JP2014201160A - Steering device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a steering device which effectively suppresses vibrations transmitted to an upstream side through a rack shaft and a pinion shaft by reverse input from a wheel side, and materializes safety and comfortable steering, in the steering device which transmits the steering force of a steering wheel to the wheel through a steering shaft and an intermediate shaft, and is equipped with the rack shaft and the pinion shaft.SOLUTION: In a steering device equipped with a rack shaft 9 and a pinion shaft 8, at an intermediate shaft side part of the pinion shaft 8, a coupling shaft 14 capable of transmitting torque in a rotating direction between the pinion shaft 8 and the coupling shaft 14 and sliding in an axial direction is provided. Therefore, vibrations transmitted from the wheel to an upstream side through the rack shaft 9 and the pinion shaft 8 are absorbed by sliding between the coupling shaft 14 and the pinion shaft 8, and can be prevented from transmitting to the intermediate shaft and the steering shaft.

Description

  The present invention relates to a steering device connected to a steering wheel and having a steering shaft, an intermediate shaft, a pinion shaft, and a rack shaft.

  In Patent Document 1, in order to prevent the unevenness of the road surface from being transmitted to the driver due to vibrations or abnormal noise of the steering wheel, the axial end of the pinion shaft that meshes with the rack shaft is set in the axial direction relative to the pinion shaft. A method is described in which the axial vibration of the pinion shaft is regulated by providing an elastic member that biases in the direction.

  However, this method is intended to regulate vibration transmission from the rack to the pinion shaft by controlling the movement in the pinion axis direction and the sound generated by the separation between the rack and the pinion. It is not possible to regulate the impact sound caused by the reverse input exceeding or the minute vibration within the urging force.

  Patent Document 2 discloses that an intermediate shaft having a slide mechanism that can transmit a steering force having a high torque by a column assist type electric power steering device without backlash and has a telescopic function at the time of installation and a collapse function at the time of a collision. As one of them, it is described that it absorbs vibration and displacement from the steering gear when the vehicle travels, and makes it difficult to transmit unpleasant vibration and sound.

  However, this slide mechanism is not mainly intended to absorb vibrations from the wheels, and it is difficult to sufficiently absorb and suppress the vibrations transmitted from the wheels through the rack shaft and pinion shaft to the intermediate shaft. .

JP 2006-335101 A JP 2004-262266 A

  In recent years, safety and comfort are strongly demanded in automobiles, and it is also required to reduce as much as possible vibration and noise transmitted from the steering wheel to the driver via the steering device by reverse input from the road surface even during steering while traveling. .

  However, with the conventional technology as described above, it is difficult to satisfy the high demand for comfortable steering that increases year by year.

  It is an object of the present invention to provide a steering device that can significantly reduce the vibration and noise transmitted from the road surface to the upstream of the steering system and further to the driver through the steering device when the vehicle is running, and can sufficiently satisfy the demand for high comfortable steering. Objective.

  In order to solve the above-described problem, the structural feature of the invention according to claim 1 is that a rack shaft formed with rack teeth, a pinion shaft formed with pinion teeth meshing with the rack teeth, and the pinion shaft And a connecting shaft that is arranged on the upstream side and is attached to the pinion shaft so that torque can be transmitted in the rotational direction and slidable in the axial direction.

  In order to solve the above-described problem, the structural feature of the invention according to claim 2 is that the first shaft and the second shaft of the intermediate shaft are coupled to each other so as to be able to transmit torque and slide in the axial direction. Compared with the sliding resistance in the 2nd sliding part, the sliding resistance in the 1st sliding part comprised by the said pinion shaft and the said connection shaft is small.

  In order to solve the above problems, the structural feature of the invention according to claim 3 is that the sliding length of the first sliding portion is shorter than the sliding length of the second sliding portion. It is.

  In order to solve the above-described problem, a structural feature of the invention according to claim 4 is that the connecting shaft is biased toward the pinion shaft toward at least one of the upstream side or the downstream side in the axial direction. A biasing member.

  In order to solve the above-mentioned problem, the structural feature of the invention according to claim 5 is that the sliding portion between the connecting shaft and the pinion shaft is an inner peripheral portion of a cylindrical portion provided on the pinion shaft. That is, it is arranged between the outer periphery of the connecting shaft.

  In order to solve the above-described problem, the structural feature of the invention according to claim 6 is that the sliding portion between the connecting shaft and the pinion shaft has an inner peripheral portion of a cylindrical portion provided on the connecting shaft. It is arranged between the outer peripheral part of the pinion shaft.

