JP2002317871A - Electric drive for transmission - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To realize a structure that can be configured to be small and lightweight and that can smoothly drive a driven member in a transmission unit. SOLUTION: A select operation is performed by displacing a switching shaft 7 in an axial direction by a pinion gear 17 rotationally driven by a first electric motor. Further, the movement of the ball nut 28 screwed to the ball screw shaft 24, which is rotationally driven by the second electric motor, is controlled by the shift arms 22, 2
2 and the shift shaft 12 via the shift sleeve 12.
To perform the shift operation. A select operation that does not require force is performed by a mechanism having no boosting action, and a shift operation that requires power is performed by a mechanism having a boosting action.
Therefore, the first and second electric motors can be downsized, and the above-mentioned problem can be solved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The electric drive device for a transmission according to the present invention is used as a drive device for automatically changing the gear ratio of an automobile transmission or in response to a driver's operation.

[0002]

2. Description of the Related Art Conventionally, as a transmission for an automobile, a manual transmission in which a driver switches gears by operating a shift arm together with a clutch pedal, or an automatic transmission in which a gear ratio is automatically switched according to driving conditions. Machine is widely used. As the automatic transmission, a combination of a torque converter and a planetary gear mechanism, a combination of a variable pulley and an endless belt, etc.
It has been used for some time. Furthermore, the transmission for automobiles, which is capable of automatically switching the transmission unit conventionally used as a manual transmission and automatically connecting and disconnecting the clutch, is also easy to operate, Moreover, since the transmission efficiency is higher than that of a general automatic transmission, it has recently been used. Conventionally, as a structure for switching gears constituting a transmission unit in such a vehicle transmission, a hydraulic type or a structure disclosed in Japanese Patent Application Laid-Open No. Hei 2-27 is known.
A mechanical type as described in Japanese Patent No. 3051 is known.

[0003]

As in the prior art, in the case of a structure in which the gears constituting the transmission unit are switched hydraulically, a power loss occurs because the hydraulic pump is always driven to rotate during operation of the vehicle. This not only adversely affects the driving performance and fuel efficiency of the car, but also complicates measures for preventing breakdown due to oil leakage. Further, a conventionally known device for mechanically performing the above-described switching is developed for a large vehicle such as a truck, and has a complicated structure and a large installation space. Therefore, the device is used for a small vehicle such as a passenger car. Is not suitable.

[0004] Japanese Patent Application Laid-Open Nos. 2-271164 and 11-6321 disclose a mechanism for mechanically transmitting the output of an electric motor to switch gears constituting a transmission unit.
Japanese Patent Application Laid-Open No. 7-107, No. 7 discloses, but the efficiency of transmitting the power of the electric motor to the transmission unit is not always good. For this reason, it is necessary to use a large motor having a large output as the electric motor. For this reason, the electric motor is not suitable for a small car such as a passenger car. The electric drive device for a transmission of the present invention has been invented in view of such circumstances.

[0005]

SUMMARY OF THE INVENTION An electric drive unit for a transmission according to the present invention includes a selecting operation for displacing a switching shaft in an axial direction in order to select a desired gear from a plurality of gears, and for selecting a selected gear. The shift operation of rotating the switching shaft to transmit power is performed by first and second actuators each using an electric motor as a drive source. In such an electric drive device for a transmission of the present invention, the first actuator for performing the select operation is a first electric motor, a pinion gear that is rotationally driven by an output shaft of the first electric motor, The pinion gear and a rack engaged with the pinion gear are provided. By connecting the rack to the switching shaft, the switching shaft can be displaced in the axial direction. The second actuator for performing the shift operation includes a second electric motor, a ball screw shaft that is rotationally driven by an output shaft of the second electric motor, and a second actuator that is arranged around the ball screw shaft. A ball nut which is displaced in the axial direction of the ball screw shaft with the rotation of the ball screw shaft, and a shift arm which pivotally supports the ball nut at a tip end thereof. And
By connecting the base end of the shift arm and the switching shaft, the switching arm is made rotatable by the shift arm. Further, a slide mechanism is provided between the switching shaft and the ball nut so that the switching shaft and the ball nut can be relatively displaced in the axial direction of the switching shaft.

