JPS61171663A - Deceleration mechanism for solenoid-operated type booster - Google Patents

Abstract

PURPOSE:To prevent vibrations and noises from occurring, by constituting a deceleration mechanism with a combination of plural rollers having a friction transmitting surface on each outer circumferential surface. CONSTITUTION:A deceleration mechanism 50 consists of two stepped planetary mechanisms 51 and 52 being set up in the perimeter of an output shaft 7. The front step planetary mechanism 51 is constituted of a common-use ring roller 53 making an inner circumferential surface of a case 3 a friction transmitting surface, a roller 38a making the circumference at the left end side of a tube shaft 38 fitly installed in the output shaft 7, three planetary rollers 54 being interposingly installed between these rollers, and a first carrier member 55 pivotally supporting this roller 54. And, the rear step planetary mechanism 52 is constituted of a ring roller 53, a sun roller 56 making the circumference of a tubular body 56 connected to the first carrier member 55 a friction transmitting surface, three planetary rollers 57 making the circumference interposingly installed between these rollers a friction transmitting surface, and a second carrier member 58 pivotally supporting this roller 57. Each friction transmitting surface of these rollers aforesaid is formed into a V-shaped groove.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a reduction mechanism for an electromagnetic booster that boosts the rotational torque of an electric motor and transmits the torque to an output shaft.

(Prior Art) Some steering devices for automobiles and the like use electric power steering devices that use an electric motor as a drive source. This electric power steering device operates an electric motor in response to the steering force from the steering wheel to generate auxiliary torque, and reduces the rotational torque of the electric motor through a reduction mechanism composed of a combination of multiple gears to generate auxiliary torque. The power is boosted and transmitted to the output shaft, thereby reducing the steering wheel operating force.

(Problems to be Solved by the Invention) However, in the electromagnetic booster as described above, since the reduction mechanism is composed of a plurality of gears, machining errors and discrepancies in the gears of the reduction mechanism, )
41 Yamaichi 171 There was a risk that the end shaft 6 would be damaged or curled due to chewing. In particular, the vibrations generated in the speed reduction mechanism are transmitted to the steering wheel via the input shaft, hindering the improvement of steering feeling, and furthermore, lost motion due to Confederate backlash occurs, and when changing the steering wheel, However, since the rotational torque of the electric motor may not act smoothly, the steering feel may be affected.
This was the cause of hindering the second.

(Means for Solving Problems) In the present invention, the speed reduction mechanism is constituted by a combination of a plurality of rollers each having a friction transmission surface on the outer peripheral surface.

(Function) With the above configuration, torque is transmitted through the friction transmission surface without meshing parts of gears, and it is possible to eliminate noise and vibration in the reduction mechanism due to machining errors, backlash, etc.

(Example) A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

1 to 3 show the speed reduction mechanism of the electromagnetic booster of this embodiment.

In Figure 1, (1) is the steering column, (2)
is the stator, (3) is the case, and (4) and (7) are the input shaft and output shaft coaxially arranged with each other.
In this embodiment, the inner end of the input shaft (0) is loosely fitted into the inner end of the output shaft (7), while these inner ends are connected by a torsion bar (8), and the human-powered shaft (0) is fitted loosely into the inner end of the output shaft (7). 9), (t
o), the output shaft (7) is connected to the bearings (11), (12),
(13), each is rotatably supported.