  In order to solve the above-mentioned problem, the structural feature of the invention according to claim 7 is that at least the connecting shaft and the pinion shaft are provided in the axial direction at the opposed inner and outer peripheral positions of the sliding portion. It has a connection structure that can be relatively moved in the axial direction and can transmit torque in the rotational direction via at least one ball respectively disposed in the pair of grooves.

  In order to solve the above-mentioned problem, the structural feature of the invention according to claim 8 is that the connecting shaft and the pinion shaft form a spline in which the sliding portion forms a spline, and is relatively movable in the axial direction and in the rotational direction. It has the connection structure which can transmit torque.

  In order to solve the above-mentioned problems, the structural feature of the invention according to claim 9 is that a surface coating that reduces frictional resistance is provided on at least one meshing surface of the spline portion of the sliding portion of the connecting shaft and the pinion shaft. It is characterized in that a covering film or a surface treatment layer is formed.

  According to the invention according to claim 1 configured as described above, the wheel is provided with a connecting shaft that is disposed on the upstream side of the pinion shaft and is attached to the pinion shaft so as to be capable of transmitting torque and slidable. Can be absorbed in the rack and pinion steering device by the first sliding part between the pinion shaft and the connecting shaft, and the intermediate part upstream of the vibration transmitted to the upstream via the rack shaft and the pinion shaft. Transmission to the steering shaft system including the shaft can be prevented.

  Thus, in addition to preventing vibrations from the wheels from being transmitted to the steering wheel as they are, it is possible to reduce the vibration of the intermediate shaft itself, thereby preventing the occurrence of secondary vibrations. Further, the second sliding portion of the intermediate shaft can be specialized in the main functions of torque transmission and the expansion / contraction function at the time of attachment and collision.

  According to the invention according to claim 2 configured as described above, the sliding resistance of the first sliding portion is made smaller than the sliding resistance of the second sliding portion. Vibration absorption can be performed more effectively.

  According to the invention according to claim 3 configured as described above, the sliding resistance of the first sliding portion is reduced by making the length of the first sliding portion shorter than the length of the second sliding portion. It is possible to more effectively achieve a reduction in the sliding resistance of the second sliding portion.

  According to the invention according to claim 4 configured as described above, a biasing member that biases the connecting shaft toward at least one of the upstream side or the downstream side in the axial direction with respect to the pinion shaft, By providing, the axial position of the connecting shaft can be determined, and a stroke capable of relative movement between the pinion shaft and the connecting shaft can be sufficiently secured.

  According to the invention according to claim 5 configured as described above, the first sliding portion is disposed between the inner peripheral portion of the cylindrical portion provided on the pinion shaft and the outer peripheral portion of the connecting shaft. The size of the first sliding part can be made compact.

  According to the invention according to claim 6 configured as described above, the first sliding portion is disposed between the inner peripheral portion of the cylindrical portion provided on the connecting shaft and the outer peripheral portion of the pinion shaft. As a result, the sliding part diameter can be increased, the transmission torque capacity can be increased, the ball diameter can be increased, and the rigidity of the sliding part can be increased.

  According to the invention according to claim 7 configured as described above, the structure of the first sliding portion is a connecting structure by rolling contact via a rolling element, thereby greatly reducing sliding resistance. It is possible to effectively absorb minute vibrations.

  According to the invention according to claim 8 configured as described above, the first sliding portion forms a spline, and has a connecting structure that can be relatively moved in the axial direction and can transmit torque in the rotational direction. Thus, it is possible to form an easily manufactured sliding portion at a low cost.

  According to the invention according to claim 9 configured as described above, a surface coating film or a surface treatment layer for reducing frictional resistance is formed on at least one meshing surface of the spline portion of the first sliding portion. Thus, the sliding resistance can be greatly reduced and minute vibrations can be effectively absorbed.

  As described above, according to the present invention, it is possible to realize an automotive steering system that can provide a driver with a safe and comfortable steering sensation by blocking vibrations from the wheels that the driver feels uncomfortable at an early stage.

1 is a schematic diagram illustrating an overall configuration of an automobile steering system according to a first embodiment of the present invention. FIG. 2 is an axial sectional view showing a connecting shaft and a pinion shaft in FIG. 1. FIG. 3 is a radial sectional view of a sliding portion between a connecting shaft and a pinion shaft of FIG. 2. It is explanatory drawing of the structure which reversed the inner and outer arrangement | positioning of the connection shaft and pinion shaft which are opposed in the sliding part in the 2nd Embodiment of this invention. (Example 2) It is a pinion axial direction sectional view of the meshing part of a pinion axis and a rack axis of a rack & pinion steering device in a conventional example.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a schematic diagram showing an overall configuration of an automobile steering system according to a first embodiment of the present invention.