[0006]

The electric drive device for a transmission according to the present invention configured as described above switches the gears of the transmission unit as follows. First, to perform a select operation, the first electric motor constituting the first actuator is rotated in a predetermined direction, and the switching shaft is displaced in the axial direction via the pinion gear and the rack. Since the force required for the above-described select operation is small, the select operation can be easily performed even with a structure in which the pinion gear and the rack are simply combined and have no boosting function. That is, a quick select operation can be performed without using a particularly large motor as the first electric motor.

Next, in order to perform the shift operation, the second electric motor constituting the second actuator is rotated in a predetermined direction, and the tip of the shift arm is displaced via the ball screw shaft and the ball nut. Then, the shift shaft is displaced in a predetermined direction by the shift arm to perform a shift operation. The output of the second electric motor can be sufficiently increased by the boosting action of the threaded portion between the ball screw shaft and the ball nut and the boosting action based on the principle of leverage of the shift arm. Therefore, a shift operation having a larger force than the select operation can be reliably performed without using a particularly large motor as the second electric motor.

[0008]

1 to 3 show a first embodiment of the present invention, corresponding to claims 1 and 2. FIG. The electric drive device 1 for a transmission according to the present invention is used in a state of being fixedly connected to the outer surface of a transmission case 2 having a built-in transmission unit similar to a manual transmission. For this purpose, the transmission electric drive device 1 has a housing 3 that can be freely coupled and fixed to the outer surface of the transmission case 2. This housing 3
Is a cylindrical main housing portion 4 and the main housing portion 4
And a cylindrical sub-housing portion 5 provided at a position closer to one end of the intermediate portion (rightward in FIGS. 1 and 3) with respect to the main housing 4 in a twisted positional relationship. A through hole 6 is formed in the middle portion of the main housing portion 4 near the other end (to the left in FIGS. 1 and 3), and the switching shaft 7 disposed in the main housing portion 4 has a base end thereof. A drive pin 8 called a striker, which is fixed and connected, protrudes out of the main housing 4. The transmission electric drive device 1 of the present invention displaces the switching shaft 7 by first and second electric motors 9 and 10 provided on both sides of the sub-housing section 5,
The drive pin 8 switches the transmission unit. Hereinafter, a mechanism for displacing the switching shaft 7 having the base end of the drive pin 8 coupled and fixed by the first and second electric motors 9 and 10 will be specifically described.

A male serration 11 is formed at an intermediate portion of the switching shaft 7, and this male serration 11 is
A serration engagement with a female serration 13 formed at the tip (left end in FIG. 3) of the shift sleeve 12 constitutes a slide mechanism capable of transmitting rotational force and displacing in the axial direction. Both ends of the shift sleeve 12 are rotatably supported in the main housing 4 by a pair of bearings 14. On the other hand, a portion of the switching shaft 7 close to the front end of the intermediate portion is provided in the main housing 4 by a bearing 15 such as a sliding bearing or a needle bearing.
Rotational and axial displacements are freely supported.

At the base end (right end in FIG. 3) of the switching shaft 7, an arc-shaped rack 16 concentric with the switching shaft 7 is formed. In the case of this example, this rack 1
6, a pinion gear 17 described below is freely meshable with any part of the peripheral surface as if the abacus balls are superimposed. That is, a through-hole 18 is formed in the shift sleeve 12, and the pinion gear 17 partially inserted into the shift sleeve 12 through the through-hole 18 is engaged with the rack 16. The shift sleeve 1
2, the length of the through hole 18 in the circumferential direction is sufficiently ensured that the edge of the through hole 18 does not interfere with the pinion gear 17 regardless of the displacement of the shift sleeve 12 in the rotation direction. .

As shown in FIG. 2, the pinion gear 17 is rotatably supported in the sub-housing 5 only by a pair of rolling bearings 19, such as a deep groove type or angular type ball bearing. . An engagement recess 20 is formed in the base end surface (right end surface in FIG. 2) of the pinion gear 17,
The engaging concave portion 20 is engaged with an engaging convex portion 21 formed on the distal end surface of the output shaft of the first electric motor 9.
Accordingly, the power supply to the first electric motor 9 causes the pinion gear 17 to rotate in a predetermined direction, and the switching shaft 7 to move axially in a predetermined direction.

