JP4782453B2 - Rack and pinion type steering device, electric power steering device, and rack displacement adjustment method for rack and pinion type steering device - Google Patents

Description

  The present invention relates to a rack and pinion steering device, an electric power steering device, and a rack displacement adjustment method for a rack and pinion steering device.

As shown in FIG. 7, a conventional electric power steering apparatus includes a rack shaft 100 that meshes with a pinion shaft (not shown) mechanically connected to a steering wheel (not shown). A rack guide 102 that guides the movement of the rack shaft 100 is disposed in the vicinity of the rack shaft 100. That is, a concave mounting portion 104 is formed at one end of the rack guide 102, and the rack shaft 100 is positioned on the pad 106 to which the mounting portion 104 is attached. Further, a screw 108 is arranged at the other end of the rack guide 102 so as to face the other end. Concave portions 110 and 112 are respectively formed in the other end portion of the rack guide 102 and the screw 108, and a spring 114 is disposed in the concave portions 110 and 112. The rack shaft 100 is pressed toward the pinion shaft via the rack guide 102 by the elastic force of the spring 114.
Japanese Utility Model Publication No.59-13359 Japanese Utility Model Publication No.58-19873 Japanese Utility Model Publication No. 61-21672

  By the way, in the above conventional electric power steering apparatus, the rack guide and the rack shaft are pressed against the pinion shaft side by the elastic force of the spring, so that the hitting sound when the rack shaft and the pinion shaft collide is prevented. If the set load (elastic force) of the spring is increased, the sliding load when sliding the rack shaft to the left and right is increased, and there is a problem that the steering feeling is deteriorated. Conversely, if the spring's elastic force is reduced in order to improve the steering feeling, the rack shaft easily separates from the pinion shaft due to vibration or impact, and the rack shaft and the pinion shaft collide with each other, and a hitting sound is generated. End up. That is, in the above conventional electric power steering apparatus, it is impossible to achieve both the prevention of hitting sound and the improvement of the steering feeling when the rack shaft and the pinion shaft (not shown) collide.

  Therefore, in consideration of the above circumstances, the present invention provides a rack and pinion type steering device, an electric power that can achieve both the prevention of hitting sound and the improvement of steering feeling when the rack shaft and the pinion shaft collide with each other. An object of the present invention is to provide a rack displacement adjusting method for a steering device and a rack and pinion type steering device.

According to the first aspect of the present invention, a pinion shaft that rotates by steering, a rack shaft that meshes with the pinion shaft, a spring member that presses the rack shaft in a predetermined direction, and movement of the rack shaft in a predetermined direction. A rack and pinion type steering apparatus having a rack guide for guiding and a screw arranged so as to form a recess between the rack guide , wherein the spring member is arranged in the recess, A space portion is formed on the outer surface of the rack guide, and the space portion is provided with an elastic member that moves by the pressing force of the viscous fluid filled in the recess, and the recess filled with the space A damping force generating means is configured by the viscous fluid and a throttle portion that communicates with the space portion and the recessed portion and guides the viscous fluid filled in the recessed portion to the space portion, and the damping force generating means includes: Serial rack shaft is characterized in that to generate a damping force as a resistance when moving in a direction away from the said pinion shaft.

  According to the first aspect of the present invention, when the elastic force of the spring member is reduced in order to reduce the sliding load when sliding the rack shaft to the left and right and improve the steering feeling, the damping force Since the damping force of the generating means becomes a resistance force when the rack shaft moves in a direction away from the pinion shaft, the movement of the rack shaft is hindered. This makes it difficult for the rack shaft to be separated from the pinion shaft, prevents the rack shaft from being pressed by the elastic force of the spring member and collides with the pinion shaft, and prevents the hitting sound that is a collision sound between the rack shaft and the pinion shaft. Occurrence can be prevented. As a result, it is possible to achieve both prevention of hitting sound and improvement of steering feeling when the rack shaft and the pinion shaft collide.

