JPH057537Y2 - - Google Patents

Description

[Detailed description of the invention] [Purpose of the invention] (Field of industrial application) The present invention is a rotation detection device for a steering wheel for an automobile, which outputs a position signal indicating the rotation angle from a specific position of the steering wheel. Regarding.

(Prior Art) In recent years, in automobiles, in order to obtain better steering stability or a more comfortable ride, suspension damping force control has been developed according to the rotation angle of the steering wheel (steering angle) and the traveling speed. It has been considered to perform shift position control of an automatic transmission, rear wheel steering control (so-called four-wheel steering system control), and the like.

For the above control, the rotation angle (and direction of rotation if necessary) of the steering wheel
A rotation detection device is required to detect this. Conventionally, as such a rotation detection device, it has been considered to use an absolute encoder that generates a position signal indicating an absolute rotation angle from a specific position (for example, a neutral position) of the steering wheel. That is, as an encoder of this kind, for example, a brush is provided on a deceleration rotating body that is rotated via a coupling body and a deceleration gear mechanism in accordance with the rotation of a steering wheel, and
A device equipped with a resistor that generates a resistance value output according to the sliding contact position of this brush has been considered, and in this case, a predetermined resistance value output (absolute The positional relationship between the deceleration rotor and the steering wheel is adjusted in advance so that an output indicating the origin of the encoder is obtained. In addition, the provision of the gear mechanism for deceleration as described above is designed to allow the steering wheel to rotate multiple times (generally about 3.5 rotations), whereas the rotation range of the brush is less than one rotation. This is because there are restrictions.

(Problem that the invention aims to solve) Before an absolute encoder is mounted (for example, when it is transported from a parts manufacturer to an automobile manufacturer), the decelerating rotor often deviates from its normal position (position corresponding to the origin). When such a situation occurs, it is inevitable that the workability of the assembly will be deteriorated, such as the need to take time to adjust the position of the deceleration rotor during assembly. Further, the steering wheel and the first stage of the gear mechanism are connected to each other by appropriate engagement means, such as engagement between a recess provided on the steering wheel side and a protrusion provided on the coupling body. At this time, if the rotatable range of the steering wheel is, for example, 3.5 rotations, the engagement between the recess and the protrusion is carried out at least three times during one rotation of the deceleration rotor (the number of recesses and protrusions, Depending on the arrangement, even more can be used. On the other hand, the positional relationship between the steering wheel and the deceleration rotating body is limited to only one positional relationship in which a position signal indicating the origin of the absolute encoder can be correctly obtained. For this reason, in reality, there is a possibility that an absolute type encoder with the deceleration rotating body shifted from its normal position may be installed as is, and therefore, after the absolute type encoder has been installed during the automobile manufacturing stage, the assembly The attachment condition must be inspected, for example, based on whether the position signal is correctly output from the encoder, and the inspection process becomes troublesome.

The present invention was developed in view of the above circumstances, and its purpose is to be able to reliably hold the deceleration rotating body in the absolute encoder in the correct position before it is mounted, thereby improving assembly work efficiency. It is an object of the present invention to provide a rotation detection device for a steering wheel for an automobile, which can improve the speed of the steering wheel and eliminate the need for inspection of the assembled state.

[Structure of the invention] (Means for solving the problems) The rotation detection device for an automobile steering wheel according to the invention is such that the steering wheel is always moved to the first position by being biased by a spring means, and the steering wheel is moved to the first position when the steering wheel is moved to the first position. A gear mechanism for decelerating the rotation of the coupling body, which is provided with a coupling body that can be moved to a second position when attached to the steering wheel and can rotate integrally with the steering wheel, and a gear mechanism that reduces the rotation of the coupling body, and a deceleration rotary body that is rotated by the gear mechanism. , and signal generating means for generating a position signal indicating the rotation angle of the steering wheel from a specific position in accordance with the rotation of the deceleration rotary body, further comprising a first and a first A second engaging means is provided, and a first locking means is provided on a suitable stationary member to engage with the first engaging means to restrain rotation of the connecting body when the connecting body is in the first position. the position signal outputted to the decelerating rotary body in accordance with its rotation is in a state indicating the specific position, and the connecting body is in a state where the first
A second locking means is provided which engages with the second engaging means and restrains the rotation of the deceleration rotating body in the state of the second locking means.

