JP2005030430A - Transmission for electric vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transmission for an electric vehicle capable of performing forward drive and backward drive of two-speed, and performing the regenerative brake in braking without enlarging a transmission itself. <P>SOLUTION: This transmission for the electric vehicle is constituted to constantly connect a sun gear 15 with an input shaft 12 driven by a motor 11. An annular gear 16 is mounted outside of the sun gear 15, and a two-way clutch 23 for permitting or inhibiting the forward and backward rotation of the annular gear 16, is assembled in the annular gear 6. Planetary gears 17 engaged with the sun gear 15 and the annular gear 16, are mounted therebetween, and a carrier 19 connected with an output shaft 13 is mounted on the planetary gears 17. A frictional element 24 for switching the two-way clutch is mounted between the input shaft 12 and the two-way clutch 23. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a power transmission device for an electric vehicle equipped with a generator motor.
[0002]
[Prior art]
An electric vehicle includes a battery that stores electric power and a motor that drives driving wheels, and can travel by electric power from the charged battery. An electric vehicle has advantages in that it does not generate exhaust gas when traveling, has high energy efficiency, and can travel backward by reverse rotation of the motor. Such electric vehicles include a hybrid type equipped with a gasoline engine or a diesel engine in addition to a motor to improve the charging mileage. In particular, these engines are used as a generator to charge a battery, and the motor is used to drive the vehicle. The one that is driven is called a series-type hybrid electric vehicle (see, for example, Patent Document 1).
[0003]
[Patent Document 1]
Japanese Patent Laid-Open No. 10-285708
[Problems to be solved by the invention]
Electric vehicles and series-type hybrid electric vehicles are driven by a motor with a wide rotational speed range, so a transmission is not always necessary. However, by providing a transmission with about two speeds, a wide vehicle speed range and a large driving force can be achieved. It becomes possible to combine. However, when a two-stage transmission is configured by a combination of a single pinion planetary gear mechanism and a one-way clutch, it is impossible to move backward by reverse rotation of the motor. Also, when a two-stage transmission capable of reverse travel is configured by a combination of a double pinion planetary gear mechanism having a reverse planetary gear and a plurality of friction clutches, the structure of the transmission itself becomes larger and complicated. End up.
[0005]
An object of the present invention is to provide a transmission for an electric vehicle that performs forward travel and reverse travel by two-speed shift without enlarging the transmission itself, and enables regenerative braking during braking.
[0006]
[Means for Solving the Problems]
An electric vehicle transmission according to the present invention includes an input shaft connected to a generator motor, an output shaft connected to drive wheels, and a case body that accommodates the input shaft and the output shaft. A transmission, a sun gear coupled to the input shaft, an annular gear disposed outside the sun gear, and a carrier coupled to the output shaft rotatably mounted on the sun gear and the annular A planetary gear mechanism including a planetary gear meshing with a gear, a fastening state that is provided between the input shaft and the annular gear, and that fastens the input shaft and the annular gear; and a release state that releases the fastening. A shift clutch that switches to the input shaft, a friction element that is coupled to the input shaft and rotates integrally with the input shaft, and is incorporated between the annular gear and the case body, and in the same direction as the rotation of the friction element. Allow rotation of the ring gear And having a two-way clutch to prevent rotation of said ring gear to rotate in the opposite direction of rotation of the friction element.
[0007]
The transmission for an electric vehicle according to the present invention is characterized in that the regenerative clutch is brought into an engaged state when regenerative braking is performed while the vehicle is running.
[0008]
In the electric vehicle transmission according to the present invention, a two-way clutch that allows or prevents forward and reverse rotation of the annular gear is incorporated in the planetary gear mechanism, so that forward traveling by forward rotation of the motor and backward traveling by reverse rotation are performed. Make it possible. Further, by incorporating a speed change clutch for fastening or releasing the input shaft and the annular gear into the planetary gear mechanism, it is possible to travel by two-stage speed change. In addition, when regenerative braking is performed during traveling at a predetermined speed or higher, energy transmission by the motor is enabled by forcibly shifting the transmission to the second speed.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a skeleton diagram showing a transmission for an electric vehicle according to an embodiment of the present invention.