  The automotive steering system includes a steering wheel 1, a steering device to which the steering wheel 1 is connected, and wheels 13a and 13b connected to the output side of the steering device.

  The steering apparatus includes a steering shaft 2 connected to a steering wheel 1, an intermediate shaft 7, a connecting shaft 14, a pinion shaft 8, a rack shaft 9, tie rods 12a and 12b, and a rack housing 10 and a joint 6, which are associated therewith. 11 etc. In the case of column-type electric power steering, an auxiliary system such as a motor 5 and a reduction gear 4 for adding a steering assist force is included in the configuration.

  The intermediate shaft has a first shaft 7a and a second shaft 7b that are connected to each other so that torque can be transmitted in the rotational direction and slidable in the axial direction, and the first shaft is connected to the steering shaft 2 via the steering joint 6a. The second shaft is connected to a connecting shaft 14 connected to the pinion shaft 8 via a steering joint 6b.

  A steering force applied to the steering wheel 1 by the driver is transmitted as a rotational force from the steering shaft 2 to the connecting shaft 14 and the pinion shaft 8 via the intermediate shaft 7. The rotational force transmitted to the pinion shaft 8 is converted into a rack axial force via a gear mechanism provided on the pinion shaft 8 and the rack shaft 9, and transmitted to the wheels 13a and 13b via the tie rods 12a and 12b. The

  On the other hand, the reaction force from the road surface and the vibration between the road surface and the tire are transmitted to the rack shaft 9, the pinion shaft 8, and the connecting shaft 14 from the wheels 13a and 13b through the tie rods 12a and 12b, contrary to the steering force. , Transmitted to the driver via the intermediate shaft 7, the steering shaft 2, and the steering wheel 1.

FIG. 2 is a sectional view in the pinion axial direction of the first embodiment of the present invention.
In the rack housing 10, the pinion shaft 8 and the rack shaft 9 are arranged in a state where the teeth provided on the pinion shaft 8 and the rack shaft 9 are engaged with each other. The pinion shaft 8 is supported by upper and lower bearings 17 and 18, and the rack shaft 9 is pressed against the pinion teeth 15 by a support yoke 20 that contacts the back surface of the rack teeth 16 and a spring 21 behind the support yoke 20.

FIG. 3 is a radial cross-sectional view of the first sliding portion constituted by the pinion shaft 8 and the connecting shaft 14 in FIG.
The first sliding portion includes a lower shaft portion 26 of the connecting shaft 14 and a cylindrical portion 27 provided on the pinion shaft 8. The connecting shaft lower shaft portion 26 and the pinion shaft upper cylindrical portion 27 are positioned at opposite positions. At least one pair of axial grooves 26g and 27g is provided, and at least one rolling element (ball) 28 is disposed therein.

  The connecting shaft 14 and the pinion shaft 8 are connected to each other through grooves 26g and 27g provided in each of them and rolling elements (balls) 28 disposed therebetween, and transmit rotational torque in the rotational direction, and transmit axially in the axial direction. Relative movement is possible with low resistance by rolling contact.

  The first sliding portion is set to have a smaller sliding stroke and smaller sliding resistance than the second sliding portion between the first shaft 7a and the second shaft 7b of the intermediate shaft 7.

Therefore, the vibration from the wheel transmitted from the rack shaft 9 to the pinion shaft 8 is absorbed by the relative movement (sliding) in the first sliding portion between the pinion shaft 8 and the connecting shaft 14.
For this reason, vibration from the wheel is hardly transmitted to the intermediate shaft 7 upstream of the pinion and connected to the connecting shaft 14 by the serration 23.

The elastic urging member 29 disposed at the end of the connecting shaft of the first sliding portion determines the relative position between the connecting shaft 14 and the pinion shaft 8 and ensures a stroke of relative movement in the axial direction to effectively vibrate. Contributes to absorbing.
The elastic urging member 29 can use various elastic materials such as metal and resin. Various member shapes such as a coil shape and a plate shape can be selected.

  The first sliding portion may be rolling sliding via a rolling element (ball) 28 or sliding sliding by a spline. When the sliding portion is formed by a spline, it is more compact and easy to manufacture, and can be provided at a low cost.

