JPH09118246A - Rear wheel steering angle control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the number of assembling processed and reduce the cost by providing such a structure as to be capable of easily connecting a rotor to a magnet in a rear wheel steering angle control device having an actuator having the rotor and the magnet to drive the steering mechanism of a rear wheel. SOLUTION: This device has an actuator 1 for driving a steering mechanism connected to the rear wheel of a vehicle, and the actuator 1 has a rotor 4 and a magnet 5. The rotor 4 and the magnet 5 have recessed parts formed on the mutually opposed surfaces, respectively, and a resin material is filled in the clearance between the both including the recessed parts followed by hardening to connect the both. Instead of the recessed parts, grooves may be formed on the mutually opposed positions of the rotor 4 and the magnet 5, respectively.

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 rear wheels of a vehicle, the actuator having a rotor and a magnet attached to the rotor. This relates to a 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. In the electric motor described in the publication, a permanent magnet is fixed to the motor shaft, and a winding and a core are arranged around them.

[0003]

In the steering control device described in the above publication, since the motor shaft is arranged in the direction orthogonal to the rack which is the drive shaft connected to the steering mechanism for the rear wheels, The whole becomes large. On the other hand, there has been proposed an actuator in which a screw is formed on a drive shaft, a nut screwed with the drive shaft is rotatably supported on a housing, and a motor is built in the housing. In this case, generally, the driving force of the motor is configured to be transmitted to the nut through the transmission mechanism, and a cylindrical rotor that is a rotor is arranged around the drive shaft, and the magnet is attached to the rotor. It is fixed. The winding portion is fixed to the housing so as to surround them.

In the actuator having the above-mentioned structure, an adhesive is generally used as a means for fixing the magnet to the rotor. However, the number of assembling steps is large, which not only causes a cost increase, but also There is concern about peeling. However, if a means such as screwing is used, the number of parts increases and the number of assembly steps cannot be reduced. Therefore, not only the number of parts is large and the entire device is large,
The assembly man-hour is large and the cost is increased.

Therefore, in the present invention, in a rear wheel steering angle control device having an actuator for driving a rear wheel steering mechanism having a rotor and a magnet, the rotor and the magnet can be easily provided without the need for an adhesive or the like. It is an object to reduce the number of assembling steps and to reduce the cost by adopting a structure capable of joining.

[0006]

In order to solve the above-mentioned problems, the present invention comprises, as described in claim 1, a steering mechanism connected to the rear wheels of a vehicle and an actuator for driving the steering mechanism. In the rear wheel steering angle control device in which the actuator includes a rotor and a magnet mounted on the outer surface of the rotor, the rotor and the magnet each have a concave portion formed on a surface facing each other, and the concave portion is included. The gap between the rotor and the magnet is filled with a resin material and cured to connect the rotor and the magnet.

Further, according to the present invention, as described in claim 2, the cylindrical housing, the cylindrical winding portion fitted on the inner surface of the housing, and the hollow portion of the winding portion are inserted. And a drive shaft supported by the housing, a rotor interposed between the drive shaft and the winding portion and supported by the housing so as to be rotatable around the drive shaft, and the rotor facing the winding portion. A magnet mounted on the outer surface of the rotor at a position, and a transmission mechanism that converts rotational movement of the rotor into linear movement of the drive shaft and transmits the linear motion of the drive shaft via a connecting member connected to the rotor. In a rear wheel steering angle control device connected to a steering mechanism of a vehicle, the magnet is formed in a cylindrical shape having an inner diameter larger than an outer diameter of the rotor and is arranged coaxially with the rotor, and each of the rotor and the magnet is arranged. Are facing each other To form a parallel grooves and the axis of rotation of each said rotor plane, may be formed of the connecting member is filled cured gaps resin material of the rotor and the magnet containing groove.

According to a third aspect of the present invention, there is provided the rear wheel steering angle control device.
It is preferable that the grooves formed in each of the rotor and the magnet are formed at positions facing each other.

