JP6358026B2 - Rack and pinion steering system - Google Patents

Description

  The present invention relates to a rack and pinion type steering device used for a steering device of an automobile.

  In a rack and pinion type steering device widely used in a steering device for a passenger car, the vibration of the rack at the meshing portion between the rack and the pinion caused by the reaction force from the road surface and the sound of the hitting may give the driver an uncomfortable feeling. is there.

  As a method for preventing the vibration of the rack and the sound caused by the vibration, Patent Document 1 discloses a rack and pinion type steering device including a synthetic resin-based shock absorber having at least a columnar member between a rack guide and a guide plug. It is disclosed.

JP 2002-67982 A

  In the configuration as described above, it is necessary to insert a shock absorber between the rack guide and the guide plug before adjusting the clearance between the rack guide and the guide plug to position the guide plug. At this time, the clearance between the rack guide and the guide plug is measured by an indirect means for measuring the displacement of the rack end when the shock absorber is added to the biasing member and the rack end is pressed against the anti-pinion side. Can only be done. In this method, it is difficult to accurately set and adjust the clearance between the rack guide and the guide plug. An object of the present invention is to provide a rack and pinion type steering device that accurately sets a clearance between a rack guide and a guide plug and at the same time realizes prevention of rack vibration and sound.

In order to solve the above-mentioned problems, the structural features of the invention according to claim 1 are: a pinion and a rack that mesh with each other; a rack guide that supports the rack from the back; and a biasing member that presses the rack guide from the back A rack and pinion type comprising: a guide plug for supporting the biasing member on the back surface; a guide hole for screwing the guide plug into an inner periphery and receiving and holding the rack guide; and a housing having a guide hole A steering device,
A measurement hole for measuring a clearance between the rack guide and the guide plug is provided in the shaft center of the guide plug, and a damper portion acting as a buffer member between the rack guide and the guide plug is inserted into the measurement hole. And a substantially cylindrical buffer sealing member having a plurality of different outer diameter portions composed of a seal portion acting as a sealing member with the guide plug,
The shock-absorbing sealing member is formed with a cavity having at least one open end at an axial center portion thereof, is easily deformed so as to pass through the measurement hole, and is inserted into the measurement hole from the back surface of the guide plug. The part is restored to the original shape in the guide hole after passing through the measurement hole, and forms a pair of contact surfaces that contact the rack guide end surface and the opposing guide plug end surface to exhibit a buffering action. It is.

  According to the invention of claim 1 configured as described above, the measurement hole provided in the center axis of the guide plug is used, the stylus of the clearance measurement gauge is inserted into the measurement hole, and the cylindrical hole inner end surface of the rack guide and the guide By measuring the distance from the bottom of the plug, the clearance between the rack guide and the guide plug can be set accurately. In addition, since the buffer sealing member can be inserted and arranged from the measurement hole, the damper portion of the buffer sealing member can sufficiently exhibit the damper effect between the rack guide and the guide plug. According to the rack and pinion type steering device assembled in this manner, rack vibration and hammering can be prevented by a synergistic effect of accurate clearance management and a damper effect.

  In order to solve the above-mentioned problem, the structural feature of the invention according to claim 2 is that the buffer sealing member is formed of a resin or a polymer material, and the shape and area of the damper section perpendicular to the axis are the same. It is to obtain an appropriate buffer characteristic by making it constant or changing in the axial direction.

  According to the invention of claim 2 configured as described above, by changing the shock absorbing characteristic of the damper portion of the shock absorbing sealing member in the axial direction, in addition to the shock absorbing characteristic in the axial direction of the urging member provided side by side, Since an optimum buffer damping characteristic can be set for the applied rack and pinion type steering device, more effective vibration damping absorption can be achieved.

  As described above, according to the present invention, it is possible to provide a rack and pinion type steering device that accurately sets the clearance between the rack guide and the guide plug, and at the same time, effectively realizes the prevention of rack vibration and sound. be able to.

It is sectional drawing which shows the structure of the rack and pinion type | formula steering device in embodiment of this invention. It is a conceptual diagram which shows the buffer attenuation | damping characteristic of the buffer sealing member in embodiment of this invention.