Further, a steering speed sensor (20) disposed around the input shaft (4) and a steering torque sensor (torque detection means) disposed around the fitting portion of the input/output shafts (4) and (7) (2
4) and an electric motor (33) disposed around the output shaft (7).
), reduction mechanism (50), electromagnetic 5-/4- (83ゝ"+@Lf, Jlllld/cTTo6°
1 To explain in more detail, the input shaft (4) is divided into a first shaft (5) and a cylindrical second shaft (6), and the input shaft (4) is divided into a first shaft (5) and a cylindrical second shaft (6). The steering wheel, which is the handle, is fixed. Furthermore, a small diameter portion formed on the inner end side of the first shaft (5) is loosely fitted into the hole provided on the inner end side of the second shaft (6), and these fitting portions are fitted with a small diameter portion formed on the inner end side. is a rubber bush (elastic means) (10) for preventing vibration transmission,
The first shaft (5) and the second shaft (6) are connected by this rubber bush (14). Then, the first axis (5) and the second axis
The shaft (6) is elastically connected to the shaft (6) by the gong L and the bush (14), and the first shaft (5) and the second shaft (6) engage after being separated by a predetermined angle due to the gap, and are twisted. The structure is such that a load exceeding a predetermined torque is not applied to the elastic member (14c) in this direction. Note that (18) is a circlip for preventing 1 hit.

Further, grooves along the axial direction are formed at 180° intervals on the other end side (left end side in the figure) of the second shaft (6), and the grooves are formed from the inner end side of the output shaft (7) with an enlarged diameter. Projecting pieces (7a) protruding in the axial direction to correspond to the bearing ( 11) within the enlarged diameter portion of the output shaft (7). In addition, 9th & IItQ) Shide Nanaka/71
Koyama Matoi bias [de-philosophical seventh book l mountain has a torsion bar (8)
is arranged along the axis, and one end side (right end side) of this torsion bar (8) is fixed to the second shaft (6) by a pin (18), while the other end side of the torsion bar (8) is fixed to the second shaft (6) by a pin (18). pin(
19) to the output shaft (7). Output shaft (
The outer end of 7) is connected to the load-side steering gear by a spline formed therein. Therefore, the rotational torque applied to the input shaft (4) by the handle is transmitted to the output shaft (7) and the load side through the torsion of the torsion bar (8). The rigidity of the rubber bush (14) is higher than that of the torsion bar (8).

The steering speed sensor (20) includes a plurality of protrusions (21) protruding from the outer periphery of the second shaft (6) at equal intervals in the radial direction.
and a photocoupler (photoelectric pickup) (22) attached to the steering column (1) so as to sandwich this protrusion (21), and receives transmitted light interrupted by the protrusion (21). This received light is converted into a pulsed electrical signal and output.

The steering torque sensor (24) includes a cylindrical movable iron core (25) provided on the outer periphery of the fitting portion between the second shaft (6) and the blade shaft (7) so as to be displaceable in the axial direction, and a steering column ( 1
) It is constituted by a differential transformer consisting of a coil part (28) fixed to the inner periphery. The movable iron core (25) is the second
When an angle difference occurs in the circumferential direction between the shaft (6) and the output shaft (7), the elongated hole and pin (2B) provided in the movable core (25),
(27) causes movement in the axial direction, and the movable iron core (25) is displaced in response to the rotational torque applied to the second shaft (6) in response to the output shaft (7). . In addition, a coil portion (2) provided around the movable iron core (25)
8) is a pair of coaxial cores disposed on both sides of a primary coil (23) into which a pulse signal is input and a primary coil (29) which outputs an output signal corresponding to the displacement of the movable iron core (25). It consists of a secondary coil (30, 31). Therefore, if an angular difference occurs between the second shaft (6) and the output shaft (7) due to the torsion of the shaft member (8), the movable iron core (2
5) the axial displacement is converted into an electrical signal.