In addition , since the spring member is disposed in the recess formed between the rack shaft and the rack guide, the space of the recess can be used effectively. Thereby, even when a spring member is used, it can prevent that a rack and pinion type steering device enlarges.

Further , the damping force generating means is composed of a viscous fluid filled in the concave portion and a throttle portion that communicates with the space portion and the concave portion and guides the viscous fluid filled in the concave portion to the space portion. When moving in a direction away from the pinion shaft, the viscous fluid filled in the concave portion is guided to the space portion through the throttle portion, and a large damping force is generated (orifice effect). This effectively prevents the rack shaft from moving away from the pinion shaft.

Further , when the rack shaft moves in a direction away from the pinion shaft, the viscous fluid filled in the concave portion is guided to the space portion through the throttle portion, and the pressing force of the viscous fluid at that time causes the viscous fluid to enter the space portion. The provided elastic member is moved. As a result, a larger damping force can be generated, and the rack shaft can be effectively prevented from moving away from the pinion shaft.

According to a second aspect of the invention, the rack-pinion type steering apparatus according to claim 1, wherein the throttle portion, wherein the rack guide is a groove formed on the outer surface of the.

According to the second aspect of the present invention, since the throttle portion is a groove formed on the outer surface of the rack guide, the throttle portion can be easily formed.

According to a third aspect of the invention, the rack-pinion type steering apparatus according to claim 1, wherein the throttle portion is characterized in that the a hole for the rack guide and the through communicating with the space portion.

According to the third aspect of the present invention, since the throttle portion is a hole portion that penetrates the rack guide and communicates with the space portion, the throttle portion can be easily formed.

The invention according to claim 4, in a rack-pinion type steering apparatus according to any one of claims 1 to 3, wherein the viscous fluid, characterized in that it is a grease or oil.

According to the fourth aspect of the present invention, since the viscous fluid is grease or oil, an existing one can be used effectively, and since the viscosity is high, a large damping force can be generated.

A fifth aspect of the present invention is an electric power steering apparatus provided with the rack and pinion type steering apparatus according to any one of the first to fourth aspects.

According to the fifth aspect of the present invention, it is possible to achieve both the prevention of hitting sound and the improvement of the steering feeling when the rack shaft and the pinion shaft collide.

The invention according to claim 6 is a rack of a rack and pinion type steering apparatus, comprising: a pinion shaft that rotates by steering ; a rack shaft that meshes with the pinion shaft; and a spring member that presses the rack shaft in a predetermined direction. A displacement adjusting method, wherein the spring member is disposed in a recess formed between a rack guide and a screw that guides the movement of the rack shaft in a predetermined direction, and the viscous fluid filled in the recess A resistance when the rack shaft moves in a direction away from the pinion shaft by a throttle portion that guides the viscous fluid filled in the concave portion to a space portion formed on an outer surface of the rack guide. The damping force generating means for generating the damping force is configured, and the elastic member provided in the space is moved by the pressing force of the viscous fluid .

According to the sixth aspect of the present invention, when the elastic force of the spring member is reduced in order to reduce the sliding load when sliding the rack shaft to the left and right and improve the steering feeling, the damping force Since the damping force of the generating means becomes a resistance force when the rack shaft moves in a direction away from the pinion shaft, the movement of the rack shaft is hindered. This makes it difficult for the rack shaft to be separated from the pinion shaft, prevents the rack shaft from being pressed by the elastic force of the spring member and collides with the pinion shaft, and prevents the hitting sound that is a collision sound between the rack shaft and the pinion shaft. Occurrence can be prevented. As a result, it is possible to achieve both prevention of hitting sound and improvement of steering feeling when the rack shaft and the pinion shaft collide.

Further , since the spring member is disposed in the recess formed between the rack guide that guides the movement of the rack shaft in the predetermined direction and the screw, the space of the recess can be used effectively. Thereby, even when a spring member is used, it can prevent that a rack and pinion type steering device enlarges.

