JPH09118245A - Rear wheel steering angle control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the size and weight of the whole device while keeping the dimensional precision of a ring gear used in a transmission mechanism, in a rear wheel steering angle control device having an actuator and the transmission mechanism. SOLUTION: This device has a transmission mechanism having a plurality of planetary gears 73a between sun gears 71a, 75a and a ring gear 72, the ring gear 72 is integrally molded in the inside of a housing 10 by use of resin material, a winding part 3 is housed in and fixed to the housing 10. The ring gear 72 and the sun gears 71a, 75 are desirably formed of a resin material containing a prescribed quantity of glass fiber, and the planetary gears 73a, 76a are formed of a resin material containing no glass fiber.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rear wheel steering angle control device, and more particularly to an actuator for driving a steering mechanism connected to the rear wheels of a vehicle and a transmission mechanism for transmitting the driving force of the actuator to the steering mechanism. It relates to a rear wheel steering angle control device.

[0002]

2. Description of the Related Art Conventionally, a steering angle control device for controlling a steering angle of a rear wheel of a vehicle is known, and various names such as a four-wheel steering device, a rear wheel steering device, and a rear wheel steering angle control device are known. It is used. This rear wheel steering angle control device, for example, while the target steering angle of the rear wheels is set to a predetermined value according to the operating state of the vehicle,
The actual steering angle of the rear wheels is detected, the actuator is driven according to the steering angle deviation between the actual steering angle and the target steering angle, and the steering angle control of the rear wheels is performed. For example, Japanese Patent Application Laid-Open No. 7-40894 discloses a steering control device for a vehicle, and a three-phase electric motor is used as an actuator for driving a steering mechanism for rear wheels.

[0003]

However, the conventional rear wheel steering angle control device including the actuator described in the above publication has a complicated structure and a large size, and it is difficult to assemble it during manufacturing. In particular, when an electric motor is used, heat is generated during driving, so there is a limit to downsizing, and it is necessary to take measures against failure due to temperature rise.

For this reason, the applicant of the present application filed Japanese Patent Application Laid-Open No. 7-21.
In No. 5226, it is an object to downsize the rear wheel steering actuator and to simplify the structure thereof and to prevent the deterioration of the reliability. Therefore, the drive source, the speed reduction mechanism, the conversion mechanism, and the output shaft are arranged on the same shaft. We have proposed a rear-wheel steering actuator in which everything is arranged. In this rear wheel steering actuator, a support member for integrally supporting the winding member with the housing member is resin-molded,
One bearing for supporting the rotor member is fixed integrally with the support member, and further, on a part of the inner peripheral wall of the support member,
The ring gear of the planetary gear mechanism is to be formed.
The rear wheel steering actuator in the same application means an actuator in a broad sense equivalent to a rear wheel steering angle control device, and an actuator when only a motor part is distinguished from a transmission mechanism is an actuator in a narrow sense. it can.

In the above rear wheel steering actuator, both the winding portion and the ring gear are formed inside the housing by integrally molding resin. At this time, since the resin thickness of the winding part is larger than that of the ring gear, the ring gear part is pulled toward the winding part side due to the shrinkage of the resin after molding, making it difficult to secure the dimensional accuracy of the gear. Becomes Therefore, a high-level resin manufacturing technique is required, which causes a new cost increase.

On the other hand, there is a demand for further reduction in size and weight of the rear wheel steering angle control device, but it is possible to further reduce the weight by making not only the ring gear but also the sun gear and the planetary gear. In this case, if a suitable resin material is used, the width of the gear can be formed thin while maintaining a predetermined strength, and the axial length can be shortened, so that the size can be reduced.

In view of the above, it is an object of the present invention to provide a rear wheel steering angle control device equipped with an actuator and a transmission mechanism, while maintaining the dimensional accuracy of the ring gear used for the transmission mechanism, while making the entire device compact and lightweight. To do.

Further, according to the present invention, in a rear wheel steering angle control device equipped with an actuator and a transmission mechanism, various gears used for the transmission mechanism are formed of appropriate resin materials, respectively, so that a predetermined strength is maintained and the device is maintained. Another challenge is to reduce the overall size and weight.

