JPH07285446A - Lubricating device for linear actuator - Google Patents

Abstract

PURPOSE:To obviate the necessity for inspection and grease supply in a short period by preventing wearing or the like in a screw part of an actuator output shaft over a long period of time. CONSTITUTION:Annular grease reservoir spaces 41e, 41c are provided respectively along internal/external peripheral walls in the central part of a nut 41, to connect these spaces by a communication hole 41d charged with grease. The periphery of the nut 41 is covered with a lock nut, to close the grease reservoir space 41c.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lubricating device for a linear actuator.

[0002]

2. Description of the Related Art For example, a linear actuator is used as an actuator for steering the rear wheels of an automobile. In this type of linear actuator, it is generally necessary to convert the rotational force of the electric motor, which is the drive source, into a moving force in the axial direction of the output shaft. Therefore, a nut that is rotatably supported is connected to the drive shaft of the electric motor, and a screw formed on the output shaft of the actuator is engaged with the nut. It is configured to move in its axial direction.

In this type of linear actuator, a relatively large force is applied to the output shaft from the load side (that is, the wheels), so that the screw portion, which is the connecting portion between the output shaft and the nut, is also compared in the axial direction. A great deal of power is added. Therefore, unless the frictional force is particularly reduced in these screw portions, inconveniences such as generation of gear noise during driving, heat generation of the screw portions, abnormal wear, and defective operation of the actuator are likely to occur.

Therefore, for this type of screw portion, conventionally, by applying grease to the contact surface, the frictional force at the contact portion is reduced so that the above-mentioned inconvenience does not occur. is there.

[0005]

However, even if a large amount of grease is applied, if the relative movement operation of the screw portion is repeated with the operation of the actuator,
Since the grease applied to that part scatters or diffuses over time, the grease is almost completely eliminated in the screw part within a relatively short period of time, frictional force increases and heat is generated, abnormal wear of the screw, actuator -There was a possibility that a malfunction of the data might occur. In order to eliminate such a problem, it is necessary to periodically apply grease in a short cycle, which increases the burden of inspection and maintenance.

Therefore, it is an object of the present invention to prevent the grease applied to the screw portion from disappearing in a short period of time in a linear actuator, and reduce the burden of repair, inspection, maintenance and the like.

[0007]

In order to solve the above problems, according to the present invention, a drive shaft (6) movably supported in the axial direction, a screw (6a) formed on the drive shaft, and In a lubrication device for a linear actuator including a nut (41) meshing with a screw and a drive mechanism connected to the nut and rotationally driving the nut: a first grease formed in an intermediate portion of an inner peripheral surface of the nut. Reservoir space (41e); second grease reservoir space (41c) formed along the outer peripheral surface of the nut; smaller than the first and second grease reservoir spaces, and the first grease reservoir space At least one communication hole (41 communicating with the second grease reservoir space)
d); and a sealing member (44) which covers the outside of the nut and closes the opening of the second grease reservoir space.

According to a second aspect of the present invention, the first grease reservoir space is an annular groove formed along the inner peripheral surface of the nut, and the second grease reservoir space is the outer peripheral surface of the nut. It is an annular groove formed along.

According to a third aspect of the present invention, screws (41f, 44a) that mesh with each other are formed on the outer peripheral surface of the nut and the inner peripheral surface of the sealing member, and the screw is provided at one end of the outer peripheral surface of the nut. A protrusion (41b) having a diameter larger than that of the portion is formed.

The symbols shown in parentheses are reference numerals of corresponding elements in the embodiments described later, but each constituent element of the present invention is a specific element in the embodiments. It is not limited to only.

[0011]

In the present invention, the nut (4) that meshes with the screw (6a) formed on the drive shaft of the linear actuator.
In the middle part of the inner peripheral surface of 1), the first grease reservoir space (41
e) is formed, the second grease reservoir space (41c) is formed along the outer peripheral surface thereof, and further, the first grease reservoir space and the second grease reservoir space have at least one communication hole (41d). Are in communication with each other. The opening of the second grease reservoir space is closed by a sealing member (44) that covers the outside of the nut.