[0010]
As shown in FIG. 1, an electric vehicle transmission 10 includes an input shaft 12 that is driven by a motor 11 that is a generator motor, a concentric arrangement with the input shaft 12, and a rotation center that matches the rotation center of the input shaft 12. The output shaft 13 is connected to drive wheels (not shown) and transmits power to the output shaft 13. The motor 11 that is a generator motor is driven by the electric power charged in the battery and can rotate the input shaft 12 in both forward and reverse directions, and reverses the rotation direction of the motor 11 when the vehicle moves backward. Thus, the rotation direction transmitted to the output shaft 13 can be reversed. Moreover, the rotational force of the input shaft 12 can be converted into electric energy as a generator, and regenerative braking can be performed by using the motor 11 when braking the vehicle.
[0011]
The input shaft 12 and the output shaft 13 are rotatably accommodated in the case body 14. An inner cylindrical housing space is formed in the case body 14, and includes a sun gear, that is, a sun gear 15 that is fixed to the input shaft 12, and a ring gear, that is, an annular gear 16 that is disposed outside the sun gear 15. A planetary gear mechanism 18 including a planetary gear, that is, a planetary gear 17 that is rotatably mounted on a carrier 19 attached to the output shaft 13 and meshes with the sun gear 15 and the annular gear 16 is housed. That is, the input shaft 12 and the output shaft 13 are always connected to the planetary gear mechanism 18, and the input shaft 12 and the output shaft 13 always rotate in conjunction with each other.
[0012]
A shift clutch 20 is provided between the input shaft 12 and the annular gear 16 for switching between a fastening state in which the input shaft 12 and the annular gear 16 are fastened and a release state in which the fastening is released. The transmission clutch 20 includes a clutch plate 21 that is attached to the input shaft 12 and a clutch plate 22 that is attached to the annular gear 16. The clutch plate 21 on the input shaft 12 side is attached to a clutch hub integral with the input shaft 12, and the clutch plate 22 on the annular gear 16 side is attached to a clutch drum integral with the annular gear 16, and when hydraulic oil is supplied, respectively. The clutch plates are engaged with each other, and the transmission clutch 20 is engaged. The transmission clutch 20 is a wet multi-plate clutch, but a single-plate clutch may be used.
[0013]
A two-way clutch 23 is provided between the outer periphery of the annular gear 16 and the case body 14, and the rotation of the annular gear 16 is allowed or prevented depending on the inclination direction of the sprag 37 of the two-way clutch 23. . Since the sprag 37 is held by the outer holding member 30 connected to the input shaft 12 via the friction element 24, the inclination is switched according to the relative rotation direction of the input shaft 12 and the annular gear 16.
[0014]
When the transmission clutch 20 is released and the motor 11 is rotated forward, the rotation of the annular gear 16 is blocked by the two-way clutch 23, the planetary gear mechanism 18 is operated, and the output shaft 13 is connected to the output shaft 13 via the carrier 19. The rotation of the motor is decelerated and transmitted. Thereby, the gear position is set to the first speed. On the other hand, when the transmission clutch 20 is in the engaged state, the rotation of the input shaft 12 is transmitted to the sun gear 15 attached to the input shaft 12 and the annular gear 16 connected via the transmission clutch 20. Since the rotation of the annular gear 16 is allowed, the sun gear 15 and the annular gear 16 rotate at the same rotational speed, and the second speed state is set.
[0015]
The friction element 24 transmits a predetermined low torque to the outer holding member 30 by pressing a plate 25 attached to the input shaft 12 against the outer holding member 30 using a disc spring or the like. By this friction element 24, a low torque rotational force in the same direction as the rotation of the input shaft 12 is transmitted to the outer holding member 30.
[0016]
FIG. 2 is a cross-sectional view taken along the line II-II shown in FIG. 1, and the same members as those shown in FIG. A cylindrical inner holding member 26 having a plurality of pockets 29 formed at predetermined intervals is fixed to the outer peripheral cylindrical surface 32 of the annular gear 16 by a method such as press fitting. In the case illustrated, the inner holding member 26 is fixed to the annular gear 16 by a fixing pin 31.
[0017]
A cylindrical outer holding member 30 is inserted between the inner peripheral cylindrical surface 28 of the case body 14 and the inner holding member 26 so as to be slidable in the circumferential direction. The outer holding member 30 is provided with a stopper 34, and the inner holding member 26 is provided with a square hole 35 corresponding to the stopper 34 with a gap on both sides in the circumferential direction of the stopper 34. It has been. Thus, the outer holding member 30 moves relative to the inner holding member 26 in the circumferential direction until the stopper 34 contacts the square hole 35, that is, the gap between the square hole 35 and the stopper 34. A plurality of pockets 33 are formed in the outer holding member 30 so as to correspond to a plurality of pockets 29 formed in the inner holding member 26, and the dimension A between the side surfaces in the circumferential direction of the pocket 29 in the outer holding member 30 is It is larger than the dimension B between the side surfaces in the circumferential direction of the pocket 33 in the inner holding member 26.
