JP2004216959A - Installation structure of key lock mechanism in electric power steering device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an installation structure of a key lock mechanism in an electric power steering device capable of simplifying and lightening a constitution of a key lock device and a steering column, and loosening restraints of a layout of the key lock device in a structure effective for preventing the theft of a vehicle. <P>SOLUTION: A gear case 11a of a deceleration gear device 11 is assembled with a steering column 9 rotatably supporting a steering shaft 2, and an electric motor 10 is attached to the gear case 11a. In this electric power steering device, the rotary driving force of the electric motor 10 is transmitted to the steering shaft 2 via the deceleration gear device 11 as a driving assist force. A key lock mechanism 22 for locking the rotation of the steering shaft 2 is installed in the gear case 11a of the deceleration gear device 11. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an arrangement structure of a key lock mechanism in an electric power steering device.
[0002]
[Prior art]
In recent years, as a steering force reducing device for an automobile, an electric power steering device that uses an electric motor (power steering motor) as a driving assisting force of a steering shaft has been mounted. On the other hand, some recent automobiles include a key lock mechanism for locking the rotation of the steering shaft when the automobile is not driving.
[0003]
FIGS. 6 and 7 show a main structure of a conventional automobile steering system provided with both an electric power steering device and a key lock mechanism. As shown in FIG. 6, the upper end of the steering shaft 2 is coaxially attached to the center of the steering wheel 1, and the lower end of the steering shaft 2 is connected to one end of the intermediate shaft 4 via the universal joint 3. And the other end of the intermediate shaft 4 is connected via a universal joint 5 to a steering gear box 6 in the engine room R. The above-mentioned steering shaft 2 is disposed so as to penetrate a cylindrical steering column 9 attached to the vehicle body 8 via column hanger brackets 7a and 7b, and is rotatably supported by the steering column 9 under this penetrating state. Have been. An electric motor 10 for power steering is attached to the lower end of the steering column 9 described above. The rotational driving force of the electric motor 10 is applied to the steering shaft 2 by a reduction gear of a reduction gear device 11 (see FIGS. (Not shown in FIG. 7). In FIG. 6, reference numeral 12 denotes a steering column upper cover, reference numeral 13 denotes a steering column lower cover, and reference numeral 14 denotes a dash panel that partitions between the vehicle compartment S and the engine room R.
[0004]
As shown in FIG. 7, a key cylinder 15 made of aluminum die-cast is attached to the upper part of the steering column 9 by bolts 16. The key cylinder 15 and a key lock mechanism (not shown) on the steering shaft 2 side. ) Constitute a key lock device. Thus, as the key 17 is inserted into the key cylinder 15 and a predetermined key operation is performed, the lock pin (not shown) of the key lock device passes through the opening 18 of the steering column 9 to the key lock mechanism of the steering shaft 2. The steering shaft 2 is locked (rotation is prevented).
[0005]
In addition, a structure for assembling a key cylinder to a steering column (see Japanese Patent No. 3171056) and a structure in which a steering lock mechanism is incorporated in a gear case (housing) of a reduction gear device in an electric power steering device (Japanese Patent Application Laid-Open No. 2001-219816). No.) has been proposed.
[0006]
[Patent Document 1]
Japanese Patent No. 3171056 [Patent Document 2]
JP 2001-219816 A
[Problems to be solved by the invention]
However, in the above-described conventional configuration, the key cylinder 15 is formed of a component different from the steering column 9 and is attached to the steering column 9 by bolting. There are points. That is, since the key cylinder 15 and the steering column 9 are separate members, a joint (joint) between these two parts may be broken, and the vehicle may be stolen. In addition, the key lock device itself must be made robust so as to withstand a large acting force, and in order to satisfy this requirement, the key lock device must be large and heavy. . Similarly, the steering column 9 must be made robust so as to withstand a large acting force, which leads to an increase in cost and weight. Further, since the key lock device is located at a location where other components such as a combination switch (not shown) are concentrated, this fact is a serious restriction on the layout of the key lock device.
[0008]
The present invention has been made to solve such a problem, and an object of the present invention is to provide an advantageous structure for preventing theft of a vehicle, and to simplify the configurations of a key lock device and a steering column, and It is an object of the present invention to provide an arrangement structure of a key lock mechanism in an electric power steering device, which can reduce the weight and can further reduce restrictions on the layout of the key lock device.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, according to the present invention, a gear case of a reduction gear device is attached to a steering column that rotatably supports a steering shaft, and an electric motor is attached to the gear case to reduce a rotational driving force of the electric motor. In an electric power steering device configured to transmit the driving force to the steering shaft via the reduction gear device, a key lock mechanism for locking the rotation of the steering shaft is provided in a gear case of the reduction gear device. In addition, a key cylinder into which a key for operating the key lock mechanism is inserted is integrally formed with a gear case of the reduction gear device.