Therefore, in advance, the first grease reservoir space,
By filling the second grease storage space and the communication hole with grease and then covering the nut with the sealing member, the grease can be stored in these spaces. In the first grease reservoir space, since the grease contacts a part of the screw (6a), the screw and the screw of the nut that meshes with the screw are naturally applied little by little. Further, since the first grease storage space is formed in the middle part of the nut and is not exposed to the outside, the grease in this space does not scatter to the surroundings, and is accompanied by the operation of the actuator. , Grease is gradually diffused and consumed.

Further, since the second grease reservoir space is closed by the sealing member, the grease in this space does not scatter around. Then, when the amount of grease in the first grease reservoir space is significantly reduced, the grease in the second grease reservoir space gradually moves to the first grease reservoir space through the communication hole, and the grease is automatically generated. Will be replenished. Since this communication hole is smaller than the first and second grease storage spaces, the phenomenon that the grease in the second grease storage space moves to the first grease storage space at once does not occur.
Therefore, the screw (6a, 41a) of the actuator can be continuously coated with grease for a long period of time, and heat generation and abnormal wear do not occur for a long period of time, so the burden of repair, inspection, maintenance, etc. is lightened. .

In the present invention, since the first grease reservoir space and the second grease reservoir space are annular grooves, it is possible to apply the grease evenly over the entire peripheral surface of the screw. You can

Further, in the present invention, screws (41f, 44a) meshing with each other are formed on the outer peripheral surface of the nut and the inner peripheral surface of the sealing member respectively, and the screw is provided at one end of the outer peripheral surface of the nut. Since the protrusion (41b) having a diameter larger than that of the portion is formed, by screwing the sealing member into the nut, the protrusion (41b) and the sealing member sandwich the member (for example, bearing) that supports the nut. Can be fixed. That is, since the sealing member can be used not only for closing the opening of the second grease storage space but also for fixing the support member,
The structure of the actuator is simplified.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A longitudinal sectional view of a rear wheel steering actuator according to one embodiment is shown in FIGS. 1 and 2 taken along the line A1-A2. Also,
The IX-IX line cross section of FIG. 1 is shown in FIG. The rear wheel steering actuator shown in FIGS. 1 and 2 will be described. The casing 1 of the rear wheel steering actuator is formed in a cylindrical shape and is made of iron. The casing 1 is formed by processing an iron pipe in order to reduce the cost.
Of course, if the pipe material has good heat dissipation and is easy to process,
Materials other than iron may be used. Case 1
Bearing members 15 and 16 are attached to both ends of the bearing member, respectively. The bearing members 15 and 16 are made of aluminum. The actuator shaft 6 is arranged so as to penetrate through the center of the casing 1, and the bearing member 1
It is supported by 5 and 16 so as to be movable in the axial direction.

As shown in FIG. 6, involute-shaped unevenness extending in the axial direction is formed over the entire circumference in the vicinity of the left end of the actuator shaft 6, and the spline 6 is formed.
forming d. A spline is also formed in the bearing portion 62 of the bearing member 15 that supports the spline 6d,
Since these splines mesh with each other, movement of actuator shaft 6 in the rotational direction is prevented.

FIG. 17 shows a vertical cross section of the bearing member 15.
The state seen from the XVIII-XVIII line in FIG. 17 is shown in FIG. As shown in FIGS. 17 and 18, in this embodiment,
The bearing portion 62 is not formed with splines all around, but the bearing portion 62 is provided with splined contact regions 62a, 62b, 62c and non-splineed non-contact regions 62d, 62e, 62f. And are formed. The contact areas 62a, 62b, 62c and the non-contact areas 62d, 62e, 62f are each 6 degrees at an angle in the circumferential direction.
It occupies a 0 degree area and is evenly arranged in the circumferential direction. Therefore, the actuator shaft 6 has its spline 6
The portions of d are the contact areas 62a, 6
It is supported in contact with 2b and 62c.

When the shaft is supported by a spline to prevent rotation, it is difficult to form a gap in that portion,
When supporting with a spline formed all around,
Since the contact area of that portion becomes very large, there is a problem that the sliding resistance becomes large. However, in this example, since the region forming the spline is only a part and there are regions 62d, 62e and 62f which do not contact, the bearing portion 6
The contact area between 2 and the actuator shaft 6 is relatively small,
Sliding resistance is also small.