Further , when the rack shaft tries to move away from the pinion shaft, the viscous fluid filled in the concave portion is guided to the space portion through the throttle portion, and a large damping force is generated (orifice effect). This effectively prevents the rack shaft from moving away from the pinion shaft.

Further , when the rack shaft moves in a direction away from the pinion shaft, the viscous fluid filled in the concave portion is guided to the space portion through the throttle portion, and the pressing force of the viscous fluid at that time causes the viscous fluid to enter the space portion. The provided elastic member is moved. As a result, a larger damping force can be generated, and the rack shaft can be effectively prevented from moving away from the pinion shaft.

The invention according to claim 7 is the rack displacement adjustment method of the rack and pinion type steering apparatus according to claim 6 , wherein the throttle portion is a groove portion formed on an outer surface of the rack guide. To do.

According to the seventh aspect of the present invention, since the throttle portion is a groove portion formed on the outer surface of the rack guide, the throttle portion can be easily formed.

The invention according to claim 8 is the rack displacement adjustment method of the rack and pinion type steering apparatus according to claim 6 , wherein the throttle portion is a hole portion that penetrates the rack guide and communicates with the space portion. It is characterized by.

According to the eighth aspect of the present invention, since the throttle portion is a hole portion that penetrates the rack guide and communicates with the space portion, the throttle portion can be easily formed.

The invention according to claim 9 is the rack displacement adjustment method for a rack and pinion steering device according to any one of claims 6 to 8 , wherein the viscous fluid is grease or oil. .

According to the ninth aspect of the invention, since the viscous fluid is grease or oil, an existing one can be used effectively, and a large damping force can be generated because the viscosity is high.

  According to the present invention, it is possible to achieve both prevention of hitting sound and improvement of steering feeling when the rack shaft and the pinion shaft collide.

  Next, a rack and pinion steering apparatus according to an embodiment of the present invention will be described with reference to the drawings. In this embodiment, a configuration in which the rack and pinion type steering device is applied to an electric power steering device will be described as an example.

  As shown in FIGS. 1 to 3, the rack and pinion type steering device 10 includes a rack shaft 12 that extends in the left-right direction of the vehicle. A pinion shaft 14 that meshes with the rack shaft 12 is disposed in the vicinity of the rack shaft 12. A steering shaft 13 is connected to the pinion shaft 14, and a steering wheel (not shown) is connected to the tip of the steering shaft 13. Thus, the pinion shaft 14 is configured to rotate by steering with the steering wheel.

  A rack guide 16 that guides the movement of the rack shaft 12 in a predetermined direction is disposed at a position opposite to the pinion shaft 14 with respect to the rack shaft 12. On one end surface of the rack guide 16, a recessed mounting portion 18 that covers a part of the outer peripheral surface of the rack shaft 12 is formed. On the surface of the mounting portion 18, a pad 20 made of resin is provided. As a result, the rack shaft 12 is configured to contact the rack guide 16 via the pad 20.

  A concave space 22 is formed on the outer peripheral surface of the rack guide 16. An O-ring (elastic member) 24 made of rubber is disposed in the space 22. That is, the length (width) of the space portion 22 along the rack guide axis direction is set to be larger than the diameter of the O-ring 24, and when a predetermined pressure acts on the internal O-ring 24, The ring 24 is configured to move along the rack guide axis direction.

  A first recess 26 is formed at the other end of the rack guide 16. Further, a groove portion (throttle portion) 28 having a diameter smaller than that of the other outer peripheral surface of the rack guide 16 is formed on the outer peripheral surface of the rack guide 16 positioned between the space portion 24 and the other end portion of the rack guide 16. Is formed.