Further, in the present invention, a lock portion of the key lock mechanism for locking the steering shaft is disposed closer to the electric motor than the reduction gear device.
Further, in the present invention, a lock portion of the key lock mechanism for locking the steering shaft is disposed closer to the electric motor than a torque limiter which is a member for protecting a reduction gear of the reduction gear device. I am trying to do it.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to FIGS. In FIGS. 1 to 5, the same parts as those in FIGS. 6 and 7 are denoted by the same reference numerals, and redundant description will be omitted.
[0011]
FIG. 1 shows an arrangement structure of a key lock mechanism in an electric power steering device according to one embodiment of the present invention. As shown in FIG. 1, a gear case (housing) 11 a of a reduction gear device 11 is attached to a lower portion of the steering column 9 that rotatably supports the steering shaft 2. An electric motor 10 is mounted. More specifically, the gear case 11a of the reduction gear device 11 is made of aluminum die cast, and the gear case 11a is integrally attached to a lower end portion of the steering column 9. As shown in FIGS. 2 and 3, the worm gear 20 is rotatably supported in the gear case 11a via bearings 19a and 19b (see FIG. 3), and is coaxially fixed to the steering shaft 2. The reduction gear device 11 is configured by meshing with the wheel gear 21.
[0012]
In the present embodiment, a key lock mechanism 22 for locking the rotation of the steering shaft 2 is provided in the gear case 11a of the reduction gear device 11. The key lock mechanism 22 includes a lock plate 24 having, for example, two lock grooves 23 at a peripheral edge thereof, and a lock pin attached to the gear case 11a at a position corresponding to the lock groove 23 of the lock plate 24 so as to be movable forward and backward. 25 (see FIGS. 3 and 4). The lock plate 24 is interposed between the torque limiter 26 coupled to the worm gear 20 and the rotary drive shaft 10a of the electric motor 10, and is integrally coupled to both members 26, 10a. Accordingly, the rotational driving force of the electric motor 10 is transmitted to the steering shaft 2 as a driving assist force via the rotary driving shaft 10a, the lock plate 24, the torque limiter 26, and the reduction gear device 11 in order. . The torque limiter 26 controls the driving assist force (torque) transmitted from the electric motor 10 to the steering shaft 2 and the torque transmitted from the steering wheel 1 via the steering shaft 2 at the time of key lock operation to a predetermined magnitude. A member provided to protect the reduction gears (the worm gear 20 and the wheel gear 21) by limiting to the following. When the torque exceeds a predetermined magnitude, the torque limiter 26 It is set to cause slippage.
[0013]
On the other hand, a key cylinder 28 into which a key 27 for operating the lock pin 25 of the key lock mechanism 22 is formed integrally with the gear case 11a of the reduction gear device 11, as shown in FIGS. The tip of the lock pin 25 is disposed so as to be movable forward and backward inside the gear case by the key 27 and the key cylinder 28. That is, by inserting the key 27 into the key cylinder 28 and performing a predetermined rotation operation, the tip of the lock pin 25 is engaged or disengaged with the lock groove 23 of the lock board 24.
[0014]
Thus, the arrangement portion of the key lock mechanism 22, that is, the lock portion α of the key lock mechanism 22 for locking the steering shaft 2, is more electrically driven than the reduction gear device 11, as shown in FIGS. It is arranged on the side closer to the motor 10. The lock portion α is disposed closer to the electric motor 10 than the torque limiter 26, which is a member for protecting the reduction gears (the worm gear 20 and the wheel gear 21) of the reduction gear device 11.
[0015]
According to such a configuration, the following advantages can be obtained. That is, since the key lock mechanism 22 is disposed inside the gear case 11a (housing of the electric power steering mechanism) of the reduction gear device 11, the key lock mechanism 22 is difficult to disassemble due to the layout of the vehicle. And an advantageous structure for preventing theft. Further, the location of the key lock mechanism 22 is changed from an upper location of the steering column 2 to a lower location (a spatial location where a combination switch or the like is not provided). The constraints will be relaxed.
[0016]
Also, the lock portion α of the key lock mechanism 22 for locking the steering shaft 2 is arranged at a position closer to the electric motor 10 than the reduction gear device 11 (reduction unit) (a position closer to the electric motor 10). As a result, when the steering shaft 2 is locked, it is only necessary to lock the lock plate 24 against the torque after deceleration by the reduction gear, so that the operation applied to the key lock mechanism 22 from the steering wheel 1 and eventually the steering shaft 2 is achieved. The force is smaller than in the case where the steering shaft 2 is directly locked (assuming that the reduction ratio of the reduction gear is M, the acting force is as small as 1 / M). Therefore, the key lock mechanism 22 can be a relatively simple structure (a structure that does not require high strength) and a lightweight mechanism. Further, since the lock plate 24 of the key lock mechanism 22 has a structure that rotates more than the number of rotations of the steering shaft 2, the number of lockable times per rotation of the steering shaft increases, which is more effective in preventing theft. Structure.