On the other hand, the base ends of the shift arms 22 and 22 are fixedly connected to two positions on the outer peripheral surface of the intermediate portion of the shift sleeve 12 so as to sandwich the through hole 18 from both sides in the axial direction. And, these two shift arms 22, 22
Are swingably displaceable by the second electric motor 10 via a ball screw mechanism 23. In the case of this example, a ball screw shaft 24 for constituting the ball screw mechanism 23
Is disposed in the sub-housing section 5 in parallel with the pinion gear 17, and is provided with a deep groove type or angular type ball bearing or the like.
Only the rotation is freely supported by the pair of rolling bearings 25, 25. An engagement recess 26 is formed in the base end surface (the left end surface in FIG. 2) of the ball screw shaft 24, and the engagement recess 26 and the distal end surface of the output shaft of the second electric motor 10 are formed. The formed engaging projection 27 is engaged. Therefore,
The energization of the second electric motor 10 causes the ball screw shaft 24 to rotate in a predetermined direction.

A ball nut 28 is screwed to such a ball screw shaft 24 via a plurality of balls (not shown). Further, a pair of locking pins 29, 29 concentric with each other, protruding from the radially opposite side surface of the ball nut 28,
The shift arms 22, 22 are engaged with locking holes 30, 30 formed at the distal end (the lower end in FIGS. 2 and 3).
Therefore, the ball nut 28 is connected to the ball screw shaft 24.
The ball screw shaft 24 is displaced in the axial direction (the left-right direction in FIG. 2 and the front-back direction in FIG. 3) as the ball screw shaft 24 rotates. The locking holes 30, 30 are long holes extending in the radial direction of the shift sleeve 12 (vertical direction in FIGS. 2 and 3), and the linear motion of the locking pins 29, 29 can be used for the shift arms. 22 and 22 can be freely converted into circular motions.

The electric drive device 1 for a transmission according to the present embodiment constructed as described above has the through hole 6 formed in a part of the main housing portion 4.
By attaching a mounting flange 31 provided in a portion surrounding the transmission case 2 to the outer surface of the transmission case 2, the transmission flange is assembled to the transmission unit. In this state, the drive pin 8 enters the transmission case 2 and is freely detachable from a plurality of driven parts provided in the transmission unit.

As shown in FIG. 4, the operation of the electric drive unit 1 for the transmission assembled on the outer surface of the transmission case 2 as described above is shown in FIG.
A description will be given of a speed change unit that realizes six types of speed change states of the stage (R). Note that, in the select operation, which is the first stage for shifting, none of the shifting states is achieved (the synchromesh mechanism is in a free state), and the left and right end positions and the left and right center positions in FIG. Are selected. Further, in the shift operation, from the three types of positions in the neutral state, the shift is performed in any direction (upward or downward in FIG. 4), and any of the synchromesh mechanisms is connected, and any of the shift states is changed. I do. The selection operation is performed by the switching shaft 7.
Is performed by displacing in the axial direction, and the shift operation is performed by rotating the switching shaft 7.

First, the first electric motor 9 constituting the first actuator for displacing the switching shaft 7 in the axial direction in order to perform the selecting operation from the neutral position indicated by N in FIG. Rotate in a predetermined direction.
Then, the rotation of the output shaft of the first electric motor 9 is transmitted to the switching shaft 7 via the pinion gear 17 and the rack 16, and the switching shaft 7 is displaced in the axial direction. The amount of displacement of the switching shaft 7 in the axial direction is detected by a selector displacement meter 32 such as a potentiometer. Then, the power supply to the first electric motor 9 is stopped while the drive pin 8 is moved to a predetermined position. Since the force required for the above select operation is small,
The select operation can be easily performed even with a structure in which the pinion gear 17 and the rack 16 are simply combined and have no boosting function. That is, a quick select operation can be performed without using a particularly large motor as the first electric motor 9.

After the drive pin 8 has been displaced to a position facing one of the driven parts, a second actuator for rotating the switching shaft 7 to perform a shift operation is constructed. The second electric motor 1
0 is rotated in a predetermined direction. Then, the distal ends of the shift arms 22, 22 are displaced via the ball screw shaft 24 and the ball nut 28. The shift sleeve 1 is moved by these two shift arms 22 and 22.
2 is pivotally displaced in a predetermined direction, and the switching shaft 7 which is serrated and engaged with the shift sleeve 12 is further pivotally displaced in a predetermined direction to perform a shift operation. The amount of displacement of the switching shaft 7 in the rotation direction is detected by a shift displacement meter 33 such as a potentiometer. Then, the power supply to the second electric motor 10 is stopped while the drive pin 8 is moved to the predetermined position.