  Further, a screw 30 is disposed at a position facing the other end of the rack guide 16. A second recess 32 is formed at one end of the screw 30 facing the first recess 26. A spring (spring member) 36 is disposed in a chamber portion (concave portion) 34 constituted by the first concave portion 26 and the second concave portion 32. In other words, a chamber portion 34 is formed between the rack guide 16 and the screw 30, and a spring 36 is arranged in the chamber portion 34. A pressing force (elastic force) acting in the direction of arrow F in FIGS. 2 and 5 acts on the rack guide 16 and the rack shaft 12 by the spring 36.

  As shown in FIG. 3, a gap 38 is formed between the other end surface of the rack guide 16 and one end surface of the screw 30. As described above, the chamber portion 34 is configured to communicate with the space portion 22 through the gap 38 and the groove portion 28.

  The chamber portion 34 is filled with grease (viscous fluid) G. As a result, when pressure in a predetermined direction acts from the rack shaft 12 and the volume of the chamber portion 34 decreases, the grease G filled in the chamber portion 34 passes through the gap 38 and the groove portion 28 from the chamber portion 34 to the space. It flows into the part 22. At this time, since the cross-sectional area of the groove portion 28 is considerably smaller than the cross-sectional area of the chamber portion 34, a large damping force is generated, which becomes a resistance force when the rack shaft 12 tries to move away from the pinion shaft 14. The rack shaft 12 is prevented from moving away from the pinion shaft 14.

  In the present embodiment, the configuration in which the chamber part 34 is filled with the grease G has been described as an example. However, the present invention is not limited to the grease G, and other viscous fluid such as hydraulic oil is supplied to the chamber part 34. You may make it fill.

  As shown in FIG. 1, the rack guide 16 and the screw 30 are accommodated in a rack housing 40. As a result, the groove 28 is defined by the outer peripheral surface of the rack guide 16 and the inner peripheral surface of the rack housing 40. Similarly, the space 22 is defined by an outer peripheral surface of the rack guide 16 and an inner peripheral surface of the rack housing 40.

  As shown in FIG. 4, ball screw grooves 42 are formed on the outer periphery of the rack shaft 12. A plurality of balls 44 are arranged in the ball screw groove 42. Further, a cylindrical ball nut 46 that rotatably supports the ball 44 is provided on the outer side in the radial direction of the rack shaft 12. The ball nut 46 is rotatably supported by the rack housing 40 via a bearing portion 48.

  Further, a large-diameter output pulley 50 is attached to the outer side (outer peripheral side) in the radial direction of the ball nut 46 so as to be rotatable together with the ball nut 46. The output pulley 50 is accommodated in a gear housing 54 that is attached to the rack housing 40 with a fastener such as a bolt 52.

An electric motor 56 that generates a steering assist force is disposed near the output pulley 50. An input shaft 60 is coaxially connected to the rotating shaft 58 of the electric motor 56. A small-diameter input pulley 62 is mounted on the radially outer side (outer peripheral side) of the input shaft 60 so as to be rotatable together with the input shaft 60. A belt 64 is stretched around the input pulley 62 and the output pulley 50.
As described above, the rack and pinion steering device 10 of the present invention is used as a constituent member of the electric power steering device 9.

  Next, the operation of the rack and pinion steering device 10 according to the present embodiment will be described.

  As shown in FIG. 2, when the elastic force of the spring 36 is reduced in order to reduce the sliding load when the rack shaft 12 is slid left and right and to improve the steering feeling, the vehicle tire (illustrated The rack shaft 12 is easily moved in a direction away from the pinion shaft 14 (in the direction of arrow B in FIGS. 2 and 5) due to vibration, impact, etc. acting on (omitted). At this time, when the pressing force from the rack shaft 12 becomes larger than the elastic force of the spring 36, the rack guide 16 tends to move to the screw 30 side.

