JPS624671A - Electromagnetic clutch for electromagnetic type booster - Google Patents

Abstract

PURPOSE:To permit the stable control for the clutch transmission torque by arranging a spring member between the first and the second clutch plates and a member for supporting these clutch plates in shiftable ways in the axial direction, in the electromagnetic clutch of an electromagnetic type booster. CONSTITUTION:Onto the outer periphery of the projection part 33a of a driven roller 33, an external gear 33b, the second clutch plate 36 which is fitted onto the external gear and is supported in shiftable ways in the axial direction, and the first clutch plate 37 which is fitted onto the internal gear of a driving rotor 29 and supported in shiftable ways in the axial direction are arranged in superposition. A corrugated spring 38 is compression-urged between the second clutch plate 36 fitted at the right edge part of the external gear 33b of the driven roller 33 and a circlip 33c integrally formed with the external gear 33b. Therefore, the gap between the first and the second clutch plates is reduced to zero independently of the pressurization error in each thickness, and the clutch electric current is made proportional from the zero state, and the control with the stable clutch transmission torque can be executed.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an electromagnetic clutch of an electromagnetic booster used in an electric power steering device.

(Prior art) An electromagnetic booster used in an electric power steering device is equipped with an electric motor, and when torque is applied to the input shaft,
The input shaft torque is reduced by detecting a torque difference between the input shaft and the output shaft, operating the electric motor based on this torque information, and applying the rotational torque to the output shaft.

Generally, the rotation torque of an electric motor is transmitted to the output shaft by operating an electromagnetic clutch. According to the electromagnetic clutch, steering is performed at an appropriate timing, that is, when the input shaft torque exceeds a predetermined value or when the vehicle speed is below a predetermined value. When a force reduction effect is required, the rotational torque of the electric motor can be applied to the output shaft.

For the electromagnetic clutch of the electromagnetic booster, it is preferable that the electromagnetic clutch does not generate operating noise, is small, has high torque transmission efficiency with respect to the clutch current, and has a substantially proportional relationship between the characteristics of the clutch current and the clutch transmission torque. As shown in Japanese Patent Application No. 59-184067, there is a first clutch plate that rotates integrally with the drive side and is movable in the axial direction, and a first clutch plate that rotates integrally with the driven side and is provided with a shaft that rotates integrally with the driven side. a second clutch plate provided movably in the direction of the second clutch plate, and a second clutch plate disposed so as to be movable in a direction, and an electromagnetic coil is disposed adjacent to each of the clutch plates, and when the electromagnetic coil is excited, the first clutch plate An electromagnetic clutch for an electromagnetic booster in which a second clutch plate is coupled and integrated has been proposed.

(Problems to be Solved by the Invention) In the electromagnetic clutch of the electromagnetic booster as described above, the first clutch plate and the second clutch plate are slightly displaced in the axial direction when the electromagnetic coil is excited. Since the two slide between the driving part side and the driven part side, a frictional force acts, and clutch transmission torque is generated only when the clutch current reaches a predetermined value Ico as shown in FIG. 4A. Therefore, in order to operate the electromagnetic clutch smoothly, a predetermined current Ico is constantly supplied as shown in Fig. 5A, or a clutch control signal is given during clutch control to cause the clutch current to flow as shown in Fig. 5B. At this time, a predetermined value of current 1co was added to and corrected by adding and correcting the Crafti current.

However, in the former case, power loss occurs and heat is generated due to this power loss, and in the latter case, the frictional force due to the sliding is unstable, so when the electromagnetic clutch is operated, the electric motor rotates. It is difficult to stably and smoothly transmit torque to the output shaft.

Therefore, the present invention was made to improve the problems of the conventional technology, and its purpose is to provide a compact device with high torque transmission efficiency relative to the clutch current, and to have a characteristic of supply current and clutch transmission torque. To provide an electromagnetic clutch of an electromagnetic type booster which has a substantially proportional relationship, can stably control clutch transmission torque from zero clutch current, and has low clutch operation noise.