By the way, the contact areas 62a, 62b, 62c of the spline 6d of the actuator shaft 6 and the bearing portion 62.
If there is a gap between and, when the actuator shaft 6 starts to move, it hits the bearing portion 62 and a tapping sound is generated. In order to suppress this tapping sound, in this embodiment, the bearing portion 62
Is made of resin.

The description will be continued with reference to FIGS. 1 and 2 again. In a typical usage form of the rear wheel steering actuator, steering members for the rear left wheel and the rear right wheel of the vehicle are connected to both ends of the actuator shaft 6 to form an actuator.
The rear wheel is steered by moving the shaft 6 in the axial direction.

The drive source for the actuator shaft 6 is an electric motor.
The steering wheel actuator is built in the rear wheel steering actuator and is integrally formed. Unlike the general electric motor, the electric motor of this embodiment is provided with the electric coil 2 on the stator and the permanent magnet 5 on the rotor inside the stator.
The electric coil 2 has a three-phase structure. By generating a predetermined moving magnetic field from the electric coil 2 in accordance with the position of the magnetic pole of the permanent magnet 5, the rotor integrated with the permanent magnet 5 is rotationally driven.

The configuration of the subassembly AS1 of the electric coil 2 is shown in FIG. 3, and the state seen from the line IV-IV in FIG. 3 is shown in FIG. Referring to FIGS. 3 and 4, the subassembly AS1 is formed in a cylindrical shape and has an outer diameter slightly smaller than an inner diameter of the casing 1 so that the subassembly AS1 can be disposed inside the casing 1. Has become. The electric coil 2 is
It is wound around an iron core 61 formed by stacking a large number of iron plates in the thickness direction and electrically connected to a terminal 64.

Further, a holder 3A which is preformed with a thermosetting resin is attached to the subassembly AS1.
The outer circumference of the holder 3A is located at the outermost circumference of the subassembly AS1 (excluding the terminal 64), and the outer diameter thereof is a case.
It is almost the same as the inner diameter of the thing 1. Therefore, when the subassembly AS1 is inserted into the casing 1, there is almost no gap between the inner wall of the casing 1 and the outer periphery of the holder 3A. An annular recess 3Aa is formed along the outer peripheral surface of the holder 3A, and a rubber O
A ring 46 is attached. Since the casing 1 is made of metal and the holder 3A is made of resin, when the temperature changes, a gap may occur at the boundary between them due to the difference in the coefficient of thermal expansion between the two, but there is a gap. Even if O
Since the ring 46 closes the gap, it is possible to reliably prevent intrusion of moisture or the like from the outside into the electric coil 2 or the like.

This subassembly AS1 is inserted into the casing 1 and then the resin material (thermoplastic resin) 3
By B, the casing 1 is integrally molded as shown in FIGS. Actually, the sub-assembly AS1 is positioned in the left-right direction in the drawing by the convex portion 1a of the inner wall surface formed by the convex protrusion from the outside of the casing 1, and is prevented from rotating by the convex portion 1b. After that, a predetermined mold is fitted into the mold, and the resin material 3B in a fluid state is injected into the mold. The resin material 3B is cured and molded into a shape that matches the mold. FIG. 5 shows a state in which the casing 1 and the subassembly AS1 are integrally fixed by the resin material 3B integrally molded in this way. Further, by integrally molding the resin material 3B, as shown in FIG. 5, a ring gear 12 of the planetary gear mechanism 7 described later is simultaneously formed.

By the way, when molding the resin material 3B,
Since it contracts, a gap is likely to be formed after the molding at the boundary portion 63 between the outer peripheral surface of the resin material 3B and the inner wall of the casing 1. If such a gap is created, moisture or the like from the outside will enter the actuator, thereby deteriorating the electrical parts and the like, and it is necessary to seal the gap to eliminate the gap. However, in this embodiment, since the outer peripheral surface of the preformed holder 3A is in close contact with the inner wall of the casing 1, a gap is formed in the boundary portion 63 between the outer peripheral surface of the resin material 3B and the inner wall of the casing 1. Even if it is possible, moisture is prevented from entering the electric coil 2 because it is reliably sealed at the holder 3A. Therefore, it is not necessary to specially seal the boundary portion 63. Since the boundary between the outer peripheral surface of the holder 3A and the inner wall of the casing 1 can be sealed by using the O-ring 46 made of an elastic body, the sealing is simple.