[0017]
In addition, since the lock portion α is disposed at a position closer to the electric motor 10 than the torque limiter 26 for protecting the reduction gear, a torque equal to or greater than a set value is generated from the steering wheel 1 during the key lock operation. 2, the steering shaft 2 can rotate due to slip rotation between the torque limiter 26 and the worm gear 20, so that the key lock mechanism 22 can be protected, and the effect of preventing theft is improved. Can be maintained. In a normal steering operation at the time of non-key lock, the rotational driving force of the electric motor 1 is transmitted to the steering shaft 2 via the torque limiter 26, so that the power steering operation is not hindered.
[0018]
Further, since the key cylinder 28 is formed integrally with the gear case 11a of the reduction gear device 11, the key cylinder 28 cannot be removed from the gear case 11a. Therefore, theft of the vehicle due to the removal of the key cylinder 28 can be prevented. . In forming the key cylinder 28 integrally with the gear case 11a, the key cylinder 28 may be provided integrally when the case 11a is formed as an aluminum die-cast, so that manufacturing costs can be reduced.
[0019]
FIG. 5 shows another example of the key lock mechanism and the torque limiter. In the case of this example, as shown in FIG. 5A, an annular tolerance ring (slip ring) 30 having a large number of teeth 30a on the outer peripheral surface is formed in a cylindrical shape of the worm gear 20 constituting the reduction gear device 11. It is coaxially and integrally fitted to the end 20a as a torque limiter. Further, a cylindrical lock member 31 as shown in FIG. 5B is coaxially fitted to an outer peripheral portion of the tolerance ring 30 described above. The lock member 31 has, for example, a pair of lock holes 32 formed of long holes, and a number of grooves 31 a corresponding to the teeth 30 a of the tolerance ring 30 are formed on the inner peripheral surface of the lock member 31. . Thus, the lock member 31 is installed so as to surround the tolerance ring 30 in a state where the teeth 30a of the tolerance ring 30 and the groove 31a of the lock member 31 are engaged with each other. A lock pin 25 provided on a key cylinder 28 integrally formed with the gear case 11a is installed at a position corresponding to the lock hole 32 of the lock member 31 so as to be movable forward and backward.
[0020]
The degree of engagement between the tooth portion 30a of the tolerance ring 30 and the groove portion 31a of the lock member 31 is such that the engagement between the tooth portion 30a and the groove portion 31a is at a torque that can be applied during normal steering operation. On the other hand, the engagement state between the tooth portion 30a and the groove portion 31a is set to be released when an excessively large torque acts as compared with the torque at the time of the normal steering operation. Therefore, the steering shaft 2 is set so as to be able to rotate with respect to the lock member 31 together with the tolerance ring 30 when an excessive torque acts.
[0021]
According to such a configuration, there are the following advantages. That is, when the lock member 31 is directly welded to the worm gear 20 (when the tolerance ring 30 is not used), the lock pin 25 is engaged in the lock operation of the key (in the lock hole 32 of the lock member 31). When excessive steering force is applied to the steering wheel 1 due to theft or the like, and an excessive rotational force acts on the lock member 31, the weld between the worm gear 20 and the lock member 31 is broken. As a result, the lock member 31 may be removed from the worm gear 20, and the key lock state may be released accordingly. On the other hand, when the lock member 31 is attached to the worm gear 20 via the tolerance ring 30 as described above, an excessive torque is applied to the lock member 31 during the key lock operation, and the tolerance ring 30 Of the lock member 31 slides (rotates) over the groove 31a of the lock member 31, and the worm gear 20 and the tolerance ring 30 slip relative to the lock member 31 in the locked state (stationary state). Since rotation is allowed, the key lock mechanism 22 can be prevented from breaking. The slip phenomenon as described above does not occur with the normal steering operation force when the key is not locked, so that the rotational driving force of the electric motor 10 is reliably transmitted to the steering shaft 2 via the reduction gear device 11.
[0022]
As mentioned above, although one embodiment of the present invention was described, the present invention is not limited to this embodiment, and various modifications and changes are possible based on the technical idea of the present invention. For example, the configurations of the reduction gear device 11, the key lock mechanism 22, the torque limiter 26, and the like are not limited to those of the above-described embodiment, and can be appropriately changed as needed.