[0009]

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 pipe having a circular cross section, and bearings 12 and 13 made of resin, for example, are joined to both ends of the main body 11.
The drive shaft 6 is slidably supported through the center of the shaft 3. 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 open end of the bearing portion 13. It is configured so as not to rotate relatively. 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, and a three-phase winding portion 3, a rotor 4, a magnet 5 and the like are housed. The actuator 1 of the three-phase motor is constituted by these components. The rotor 4 is connected to the drive shaft 6 via the transmission mechanism 7 in the molding unit 2,
In the transmission mechanism 7, after the rotation of the rotor 4 is decelerated via the first and second two sets of planetary gear mechanisms (representatively represented by 70), the rotational movement of the rotor 4 is reduced by the conversion mechanism 80. 6
Is converted into a reciprocating motion in the axial direction and transmitted.

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.

The coil 3a is wound around the laminated core 3b, and the winding portion 3 is molded into a cylindrical shape by a resin material together with a resin holder 3d for holding a lead 3c for energizing the coil 3a. 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, as shown in an enlarged view in FIGS. 3 and 4, the rotor 4 is made of a steel pipe having a circular cross section and has stepped portions 4a, 4b and 4c having a concentric circular cross section. Further, in a state in which the magnet 5 of a cylindrical permanent magnet shorter than this is fitted to the outer surface of the step portion 4c of the rotor 4,
A cylindrical connecting member 71 formed by molding a resin material.
Are integrally formed. The inner diameter of the magnet 5 is set to be slightly larger than the outer diameter of the stepped portion 4c of the rotor 4, and a gap is formed between the two, and the outer surface of the rotor 4 and the inner surface of the magnet 5 are opposed to each other and have a shaft. The key grooves 4k and 5k extending in the direction are formed. Therefore, when the connecting member 71 is molded, the gap between the rotor 4 and the magnet 5 and the resin between the key grooves 4k and 5k are formed. The material penetrates and they are firmly bonded.

As shown in FIG. 3, the connecting member 71 has a cylindrical body portion 71b joined to the rotor 4, a tooth groove is formed on the outer peripheral surface of one end portion thereof, and a sun gear 71a is integrally formed. It has a shape. An annular convex portion 71c is formed on the outer peripheral surface of the cylindrical body portion 71b.
Via the bearing 91 whose inner ring is locked to c, the connecting member 71
Is rotatably supported by the molding portion 2 at one end of the ring gear 72. As a result, the connecting member 71 rotates about the drive shaft 6 with respect to the molding portion 2 and then the main body portion 11. A bearing 92 made of, for example, a sintered metal is interposed between the step portion 4a at the tip of the rotor 4 and the bearing portion 12, and the rotor 4 drives the drive shaft 6 also with respect to the bearing portion 12. As a result, 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 7, and the first and second planetary gear mechanisms 7 are provided.
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 constitute the second planetary gear mechanism 70, and the rotary shafts 77a to 7a.
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.

FIG. 9 is an enlarged view showing an example of a meshing portion between the screw groove of the nut 81 and the trapezoidal screw 6a of the drive shaft 6, and the grooves 81r and 6r are opposed to each other on their tooth surfaces. Has been formed. These grooves 81r and 6r are formed so that a part of each overlaps, and when grease is supplied between the nut 81 and the trapezoidal screw 6a, the grooves 81r and 6r.
It is configured to accumulate in r. Then, the nut 81
The rotation of does not prevent the grease from being supplied between the nut 81 and the trapezoidal screw 6a by applying a centrifugal force to the grease, and the grease is securely held between the grooves 81r and 6r. As a result, good durability can be secured without causing wear or seizure of the threaded portion.

FIG. 10 is an enlarged view showing another example of the meshing portion between the screw groove of the nut 81 and the trapezoidal screw 6a of the drive shaft 6, in which the convex portion 6p is formed on the tooth surface of the trapezoidal screw 6a. The central part of the surface is formed into a raised curved surface. This is because if the tooth surface of the trapezoidal screw 6a is a flat surface, a difference in the left and right surface contact due to the inclination of the drive shaft 6 and the like causes a left-right difference in efficiency, and especially a large difference in reverse input characteristics. The difference between the left and right contact surfaces is kept small. That is, by forming the curved convex portion 6p on the trapezoidal screw 6a as shown in FIG. 10, stable reverse input characteristics can be secured.

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 motion of the rotor 4 is decelerated by the first and second planetary gear mechanisms 70, and further converted into the linear motion of the drive shaft 6 by the conversion mechanism 80 and transmitted.