According to this embodiment, since the electric coil 2 and the iron core 61 and the casing 1 are arranged close to each other, the heat generated by the electric coil 2 is applied to the casing 1.
The temperature rise inside the actuator can be suppressed.

On the other hand, as shown in FIG. 7, the rotor of the electric motor of the actuator shown in FIGS. 1 and 2 has a cylindrical iron rotor member 4 and rotor member 4 as shown in FIG. It is composed of a cylindrical permanent magnet 5, an annular permanent magnet 13 and a power transmission member 11 mounted on the outer periphery, and both ends thereof are fixed to a bearing 10 fixed to the power transmission member 11 and a bearing member 16. It is rotatably supported by the bearing 17.

The permanent magnet 5 is made of rare earth neodymium, and as shown in FIG. 12, four magnetic poles are formed in the circumferential direction. The outer diameter of the permanent magnet 5 is slightly smaller than the inner diameter of the subassembly AS1 of the electric coil 2,
The inner diameter of the rotor member 4 is slightly larger than the outer diameter of the actuator shaft 6. Therefore, as shown in FIG. 9, this rotor includes an actuator and a subassembly AS1.
It can rotate in a ring-shaped space with the rotary shaft 6.

The power transmission member 11 is formed by integral molding of resin and has a substantially cylindrical shape. The power transmission member 11 is arranged coaxially with the rotor member 4, and is fixed to one end of the rotor member 4 integrally with the rotor member 4 by a projection 11c formed by integral molding. Further, the outer diameter of the large diameter portion 11c of the power transmission member 11 is formed to be larger than the inner diameter of the bearing 10, and the large diameter portion 1
1c fixes the bearing 10. That is, when molding the power transmission member 11, a part of the bearing 10 is also fixed integrally with it. Further, a gear 11a is formed on the outer periphery of the small diameter portion protruding from the rotor member 4 at one end of the power transmission member 11. This gear 11a constitutes one sun gear of the planetary gear mechanism 7, as shown in FIG. Therefore, when the electric motor is driven, the gear 11a of the power transmission member 11 rotates and the driving force is changed to the planetary gear mechanism 7.
Be transmitted to.

The structure of the planetary gear mechanism 7 is shown in FIG.
10 shows a section taken along line XX in FIG. 10, and FIG. 11 shows a section taken along line XI-XI in FIG. This will be described with reference to FIGS. 8, 10 and 11. The planetary gear mechanism 7 is configured by connecting two sets of planetary gears in series. As shown in FIG. 10, the first set of planetary gears is composed of a gear (sun gear) 11a, planetary gears 21, 22, 23 and 24, and a ring gear 12, and the second set of planetary gears is shown in FIG. 11, the sun gear 29a, the planetary gears 31, 32, 3
3 and 34, and the ring gear 12. Ring gear 12 commonly used by two sets of planetary gears
When integrally molding the resin member 3B on the casing 1,
Molded at the same time.

The first set of planetary gears 21, 22, 23
And 24 are rotatably supported by shafts 25, 26, 27 and 28, respectively, and the shafts 25, 26, 27 and 28 are fixed to a doughnut-shaped connecting plate 29. A second set of sun gears 29a is formed on the outer periphery of the cylindrical protruding portion provided in the central portion of the connecting plate 29. Second
The planetary gears 31, 32, 33, and 34 of the set are rotatably supported by shafts 35, 36, 37, and 38, respectively, and the shafts 35, 36, 37, and 38 have nuts 41 as shown in FIG. It is fixed to.

Therefore, when the rotor member 4 rotates, the sun gear 11a integrated with the rotor member 4 rotates, so that the planetary gears 21, 22, 23 and 24 of the first set revolve around the sun gear 11a and the planetary gear 21. , 22, 2
As the connecting plate 29 connected to the shafts 25 to 28 of 3 and 24 rotates, the second set of sun gears 29a formed on it.
Rotates, the second set of planetary gears 31, 32, 33 and 34 revolves around the sun gear 29a, and the nut 41 connected to the shafts 35 to 38 supporting the planetary gears 31, 32, 33 and 34 rotates. To do.