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

  First, the configuration of a rack and pinion type steering apparatus according to an embodiment of the present invention will be described with reference to FIG.

  The rack and pinion engaging structure peripheral structure of the rack and pinion type steering apparatus includes a pinion 1, a rack 3, a rack housing 5, a rack guide 8, a biasing member 13, a guide plug 15, and a buffer sealing member 20. .

  The pinion 1 is rotatably supported by the rack housing 5 by bearings 30 and 31. The rack 3 is accommodated in the rack housing 5 so as to be movable in the axial direction, and the rack teeth 4 are engaged with the pinions 1 by meshing with the pinion teeth 2. A rack guide 8 having a rack support portion 9 having a shape corresponding to the shape of the back surface of the rack is disposed on the back surface of the rack 3. The rack guide 8 is provided with a cylindrical hole 12 on the opposite side of the rack support portion 9, and the biasing member 13 is stored in a compressed state therein. Both ends of the urging member 13 are in contact with the end surface 10 in the cylindrical hole 12 of the rack guide 8 and the end surface 16 of the guide plug 15. A guide plug 15 is disposed behind the end surface 11 of the rack guide 8 so that the end surface 16 faces the gap 14 therebetween.

  The guide plug 15 is screwed and fixed near the opening of the inner periphery 7 of the guide hole 6 of the rack housing 5. A measurement hole 18 is provided in the axial center of the guide plug 15, and a buffer sealing member 20 is inserted into the measurement hole 18.

  The shock-absorbing sealing member 20 is made of silicon rubber, and has a damper portion 22 formed in a substantially conical shape whose diameter decreases toward the tip portion, and a seal portion 23 formed in a substantially cylindrical shape continuously to the damper portion 22. doing. The damper portion 22 has a damper tip 24 that is formed flat, and a damper seat surface 25 on the end surface that becomes the maximum diameter of the damper portion 22. The seal portion 23 has a small diameter portion and a large diameter portion. The axial length of the small diameter portion is the same as the length of the measurement hole 18, and the diameter of the small diameter portion is the same as the diameter of the measurement hole 18. The large diameter portion is formed in a bowl shape larger than the diameter of the measurement hole 18. A cavity 21 with a closed tip is formed inside the buffer sealing member 20.

  After the buffer sealing member 20 is inserted into the measurement hole 18, the radial direction is in the state where the outer peripheral surface of the seal portion 23 is in contact with the inner peripheral surface of the measurement hole 18, and the axial direction is the large diameter portion and the damper seat surface 25. Are fixed to the guide plug 15 in contact with the bottom surface and the end surface of the guide plug 15. The shock-absorbing sealing member 20 is arranged such that the damper tip 24 abuts against the end face 10 in the cylindrical hole 12 of the rack guide 8 and the damper seating face 25 abuts against the end face 16 of the guide plug 15.

  Next, the operation of the rack and pinion type steering device in the embodiment of the present invention will be described.

  The rack 3 is urged from the back by a rack guide 8 that abuts on a rack support portion 9, and is always in meshing contact with the pinion 1. The urging force by the rack guide 8 is due to the extension force of the urging member 13 disposed between the rack guide 8 and the guide plug 15. Although it is rare that the rack 3 and the pinion 1 are separated from each other by a normal steering operation, the rack 3 vibrates due to vibrations from the road surface or the vehicle body, and a separation force exceeding the urging force is generated, so that the rack 3 and the pinion 1 are separated. May be separated. At this time, a hitting sound is generated between the rack 3 and the pinion 1 during re-engagement, and the driver may feel uncomfortable.

  Since the magnitude of the hitting sound generated between the rack 3 and the pinion 1 corresponds to the distance between the rack 3 and the pinion 1, a general method is to keep the distance as small as possible in order to suppress the hitting sound. Adopted. As one of the methods, the end surface 11 of the rack guide 8 and the end surface 16 of the guide plug 15 are brought into contact with each other to stop the movement of the rack guide 8 in the axial direction. Is set and managed as the maximum separation distance.