On the other hand, a magnetic pole sensor 40, which is a relative steering angle detection sensor, and a rear wheel steering angle sensor 60, which is an absolute steering angle detection sensor, are arranged close to the bearing portion 12. The magnetic pole sensor 40 is formed by mounting three Hall elements (representatively represented by 42) on a substrate 41 and screwing the substrate 41 to the bearing portion 12. A magnet 43 is supported by a rotating plate 44 so as to face the Hall elements 42, and magnetic poles N and S are alternately formed on the magnet 43 as shown in FIG. The center of the rotary plate 44 is fitted to the step 4b (FIG. 3) on the outer peripheral surface of the rotor 4, and rotates together with the rotor 4. Since the magnetic poles of the magnet 43 rotate according to the rotation of the rotor 4, pulse signals corresponding to the rotation of the rotor 4 are output from the three Hall elements 42. In the rear wheel steering angle sensor 60, a hall element 62 is mounted on the bearing portion 12, and a magnet 63 is embedded in the drive shaft 6 at a position facing the hall element 62. The Hall element 62 is connected to the substrate 41 via a plurality of leads 64 (only one is shown in FIG. 1). This substrate 4
1 includes a detection circuit (not shown) for both the magnetic pole sensor 40 and the rear wheel steering angle sensor 60.

The magnetic pole sensor 40 detects the position of the magnetic pole of the rotor 4, which is the rotor. The detection signal is input to, for example, an input port of a microcomputer (not shown), and the microcomputer detects the detected signal. The position of the magnetic pole is detected, and a phase switching signal is output from an output port (not shown) based on the position of the magnetic pole. Also,
The detection signal of the rear wheel steering angle sensor 60 is supplied to the microcomputer, and 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 output of the magnetic pole sensor 40. The actual steering angle of the rear wheels (not shown) is determined from the steering angle change amount (relative steering angle) determined based on the signal. Since the specific contents of the steering angle control including the energization control for the coil 3a are the same as the method described in Japanese Patent Laid-Open No. 7-2122, the description thereof will be omitted.

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. 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. In addition, the molding portion 2 has a convex portion 11c.
Since the concave portion corresponding to is formed, 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 inserted into the main body portion 11 from the other end side of the main body portion 11, and the step portion of the main body portion 11 and the winding portion 3 are inserted.
It is pushed in until the ends of the contact.

On the other hand, the magnet 5 is fitted to the rotor 4 with a slight gap, and is held at a position where one end of the magnet 5 abuts on the end face of the stepped portion 4c (FIG. 3). -Shaped connecting member 71 is integrally formed.
At this time, since the resin material enters between the annular gap between the rotor 4 and the magnet 5 and the key grooves 4k, 5k of the both, the rotor 4, the magnet 5 and the connecting member 71 are firmly joined together. Relative rotation between them is prevented. That is, a so-called key is integrally formed of the resin material forming the connecting member 71. In addition, the keyway 4
It is desirable that the connecting member 71 is formed at a position where k and 5k face each other, but the positions of the key grooves 4k and 5k may be shifted. Also, instead of the keyways 4k and 5k,
A recess having a desired shape may be formed. Furthermore,
The sun gear 71a, the cylindrical body portion 71b, and the convex portion 71c are formed on the connecting member 71 as described above. And the rotor 4
After the rotary plate 44 is fitted to the stepped portion 4b and the bearing 92 is fitted to the stepped portion 4a, the rotary plate 44 is inserted into the hollow portion of the winding portion 3, and the convex portion 71c of the connecting member 71 is attached to the inner ring of the bearing 91. It is pushed until it touches.

Next, regarding the right side portion of FIG.
After the inner ring of the bearing 93 is fitted on 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 are mounted respectively. 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, all the three pins 79p are press-fitted into the nut 81 so that the holding member 7
9 is fixed to the nut 81. Subsequently, the sun gear 75a of the connecting member 75 is mounted so as to mesh with the planetary gears 76a to 76c, and on the opposite side thereof, the annular plate 75 is attached.
The rotating shafts 74a to 74c are supported with respect to b. These rotary shafts 74a to 74c are provided with planetary gears 73, respectively.
After the a to 73c are mounted, the holding member 78 is mounted and, for example, the three pins 78p are caulked and fixed. 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.

These subassemblies are accommodated 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 main body 11, and then locked by the main body 11 by the lock nuts 14 and 15. After being assembled in this way, ball joints 100 are screwed onto both ends of the drive shaft 6, respectively. Thus, as shown in FIG. 1, the housing 10 is configured, and the magnetic pole sensor 40, the rear wheel steering angle sensor 60, and the components forming the actuator 1 and the transmission mechanism 7 are accommodated therein.