[0018]
3A is a cross-sectional view of the sprag 37 alone, and FIG. 3B is an enlarged view of a main part of the outer holding member 30. FIG. A sprag 37 having a specific shape is stored in each of the plurality of pockets 29 and 33. A concave portion 29a is formed in the central portion of the side surface of the outer holding member 30 facing the pocket 29 in the circumferential direction, and a pair of elastic bodies 36 are incorporated in the concave portion 29a. The elastic body 36 presses the outer diameter side end portions 37c and 37d of the sprag 37 from both sides, and applies a spring force in a direction to hold the sprag 37 in a neutral state as shown in FIG. The outer diameter side arc surface 37a and the inner diameter side arc surface 37b of the sprag 37 are arc surfaces having radii of curvature R1 and R2, respectively. The radii R1 and R2 are both set to be larger than ½ of the interval δ between the inner peripheral cylindrical surface 28 of the case body 14 and the outer peripheral cylindrical surface 32 of the annular gear 16.
[0019]
The radii R1 and R2 overlap each other by a distance L, and the distance between the circular arc surface 37a and the circular arc surface 37b in the neutral line N passing through the center points O1 and O2 of the respective curvature radii is the minimum height. h, which is set slightly smaller than the interval δ. Further, when the respective arc surfaces 37a and 37b are separated from the position of the neutral line N, the distance between the arc surfaces 37a and 37b is set to be neutral as shown by a portion facing through the sprag center O, for example, the inclined line M. The distance increases as the distance from the position of the line N increases, and the distance δ increases after a predetermined distance. Therefore, when the sprag 37 is in a neutral state in which the extension line of the neutral line N passes through the rotation center of the annular gear 16 and rises in the radial direction of the annular gear 16 between the cylindrical surfaces 28 and 32, the arc of the sprag 37 A radial gap is formed between the surfaces 37 a and 37 b and the cylindrical surfaces 28 and 32. Then, when tilted in the circumferential direction of the cylindrical surfaces 28 and 32 from the neutral state, as shown by the inclined line M, the outer diameter side arc surface 37a and the inner diameter side arc surface 37b are engaged with the opposing cylindrical surfaces 28 and 32. To do.
[0020]
As the elastic body 36, a leaf spring, a coil spring, or the like can be used. As shown in FIG. 3, in this embodiment, an example is shown in which a metal leaf spring is attached as an elastic body 36 from the outer diameter portion 26 b of the outer holding member 30, but it is attached from the inner diameter side of the outer holding member 30. May be.
[0021]
Next, the operation of the two-way clutch 23 will be described. FIG. 4A is an operation state explanatory diagram at the time of motor forward rotation, and FIG. 4B is an operation state explanatory diagram at the time of motor reverse rotation. A rotational force in the same direction as the rotation of the input shaft 12 driven by the motor 11 is transmitted to the outer holding member 30 of the two-way clutch 23 via the friction element 24. Therefore, when the motor 11 is driven to rotate in the forward direction, the outer holding member 30 is rotated in the forward direction, and when the motor 11 is driven to rotate in the reverse direction, the outer holding member 30 is applied with the torque in the reverse direction with a low torque.
[0022]
Assuming that the rotation direction of the sun gear 15 during forward rotation of the motor is the right rotation direction indicated by the arrow in FIG. Relative rotation in the rolling direction. At this time, the sprag 37 stored in the pocket 29 of the outer holding member 30 is pushed by the outer holding member 30 and tilts. Thereby, the outer diameter side arc surface 37a and the inner diameter side arc surface 37b of the sprag 37 are respectively engaged with the portions separated from the neutral lines M of the opposed cylindrical surfaces 28 and 32, and the annular gear 16 is brought into a fastening state. When the input shaft 12 rotates in the forward direction, the rotational force in the forward direction is always transmitted to the sun gear 15, and the reverse direction is transmitted to the annular gear 16 connected to the sun gear 15 via the planetary gear 17. The reaction force of is transmitted. At the time of forward rotation of the motor shown in FIG. 4A, a reaction force in the left rotation direction is transmitted to the annular gear 16, but the rotation of the annular gear 16 is prevented by the sprag 37 in the left rotation direction.