(Means for Solving the Problems) The present invention provides a first clutch plate (37) which rotates integrally with the drive unit side consisting of an electric m (28) etc. and is movable in the axial direction. , a second clutch plate (3B) which rotates integrally with the side of the driven part such as the output shaft (8) and is movable in the axial direction, are arranged so as to overlap each other, and the first
．． An electromagnetic coil (40) is disposed close to the second clutch plate (37), (3B), and the electromagnetic coil (40)
) is excited, the above 1. Second clutch plate (37
), (3B) are coupled and integrated into an electromagnetic clutch (27) of an electromagnetic type booster, in which the first. A spring material is installed between the second clutch plates (37), (3El) and a member that supports these clutch plates (37), (3B) movably in the axial direction, that is, the driving part side or the driven part side. , or an elastic member (38) such as a rubber material is bent and arranged to connect the first clutch plate (37) and the second clutch plate (37).
B) is constructed so as to eliminate the gap between it and B).

(Embodiment) A preferred embodiment of the present invention will be described below based on the accompanying drawings.

FIG. 1 is a longitudinal sectional view of an electromagnetic booster according to the present invention, and the cross section is formed by bending the cut surface 906 at the center. FIG. 2 is a left side view of FIG. 1. (1) is the bearing (
2), (3), (4), and (5) are input shafts rotatably supported and equipped with a steering wheel (not shown) at the outer end, and (6) is an input shaft that is rotatably supported by bearings (7) and (4). ).

(5) is an output shaft which is rotatably supported and to which a universal joint (not shown) for driving the rack and binion mechanism is connected to the outer end. Input shaft (1) and output shaft (
6) are arranged coaxially, and each inner end is connected integrally by a torsion member (8) located at the central shaft portion. The inner end of the input shaft (1) facing the output shaft (6) is rotatably fitted into the enlarged diameter opening of the output shaft (6) via the bearings (4) and (5). .

This fitting part has seal members (10) and (11).
are arranged, and these seal members (10) and (11)
A viscous material such as grease is sealed in the space formed by the input shaft (1) to lubricate the bearings (4) and (5).
) and the output shaft (6) constitute a rotary damper mechanism that generates viscous resistance proportional to the relative rotational speed of the output shaft (6).

In the above talk 1 bar (9), the input shaft (1) is the output shaft (
6) is adjusted to a predetermined intermediate angle with respect to
The bins (9a) and (9b) are connected to the input and output shafts (1) and (8).

The input shaft (1) is divided into a first human power shaft (1a) and a second human power shaft (1b) shown in the perspective view of FIG. 3, which have low rigidity in the torsional direction and high rigidity in the radial direction. Elastic member (1
2), and is adjusted so that the first human power axis (la) is at a predetermined intermediate angle with respect to the second human power axis (1b).

In the above, the rotational torque applied to the input shaft (1) is transmitted to the torsion bar (8) while being twisted by the elastic member (12) in the input shaft (1), and the torsion bar (8) is transmitted to the output shaft (6) while causing torsion.

Note that (13) is a steering column that forms part of the case of an electromagnetic booster that houses and surrounds the input shaft (1).

A steering rotation detection section (14) is provided between the input shaft (1) and the steering column (13) to detect the rotation speed and direction of the input shaft (1). The steering rotation detection unit (14) is integrally provided on the outer periphery of the input shaft (1), and includes a seven-lunge-shaped light-shielding plate (1) having elongated holes (!5) drilled at regular intervals.
B), and a photocoupler (photoelectric converter) (17) fitted across the light shielding plate (1B) and integrally installed on the steering column (13).

Inside the photocoupler (17), two pairs of light emitting diodes and two opposing phototransistors that receive light energy emitted from the light emitting diodes are provided, and these are connected to the elongated holes (15) of the light shielding plate (16). The light energy emitted from the 0 light emitting diode, which is arranged with an electrical phase shifted by about 90° from the elongated hole (15) of the light shielding plate (16),
When the light passes through and is received by the phototransistor, the phototransistor is turned ON, and the phototransistor blocked between the elongated holes of the light shielding plate is turned OFF. Therefore, due to the electrical phase difference, the rotation direction can be changed to 0N-O of the phototransistor.
Each rotation speed can be detected by the FF signal.