[0026]

Since the present invention is configured as described above, the following effects can be obtained. That is, in the rear wheel steering angle control device according to the first aspect of the present invention, the rotor and the magnet each have a concave portion formed on each of the surfaces facing each other, and the gap between the rotor and the magnet including the concave portion is filled with a resin material and cured. Since the rotor and the magnet are connected to each other, the rotor and the magnet can be easily and reliably joined together. Moreover, the number of parts is smaller than that of the conventional device, and the number of assembling steps can be reduced, so that the cost can be reduced.

Particularly, in the rear wheel steering angle control device according to the second aspect, the magnet is formed in a cylindrical shape having an inner diameter larger than the outer diameter of the rotor and is arranged coaxially with the rotor, and each of the rotor and the magnet is arranged. Grooves are formed on the surfaces facing each other in parallel to the rotation axis of the rotor, and the gap between the rotor and the magnet including the grooves is filled with resin material and cured to form the connecting member. The rotor and the magnet can be bonded more easily and reliably, and the number of assembling steps can be reduced.

Further, in the rear wheel steering angle control device according to a third aspect of the present invention, the grooves formed in the rotor and the magnet are formed at the positions facing each other, so that the rotor and the magnet are formed. Can be joined more reliably.

[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 cross-sectional view showing a rotor, a magnet and a connecting member according to an embodiment of the present invention.

FIG. 4 is a sectional view taken along line DD of FIG. 3;

5 is a view of FIG. 2 with the holding member 78 removed;
FIG. 3 is a sectional view taken along line A.

FIG. 6 is a sectional view taken along line BB of FIG. 2;

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

FIG. 8 is a front view showing a magnet for a magnetic pole sensor according to an embodiment of the present invention.

FIG. 9 is an enlarged sectional view showing an example of a meshing portion between a trapezoidal screw and a nut of a drive shaft according to an embodiment of the present invention.

FIG. 10 is an enlarged cross-sectional view showing another example of the meshing portion of the trapezoidal screw and the nut of the drive shaft according to the embodiment of the present invention.

[Explanation of symbols]

1 actuator 2 molding part 3 winding part 3a coil, 3b laminated core, 3c lead,
3d holder 4 rotor, 4k, 5k key groove 5 magnet 6 drive shaft, 6a trapezoidal screw, 6b spline 7 transmission mechanism 10 housing 11 body part, 11c convex part 12,13 bearing part 40 magnetic pole sensor, 41 substrate 42 hall element, 43 Magnet 44 Rotating plate 60 Rear wheel rudder angle sensor 62 Hall element, 63 Magnet 64 Lead 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

Claims (3)

[Claims] 1. A rear wheel steering angle control device comprising: a steering mechanism connected to a rear wheel of a vehicle; and an actuator for driving the steering mechanism, the actuator comprising a rotor and a magnet mounted on an outer surface of the rotor. The rotor and the magnet are each formed with a concave portion on a surface facing each other, and a resin material is filled and cured in a gap between the rotor and the magnet including the concave portion to connect the rotor and the magnet. A characteristic rear wheel steering angle control device. 2. A cylindrical housing, a cylindrical winding portion fitted to an inner surface of the housing, a drive shaft which is inserted through a hollow portion of the winding portion and supported by the housing, and the drive shaft. A rotor that is interposed between the winding part and the winding part and is supported by the housing so as to be rotatable about the drive shaft; a magnet that is mounted on an outer surface of the rotor at a position facing the winding part; A rear wheel steering angle control device, comprising: a transmission mechanism that converts rotational movement of the rotor into linear movement of the drive shaft and transmits the linear motion of the drive shaft via a connecting member that connects to the rotor, and connects the drive shaft to a steering mechanism of a vehicle. In, the magnet is formed in a cylindrical shape having an inner diameter larger than the outer diameter of the rotor and is arranged coaxially with the rotor, and the rotor and the magnet respectively have rotation shafts on the surfaces facing each other. Form a groove parallel to The rear wheel steering angle control device is characterized in that the connecting member is formed by filling and hardening a resin material in a gap between the rotor and the magnet including the groove. 3. The rear wheel steering angle control device according to claim 2, wherein grooves formed in each of the rotor and the magnet are formed at positions facing each other.