[0023]
On the other hand, when the motor is reversely rotated, as shown in FIG. 4B, the stopper 34 provided on the outer holding member 30 rotates relatively in the reverse direction until it comes into contact with the left side surface of the square hole 35 in the drawing. At this time, the sprag 37 stored in the pocket 29 of the outer holding member 30 is pushed by the outer holding member 30 and tilted in the direction opposite to that shown in FIG. Thereby, the outer diameter side arc surface 37a and the inner diameter side arc surface 37b of the sprag 37 are respectively engaged with the portions separated from the neutral lines M of the opposed cylindrical surfaces 28 and 32, and the annular gear 16 is brought into a fastening state. At the time of the reverse rotation of the motor shown in FIG. 4B, a reaction force in the clockwise direction is transmitted to the annular gear 16, but the rotation of the annular gear 16 is prevented by the sprag 37 in the clockwise direction.
[0024]
Thus, when the clutch plate 25 of the friction element 24 is in the engaged state by the slip sprag 37 and the two-way clutch 23 is in the engaged state, the annular gear 16 can be prevented from rotating in the direction opposite to the rotation direction of the motor 11, The planetary gear mechanism 18 is in the first speed power transmission state.
[0025]
Next, the operation of the electric vehicle transmission 10 of the present invention will be described.
[0026]
FIG. 5 is an explanatory diagram of the switching state of the transmission clutch 20. When traveling in the first speed such as when starting forward, the forward rotation of the input shaft 12 driven by the motor 11 is decelerated and transmitted to the output shaft 13. At this time, as shown in FIG. 5, the transmission clutch 20 is in a released state. The two-way clutch 23 prevents the annular gear 16 from rotating in the direction opposite to the rotation direction of the input shaft 12. Then, the planetary gear 17 to which the rotational force of the input shaft 12 is transmitted via the sun gear 15 revolves around the sun gear 15 in the normal rotation direction while rotating. As a result, the output shaft 13 rotates in the forward rotation direction in the same manner as the rotation direction of the input shaft 12 through the carrier 19 connected to the planetary gear 17. At this time, the rotational speed of the output shaft 13 is reduced and transmitted according to the number of teeth of the sun gear 15 and the annular gear 16.
[0027]
When the vehicle reaches a predetermined speed or higher, the shift clutch 20 is brought into an engaged state in order to shift up to the second speed. By engaging the speed change clutch 20, the annular gear 16 starts to rotate at the same rotational speed as the rotational speed of the input shaft 12, that is, the rotational speed of the sun gear 15. At this time, the two-way clutch 23 does not prevent the annular gear 16 from rotating forward. Then, the planetary gear 17 does not rotate, and the annular gear 16 and the planetary gear 17 rotate around the sun gear 15 as one body. The rotation speed of the output shaft 13 at this time is transmitted at the same rotation speed as that of the input shaft 12 by preventing the planetary gear 17 from rotating.
[0028]
During reverse travel, the motor 11 is rotated in the direction opposite to the normal direction. At this time, as shown in FIG. 5, the transmission clutch 20 is in a released state. As the friction element 24 transmits torque, the two-way clutch 23 prevents the annular gear 16 from rotating in the direction opposite to the rotation direction of the input shaft 12. As a result, the rotation decelerated through the planetary gear 17 is transmitted to the output shaft 13 as a rotational force in the reverse rotation direction that is the same as the rotation direction of the input shaft 12. Retreat with a considerable gear ratio.
[0029]
FIG. 6 is a block diagram showing a control circuit for controlling the operation of the electric vehicle transmission. The main controller 38 includes an accelerator opening sensor 39 for detecting the opening degree of the accelerator pedal, a vehicle speed sensor 40 as a vehicle speed detecting means for detecting the traveling speed of the vehicle, a brake sensor 41 as a load detecting means for detecting the traveling load of the vehicle, In addition, a detection signal from a motor rotation speed sensor 42 that detects the rotation speed of the motor 11 is sent. From the main controller 38 to a motor controller 43 as motor control means for controlling the operation of the motor 11 and a shift clutch controller 44 as shift control means for controlling the engagement between the input shaft 12 and the annular gear 16 by the shift clutch 20. A control signal is sent to each.
[0030]
As described above, the clutch 20 is switched by controlling the hydraulic pressure supplied to the hydraulic chamber. These switching operations are performed by controlling the hydraulic pressure supplied to the hydraulic chamber by a signal from the transmission clutch controller 44. The switching timing is detected by the vehicle speed detected by the vehicle speed sensor 40 and the accelerator opening sensor 39. It is determined based on the signal from the accelerator opening sensor.