[0009]

In order to solve the above-mentioned problems, the present invention, as set forth in claim 1, has a steering mechanism connected to a rear wheel of a vehicle, a winding portion and a rotor. An actuator for driving a steering mechanism and a cylindrical housing for accommodating the actuator are provided, and a winding portion and a rotor of the actuator and a driving force of the actuator connected to the rotor are provided in the housing. In a rear wheel steering angle control device configured by arranging a transmission mechanism for transmitting to a mechanism adjacent to each other, the transmission mechanism connects a ring gear fixed to an inner surface of the housing and a shaft connected to the rotor to the same shaft as the ring gear. A sun gear that rotates together with the rotor at the center, and a plurality of planetary gears that are interposed and connected between the sun gear and the ring gear are provided. The integrally molded on the inside of the housing, in which the winding portion was be configured to fixedly accommodated in the housing by fee.

According to a second aspect of the present invention, there is provided the rear wheel steering angle control device.
As described in (1), a bearing that rotatably supports the rotor may be integrally held at one end of a ring gear that is integrally molded with a resin material inside the housing.

Further, in the above rear wheel steering angle control device, as described in claim 3, the ring gear and the sun gear are made of a resin material containing a predetermined amount of glass fiber, and the planetary gear is made of glass fiber. It is desirable to form it with a resin material not containing.

[0012]

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows a rear wheel steering angle control device according to an embodiment of the present invention, which includes a steering mechanism (not shown) such as a knuckle arm and a ball joint connected to rear wheels (not shown) of a vehicle. , A rear wheel is connected to both ends of the drive shaft 6 shown in FIG. 1 via a ball joint or the like, and the steering angle control of the rear wheel is performed according to the axial movement of the drive shaft 6. It is configured to First, the housing 10 has, for example, a main body 11 of a steel tube having a circular cross section, bearings 12 and 13 made of, for example, aluminum are joined to both ends of the main body 11, and the drive shaft 6 is inserted through the centers of the bearings 12 and 13. Is slidably supported. A spline 6b is formed at one end of the drive shaft 6, and a groove 13b that meshes with the spline 6b is formed at the opening end of the bearing portion 13.
Is configured so as not to rotate relative to the bearing portions 12 and 13. A bush 12b is interposed between the drive shaft 6 and the bearing portion 12.

In the main body 11 of the housing 10, a cylindrical molding portion 2 is integrally formed by molding a resin material containing a predetermined amount of glass fiber, and the transmission mechanism 7 is formed therein. There is. Furthermore, in the main body 11,
The three-phase winding portion 3, the rotor 4, the magnet 5, and the like are housed so as to be adjacent to the molding portion 2, and the actuator 1 of the three-phase motor is constituted by these. The rotor 4 is connected to the drive shaft 6 via a transmission mechanism 7 in the molding unit 2, and the rotation of the rotor 4 in the transmission mechanism 7 includes two sets of first and second planetary gear mechanisms (typically 70). The rotational movement of the rotor 4 is converted into a reciprocating movement in the axial direction of the drive shaft 6 and transmitted by the conversion mechanism 80 after being decelerated via the ().

Molding portion 2 formed inside the main body portion 11
Has the first and second planetary gear mechanisms 70, 70 on its inner surface.
The ring gear 72 is integrally formed, and the bearing 91 is integrally fixed to one end of the ring gear 72. This bearing 9
For example, a ball bearing is used as shown in FIGS. 1 and 2. Further, the molding portion 2 for the main body portion 11 is formed by the convex portion 11c formed inside the main body portion 11.
Is configured to be prevented from moving. Therefore, the ring gear 72 is integrally fixed to the housing 10.

In the winding portion 3, a coil 3a is wound around a laminated core 3b, and a resin holder 3d holding a lead 3c for energizing the coil 3a is molded in a cylindrical shape by a resin material and supported. A cylindrical subassembly including the portion 3e is configured. The subassembly including the winding portion 3 is housed in the main body portion 11, fitted closely to the inner surface of the main body portion 11, and the rotor 4 and the drive shaft 6 are housed in the hollow portion of the winding portion 3. Is configured. Therefore, the heat generated in the winding portion 3 is easily radiated through the main body portion 11.