A front view of the nut 41 is shown in FIG. 15, and its longitudinal section is shown in FIG. As shown in FIG. 16, the nut 4
A screw hole 41g is formed on one end surface of the shaft 1 and is connected to the shafts 35 to 38 at that portion. The nut 41 is rotatably supported inside the casing 1 by a bearing 42 arranged on the outer periphery thereof, but its axial movement is prevented. The member on the outer peripheral side of the bearing 42 is sandwiched between the bearing member 15 and the step on the inner peripheral surface of the casing 1 as shown in FIG. As shown in FIG. 13, a member on the inner peripheral side of the bearing 42 that abuts on the peripheral surface of the nut 41 has one end in the axial direction abutting on the protrusion 41b and the other end side of the lock nut 44 as shown in FIG. Since it is pressed by the end surface 44d, it is fixed to the nut 41.

As shown in FIG. 16, a trapezoidal screw (having a trapezoidal thread) 41a is formed on the inner peripheral surface of the nut 41. The trapezoidal screw 41a, as shown in FIG. -It meshes with a trapezoidal screw 6a formed on the shaft 6. Therefore, when the nut 41 rotates, the trapezoidal screw 41
The screw thread of "a" moves in the axial direction, and the trapezoidal screw 6a meshing with it moves in the axial direction, so that the actuator shaft 6 moves in the axial direction. That is, the rotational movement of the planetary gear mechanism 7 is converted into the linear movement of the actuator shaft 6 by the conversion mechanism 8 including the nut 41 and the trapezoidal screw 6a. The conversion mechanism 8 may be composed of a ball screw.

By the way, a relatively large external force from the wheels is applied to the actuator shaft 6. Therefore, when the actuator shaft 6 is moved, the contact portion between the trapezoidal screw 6a that is the driving portion and the trapezoidal screw 41a of the nut 41 is
A large frictional force is generated. Therefore, the trapezoidal screws 6a, 41
Unless a lubricant such as grease is applied to the contact portion of a to reduce the friction coefficient of the portion, remarkable wear may occur in a short period of time or malfunction may occur. However, the grease applied to such a contact portion scatters around the contact portion each time the portion moves, or diffuses with the passage of time, and is not consumed in a relatively short period of time. For this reason, it is usually necessary to perform inspections at short intervals and reapply grease every time.

In this embodiment, the grease at the contact portions of the trapezoidal screws 6a and 41a is prevented from running out in a short period of time.
A special mechanism is provided. This will be described with reference to FIGS. 13, 15, 16 and 19. FIG. 19 shows XIX-X of FIG.
FIG. 9 is a sectional view taken along line IX. As shown in FIG. 16, in the central portion of the nut 41 in the axial direction, an annular groove portion 41e formed in a position along the inner peripheral surface thereof, an annular groove portion 41c formed in a position along the outer peripheral surface, and a communication hole. 41d is formed. The communication hole 41d connects the groove portions 41e and 41c. Further, as shown in FIG. 13, since the cylindrical lock nut 44 fixed with screws 44a and 41f covers the outer periphery of the nut 41, the groove 41c forms a closed annular space, that is, a grease reservoir. Further, as shown in FIG. 19, the groove portion 41e
Also forms a closed annular space, that is, a grease reservoir.

When assembling this actuator,
After the grooves 41e and 41c of the nut 41, which is a grease reservoir, and the communication hole 41d are filled with grease, the lock nut 44
Is attached to close the groove 41c. Therefore, when this actuator is used, grease is accumulated in the groove portions 41e and 41c and the communication hole 41d. And nut 4
When 1 rotates and the trapezoidal screws 41a and 6a move, the grease in the groove 41e naturally and little by little is applied to the contact portions of the trapezoidal screws 41a and 6a. Since the grease reservoir is a closed space, the grease in the space does not scatter with the operation of the actuator. When the amount of grease in the groove 41e decreases, the communication hole 41
The grease in the groove portion 41c is moved into the groove portion 41e via d and is replenished. In addition, the space of the communication hole 41d has a groove portion 4
Since it is smaller than the size of 1e and 41c, the groove 41
The grease in c does not move all at once into the groove 41e in a short time, and the grease gradually moves over time. Therefore, since the grease is held in the grease reservoir for a long period of time and the grease is consumed little by little, the grease can be continuously applied to the contact portions of the trapezoidal screws 41a and 6a for a long period of time. That is, abnormal wear or the like is unlikely to occur at the contact portion even if inspection and grease replenishment are not performed for a long period of time.