(Operation) Before the steering wheel is attached to the steering shaft, the coupling body is urged to the first position by the spring means. In this state, the rotation of the coupling body is restrained by the engagement between the first engagement means and the first locking means, and the rotation is decelerated by the engagement between the second engagement means and the second locking means. The rotation of the body is restrained, and as a result, the deceleration rotating body remains held at its normal position (the position where the position signal output in response to its rotation indicates a specific position). As a result, there is no need to adjust the position of the deceleration rotor as in the prior art when assembling it to the steering wheel. On the other hand, when the steering wheel is attached to the steering shaft, the connecting body is moved to the second position and can rotate together with the steering wheel.
As a result, each of the above-mentioned engagement states is released, and the coupling body and thus the deceleration rotating body begin to rotate in conjunction with the steering wheel.
The absolute encoder will now function normally.

(Example) FIGS. 1 and 2 show the overall vertical cross-sectional structure in different states. That is, FIG. 1 shows the state before mounting, and FIG. 2 shows the state where the steering wheel 2 is attached to the steering shaft 1. In these figures 1 and 2,
3 is a column cover having a cylindrical portion 3a shaped to surround the steering shaft 1; 4 is an annular base fixed to the column cover 3 in a state surrounding the cylindrical portion 3a; It is formed into a double cylinder shape with a side wall 4b.
Reference numeral 5 denotes a cylindrical connecting body rotatably disposed between the periphery of the cylindrical portion 3a and the inner periphery of the base 4, which is in a first position (first position) biased upward by a compression coil spring 6 serving as a spring means. 1) and a second position (position shown in FIG. 2), which is moved downward in accordance with the mounting of the steering wheel 2.

A first engagement protrusion 5a, which is a first engagement means, is protruded from the lower outer periphery of the connecting body 5, and a first engaging protrusion 5a, which is a first engaging means, is provided on the inner peripheral side wall 4b of the base 4, which is a suitable stationary member. A first engaging recess 4c is formed as a first locking means that engages with the first engaging protrusion 5a only when the first engaging protrusion 5a is in the first position.
(see figure). As a result, in the case of the connected body 5, the first
In the state at the position, the rotation is restrained due to the engagement between the first engagement protrusion 5a and the first engagement recess 4c, but in the state moved to the second position, the rotation is restrained. It will be canceled. When the steering wheel 2 is attached to the connecting body 5 (moved to the second position), the projection 5b protruding from the top surface is engaged with the recess on the steering wheel 2 side. , it comes to rotate integrally with the steering wheel 2. Note that 7 is an annular plate interposed between the connecting body 5 and the compression coil spring 6.

Reference numeral 8 denotes a cylindrical rotor that is rotatably arranged to surround the inner circumferential side wall 4b of the base 4 and the connecting body 5, and the engagement groove 8a (see FIG. 6) on the inner circumferential surface of the rotor 8 is located on the connecting body 5 side. The rotor 8 is engaged with the first engaging protrusion 5a of the rotor 8, so that the rotor 8 is configured to rotate together with the connecting body 5. Furthermore, a sun gear 10 is provided on the outer peripheral surface of the rotor 8, which forms a part of a gear mechanism 9 consisting of a planetary gear mechanism.