On the other hand, the rotor 4 is made of a steel pipe having a circular cross section, and a step portion 4a having a concentric circular cross section is formed on one end side thereof.
A recess 4b is formed on the other end side. On the outer side surface of the rotor 4, a magnet 5 composed of a pair of permanent magnets formed in a cylindrical shape shorter than this is fitted and joined by an adhesive. Further, the cylindrical connecting member 71 is integrally formed with the rotor 4 by molding a resin material containing a predetermined amount of glass fiber.

The connecting member 71 has a cylindrical body portion 71b joined to the rotor 4, a tooth groove is formed on an outer peripheral surface of one end portion thereof, and a sun gear 71a is integrally formed. An annular convex portion 71c is provided on the outer peripheral surface of the cylindrical body portion 71b.
Is formed, and the coupling member 71 is rotatably supported by the molding portion 2 at one end of the ring gear 72 via a bearing 91 whose inner ring is locked to the convex portion 71c. Further, on the inner surface of the connecting member 71, a resin material enters the concave portion 4b of the rotor 4 to form a convex portion 71d. As a result, the connecting member 71 is integrated with the rotor 4 and rotates about the drive shaft 6 with respect to the molding portion 2 and then the main body portion 11. A bearing 92 of a ball bearing is interposed between the step portion 4a at the tip of the rotor 4 and the bearing portion 12, and the rotor 4 also rotates about the drive shaft 6 with respect to the bearing portion 12. Therefore, after all, the rotor 4 is rotatably supported by the housing 10.

The transmission mechanism 7 is constructed as shown in an enlarged scale in FIGS. 2 to 5, and has first and second planetary gear mechanisms 7.
0 and a conversion mechanism 80. First, the sun gear 71
The first planetary gear mechanism 70 is constituted by a, the ring gear 72, and the three planetary gears 73a to 73c interposed therebetween. Planetary gears 73a to 7
The rotating shafts 74a to 74c of 3c are supported between the holding member 78 and the annular plate 75b of the connecting member 75, and the sun gear 75a integrally formed with the annular plate 75b is arranged around the axis of the drive shaft 6. Has been done.

The planetary gears 76a to 76c are interposed between the sun gear 75a and the ring gear 72 to form the second planetary gear mechanism 70, and the rotary shafts 77a to 77a.
7c is supported between the holding member 79 and the nut 81 of the conversion mechanism 80. The holding member 78 and the annular plate 7
5b and between the holding member 79 and the nut 81 are three pins (represented by 78p and 79p, respectively).
Are supported and the respective gaps are maintained. The nut 81 is made of, for example, brass and formed in a cylindrical shape, and is rotatably supported on the inner surface of the main body 11 via a bearing 93 of a ball bearing. A screw groove (female screw) is formed in the hollow portion of the nut 81, and the trapezoidal screw (male screw) 6 a of the drive shaft 6 is arranged so as to mesh with this screw groove.

In this embodiment, the molding portion 2 including the ring gear 72 and the connecting members 71 and 75 including the sun gears 71a and 75a are both made of a resin material containing a predetermined amount of glass fiber. As described above, since the resin material contains the glass fiber, the strength is increased, the axial length of each gear can be shortened, and the size can be reduced. On the other hand, the planetary gears 73a to 73c and 76
a to 76c are made of a resin material containing no glass fiber. Therefore, at the time of meshing these planetary gears with the ring gear 72 and the sun gears 71a and 75a, the resin material containing the glass fiber and the resin material not containing the glass fiber are meshed with each other, and the glass fiber is contained. The meshed state of the resin materials is avoided, and the wear between the gears can be reduced.

When the rotor 4 rotates, the sun gear 71a integral with the rotor 4 rotates, but since the ring gear 72 is fixed to the main body 11 of the housing 10, the planetary gears 73a to 73c are centered on the sun gear 71a. Revolve around. Thereby, the planetary gears 73a to 73a
The connecting member 75 supporting c rotates, and therefore the sun gear 7
5a rotates. Therefore, the planetary gears 76a to 76c revolve around the sun gear 75a, and the nut 81 that supports them revolves. Since the nut 81 is supported by the housing 10 via the bearing 93, the nut 81 rotates around the drive shaft 6, but does not move in the axial direction of the drive shaft 6. A trapezoidal screw 6a that meshes with the nut 81 is formed integrally with the drive shaft 6, and the drive shaft 6 is held by the spline 6b and the groove 13b so as not to rotate with respect to the bearing portion 13. Therefore, the trapezoidal screw 6a moves in the axial direction, and eventually the drive shaft 6 moves in the axial direction. That is, in the transmission mechanism 7, the rotational movement of the rotor 4 is decelerated by the first and second planetary gear mechanisms 70, and further converted into the linear movement of the drive shaft 6 by the conversion mechanism 80 and transmitted.