Referring to FIG. 1, on the rotor member 4,
Another small permanent magnet 13 is installed at a position apart from the permanent magnet 5. The magnetic poles formed on the permanent magnet 13 have the same arrangement as the magnetic poles of the permanent magnet 5 (see FIG. 12). Further, a hall element 9 is arranged near the permanent magnet 13. The hall element 9 is fixed on a bearing member 16 integrated with the casing 1. Therefore, when the rotor member 4 rotates and the magnetic pole of the permanent magnet 13 rotates, a pulse signal is generated from the hall element 9. The magnetic pole position of the rotor of the electric motor can be known by referring to the pulse signal output by the hall element 9.

FIG. 14 shows a cross section taken along line XIV-XIV in FIG.
2 and 14, the actuator shaft 6 is formed with an annular groove 6e, and the bearing member 15 is provided with a potentiometer 43. The tip end of the lever 43a coupled to the rotary shaft of the potentiometer 43 is engaged with the groove 6e of the actuator shaft 6. Therefore, when the actuator shaft 6 moves in its axial direction, the lever 43a rotates, so that the potentiometer 43 can output an electric signal corresponding to the position of the actuator shaft 6, that is, a position signal. it can. Since the actuator shaft 6 does not rotate, only the tip position of the lever 43a is
A notch may be provided instead of the groove 6e, but in that case, when the actuator is assembled, the actuator shaft 6
It is necessary to pay attention to the direction of. When the annular groove 6e is used as in this embodiment, it is not necessary to consider the orientation of the actuator shaft 6.

By the way, as shown in FIG. 6, the actuator shaft 6 has a large diameter portion 6b and a small diameter portion 6c having different diameters.
have. The small diameter portion 6c is a simple shaft having a constant diameter, and the large diameter portion 6b is formed with the trapezoidal screw 6a, the spline 6d and the groove 6e. Also, the small diameter portion 6c is
As shown in FIG. 1, it exists at a position that penetrates the inside of the rotor member 4.

In order to miniaturize the actuator of this embodiment, it is effective to make the diameter of the electric motor portion as small as possible. Further, since the actuator shaft 6 exists inside the electric motor, if the diameter of the actuator shaft 6 is reduced, the size of the entire electric motor arranged outside thereof can be reduced. However, since the actuator shaft 6 is required to have a sufficiently large mechanical strength, there is a limit to making the actuator shaft 6 thin. Moreover, since the actuator shaft 6 is provided with the trapezoidal screw 6a, the spline 6d and the groove 6e, the recesses have a small diameter and a small mechanical strength. Therefore, if the actuator shaft 6 is constructed by processing one shaft material with a uniform diameter, the trapezoidal screw 6
Due to the restriction of the mechanical strength of a, the spline 6d and the groove 6e, the diameter of the actuator shaft 6 in the non-machined portion has to be made considerably larger than the required mechanical strength.

In this embodiment, the large diameter portion 6b and the small diameter portion 6c are
The actuator shaft 6 is formed by processing one shaft material having the above, the large diameter portion 6b is processed to form the trapezoidal screw 6a, the spline 6d and the groove 6e, and the small diameter portion 6c. Is placed in a position that passes through the center of the electric motor without processing. The small diameter portion 6c has the minimum necessary diameter that can obtain the mechanical strength required for the actuator shaft 6. Since the large-diameter portion 6b has a large diameter of the initial material, it has a sufficiently large mechanical strength even after it is processed to form the trapezoidal screw 6a, the spline 6d, and the groove 6e as the recessed portion. Therefore, the diameter of the small diameter portion 6c of the actuator shaft 6 passing through the center of the electric motor is much smaller than that of the conventional actuator, and as a result, the size of the electric motor as a whole is also reduced. It is sufficiently miniaturized.

Next, the rear wheel steering actuator of this embodiment will be described.
The process of manufacturing the tape will be described. First, a sub-assembly AS1 is assembled by winding the electric coil 2 on a predetermined winding frame having an iron core 61, further mounting a preformed holder 3A and wiring terminals 64 and the like. In this embodiment, the electric coil 2 is wound so as to circulate in an oval shape in the cross section of FIG.

This subassembly AS1 is used as a casing 1
After being inserted into the casing 1 from the right side of FIG. 1 and fixed at a predetermined position, a mold A (not shown) and a mold B (not shown) are inserted into the casing 1 to position the mold A and the mold B. To do.