  In the case of sliding, the vibration absorption effect can be enhanced by providing a surface coating film or a surface treatment layer that reduces frictional resistance on at least one of the surfaces that are in contact with each other.

  The first sliding portion can also be disposed between the inner diameter of the cylindrical portion provided on the connecting shaft 14 and the outer diameter of the pinion shaft 8.

FIG. 4 is a sectional view in the pinion axis direction of the embodiment.
The first sliding portion is provided with grooves on the inner diameter side of the connecting shaft lower cylindrical portion 30 and the outer shape side of the pinion shaft upper shaft portion 31, and the rolling elements (balls) 28 are disposed therebetween.

The connecting shaft 14 and the pinion shaft 8 transmit rotational torque in the rotational direction, and can be relatively moved with low resistance by rolling contact in the axial direction.
Due to this relative movement, the vibration from the wheel transmitted from the rack shaft 9 to the pinion shaft 8 is hardly transmitted to the intermediate shaft 7 upstream of the pinion and connected to the connecting shaft 14.

  In this arrangement, since the distance from the rolling element center to the shaft center can be increased, a larger rotational torque can be transmitted. In addition, the rolling element diameter can be increased, and the rigidity can be increased. Therefore, it can be used for applications that require high torque and high rigidity.

FIG. 5 is a cross-sectional view in the pinion axis direction of a meshing portion between the pinion shaft 8 and the rack shaft 9 of the rack and pinion steering device in the conventional example.
The vibrations of the wheels are transmitted to the rack shaft 9 as vibrations in the rack axis direction, and are transmitted to the pinion teeth 15 provided at the lower part of the pinion shaft that meshes with the rack teeth 16 to become vibrations of the pinion shaft 8.
The vibration is transmitted as it is to the intermediate shaft 7 connected upstream via the serration 23.

1: Steering wheel, 2: Steering shaft, 3: Steering column 4: Reduction gear, 5: Motor, 6a, 6b: Steering joint, 7: Intermediate shaft,
7a: first shaft, 7b: second shaft, 8: pinion shaft, 9: rack shaft,
10: rack housing, 12a, 12b: tie rods, 13a, 13b: wheels,
14: connecting shaft, 15: pinion teeth, 16: rack teeth, 17: upper bearing,
18: Lower bearing, 19: Seal, 20: Support yoke, 21: Spring,
22: Nut, 23: Serration, 24: Intermediate shaft fixing groove, 25: Sliding part seal,
26: connecting shaft sliding part, 26g: connecting shaft rolling groove, 27: pinion shaft sliding part,
27 g: pinion shaft rolling groove, 28: rolling element (ball), 29: biasing member

Claims (9)

An intermediate shaft having a second sliding portion in which the first shaft and the second shaft are connected to transmit torque in the rotational direction and are slidable in the axial direction, and a rack shaft in which rack teeth are formed on a part of the shaft surface When,
A pinion shaft formed with pinion teeth that mesh with the rack teeth;
A connecting shaft disposed on the intermediate shaft side of the pinion shaft;
A first sliding part configured to connect the pinion shaft and the connecting shaft so that torque can be transmitted in the rotational direction and slidable in the axial direction;
A steering apparatus comprising: The steering device according to claim 1, wherein a sliding resistance of the first sliding portion is smaller than a sliding resistance of the second sliding portion.   The steering device according to claim 1 or 2, wherein a sliding length of the first sliding portion is shorter than a sliding length of the second sliding portion. 4. The steering device according to claim 1, further comprising an urging member that urges the connection shaft in an axial direction with respect to the pinion shaft. 5.   The said 1st sliding part is arrange | positioned between the inner peripheral part of the cylindrical part provided in the pinion shaft, and the outer peripheral part of a connection shaft, The any one of Claim 1 to 4 characterized by the above-mentioned. A steering device according to claim 1.   The said 1st sliding part is arrange | positioned between the outer peripheral part of a pinion shaft, and the inner peripheral part of the cylindrical part provided in the connection shaft, The any one of Claim 1 to 4 characterized by the above-mentioned. The steering apparatus as described.   The steering according to claim 5 or 6, wherein the first sliding portion has at least a pair of grooves provided in the axial direction at opposing inner and outer peripheral positions, and at least one ball disposed in the grooves. apparatus.   The steering apparatus according to any one of claims 1 to 6, wherein the first sliding portion has a spline structure between a pinion shaft and a connecting shaft.   The steering apparatus according to claim 8, wherein a surface coating film or a surface treatment layer for reducing frictional resistance is formed on at least one meshing surface of the spline structure.

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