On the other hand, as shown in FIG. 1, a magnetic pole sensor 40 serving as a relative steering angle detection sensor is provided in the main body 11 of the bearing 12.
The rear wheel steering angle sensor 60, which is an absolute steering angle detection sensor, is provided outside the main body 11. The magnetic pole sensor 40 detects the position of the magnetic pole of a permanent magnet (not shown) that rotates together with the rotor 4, which is the rotor.
A permanent magnet is buried in the rotary plate 44 fitted in the bearing 12, and a hall element (not shown) is arranged in the bearing 12 so as to face the permanent magnet. The detection signal of the magnetic pole sensor 40 is input to, for example, an input port of a microcomputer (not shown), the position of the magnetic pole is detected by the microcomputer based on the detection signal, and the phase switching signal is sent based on the position of the magnetic pole. It is output from an output port (not shown). The rear wheel steering angle sensor 60 is composed of, for example, a potentiometer, and this detection signal is supplied to the microcomputer. Thus, the steering angle initial value (absolute steering angle) initially set based on the detection signal of the rear wheel steering angle sensor 60 and the steering angle change amount (relative steering angle) obtained based on the output signal of the magnetic pole sensor 40. Corner), rear wheel (not shown)
The actual steering angle of is required. Note that the specific contents of the steering angle control including the energization control for the coil 3a are well known in the art. The steering angles are controlled so that they match.

A method of manufacturing the rear wheel steering angle control device having the above-described structure will be described. First, the convex portion 11c is formed by stamping from the outside of the main body portion 11 of the steel pipe, and the inner surface on one end side of the main body portion 11 is formed. The molding part 2 is molded with a resin material containing glass fibers. At this time, the ring gear 72 is formed at the same time, and the outer ring of the ball bearing forming the bearing 91 is integrally molded. Also,
Since the concave portion corresponding to the convex portion 11c is formed in the molding portion 2, it does not move with respect to the main body portion 11. Next, the subassembly of the winding portion 3 configured as described above is pushed from the other end side of the main body portion 11 until the step portion of the main body portion 11 and the end portion of the winding portion 3 come into contact with each other.

On the other hand, after the magnet 5 is fitted to the rotor 4, a cylindrical connecting member 71 is integrally formed by molding a resin material containing glass fiber.
The connecting member 71 is formed with the sun gear 71a, the cylindrical body portion 71b, and the convex portion 71c as described above. Then, the rotating plate 44 is fitted to the rotor 4, and the bearing 9 is attached to the step portion 4a.
After 2 is fitted, it is inserted into the hollow portion of the winding portion 3 and is pushed in until the convex portion 71c of the connecting member 71 comes into contact with the inner ring of the bearing 91.

Next, regarding the right side portion of FIG.
After the inner ring of the bearing 93 is fitted to the outer peripheral surface of the and the nut 81 supports one end of each of the rotating shafts 77a to 77c, the planetary gears 76a to 76c made of a resin material containing no glass fiber are mounted respectively. To be done. Further, a holding member 79 is attached, and the other ends of the rotary shafts 77a to 77c are supported by the holding member 79. At this time, for example, pin 79p
All three are pressed into the nut 81 and the holding member 79 is fixed to the nut 81. Then, the sun gear 75a of the connecting member 75 formed of a resin material containing glass fiber,
It is mounted so as to mesh with the planetary gears 76a to 76c, and the rotating shafts 74a to 74c are supported by the annular plate 75b on the opposite side. These rotating shafts 74a
The planetary gears 73a to 73c made of a resin material containing no glass fibers are mounted on the base plates 74 to 74c, respectively, and then the holding member 78 is mounted on the planetary gears 73a to 73c, for example, three pins 78p are fixed by caulking. Then, the drive shaft 6 is inserted into the housing 10, and the trapezoidal screw 6 a of the drive shaft 6 is screwed into the nut 81.