  In the embodiment of the present invention, using the measurement hole 18 provided in the axial center of the guide plug 15, a stylus of a clearance measurement gauge fixed to the bottom surface 17 of the guide plug 15 is inserted into the measurement hole 18, and the rack guide is inserted. 8, the distance between the cylindrical hole inner end surface 10 of the rack guide 8 and the bottom surface 17 of the guide plug 15 is accurately measured, and then the clearance 14 is set accurately to guide the guide plug. 15 is fixed to the inner periphery 7 of the guide hole 6 of the rack housing 5 to be screwed. Thereafter, the buffer sealing member 20 is deformed and inserted from the measurement hole 18 into the cylindrical hole 12 provided in the rack guide 8.

  The damper portion 22 in the front half of the deformed shock-absorbing sealing member 20 is restored to its original shape in the cylindrical hole 12 by the elasticity of the shock-absorbing sealing member 20, that is, the restoring function, and the damper tip 24 is the cylinder of the rack guide 8. The damper seat surface 25 abuts on the end surface 16 of the guide plug 15. The seal portion 23 of the buffer sealing member 20 is placed in the measurement hole 18 with the outer periphery of the small diameter portion contacting the inner periphery of the measurement hole 18 and is fixed in the axial direction by the outer flange-shaped large diameter portion and the seat surface 25. Is done.

  When the rack 3 and the rack guide 8 vibrate due to vibration from the road surface or the vehicle body, first, the biasing member 13 exhibits a buffering action against the separation force between the rack 3 and the pinion 1 due to vibration. The damper portion 22 of the buffer sealing member 20 cooperates with the buffering action of the urging member 13 to provide a buffering action between the end face 10 in the cylindrical hole 12 of the rack guide 8 and the end face 16 of the guide plug 15. Demonstrate. Further, the buffer sealing member 20 also has a damping function due to the characteristics of silicon rubber, and exhibits a damper effect and absorbs vibration energy against shock vibration.

  The buffer damping characteristic at this time is determined by the material of the buffer sealing member 20 and the shape of the damper portion 22. A rack-and-pinion steering device to which the buffer sealing member 20 is applied by changing the shape and area of the cross section perpendicular to the axis formed on the outer periphery and inner periphery of the damper portion 22 (that is, the inner periphery of the cavity 21) in the axial direction. Optimum characteristics can be set. The buffer damping characteristic for the vibration of the rack 3 is a combination of the elastic characteristics of the urging member 13 and the buffer sealing member 20. Therefore, when setting the buffer damping characteristic of the buffer sealing member 20, the cylindrical hole of the rack guide 8 is used. It is natural to consider the elastic characteristics of the biasing member 13 provided in the interior 12.

Next, buffer damping characteristics of the urging member 13 and the buffer sealing member 20 will be described.
FIG. 2 shows a conceptual diagram of the buffer damping characteristics of the urging member 13 and the buffer sealing member 20. The vertical axis represents the biasing force of the rack guide 8 (that is, the separation force between the rack 3 and the pinion 1), and the horizontal axis represents the axial displacement of the rack guide 8. Line A is a displacement when the tip 24 of the buffer sealing member 20 and the end face 10 in the cylindrical hole 12 of the rack guide 8 are in an initial contact state, and then the rack guide 8 is moved in the axial direction by the vibration of the rack guide 8. Is the relationship between the power and the force.
In this case, it is shown that the elastic force of both the urging member 13 and the buffer sealing member 20 acts in an overlapping manner from the beginning of the movement of the rack guide 8 and buffers the separation force with a certain elastic coefficient.

  Line B shows a state in which the end surface 11 of the rack guide 8 is in contact with the end surface 16 of the guide plug 15 and the movement of the rack guide 8 in the axial direction is restrained. To increase. When this state is reached, the separation between the rack 3 and the pinion 1 is not further expanded.

  In other embodiments, a gap may be set in advance between the tip 24 of the buffer sealing member 20 and the end surface 10 in the cylindrical hole 12 of the rack guide 8 in order to obtain optimum buffer damping characteristics. . In this case, the relationship between the displacement of the rack guide 8 and the urging force is as shown by line C and line D. Line C shows the state where only the elasticity of the urging member 13 acts, and line D shows the state in which the buffer sealing member 20 starts to deform in addition to the urging member 13 and both elastic characteristics overlap and act on the rack guide 8. ing.

