JP2013237391A - Rack-and-pinion type steering device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rack-and-pinion type steering device capable of reducing the abrasion of a rack guide stored in a housing and inhibiting noise generation even if a rack bar fluctuates leading to large shaft movement.SOLUTION: A rack-and-pinion type steering device includes: a gear housing 14; a pinion 15 which is rotatably supported by the gear housing 14; a rack shaft 12 which has a rack engaging with the pinion 15; a rack guide 21 which slidably supports the rack shaft 12; and a spring 25 which pushes the rack guide 21 toward the rack shaft 12. The rack guide 21 has a tube-like outer peripheral surface 14a which is slidably in contact with the tube-like inner peripheral surface of the gear housing 14. On the outer peripheral surface 14a, a first oil groove 22 with a passage narrowly tapered toward the axial direction of the rack guide 21, and a second oil groove 23 with a passage expanded toward the axial direction of the rack guide 21 are formed so that the oil grooves 22, 23 are disposed alternately on the outer peripheral surface 14a.

Description

  The present invention relates to a rack and pinion type steering device.

  Conventionally, as a steering device for steering a vehicle, the rotation of a pinion according to the rotation operation of a steering member is converted into movement in the axial direction of a rack shaft having a rack meshing with the pinion and connected to both ends of the rack shaft A rack and pinion type steering device configured to push and pull the left and right front wheels to steer is widely used. This rack-and-pinion steering device generally includes a rack guide that elastically contacts a rack shaft and applies pressure to the meshing portion. The rack and pinion are respectively formed on a tooth having a large meshing rate so as to transmit a large-capacity load.

  In such a rack-and-pinion type steering device, the axial movement of the rack guide and the radial movement of the rack guide occur simultaneously with the engagement of the rack and the pinion during steering. In order to prevent contact between the rack guide and the housing, an O-ring is provided on the outer peripheral surface of the rack guide, or a spiral groove is formed on the outer peripheral surface of the rack guide as shown in Patent Document 1, and a lubricant is provided in the spiral groove. Injecting.

JP 2004-351996 A

  The spiral groove does not actively generate a lubricant pressure by the axial movement of the rack guide, and when the rack guide moves greatly in the radial direction, the rack guide and the housing come into contact with each other and a hitting sound is generated. Wear occurs. Accordingly, an object of the present invention is to generate rack pressure positively by the axial movement of the rack guide, prevent the rack guide from moving greatly in the radial direction, and prevent racking and wear caused by contact. A pinion type steering device is provided.

  In order to solve the above-mentioned problem, the invention according to claim 1 is a housing, a pinion shaft rotatably supported by the housing, a rack shaft meshing with the pinion shaft, and a slidable rack shaft. And a rack guide that is slidably supported by the housing and a spring that presses the rack guide toward the rack shaft. The rack guide has a cylindrical inner shape of the housing. A first oil groove having a cylindrical outer peripheral surface slidably in contact with the peripheral surface, the first oil groove having a passage narrowing in one of the rack guide axial directions, and a second expanding passage in one of the rack guide axial directions; The first oil groove and the second oil groove are alternately provided in the circumferential direction on the outer peripheral surface.

  According to the structure of the present invention, the axial movement of the rack guide and the radial movement simultaneously occur due to the meshing of the rack shaft and the pinion shaft, and the first oil groove or the second oil groove is positively generated by the axial movement of the rack guide. Thus, it is possible to provide a rack and pinion type steering device that can generate a lubricant pressure, prevent the rack guide from moving greatly in the radial direction, and prevent hitting sound and wear due to contact.

  According to a second aspect of the present invention, the first oil groove narrows in a triangular shape on one side in the rack guide axial direction when viewed from the outer diameter side of the outer peripheral surface, and the second oil groove extends in the rack guide axial direction. On the other hand, the gist is to have a shape that widens in a triangular shape. Therefore, the oil groove for generating the oil film pressure and the oil groove for holding the lubricant are formed and installed so that the passage of the lubricant is narrow in the circumferential width direction so that it can be adapted to the inclination directions in both the left and right directions of the rack guide. Therefore, the rack and pinion type steering device can positively generate the lubricant pressure by the axial movement of the rack guide, prevent the rack guide from moving greatly in the radial direction, and prevent hitting sound and wear due to contact. Can provide.

  According to a third aspect of the present invention, the first oil groove is shallow in a triangular shape on one side in the rack guide axis direction when viewed in the radial section of the outer peripheral surface, and the second oil groove is in the rack guide axis direction. On the other hand, the gist is to have a shape that is deepened in a triangular shape. For this reason, the oil groove for generating the oil film pressure and the oil groove for holding the lubricant are installed so that the passage of the lubricant becomes narrower in the depth direction in the radial section so that it can be adapted to both the left and right inclination directions of the rack guide. Therefore, the oil groove that generates the oil film pressure and the oil groove that holds the lubricant are installed circumferentially, so that the rack guide positively generates the lubricant pressure by the axial movement of the rack guide. It is possible to provide a rack-and-pinion type steering device that can prevent the wheel from moving greatly in the radial direction and can prevent hitting sound and wear due to contact.

  According to the structure of the present invention, even if the rack shaft swings and tilts greatly, the axial movement of the rack guide positively generates lubricant pressure to prevent the rack guide from moving greatly in the radial direction. In addition, it is possible to provide a rack and pinion type steering device that can prevent a hitting sound and wear due to contact.