Thus, these subassemblies are housed in the ring gear 72 from the right side of FIG. 1, and the planetary gears 73a to 73c and the planetary gears 76a to 76 are included.
c meshes with the ring gear 72, and the outer ring of the bearing 93 is fitted on the inner surface of the main body portion 11 adjacent to the ring gear 72. Finally, the bearings 12 and 13 are inserted into the drive shaft 6, fitted into the body 11, and then locked by the body 11 by the lock nut 14. After being assembled in this way, ball joints 100 are screwed onto both ends of the drive shaft 6, respectively. Thus, the housing 10 is configured as shown in FIG. 1, and the magnetic pole sensor 40, the actuator 1, and the components forming the transmission mechanism 7 are accommodated in the housing 10.

[0027]

Since the present invention is configured as described above, the following effects can be obtained. That is, the rear wheel steering angle control device according to the first aspect is configured such that the ring gear of the transmission mechanism is integrally molded with the resin material inside the housing, and the winding portion is housed and fixed in the housing. ,
The entire device can be made small and lightweight without impairing the dimensional accuracy of the ring gear.

Further, in the rear wheel steering angle control device according to the second aspect of the invention, the bearing for rotatably supporting the rotor is also configured to be integrally held at one end of the ring gear. The number of steps can be reduced.

Further, in the rear wheel steering angle control device according to the third aspect, the ring gear and the sun gear are made of a resin material containing a predetermined amount of glass fiber, and the planetary gear is made of a resin material containing no glass fiber. Since it is formed, the wear between the gears can be suppressed as much as possible while maintaining the predetermined strength, the durability can be secured, and the length in the axial direction can be shortened, so that it is possible to further reduce the size and weight.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a rear wheel steering angle control device according to an embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view showing a part of a rear wheel steering angle control device according to an embodiment of the present invention.

FIG. 3 is a sectional view taken along line AA of FIG. 2;

FIG. 4 is a B-state in which a holding member 78 is removed in FIG.
It is a B sectional view.

5 is a cross-sectional view taken along line CC of FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 actuator 2 molding part 3 winding part, 3a coil, 3b laminated core 4 rotor 5 magnet 6 drive shaft, 6a trapezoidal screw, 6b spline 7 transmission mechanism 10 housing 11 main body part, 11c convex part 12, 13 bearing part 40 magnetic pole sensor 60 rear wheel rudder angle sensor 70 planetary gear mechanism 71 connecting member, 71a sun gear, 71b
Cylindrical body part 72 Ring gear 73a-73c Planetary gear 74a-74c Rotating shaft 75 Connecting member, 75a Sun gear, 75b
Annular plate 76a-76c Planetary gear 77a-77c Rotating shaft 78,79 Holding member 80 Conversion mechanism 81 Nut 91,92,93 Bearing

Front page continued (72) Inventor Tsukasa Watanabe 2-1-1 Asahi-cho, Kariya city, Aichi, Aisin Seiki Co., Ltd. (72) Inventor Kaoru Ohashi 1-cho, Toyota-cho, Aichi prefecture Toyota Motor Co., Ltd. (72 ) Inventor Hisashi Masuda 1 Toyota-cho, Toyota-shi, Aichi Toyota Motor Co., Ltd.

Claims (3)

[Claims] 1. A steering mechanism connected to a rear wheel of a vehicle, an actuator having a winding portion and a rotor for driving the steering mechanism, and a cylindrical housing for accommodating the actuator. A rear wheel steering angle control device in which a winding portion and a rotor of the actuator and a transmission mechanism that is connected to the rotor and transmits the driving force of the actuator to the steering mechanism are adjacently arranged. A ring gear fixed to the inner surface of the housing, a sun gear connected to the rotor and rotating together with the rotor about the same axis as the ring gear, and a sun gear and the ring gear interposed between the sun gear and the ring gear. A plurality of planetary gears, and the ring gear is integrally molded with a resin material inside the housing, and the winding portion is housed in the housing. A rear wheel rudder angle control device characterized in that the rear wheel steering angle control device is configured to be fixed. 2. A bearing for rotatably supporting the rotor is integrally held at one end of a ring gear integrally molded with a resin material inside the housing. The described rear wheel steering angle control device. 3. The ring gear and the sun gear are made of a resin material containing a predetermined amount of glass fibers, and the planetary gear is made of a resin material containing no glass fibers. Rear wheel steering angle control device.