Around the area where the opposite ends of the input shaft (1) and the output shaft (8) fit together, there is a torque difference generated between the input shaft (1) and the output shaft (8), that is, the direction of the acting torque. A torque detection section (18) is provided to detect the magnitude.

The torque detection part (!8) is located on the steering column (13)
A differential transformer (19) consisting of a partial coil (113a) and secondary coils (113b) and (19c) fixed to the inner peripheral surface of the differential transformer (19).

It is composed of a cylindrical movable part (22) supported by the enlarged diameter part (6a) of the output shaft (8) via sliding rings (20) and (21) so as to be freely movable in the axial direction. The movable part (22) includes a first movable part (22a) which is a magnetic material mainly composed of silicon.

At both ends of the first movable part (22a), there are second movable parts (22b) and (22, c) which are made of copper or aluminum as a main component and are both non-magnetic and good conductors. .

An alternating current voltage is applied to the secondary coil (113a) of the differential transformer (13), and an induced voltage is generated in each of the secondary coils (19b) and (18C) via the first movable part (22a). When the first movable part (22a) approaches the secondary coil (19b), the induced voltage in the secondary coil (19b) increases in proportion to the displacement of the first movable part (22a). ) decreases in proportion to the displacement, and conversely, when the first movable part (22a) approaches the secondary coil (19c), the induced voltage in the secondary coil (19c) decreases in proportion to the displacement.
2a) increases in proportion to the displacement of the secondary coil (
The induced voltage at tab) decreases in proportion to the displacement. Therefore, by rectifying and smoothing the outputs of the secondary coils (19b) and (19c), respectively, and then performing subtraction processing, it is possible to detect a DC voltage proportional to the displacement of the second movable part and its direction.

At the right end of the movable part (22), two circular holes (22d) into which the pole (23) is fitted are bored at 180° symmetrical positions, and are 90" out of phase with the one circular hole (22d). 18
Two elongated holes (22e) parallel to the axial direction are bored at 0° symmetrical positions. This elongated hole (22e) is a protrusion (6
b) is fitted into a pin (Be) fixed to the side surface of the input shaft (1), and the protruding portions (8b) are provided in two symmetrically protruding locations, and the input shaft (1) is fitted with a groove (lc) having a fan-shaped cross section. ).

(lc) with an appropriate gap. Therefore, the input shaft (υ) is arranged at a predetermined intermediate angle with respect to the output shaft (8). The groove (lc) of the input shaft (1), (
Spiral grooves (ld), (ld) having a substantially V-shaped cross section are bored at positions 90'' out of phase with lc) and 180'' symmetrical, and the poles (23), (23) are engaged with them. , is covered by a ring body (22d). And Paul (2
3).

(23) is pressed in the radial direction by a spring (24) compressed from the left end of the movable part (22).

According to the above configuration, when the input shaft (1) rotates, rotational torque is transmitted to the output shaft (8) via the torsion bar (9), but at this time, the input shaft (1) and the output shaft (6) A relative angular difference occurs between the two, and in response to the rotational direction of the input shaft (1) and the above-mentioned angular difference, the movable part (22), which normally resides in the electrically central position, moves toward the wheel or to the right in Figure 1. Moving. The amount of movement of the movable part (22) is proportional to the torque difference generated between the input shaft (1) and the output shaft (8), and the amount of movement and direction of movement are electrically determined by the differential transformer (19). By detecting the above torque, it is possible to detect the torque. Around the output shaft (8), a reduction gear (2B) and an electromagnetic clutch (27) housed in a substantially cylindrical case (25) are arranged, and an electric motor is installed in a direction perpendicular to the side surface of the case (25). (2
8) are provided in one piece. A bearing (29) is attached to the output shaft (6).
A large-diameter bevel gear (30) is integrally provided on the outer periphery of the drive rotor (29), which is on the side of the drive unit and has an inverted U-shaped cross section and is rotatably supported via the motor (28). )
It meshes with a small-diameter bevel gear (not shown) that is integrally provided on the output shaft of the gear reducer (2B).

Therefore, the rotation of the electric motor (28) is decelerated by the speed reduction device (2G) and transmitted to the drive rotor (29). An internal gear (31) is bored on the outer periphery of the drive rotor (28) on the side opposite to the bevel gear (30).