[0031]
When the vehicle is braked, regenerative braking can be performed in which the motor 11 functions as a generator and brakes while charging. However, when regenerative braking is performed during traveling in the first speed, it is necessary to switch the clutch 20. This is because, as shown in FIG. 4 (a), the annular gear 16 is in a clutch operable state in the same rotational direction as the input shaft 12 and the output shaft 13, but against the rotational force in the opposite direction. Because it will run idle. That is, the braking force in the direction opposite to the rotation direction of the output shaft 13 is not transmitted to the motor 11 and energy regeneration cannot be performed as it is. Therefore, when regenerative braking is performed during traveling in the first speed, the shift clutch 20 is switched according to the flowchart shown in FIG. Each process is executed every predetermined time, for example, every 10 msec.
[0032]
As shown in the figure, the presence or absence of braking is detected by the brake sensor 41 in step S1. Next, in step S2, it is determined whether or not the transmission 10 is at the first speed during braking. In step S3, the vehicle speed detected by the vehicle speed sensor 40 is compared with a determination threshold value stored in the memory of the main controller 38. If it is determined that the vehicle speed is equal to or higher than a predetermined vehicle speed that requires energy regeneration, the process proceeds to step S4. Thus, the transmission 10 is forcibly set to the second speed state. When the second speed traveling is already performed at the time of the regenerative braking, the regenerative braking of step S5 is performed in the clutch state as it is as branched at step S2. By setting the second speed state, a braking force reverse to the driving force can be transmitted from the output shaft 13 to the input shaft 12, and the motor 11 can generate power to charge the battery.
[0033]
It goes without saying that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention. For example, an engine may be provided in addition to the motor 11, and the output shaft of the engine may be connected to the input shaft 12 in series.
[0034]
【The invention's effect】
According to the present invention, a two-way clutch that allows or prevents the forward and reverse rotation of the annular gear is incorporated in the planetary gear mechanism, so that the forward traveling by the motor forward and the reverse by the reverse rotation are performed without increasing the size of the transmission itself. Running.
[0035]
By incorporating a speed change clutch for fastening or releasing the input shaft and the annular gear into the planetary gear mechanism, it is possible to perform two-speed shifting without increasing the size of the transmission itself.
[0036]
When regenerative braking is performed while traveling at a predetermined speed or higher, the transmission is forcibly shifted to the second speed, so that the braking force can be transmitted from the output shaft to the input shaft. Can be performed efficiently.
[Brief description of the drawings]
FIG. 1 is a skeleton diagram showing a transmission for an electric vehicle according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view taken along the line II-II shown in FIG.
3A is a cross-sectional view of a sprag alone, and FIG. 3B is an enlarged view of a main part of an outer holding member.
4A is an explanatory diagram of an operating state during forward rotation of the motor, and FIG. 4B is an explanatory diagram of an operating state during reverse rotation of the motor.
FIG. 5 is an explanatory diagram of a changeover state of a transmission clutch.
FIG. 6 is a block diagram showing a control circuit for controlling the operation of the electric vehicle transmission.
FIG. 7 is a flowchart showing a switching control procedure for controlling a shift clutch during regenerative braking.
[Explanation of symbols]
11 Motor 12 Input shaft 13 Output shaft 14 Case body 15 Sun gear 16 Ring gear 17 Planetary gear 20 Shifting clutch 23 Two-way clutch 24 Friction element 26 Inner holding member 29 Pocket 30 Outer holding member 33 Pocket 34 Stopper 35 Square hole 36 Elastic body 37 Sprag

Claims (2)

A transmission for an electric vehicle comprising an input shaft connected to a generator motor, an output shaft connected to a drive wheel, and a case body that houses the input shaft and the output shaft,
A sun gear coupled to the input shaft, an annular gear disposed outside the sun gear, and a planetary gear that is rotatably mounted on a carrier coupled to the output shaft and meshes with the sun gear and the annular gear. A planetary gear mechanism with
A speed change clutch that is provided between the input shaft and the annular gear and switches between a fastening state for fastening the input shaft and the annular gear and a release state for releasing the fastening;
A friction element coupled to the input shaft and rotating integrally with the input shaft;
Incorporated between the annular gear and the case body, allowing the rotation of the annular gear in the same direction as the rotation of the friction element, and allowing the rotation of the annular gear in the direction opposite to the rotation of the friction element. A transmission for an electric vehicle comprising a two-way clutch for blocking. 2. The electric vehicle transmission according to claim 1, wherein the regenerative clutch is engaged when regenerative braking is performed while the vehicle is running.

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