As indicated by the circle, the pinion 9 stops rotating by abutting the parking blade 19 with the pinion blade 17. If the pinion 9 stops rotating, the planetary carrier 10 cannot rotate, thus fixing the planetary gear mechanism 2 as a whole. Therefore, for example, in a vehicle, with the planetary carrier 10 connected to a wheel (not shown) via an output component, the vehicle is kept in a parked state.

[0028] In this case, the motor housing 3 bears the torque for maintaining the vehicle in a stopped state via the pinion 9 and the parking plate 18. Stress acts on the pinion blade 17 of the pinion 9 and the parking blade 19 of the parking plate 18. This stress is caused by the torque at which the pinion 9 attempts to rotate, but for the torque acting on the pinion 9 based on the torque for maintaining the vehicle in a stopped state, since the pinion 9 has a small diameter and bears the torque on the outer periphery of the planetary gear mechanism 2, it becomes a relatively small torque. Therefore, the pinion blade 17, the parking blade 19, or the parking plate 18 do not require particularly high rigidity or strength. In this respect, these components and the locking mechanism 16 can be miniaturized, thereby miniaturizing the overall configuration of the power transmission device 1. Furthermore, the locking mechanism 16 can be provided on the outer periphery of the planetary carrier 10, so the number of components arranged coaxially with the sun gear 7 does not increase. Therefore, in this embodiment of the invention, the increase in the shaft length of the power transmission device 1 can be avoided or suppressed; in other words, a power transmission device 1 with a parking function and a shorter shaft length can be obtained.

[0029] Furthermore, if the parking plate 18 moves towards the pinion 9 while the pinion 9 is rotating, the parking blade 19 may sometimes be bounced back by the pinion blade 17, and the two may not engage, depending on the rotational speed of the pinion 9. This is caused by the compression of the elastic member 21 on the back side of the parking plate 18, resulting in a temporary retraction of the parking plate 18. This is to prevent the parking blade 19 from engaging abruptly with the pinion blade 17, which could cause impact or damage. Therefore, in order to reliably generate the so-called ratchet effect of the temporary bounce of the parking blade 19, it is preferable to have a configuration that converts the torque acting between the parking blade 19 and the pinion blade 17 into a thrust in the axial direction. For example, such as Figure 5 As shown, chamfer C is provided at the corners of the parking blade 19 and the pinion blade 17. The chamfer angle can be about 45 degrees, so that the chamfer C contacts each other, thereby generating a component force (axial thrust) in the axial direction. As a result, the parking blade 19 and the parking plate 18 on which the parking blade 19 is provided are pushed back. As a result, when the pinion 9 is rotating, the parking blade 19 and the pinion blade 17 can be prevented from or suppressed from engaging abruptly.

[0030] The above describes one embodiment of this utility model, but the utility model is not limited to the above embodiment. The engaging part and the engaged part in this utility model do not need to be both protruding parts; one can be a convex part and the other a concave part. Furthermore, the planetary gear mechanism in this utility model is not limited to a single-pinion type planetary gear mechanism; it can also be a double-pinion type planetary gear mechanism. Moreover, the power transmission device involved in this utility model is not limited to a power transmission device mounted on a vehicle; in short, any device that transmits the torque output from a power source such as a motor or engine to a specified output component is acceptable.

Claims

1. A power transmission device comprising: a sun gear, which is an external gear; a ring gear, which is an internal gear arranged concentrically with the sun gear; a pinion, which is disposed between the sun gear and the ring gear in a state of meshing with the sun gear and the ring gear; and a planet carrier for holding the pinion so that it can rotate on its own axis, characterized in that, The sun gear connection input component The gear ring is fixed at a designated location. The output component is connected to the planetary carrier. A portion of the outer periphery of the pinion becomes a protrusion that extends toward the outer periphery of the planet carrier. An engaging portion is formed on the side of the protrusion. The locking plate, which moves back and forth toward the side, is arranged to be integrated with the predetermined fixing part in the rotational direction of the planet carrier. The locking plate is provided with a locking part that engages with the locking part in the rotational direction of the pinion.

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