Next, the F electric motor (33) includes a cylindrical stator (2) that is integrally fixed to the steering column (+) and (3) by bolts (34), and a cylindrical stator (2) that is fixed to the inner surface of this stator (2). at least one pair of magnets (36), and a rotor (37) rotatably disposed around the output shaft (7).
The zero rotor (37) is equipped with a sleeve (3B) rotatably mounted on the output shaft (7) via a bearing (IIA) and (13), and the outer periphery of the sleeve (38) An iron core (39) having a skew groove and a multiple winding (41) are sequentially wrapped in a single body, and a minute air gap is provided between the magnet (36) and the outer periphery of the iron core (39). There is. Further, the sleeve sleeve (38) is equipped with a commutator (43) connected to the multiplex winding (41), and a brush (4B) that is in pressure contact with the commutator (43) is attached to a brush holder (47) fixed to the case. A lead wire that is stored and connected to the brush (46) is taken out to the outside of the stator (2) through a pipe made of a magnetic material. Therefore, multiple winding i! (4
1) By supplying power to the rotary torque 9 * #
t''M As shown in FIG. As shown in FIG. 3, the mechanism (51) includes a common ring roller (53) that uses the inner peripheral surface of the case (3) as a friction transmission surface, and a common ring roller (53) that uses the inner circumferential surface of the case (3) as a friction transmission surface, and (left end side) a roller (38a) whose outer periphery is a friction transmission surface;
A planetary mechanism in the latter stage, consisting of three planetary rollers (54) interposed between these and whose outer periphery serves as a friction transmission surface, and a first carrier member (55) that pivotally supports these planetary rollers (54). (52) is arranged around the shared ring roller (53) and the output shaft (7) and is arranged around the first
A cylindrical body (5B) integrally connected to a carrier member (55)
) with the outer periphery of the sun roller (5Ela) serving as a friction transmission surface, three planetary rollers (57) interposed between these and having the outer periphery as a friction transmission surface, and pivotally supporting these planetary rollers (57). A cylindrical body (60) supported by the output shaft (7) via a bearing (59) is mounted on the inner edge side of the second carrier member (58). On the other hand, a cylinder (61) along the inner periphery of the case (3) is integrally connected to the outer edge of the cylinder (61). 81
a) is formed. Furthermore, in this embodiment, a ring roller (53), each sun roller (38a), (56
a) and planetary rollers (54), (57),
Each of them is made of metal (for example, iron, aluminum, etc.), and each friction transmission surface is formed into a V-shaped groove in cross section that can be fitted into each other. Therefore, the electric motor (33)
When the motor (33) rotates, the rotational torque of the electric motor (33) is transmitted to the cylinder (6) via the planetary mechanisms (51) and (52) in the front and rear stages.
1), the generation of noise and vibration caused by conventional gear mechanisms is reduced. Further, since the friction transmission surface of each roller is formed in a V-shaped groove, the transmission area is increased and axial fluctuation of each roller can be prevented by 1F. In addition, each roller (53 * 38 a * 58 a, 54.5
7) is not limited to a metal mold, but can also be formed of resin or the like.

The electromagnetic clutch (63) has a rotor (64) that
The output shaft (7) is rotatably supported via a bearing (6G) by an annular body (65) spline-coupled to the output shaft (7), while the blade shaft is output via an annular elastic member (67) that absorbs torsional vibration. (
7) is fixed. Further, the rotor (64) is formed in a cylindrical shape, and the second carrier member (58) and the cylindrical body (
A pair of protrusions (84
a) is provided protrudingly. These protrusions (134a) are inserted into notched grooves formed in the ring body (65) with a required gap in the circumferential direction, and are inserted into the ring body (65) in the circumferential direction.
5) and an engagement relationship. Therefore, the rotor (6
Until the projection (84a) of 0 and the ring body (θ5) are engaged, they are elastically connected. In addition, the rotor (84
), external teeth (84b) are formed on the outer periphery of the extending portion, and a disk-shaped support plate (64c) is provided at a position on the opposite side of the extending portion from the second carrier member (58). is installed protrudingly. This support plate (84c) and the second carrier member (5B)
A disc-shaped play (8B) having a groove on the outer periphery that meshes with the inner 1 (131a) of the cylinder (61) and a disc-shaped play (8B) that meshes with the external teeth (84b) of the rotor (64). Disk-shaped plates (1119) having grooves on the inner periphery are arranged alternately to constitute a multi-plate clutch mechanism. Further, a frame (71) having a double-shaped longitudinal section is fixed to the case (3), and a ring-shaped excitation coil (72) is housed within this frame (71). Connected to the control device through lead wires.