A resin material 3B in a fluidized state for molding is poured from the outside into a space (gap) formed by the casing 1, the subassembly AS1, the die A and the die B,
Fill the gap with resin. After the resin is cured, the mold A and the mold B are removed from the casing 1.

As a result, the resin member 3B is molded by the cured resin, and at the same time, the subassembly AS1 including the holder 3A is fixed in the casing 1 by the resin member 3B. The outer diameter of the mold B is
The ring gear 12 is formed on a part (inner wall) of the resin member 3B by molding since it is slightly smaller than the inner diameter of the sing 1 and has a tooth profile on a part of its outer circumference.

When manufacturing the rotor subassembly, first, the mold C and the mold D (not shown) are mounted on the rotor member 4, and the bearing 10 is arranged at a predetermined position to mount the mold C and the mold. Insert with D. Mold molding resin is injected into the gap between the mold C and the mold D (the portion of the power transmission member 11). When this resin is cured, the power transmission member 11 is formed. During this molding, the power transmission member 1
A gear (sun gear) 11a is formed on the outer periphery of the protruding portion 1 and the bearing 10 is integrally fixed. Since the hole 4a is formed at the tip of the rotor member 4, the protrusion 11b is formed on the power transmission member 11 by molding.
Is formed. Therefore, the power transmission member 11 and the rotor member 4 are reliably connected by the engagement of the hole 4a of the rotor member 4 and the protrusion 11b of the power transmission member 11. After that, the cylindrical permanent magnet 5 and the ring-shaped permanent magnet 13 are fixed onto the rotor member 4.

A nut 41 is mounted on the actuator shaft 6, shafts 35, 36, 37 and 38 are mounted on the nut 41, and the planetary gear 3 is mounted on the shafts 35, 36, 37 and 38.
1, 32, 33 and 34 are attached. Further, a connecting plate 29 is attached to the actuator shaft 6, and the connecting plate 29 is connected to the shaft 25,
26, 27 and 28 are mounted, and the planetary gears 21, 22, 23 and 24 are mounted on the shafts 25, 26, 27 and 28. Next, after mounting the rotor subassembly on the actuator shaft 6, the actuator shaft 6 together with the parts integrated with the actuator shaft 6 are placed inside the casing 1 after the molding of the mold from the left end. Insert toward the right. Further, the bearing 42 is inserted into the casing 1 from the left end side, and the lock nut 44 is fixed to the nut.
Put on 5. Then, the potentiometer 43 is attached to the bearing member 15, and further the hall element 9 and the bearing 1 are mounted.
7 and the sub-assembly in which the bearing member 16 is integrated is inserted from the right end side of the casing 1 to form the casing 1.
Fixed to.

Of course, the procedure of assembling the various parts described above is an example, and the procedure of assembling may be changed as necessary if possible.

In this actuator, since the electric coil 2 is on the casing 1 side, and the casing 1 is an iron pipe, the subassembly AS1 and the casing 1 are in direct contact with each other, or Since they are adjacent to each other via a thin resin, the heat resistance of that portion is small, and even if the actuator itself is small, the heat dissipation is very good. Further, since the electric coil 2 does not rotate, the inertia is small and a large output can be obtained even in a small size.

In the above embodiment, since the trapezoidal screw is used for the converting mechanism, the rotor does not rotate even if the wheel receives a force from the road surface, and the reverse efficiency becomes zero. Therefore, it is suitable for steering the rear wheels. In addition, if a ball screw is used for the conversion mechanism, the reverse efficiency will not be completely zero, but in this case, by taking into consideration the gear ratio of the planetary gear mechanism in advance, there will be no malfunction in operation. can do.

[0053]

As described above, according to the present invention, the screws (6a, 41a) of the actuator can be used for a long period of time.
The grease can be applied continuously, and heat and abnormal wear will not occur for a long time, so the burden of repairs, inspections, and maintenance will be reduced.