[0023]
【The invention's effect】
According to a first aspect of the present invention, in the electric power steering device, a key lock mechanism for locking rotation of a steering shaft is provided in a gear case of the reduction gear device, and the key lock mechanism is operated. Since the key cylinder into which the key is inserted is formed integrally with the gear case of the reduction gear device, the key lock mechanism is housed in the hardly crushable gear case, and therefore, in order to prevent the vehicle from being stolen. An advantageous structure can be obtained. Further, in the conventional structure in which the key cylinder as a separate part is attached to the steering column with bolts, there is a possibility that the joint between the key cylinder and the steering column may be broken. By integrating the key cylinder with the gear case of the device, the risk of breakage of the key cylinder can be eliminated, and a more advantageous structure can be achieved in preventing theft of the vehicle. In addition, since the above-mentioned gear case is usually located at the lower side of the steering column where no automobile parts such as a combination lamp are arranged, it is possible to ease restrictions on the layout of the key lock device including the key lock mechanism and the key cylinder. . In addition, since the location of the key lock mechanism is changed from the steering column to the gear case of the reduction gear device, it is possible to reduce the weight of the key lock device and hence the weight of the entire steering column.
[0024]
According to the second aspect of the present invention, the lock portion for locking the steering shaft by the key lock mechanism is arranged closer to the electric motor than the reduction gear device. The effect can be achieved. That is, when an excessive turning operation force (steering operation force) is applied to the steering shaft (specifically, the steering wheel) due to theft or the like during the key lock operation, the lock mechanism performs comparison after deceleration by the reduction gear. Since it is sufficient to receive a relatively small torque, the lock mechanism can be made relatively simple (a structure that does not require high strength) and lightweight. The cost can be reduced by simplifying and reducing the weight of the key lock device including the key lock mechanism and the key cylinder and the configuration of the steering column. Further, since the lock portion is disposed closer to the electric motor than the reduction gear device, the number of locks per rotation of the steering shaft can be increased, and a more effective anti-theft effect can be obtained. .
[0025]
According to the third aspect of the present invention, the lock portion for locking the steering shaft by the key lock mechanism is disposed closer to the electric motor than the torque limiter which is a member for protecting the reduction gear of the reduction gear device. Thus, the following operation and effect can be obtained. That is, since the torque limiter is interposed between the lock portion and the reduction gear device, even if an excessive torque is applied to the reduction gear via the steering shaft at the time of key lock operation, the function of the torque limiter described above allows Excessive torque exceeding a predetermined torque can be prevented from being transmitted to the key lock mechanism, and thus the reduction gear and the key lock mechanism can be effectively protected.
[Brief description of the drawings]
FIG. 1 is an exploded perspective view showing an arrangement structure of a key lock mechanism in an electric power steering device according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view schematically showing a configuration of a key lock mechanism in the electric power steering device.
FIG. 3 is a side view showing a configuration of a key lock mechanism in the electric power steering device.
FIG. 4 is a sectional view taken along line XX in FIG. 2;
5A and 5B are diagrams showing another example of the key lock mechanism and the torque limiter, wherein FIG. 5A is a sectional view of the key lock mechanism, and FIG. 5B is a perspective view of a lock member used in the key lock mechanism. It is.
FIG. 6 is a side view showing a configuration of a steering system of the vehicle.
FIG. 7 is an exploded perspective view showing an arrangement structure of a key lock mechanism in a conventional electric power steering device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Steering wheel 2 Steering shaft 9 Steering column 10 Electric motor 10a Rotation drive shaft 11 Reduction gear device 11a Gear case 20 Worm gear 21 Wheel gear 22 Key lock mechanism 23 Lock groove 24 Lock board 25 Lock pin 26 Torque limiter 27 Key 28 Key cylinder 30 Tolerance Ring 30a Tooth 31 Locking member 31a Groove α Locking

Claims (3)

A gear case of a reduction gear device is mounted on a steering column that rotatably supports a steering shaft, and an electric motor is mounted on the gear case, and a rotational driving force of the electric motor is assisted to the steering shaft via the reduction gear device. In an electric power steering device configured to transmit as a force, a key lock mechanism for locking rotation of the steering shaft is disposed in a gear case of the reduction gear device, and a key lock mechanism for operating the key lock mechanism is provided. A key lock mechanism in an electric power steering device, wherein a key cylinder into which a key is inserted is integrally formed with a gear case of the reduction gear device. 2. The key according to claim 1, wherein a lock portion of the key lock mechanism for locking the steering shaft is disposed closer to the electric motor than the reduction gear device. 3. Arrangement structure of lock mechanism. A lock portion of the key lock mechanism for locking the steering shaft is disposed closer to the electric motor than a torque limiter which is a member for protecting a reduction gear of the reduction gear device. An arrangement structure of a key lock mechanism in the electric power steering device according to claim 1 or 2.

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