Therefore, due to the electromagnetic force generated as the excitation coil (72) is energized, play) (611) and (B8)
is attracted to the excitation coil (72) side, so the deceleration device (
The rotational torque of the electric motor (33) transmitted through the multi-disc clutch mechanism and the protrusion (ll) of the rotor (64)
14a) to the output shaft (7).

In the above, steering torque is applied to the input shaft (4), and from the input shaft (4) via the torsion bar (8) the output shaft (
7), and when the steering torque direction and torque amount are detected by the steering torque sensor (24), the signal is processed by the control circuit, and the steering torque is transmitted to the brush (46).
Power is supplied to the multiplex winding (41) through the motor (
33) rotates in the same direction as the steering torque. Electric motor(
The rotational torque of the rotor (37) of the rotor (33) is
o), the first carrier member (55);
It is transmitted to the output shaft (7) via the second carrier member (58) and output through the electromagnetic clutch (83).

As described above, since the speed reduction mechanism (5o) is configured by a combination of rollers having friction transmission surfaces, the generation of noise and vibration caused by the gears of the conventional speed reduction mechanism is eliminated, and the noise and vibration are transmitted to the input shaft (4). Not only can this reduce vibrations caused by gears, but since there is no lost motion due to gear backlash, it is possible to improve the steering feel when changing the steering wheel.

In the example described in -F, the case where the friction transmission surface of each roller is formed into a groove with a V-shaped cross section is explained, but the same effect is not limited to this, and the same effect can be obtained even if the friction transmission surface is formed into a flat surface. Obtainable. Further, although the description has been given using a planetary type speed reduction mechanism as an example, the present invention is not limited to this, and the present invention can also be applied to a multi-axis type speed reduction mechanism. Furthermore, it goes without saying that the present invention can be applied to an electromagnetic booster that does not include a clutch device.

(Effects of the Invention) As explained above, according to the present invention, the speed reduction mechanism that transmits the rotational torque of the electric motor to the output shaft is configured by a combination of rollers having frictional transmission surfaces, thereby eliminating the need for a conventional speed reduction mechanism. This eliminates noise and vibration caused by gears, which not only reduces vibrations transmitted to the input shaft, but also eliminates lost motion due to backlash of gears, resulting in less noise and vibration in the steering wheel. The steering feeling can be improved.In addition, in the above embodiment, the friction transmission surface of each roller is formed into a groove with a V-shaped cross section, so that the transmission area for torque transmission can be increased, so the torque transmission capacity can be improved. In addition, since the rollers are fitted into each other through their V-grooves, axial fluctuation of the rollers can be prevented, and durability can also be improved.

[Brief explanation of drawings]

1 to 3 relate to one embodiment of the present invention, in which FIG. 1 is a longitudinal sectional view of an electromagnetic booster, FIG. 2 is an enlarged sectional view of essential parts showing the speed reduction mechanism, and FIG. 2 is a sectional view taken along the line m-■ in FIG. 2. FIG. In the drawing, 7... Output shaft 33... Electric motor 38a, 56a... Sun roller 50
...... Deceleration mechanism 53 ...... Ring roller 54.57 ...... Planetary roller 55
．． 58... Carrier member.

Claims (3)

[Claims] (1) In an electromagnetic booster equipped with an electric motor that generates auxiliary torque and a speed reduction mechanism that transmits the auxiliary torque of this electric motor to an output shaft, the speed reduction mechanism is connected to a plurality of rollers having a friction transmission surface on the outer peripheral surface. A reduction mechanism for an electromagnetic booster, characterized in that it is configured by a combination of the following. (2) The combination of the rollers is a sun roller on the input side,
A ring roller arranged concentrically with this sun roller,
The electromagnetic booster according to claim 1, which is constituted by a planetary roller interposed between the sun roller and the ring roller, and an output side carrier member that pivotally supports the planetary roller. reduction mechanism. (3) A speed reduction mechanism for an electromagnetic booster according to claim 1 or 2, wherein the outer periphery of each roller is formed in a V-groove shape.