In the second aspect, since the first grease reservoir space and the second grease reservoir space are annular grooves, it is possible to apply the grease evenly over the entire peripheral surface of the screw. You can

Further, in the present invention, screws (41f, 44a) meshing with each other are formed on the outer peripheral surface of the nut and the inner peripheral surface of the sealing member, respectively, and the screw is provided at one end of the outer peripheral surface of the nut. Since the protrusion (41b) having a diameter larger than that of the portion is formed, by screwing the sealing member into the nut, the protrusion (41b) and the sealing member sandwich the member (for example, bearing) that supports the nut. Can be fixed. That is, since the sealing member can be used not only for closing the opening of the second grease storage space but also for fixing the support member,
The structure of the actuator is simplified.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing a right half of a rear wheel steering actuator according to an embodiment.

2 is a vertical cross-sectional view showing the left half of the device of FIG.

FIG. 3 is a vertical sectional view showing a subassembly of an electric coil.

FIG. 4 is a side view seen from line IV-IV in FIG.

FIG. 5 is a vertical cross-sectional view of a casing integrally formed with a resin material 3B on the inner peripheral surface thereof.

6 is a front view showing a part of the actuator shaft 6. FIG.

FIG. 7 is a vertical sectional view showing a rotor portion of the electric motor.

FIG. 8 is a vertical sectional view showing a planetary gear mechanism 7 connected to a rotor.

9 is a sectional view taken along line IX-IX in FIG.

10 is a cross-sectional view taken along line XX of FIG.

11 is a sectional view taken along line XI-XI of FIG.

12 is a sectional view taken along line XII-XII of FIG.

FIG. 13 is a vertical sectional view showing a nut 41 and a lock nut 44.

14 is a sectional view taken along line XIV-XIV in FIG.

FIG. 15 is a front view showing the outer appearance of a nut 41.

16 is a vertical sectional view of a nut 41. FIG.

17 is a vertical cross-sectional view showing the bearing member 15. FIG.

FIG. 18 is a side view taken along line XVIII-XVIII in FIG.

FIG. 19 is a vertical sectional view taken along line XIX-XIX in FIG. 13.

[Explanation of symbols]

1: Casing 1a, 1b: Convex part 2: Electric coil 3A: Holder 3Aa: Recessed part 3B: Resin material 4: Rotor member 4a: Hole 5,13: Permanent magnet 6: Actuator shaft 6a: Trapezoidal screw 6b : Large diameter part 6c: Small diameter part 6d: Spline 6e: Groove 7: Planetary gear mechanism 8: Conversion mechanism 9: Hall element 10, 17: Bearing 11: Power transmission member 11a: Gear 11b: Protrusion 11c: Large diameter part 12: Ring gear 15, 16: Bearing member 21, 22, 23, 24: Planetary gear 25, 26, 27, 28: Shaft 29: Connection plate 29a: Sun gear 31, 32, 33, 34: Planetary gear 35, 36, 37, 38: Shaft 41: Nut 41a: Trapezoidal screw 41b: Protrusion 41c: Groove 41d: Communication hole 41e: Groove 41f, 44a: Screw 42: Bearing 43: Po Inverter 43a: Lever 44: Lock nut 44a: Screw 44c: Inner peripheral surface 44d: End surface 46: O-ring 61: Iron core 62: Bearing portion 62a, 62b, 62c: Contact area 62d, 62e, 62f: Non-contact area 63: boundary part 64: terminal AS1: subassembly

Claims (3)

[Claims] 1. A linear including a drive shaft movably supported in the axial direction, a screw formed on the drive shaft, a nut meshing with the screw, and a drive mechanism connected to the nut and rotationally driving the nut. In an actuator lubricator: a first grease reservoir space formed in an intermediate portion of an inner peripheral surface of the nut; a second grease reservoir space formed along an outer peripheral surface of the nut; The second grease storage space is smaller than the second grease storage space and is smaller than the second grease storage space.
Linear actuator, which has at least one communication hole communicating with the grease reservoir space; and a sealing member that covers the outside of the nut and closes the opening of the second grease reservoir space. Lubricator. 2. The first grease storage space is an annular groove formed along the inner peripheral surface of the nut, and the second grease storage space is formed along the outer peripheral surface of the nut. The linear actuator lubricator according to claim 1, wherein the lubricator is an annular groove. 3. A screw engaging with each other is formed on each of an outer peripheral surface of the nut and an inner peripheral surface of the sealing member, and a protrusion having a diameter larger than that of the threaded portion is formed at one end of the outer peripheral surface of the nut. The lubrication device for a linear actuator according to claim 1, which has been applied.