A bearing (34) is provided between the ring body (32) having splines perforated on the inner peripheral surface and the driven rotor (33) on the driven side.
and an elastic member (35) are respectively arranged in parallel, and grooves (32a) are bored at two 180° symmetrical positions on the right end of the ring body (32). Similarly, a protrusion (33a) protruding from the driven rotor (33) toward the output shaft so as to be fitted with a gap is 18.
Two locations are provided at 0° symmetrical positions.

Therefore, the relationship between the ring body (32) and the driven rotor (33) is as follows:
Until the grooves (32a) of 2) are engaged, they are elastically connected by the elastic body (35). On the outer periphery of the protrusion (33a) of the driven rotor (33), external teeth (33b), a second clutch plate (3B) fitted to the external teeth and supported so as to be movable in the axial direction, The inner teeth (31) of the drive rotor (29)
) and are supported so as to be movable in the axial direction.

A second clutch plate (38) fitted to the right end of the external teeth (33b) of the driven rotor (33) and the external teeth (33b)
A wavy spring (3B) is compressed and biased between the circlip (33c) that is integrally provided on the circlip (3b). Therefore,
First clutch plate (37) and second clutch plate (3B)
The gap is zero regardless of the machining error in each thickness.

In addition, arc-shaped long holes (3
3) is drilled. Driven rotor (33) and case (2)
5), an electromagnetic coil (40) is disposed between them. This electromagnetic coil (40) is fixed to the inner peripheral surface of the case (25), and is made of a magnetic material and has a U-shaped cross section (
41), and a driven rotor (33) is rotatably supported by the ring body (41) by a sliding bearing (8).

With such a configuration, the first
It is possible to eliminate the gap between the second clutch plate (37) and the second clutch plate (3B), so that when the electromagnetic clutch is operated, these clutch plates (37).

(38) is not affected by the frictional force, and the relationship between the clutch current and clutch transmission torque becomes approximately proportional from the state where the clutch current is zero, as shown in Figure 4B.
Stable clutch transmission torque control can be performed.

Note that the present invention is not limited to the embodiments, and for example, a wave spring (3
8) may be any other elastic member such as a spring material or a rubber material.

(Effects of the Invention) As is clear from the above explanation, according to the present invention, the characteristics of the supply current and the clutch transmission torque have a substantially proportional relationship from the state where the clutch current is zero, and the characteristics become stable from the state where the clutch current is zero. It is possible to provide an electromagnetic clutch of an electromagnetic type booster that can control the clutch transmission torque, is small, has a high torque transmission ability with respect to the clutch current, and has low clutch operation noise.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view of an electromagnetic booster according to the present invention, and the cross section is formed by bending the cut surface at 90 degrees at the center, and FIG. 2 is a left side view of FIG. 3 is a perspective view showing the divided portion of the input shaft, FIG. 4 is a diagram showing the relationship between clutch current and clutch transmission torque, and FIG. 5 is a diagram showing the relationship between clutch control signal and clutch current. In FIG. 5, A shows the conventional example and B shows the present invention. In the drawing, (1) is the input shaft, and (6) is the output shaft. (28) is the electric motor, (3B) is the second clutch plate, (3
7) is. The first clutch plate (38) is a wavy spring which is an elastic member. Patent applicant: Agent for Honda Motor Co., Ltd.
Patent Attorney Part 2 1) Patent Attorney Kuni Ohashi Onma Patent Attorney Yuyuki Koyama Patent Attorney No 1)
Shigeru Figure 4 Figure 5

Claims (1)

[Claims] A first clutch plate that rotates integrally with the drive side and is movable in the axial direction, and a second clutch plate that rotates integrally with the driven side and is movable in the axial direction. are arranged one on top of the other, and an electromagnetic coil is arranged close to each of the clutch plates, and when the electromagnetic coil is excited, the clutch plates are coupled and integrated. In the electromagnetic clutch of the power device, an elastic member is provided in a flexible manner between the clutch plate and a member that supports the clutch plate so as to be movable in the axial direction, and the first clutch plate and the second clutch plate are bent.
An electromagnetic clutch of an electromagnetic type booster characterized by eliminating the gap between the clutch plates.