When the shift operation is performed in this manner, the output of the second electric motor 10 is applied to the ball screw shaft 24.
It can be made sufficiently large by the boosting action of the threaded portion between the shift arm 22 and the ball nut 28 and the boosting action based on the principle of leverage of the shift arms 22, 22. Therefore, the shift operation having a greater force than the select operation can be reliably performed without using a particularly large motor as the second electric motor 10.

Next, FIG. 5 shows a second example of the embodiment of the present invention, which also corresponds to claims 1 and 2. In the case of this example, the male serration 11a and the rack 16a are formed in the base half (the right half in FIG. 5) of the switching shaft 7a. That is, by making the outer peripheral surface shape of the base half of the switching shaft 7a have a waveform in both the axial direction and the circumferential direction, the male serration portion 11a is formed in the base half.
And the function as the rack 16a. At the same time, the female sleeve 13a is formed on the entire inner peripheral surface of the shift sleeve 12a. The configuration and operation of the other parts are the same as those described in the first embodiment.
Since it is the same as the case of the example, illustration and description of the equivalent parts are omitted.

Next, FIG. 6 also shows a third embodiment of the present invention, which also corresponds to claims 1 and 2. In the case of this example, a part of the base half (the right half in FIG. 6) of the switching shaft 7b in the circumferential direction (slightly wider than the range in which the switching shaft 7b swings with the shift operation). Only in the range, the rack 16b is formed. A keyway 34 is formed in a portion of the base half of the switching shaft 7b where the phase in the circumferential direction deviates from the rack 16b. The key groove 34 and the shift sleeve 1
By engaging a key 35 fixed to 2b, the shift sleeve 12b and the switching shaft 7b are combined so that rotational force can be transmitted and relative displacement can be performed in the axial direction. The configuration and operation of the other parts
Since this is the same as the case of the first example described above, illustration and description of the equivalent parts are omitted.

Next, FIG. 7 corresponds to claims 1 and 3.
14 shows a fourth example of an embodiment of the present invention. In the case of this example, a hollow tubular rack 16c is provided at a base end portion (right end portion in FIG. 7) of the switching shaft 7c inside the shift sleeve 12, and a rotatable and axially movable shaft 16c with respect to the switching shaft 7c. They are arranged in a state where relative displacement is prevented. In the case of this example, the edge of the rack 16c is formed in a straight line like a general rack.
Does not rotate based on the engagement with the pinion gear 17. Therefore, during the shift operation, the switching shaft 7
Only c rotates. On the other hand, the axial displacement of the rack 16c is directly transmitted to the switching shaft 7c,
This switching shaft 7c is displaced in the axial direction. The configuration and operation of the other parts are the same as in the case of the above-described first example, and illustration and description of equivalent parts are omitted.

Next, FIG. 8 corresponds to claims 1 and 4.
15 shows a fifth example of the embodiment of the present invention. In the case of this example, the base ends of the pair of shift arms 22a, 22a are fixed to the outer peripheral surface of the switching shaft 7d at a sufficient interval from each other. And, these two shift arms 22
A circular locking hole is formed concentrically at each of the distal ends of the a and 22a. On the other hand, a pair of rods 36, 36
And the switching shaft 7 concentrically with each other.
It is connected and fixed so as to be parallel to d. And
An intermediate portion of each of the rods 36, 36 is inserted into a locking hole formed at the tip of each of the shift arms 22a, 22a. The shift sleeve as provided in the above-described first to fourth examples is omitted. Therefore, the rack 16d formed in the base half (the right half in FIG. 8) of the switching shaft 7d and the pinion gear 17 are directly opposed to and mesh with each other. In the case of this example, when the switching shaft 7d is displaced in the axial direction with the rotation of the pinion gear 17, the rods 36, 36 are moved by the shift arms 22a, 22a.
With respect to a, it is displaced in the axial direction of the switching shaft 7d.
The configuration and operation of the other parts are the same as in the case of the above-described first example, and illustration and description of equivalent parts are omitted.

[0023]

Since the present invention is constructed and operates as described above, it is possible to realize an electric drive device for a transmission that can be made small and lightweight and can switch the transmission of a small car such as a passenger car. I can do it.