  When the rack guide 16 tries to move to the screw 30 side, the volume of the chamber portion 34 constituted by the first recess 26 and the second recess 32 decreases. When the volume of the chamber portion 34 is reduced, the grease G filled in the chamber portion 34 overflows to the outside from the gap 38 between the rack guide 16 and the screw 30, and the grease G further flows to the outer peripheral surface of the rack guide 16 and the rack housing 40. The fluid flows through the groove 28 partitioned by the inner peripheral surface of the gas and flows into the space 22.

  Here, when the grease G flows in the groove portion 28, the cross-sectional area of the groove portion 28 is much smaller than the cross-sectional area of the chamber portion 34, so that a large damping force is generated and the resistance force against the movement of the rack shaft 12 is Acts on the rack shaft 12 side (orifice effect). For this reason, the movement of the rack shaft 12 in the direction away from the pinion shaft 14 is prevented. This makes it difficult for the rack shaft 12 to be separated from the pinion shaft 14, so that the rack shaft 12 can be prevented from being pressed against the pinion shaft 14 by the elastic force of the spring 36, and the rack shaft 12 and the pinion shaft 14 can be prevented from colliding with each other. Generation of a hitting sound that is a collision sound can be prevented. As a result, it is possible to achieve both prevention of hitting sound and improvement of steering feeling when the rack shaft 12 and the pinion shaft 14 collide.

  In particular, as shown in FIG. 5, when the rack shaft 12 attempts to move away from the pinion shaft 14, the grease G filled in the chamber portion 34 enters the space portion 22 via the gap 38 and the groove portion 28. However, the O-ring 24 provided in the space 22 is moved by the pressing force of the grease G at that time. Thereby, a larger damping force can be generated, and the movement of the rack shaft 12 in the direction away from the pinion shaft 14 can be effectively prevented.

  Further, since the spring 36 is disposed in the chamber portion 34 formed inside the rack shaft 12 and the rack guide 16, the space of the chamber portion 34 can be used effectively. Thereby, even when the spring 36 is used as a means for pressing the rack shaft 12, it is possible to prevent the rack and pinion type steering device 10 from becoming large.

  Moreover, since the groove part 28 as a narrowing part is formed and formed in the outer peripheral surface of the rack guide 16, a narrowing part can be formed easily. Thereby, it can prevent that the manufacturing cost of the rack and pinion type steering apparatus 10 increases significantly.

  Furthermore, by using grease G or oil as the viscous fluid, the existing one can be used effectively, and a large damping force can be generated due to the high viscosity. Further, since it is sufficient to fill the chamber 34 with a viscous fluid such as grease G or hydraulic oil, the structure of the rack and pinion type steering device 10 can be simplified, and the manufacturing cost of the rack and pinion type steering device 10 can be simplified. Can be prevented from greatly increasing.

  According to the rack and pinion type steering apparatus 10 of the present embodiment, the viscosity of the viscous fluid (kind of viscous fluid) filled in the chamber portion 34, the cross-sectional area and length of the groove portion 28, and the volume of the chamber portion 34 ( By appropriately changing the cross-sectional area), the size and material of the O-ring 24, the volume of the space portion 22, and the like, the magnitude of the damping force can be easily adjusted.

  Further, as shown in FIG. 6, a through hole 70 (hole) that allows the chamber portion 34 and the space portion 22 to communicate with each other may be formed in the rack guide 16. By forming the through hole 70, it is not necessary to form the groove portion 28, and a large damping force can be generated by allowing the grease G filled in the chamber portion 34 to flow into the space portion 22 through the through hole 70. Yes (orifice effect). In particular, by reducing the cross-sectional area of the through hole 70 as much as possible, the rack shaft 12 can be effectively prevented from being separated from the pinion shaft 14, and a hitting sound that is a collision sound between the rack shaft 12 and the pinion shaft 14 can be obtained. Generation of sound can be effectively prevented.

  Further, since the throttle portion is the through hole 70 that penetrates the rack guide 16 and communicates with the space portion 22, the throttle portion can be easily formed.