  Such characteristics can keep the biasing force small while the separation between the rack 3 and the pinion 1 is small, and can limit the separation with a larger force when the separation becomes large. Such characteristics are desirable when the normal rotational torque of the pinion 1 is kept low while maintaining the buffer damping characteristics. In order to further increase this effect, it is possible to set a non-linear elastic characteristic such as the line G.

  A position E indicates an initial clearance between the front end 24 of the buffer sealing member 20 and the end face 10 in the cylindrical hole 12 of the rack guide 8, and a position F is between the end face 11 of the rack guide 8 and the guide plug end face 16. The clearance 14 is shown.

  In other embodiments, it is also possible for the closed cavity 21 in this embodiment to reach the tip 24 and open in order to obtain optimum damping characteristics. Further, the outer periphery and inner periphery of the damper portion 22 can have not only the conical surface shown in the drawing but also a cylindrical surface, a spherical surface, or a more complicated surface shape. In this case, it is possible to have a nonlinear elastic characteristic as indicated by a line G in FIG.

  The seal part 23 in the rear half of the shock-absorbing sealing member 20 is left in the measurement hole 18 even after the damper part 22 in the front half is restored to the original shape, and the end face 16, the bottom face 17 and the measurement hole 18 of the guide plug 15 are retained. A sealing action is expressed between the inner peripheral surface. Therefore, the grease sealed in the rack housing 5 for lubricating the meshing portion of the rack 3 and the pinion 1 does not leak from the measurement hole 18.

  As described above, according to the embodiment of the present invention, the clearance 14 between the rack guide 8 and the guide plug 15 can be accurately set, and at the same time, the rack 3 can be effectively prevented from vibration and sound. The rack and pinion type steering device can be provided.

  The present invention is not limited to the embodiment described above. Needless to say, the present invention can be implemented in various modes without departing from the gist of the present invention.

1: pinion, 2: pinion tooth, 3: rack, 4: rack tooth,
5: rack housing, 6: guide hole, 7: inner circumference of guide hole, 8: rack guide,
9: Rack support part, 10: End face of cylindrical hole, 11: End face of rack guide,
12: cylindrical hole, 13: biasing member, 14: clearance, 15: guide plug,
16: guide plug end face, 17: guide plug bottom face, 18: measurement hole,
20: Buffer sealing member, 21: Cavity, 22: Damper part, 23: Seal part,
24: Damper tip, 25: Damper seat, 30, 31: Bearing,
32: Seal, 33: O-ring

Claims (2)

A pinion and a rack that mesh with each other, a rack guide that supports the rack from the back, a biasing member that presses the rack guide from the back, a guide plug that supports the biasing member from the back, and the guide plug on the inner periphery A rack and pinion type steering device comprising: a guide hole that is screwed and accommodates and holds the rack guide; and a housing having a guide hole,
A measurement hole for measuring a clearance between the rack guide and the guide plug is provided in the shaft center of the guide plug, and a damper portion acting as a buffer member between the rack guide and the guide plug is inserted into the measurement hole. And a substantially cylindrical buffer sealing member having a plurality of different outer diameter portions composed of a seal portion acting as a sealing member with the guide plug,
The shock-absorbing sealing member is formed with a cavity having at least one open end at an axial center portion thereof, is easily deformed so as to pass through the measurement hole, and is inserted into the measurement hole from the back surface of the guide plug. The part is restored to the original shape in the guide hole after passing through the measurement hole, and forms a pair of contact surfaces that contact the rack guide end surface and the opposing guide plug end surface to exhibit a buffering action. A rack and pinion type steering device characterized by the above.   The shock-absorbing sealing member is formed of a resin or a polymer material, and an appropriate shock-absorbing characteristic is obtained by changing the shape and area of the damper section perpendicular to the axis in the axial direction. The rack and pinion type steering device according to claim 1.

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