[Brief description of the drawings]

FIG. 1 is an external view showing a first example of an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a sectional view taken along the line BB in FIG.

FIG. 4 is a schematic plan view showing an example of a shift pattern of the transmission.

FIG. 5 is a partial sectional view showing a second example of the embodiment of the present invention.

FIG. 6 is a partial sectional view showing the third example.

FIG. 7 is a partial sectional view showing the fourth example.

FIG. 8 is a partial sectional view showing the fifth example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electric drive device for transmission 2 Transmission case 3 Housing 4 Main housing part 5 Sub-housing part 6 Through-hole 7, 7a, 7b, 7c, 7d Switching shaft 8 Drive pin 9 First electric motor 10 Second electric motor 11 , 11a Male serration part 12, 12a, 12b Shift sleeve 13, 13a Female serration part 14 Bearing 15 Bearing 16, 16a, 16b, 16c, 16d Rack 17 Pinion gear 18 Through hole 19 Rolling bearing 20 Engagement concave part 21 Engagement convex part 22 , 22a shift arm 23 ball screw mechanism 24 ball screw shaft 25 rolling bearing 26 engaging concave portion 27 engaging convex portion 28 ball nut 29 locking pin 30 locking hole 31 mounting flange 32 selection displacement meter 33 shift displacement meter 34 key Groove 35 Key 36 Rod

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Minao Umeda 78 Tobacho, Maebashi-shi, Gunma Nippon Seiko Co., Ltd. F-term (reference) 3J067 AB23 BA56 DA41 DA42 DB32 FB83

Claims (4)

[Claims] 1. A select operation for displacing a switching shaft in an axial direction to select a desired gear from among a plurality of gears, and rotating the switching shaft to bring the selected gear into a state of transmitting power. And a shift operation to be performed by the first and second actuators each having an electric motor as a drive source, wherein the first actuator for performing the select operation is a first actuator. An electric motor, a pinion gear that is driven to rotate by an output shaft of the first electric motor, and a rack that meshes with the pinion gear. The second actuator, which can be displaced in the axial direction and performs the shift operation, includes a second electric motor and the second electric motor. A ball screw shaft rotationally driven by an output shaft of a motor, a ball nut disposed around the ball screw shaft, and displaced in the axial direction of the ball screw shaft with rotation of the ball screw shaft; A shift arm having a nut pivotally supported at its distal end is provided.By connecting the base end of the shift arm and the switching shaft, the switching arm is made rotatable by the shift arm. An electric drive device for a transmission, comprising a slide mechanism provided between the switching shaft and the ball nut to make the switching shaft and the ball nut relatively displaceable in the axial direction of the switching shaft. 2. An inner peripheral surface of a tubular shift sleeve to which a base end of a shift arm is fixedly connected and an outer peripheral surface of a switching shaft are engaged so as to be able to transmit rotation and to be axially displaceable. An arc-shaped rack concentric with the switching shaft is formed at a portion of the base end of the switching shaft located inside the shift sleeve, and a transparent mechanism formed on the shift sleeve is formed. A pinion gear arranged in the hole portion is meshed with the rack,
An electric drive device for a transmission according to claim 1. 3. An inner peripheral surface of a tubular shift sleeve to which a base end of a shift arm is fixedly connected and an outer peripheral surface of a switching shaft are engaged so as to be able to transmit rotation and to be axially displaceable. A slide mechanism is configured, and a hollow tubular rack is disposed in a portion existing inside the shift sleeve at a base end of the switching shaft, in a state where the rack is rotatable with respect to the switching shaft and an axial relative displacement is prevented. The electric drive device for a transmission according to claim 1, wherein a pinion gear disposed in a through-hole formed in the shift sleeve meshes with the rack. 4. A circular locking hole provided in a pair of shift arms spaced apart from each other, and a rod protruding in opposite directions from the outer peripheral surface of the ball nut and disposed in parallel with the switching shaft. The sliding mechanism is constituted by engaging the relative rotation and the displacement in the axial direction so as to be freely displaceable, and a portion located between the pair of shift arms on the outer peripheral surface of the switching shaft is concentric with the switching shaft. The electric drive device for a transmission according to claim 1, wherein an arc-shaped rack is formed, and a pinion gear disposed at a portion located between the pair of shift arms is meshed with the rack.