It is a fragmentary sectional view (partial sectional view between XX of Drawing 4) showing the composition of the rack and pinion type steering device concerning one embodiment of the present invention. It is sectional drawing which shows the structure (before a rack shaft displacement) of the principal part which comprises the rack and pinion type steering device which concerns on one Embodiment of this invention. FIG. 3 is a front view of a rack guide viewed from the YY direction in FIG. 2. It is a fragmentary sectional view showing the composition of the electric power steering device to which the rack and pinion type steering device according to an embodiment of the present invention is applied. It is sectional drawing which shows the structure (after rack shaft displacement) of the principal part which comprises the rack and pinion type steering device which concerns on one Embodiment of this invention. It is sectional drawing which shows the structure (before a rack shaft displacement) of the modification of the principal part which comprises the rack and pinion type steering apparatus which concerns on one Embodiment of this invention. It is sectional drawing which shows the structure of the principal part which comprises the conventional rack and pinion type steering device.

Explanation of symbols

9 Electric Power Steering Device 10 Rack and Pinion Steering Device 12 Rack Shaft 14 Pinion Shaft 16 Rack Guide 22 Space 24 O-Ring (Elastic Member)
28 Groove (throttle part, damping force generating means)
30 screw 34 chamber (recess)
36 Spring (spring member)
70 Through-hole (hole part, throttle part, damping force generating means)
G grease (viscous fluid, damping force generation means)

Claims (9)

A pinion shaft that rotates by steering, a rack shaft that meshes with the pinion shaft, a spring member that presses the rack shaft in a predetermined direction, a rack guide that guides the movement of the rack shaft in a predetermined direction, and the rack guide A rack and pinion type steering device having a screw disposed so that a recess is formed between
The spring member is disposed in the recess,
A space portion is formed on the outer surface of the rack guide,
The space portion is provided with an elastic member that moves due to the pressing force of the viscous fluid filled in the concave portion,
Damping force generating means is constituted by the viscous fluid filled in the concave portion, and a throttle portion that communicates with the space portion and the concave portion and guides the viscous fluid filled in the concave portion to the space portion,
The rack and pinion type steering apparatus according to claim 1, wherein the damping force generating means generates a damping force that becomes resistance when the rack shaft moves in a direction away from the pinion shaft . The rack and pinion type steering apparatus according to claim 1, wherein the throttle portion is a groove portion formed on an outer surface of the rack guide . The rack and pinion type steering apparatus according to claim 1 , wherein the throttle portion is a hole portion that penetrates the rack guide and communicates with the space portion . The rack and pinion steering device according to any one of claims 1 to 3, wherein the viscous fluid is grease or oil . An electric power steering apparatus comprising the rack and pinion steering apparatus according to any one of claims 1 to 4 . A rack displacement adjustment method for a rack and pinion type steering apparatus, comprising: a pinion shaft that rotates by steering; a rack shaft that meshes with the pinion shaft; and a spring member that presses the rack shaft in a predetermined direction.
The spring member is disposed in a recess formed between a rack guide and a screw that guides the movement of the rack shaft in a predetermined direction,
The rack shaft is connected to the pinion shaft by a viscous fluid filled in the concave portion and a throttle portion that guides the viscous fluid filled in the concave portion to a space portion formed on an outer surface of the rack guide. A damping force generating means for generating a damping force that becomes a resistance when moving in the separating direction is configured,
A rack displacement adjustment method for a rack and pinion type steering apparatus, wherein an elastic member provided in the space is moved by a pressing force of the viscous fluid . 7. The rack displacement adjustment method for a rack and pinion type steering apparatus according to claim 6, wherein the narrowed portion is a groove formed on an outer surface of the rack guide . 7. The rack displacement adjustment method for a rack and pinion steering apparatus according to claim 6, wherein the throttle portion is a hole portion that penetrates the rack guide and communicates with the space portion . The rack displacement adjustment method for a rack and pinion type steering apparatus according to any one of claims 6 to 8, wherein the viscous fluid is grease or oil .

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