The gear mechanism 9 includes, in addition to the sun gear 10, an internal gear 11 formed on the inner periphery of the outer peripheral side wall 4a of the base 4, and a planetary gear consisting of a two-stage gear interposed between the sun gear 10 and the internal gear 11. It has 12. Further, reference numeral 13 denotes a deceleration rotating body which is driven by the gear mechanism 9, and this is made of an annular plate and is arranged within the outer peripheral side wall 4a of the base 4 so as to rotate around the rotor 8. The planetary gear 12 is rotatably supported on a support shaft 13a that is integrally provided on the deceleration rotary body 13. Here, the small diameter pinion 12a located at the upper stage of the planetary gear 12 is meshed with the internal gear 11, and the large diameter pinion 12b located at the lower stage is meshed with the sun gear 10. In the gear mechanism 9, the rotation of the rotor 8 is converted into the revolving force of the planetary gear 12, and the revolving force is transmitted to the deceleration rotating body 13. The reduction ratio at this time is set to about 1/4. In this case, in a typical car, the movable range of the steering wheel 1 (so-called lock-to-lock range) is 3.5 mm.
Therefore, the rotation range of the deceleration rotor 13 is suppressed to less than one rotation.

Reference numeral 14 denotes a composite substrate fixed to the lower surface of the base 4. On the lower surface of this composite substrate, an endless annular electrode pattern 15 is formed by printing, as shown in FIG. An annular resistance pattern 16 with ends is formed by printing. In addition, composite substrate 1
4 is provided with a terminal 15a connected to the electrode pattern 15, and terminals 16a, 16 connected to both ends of the resistance pattern 16.
b is provided. Incidentally, in FIG. 3, an insulating coating 17 is applied to a portion indicated by a two-dot chain line.

The electrode pattern 15 is provided on the deceleration rotating body 13.
A brush 18 is provided to bridge between the resistor pattern 16 and the resistor pattern 16. The brush 18, the electrode pattern 15, and the resistor pattern 16 constitute a signal generating means 19. Moreover, this signal generating means 19
An absolute type encoder 20 is constituted by the deceleration rotating body 13. At this time, the brush 19 is provided so as to be movable and adjustable in the circumferential direction of the rotor 8, and when the steering wheel 2 is at a specific neutral position, the brush 19 is moved to the intermediate point of the resistance pattern 16 (point C in FIG. 3). ) and the electrode pattern 15.

Therefore, when the steering wheel 2 is in the neutral position, the terminals 15a, 16
The resistance value between terminals a and terminals 15a and 16b are equal, but the steering wheel 2
Each of the above-mentioned resistance values changes in response to rotation of the rotor to the right or left. In particular, terminal 15a,
When focusing on the resistance value between 16b and 16b, the resistance value increases linearly as the steering wheel 2 is rotated to the right (rotation in the direction of arrow A in FIG. 3), and increases linearly as the steering wheel 2 is rotated to the left. It begins to decrease linearly. And in this case, terminal 16
A constant voltage Vc is applied between terminals a and 16b so that the terminal 16b side is at ground potential,
Therefore, a voltage signal Vx, which is a position signal, is output from between the terminals 15a and 16b, which changes as shown in FIG. 4 in accordance with the rotation of the steering wheel 2. In other words, the voltage signal Vx changes from zero as the steering wheel 2 is rotated approximately 3.5 times.
Vc, and this changes the neutral position of the steering wheel 2 (Vx=
It is possible to detect the rotation angle and rotation direction from a position having a relationship of Vc/2.

Now, on the lower outer periphery of the connecting body 5, the first
In addition to the engaging protrusion 5a, a second engaging protrusion 5c serving as a second engaging means is protruded, and the inner circumference of the decelerating rotary body 13 is provided with a state in which the voltage signal Vx indicates the neutral position. (state of Vx=Vc/2) and a second engaging recess 13b is formed as a second locking means that engages with the second engaging protrusion 5c only when the connecting body 5 is in the first position. (See FIG. 7), and in the assembly stage of the absolute type encoder 20, the engaging protrusion 5c and the engaging recess 13b are
are adjusted so that they are in an engaged state. As a result,
Regarding the deceleration rotary body 13, its rotation is restrained by the coupling body 5 when the coupling body 5 is in the first position, but when the coupling body 5 is moved to the second position. Then, the rotational restraint state described above is released.

According to the above configuration, the voltage signal Vx from the absolute encoder 20 varies linearly even when the steering wheel 2 is rotated multiple times, and therefore, the voltage signal Vx from the absolute encoder 20 varies linearly. The absolute rotation angle and rotation direction from the neutral position of No. 2 can be detected in real time over a wide range. Furthermore, before the device according to this embodiment including such an encoder 20 is mounted, the connecting body 5 is urged to the first position by the compression coil spring 6, and the rotation of the connecting body 5 is prevented. While being restrained, the decelerating rotor 13 is held at the normal position (the position where the voltage signal Vx from the signal generating means 19 indicates the neutral position). Therefore, there is no risk of positional deviation of the deceleration rotor 13 before the device according to the present embodiment is mounted, and there is no need to adjust the position of the deceleration rotor 13 during assembly. As a result, assembly work efficiency is improved. Furthermore, since there is no risk that the decelerating rotary body 13 will be assembled with its position shifted, the process of inspecting the assembled state can be made unnecessary. Furthermore, even if the connecting body 5 is inadvertently moved to the second position and the decelerating rotary body 13 is displaced, the second engagement protrusion 5c and the second Since the deceleration rotating body 13 can be returned to the normal position simply by engaging the engagement recess 13c, deterioration of assembly workability can be prevented as much as possible.

In the above embodiment, the gear mechanism 9 made of a planetary gear mechanism is used, but a gear mechanism having another configuration may be used.

In addition, the present invention is not limited to the embodiments described above and shown in the drawings, and may be modified in various ways without departing from the gist, such as adopting other structures as an absolute encoder. It can be implemented by

[Effects of the invention] According to the invention, as is clear from the above explanation, an absolute encoder using a gear mechanism for deceleration can be used to indicate the absolute rotation angle from a specific position of the steering wheel. Although it is configured to obtain signals, it is possible to reliably hold the deceleration rotating body in the absolute type encoder in the correct position before mounting, thereby improving the workability of assembling it to the steering wheel. In addition, it has the practical effect of eliminating the need for inspecting the assembled state.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIGS. 1 and 2 are longitudinal cross-sectional views of the whole in different states, FIG. 3 is a front view showing the main parts, and FIG. 4 is an absolute type. Output characteristic diagram of the encoder. FIG. 5 is a sectional view taken along the line V-V in FIG. 1, FIG. 6 is a sectional view taken along the - line in FIG. 1, and FIG.
It is a sectional view along the - line in the figure. In the figure, 1 is the steering shaft, 2 is the steering wheel, 4 is the base (stationary member), and 4c
5 is a first engagement recess (first locking means); 5 is a connecting body;
5a is a first engagement protrusion (first engagement means), 5c is a second engagement protrusion (second engagement means), 6 is a compression coil spring (spring means), 8 is a rotor, 9 is a gear mechanism, 1
0 is a sun gear, 11 is an internal gear, 12 is a planetary gear,
13 is a deceleration rotating body, 13b is a second engagement recess (second
14 is a composite substrate, 15 is an electrode pattern, 16 is a resistor pattern, 18 is a brush, 19 is a signal generating means, and 20 is an absolute encoder.

Claims (1)

[Scope of utility model registration request] a connecting body that is provided so as to be movable back and forth between a first and second position, and that can be moved to the second position while the steering wheel is attached to the steering shaft and can rotate integrally with the steering wheel; a spring means that always urges the connecting body toward the first position; a gear mechanism that decelerates the rotation of the connecting body and transmits it to the decelerating rotary body; and an absolute type encoder is configured together with the decelerating rotary body and the gear mechanism. a signal generating means for generating a position signal indicating a rotation angle of the steering wheel from a specific position in accordance with the rotation of the deceleration rotor, and first and second engaging means provided for the coupling body; a first locking means provided on a suitable stationary member and engaging the first engaging means to restrain rotation of the connecting body when the connecting body is in a first position; When the position signal provided and output in accordance with the rotation indicates the specific position and the connecting body is at the first position, the connecting body engages with the second engaging means and decelerates its rotation. 1. A rotation detection device for a steering wheel for an automobile, comprising a second locking means for restraining rotation of the steering wheel.