1 is a front view of a rack and pinion type steering device for a vehicle according to an embodiment of the present invention. FF sectional view taken on the line of FIG. 1 in the embodiment of the present invention. FIG. 1 is an external view of a rack guide according to an embodiment of the present invention. AA and BB cross-sectional views of FIG. 3 in the embodiment of the present invention It is a flow situation figure of the lubricant at the time of the rack axis side sliding of the rack guide in the embodiment of the present invention, and the situation figure seen from the outer diameter side of the outer peripheral surface It is a flow situation figure of the lubricant at the time of rack axis side sliding of the rack guide in an embodiment of the present invention, and a situation figure seen in a radial section of an outer peripheral surface It is a flow situation figure of the lubricant at the time of sliding on the opposite side to the rack axis of the rack guide in the embodiment of the present invention, and the situation figure seen from the outer diameter side of the outer peripheral surface It is a flow situation figure of the lubricant at the time of sliding on the opposite side to the rack axis of the rack guide in the embodiment of the present invention, and the situation figure seen in the radial cross section of the outer peripheral surface External view of a rack guide according to another embodiment of the present invention CC, DD sectional drawing of FIG. 9 in other embodiment of this invention.

  Hereinafter, an embodiment of a rack and pinion type steering apparatus of the present invention will be described with reference to the drawings. As shown in FIG. 1, the vehicle rack and pinion type steering device includes a rack housing 11, a rack bar 12 (rack), a tie rod 13, a gear housing portion 14, a pinion shaft 15 (pinion), and a rack bar support device 20. ing.

  The rack housing 11 extends in the left-right direction (left-right direction in FIG. 1) of the vehicle (not shown) and is assembled to the vehicle. The rack bar 12 is assembled to the rack housing 11 so as to be slidable in the rack axial direction (left-right direction in FIG. 1).

  The base ends of the tie rods 13 are assembled to both ends of the rack bar 12, respectively. Each other end of the tie rod 13 is connected to each knuckle arm (not shown) of a steering wheel (for example, left and right front wheels). Thereby, since the movement of the rack bar 12 is transmitted to the knuckle arm via the tie rod 13, the vehicle can be steered according to the steering operation.

  The gear housing portion 14 is integrally formed with the rack housing 11 by casting, and is formed orthogonal to the rack bar 12. As shown in FIG. 2, the gear housing portion 14 has a receiving hole 14a having a circular cross section. A rack guide 21 is slidably assembled in the accommodation hole 14a.

  The pinion shaft 15 is rotatably assembled to the rack housing 11 via ball bearings 16 and roller bearings 17. The pinion shaft 15 is connected to a steering shaft (not shown). A pinion 15 a is formed on the pinion shaft 15. The pinion 15a is formed with helical teeth and meshes with the rack 12a of the rack bar 12.

  The rack bar support device 20 includes a rack guide 21, an adjustment screw 24, and a spring 25.

  The adjustment screw 24 is disposed on the back side of the rack guide 21 and closes the accommodation hole 14 a of the gear housing portion 14. The adjusting screw 24 is screwed into the opening end of the accommodation hole 14a. The spring 25 is disposed between the rack guide 21 and the adjustment screw 24 in a compressed state, and is accommodated in the back recess 21 b of the rack guide 21. Thereby, the rack guide 21 presses the rack bar 12 against the pinion shaft 15 by the urging force of the spring 25. That is, the rack bar 12 is supported by the rack bar support device 20 so as to be slidable in the rack bar axial direction while being pressed toward the pinion 15a.

  The rack guide 21 has a cylindrical shape made of aluminum or aluminum alloy, in this example, a cylindrical outer peripheral surface 21a, and a cylindrical portion of the cylindrical portion of the gear housing 14, in this example, a cylindrical inner peripheral surface 14a with a sliding clearance. The rack guides 21 are slidably in contact with each other, so that the rack guide 21 is movable in a direction perpendicular to the axis of the rack bar 12.

As shown in FIGS. 3 and 4, the outer peripheral surface 21a of the rack guide 21 has a substantially triangular shape when viewed from the outer diameter side of the outer peripheral surface 21a, and has a first triangular shape in the radial cross section of the outer peripheral surface 21a. The oil groove 22 and the second oil groove 23 are formed. The first oil groove 22 and the second oil groove 23 have a depth D of 10 to 1000 μm, a length L of 1 to 5 mm, and one width W
Has a width W of 50 to 500 μm. The first oil grooves 22 and the second oil grooves 23 are alternately formed in the circumferential direction of the outer peripheral surface 21a, and are formed in directions opposite to each other. A plurality of first oil grooves 22 and second oil grooves 23 are arranged in the axial direction of the rack guide 21. The first oil groove 22 and the second oil groove 23 are filled with grease as a lubricant.

  The operation of the first oil groove 22 and the second oil groove 23 will be described in detail with reference to FIGS. Due to the meshing of the rack shaft 12 and the pinion shaft 15, the rack guide 21 is simultaneously moved in the axial direction and in the radial direction. For example, when the rack guide 12 is moved to the rack shaft 12 side, the second oil groove 23 becomes narrower in the circumferential direction of the outer peripheral surface 21a as shown in FIG. Oil film pressure is generated in the second oil groove 23, and direct contact between the rack guide 12 and the gear housing 14 can be prevented. On the contrary, when the rack guide 21 is axially moved to the opposite side of the rack shaft 12, the passage of the lubricant becomes narrow in the circumferential direction of the outer peripheral surface 21a of the first oil groove 22, as shown in FIG. Further, the oil film pressure of the lubricant is generated by the first oil groove 22, and the direct contact between the rack guide 12 and the gear housing 14 can be prevented.

Further, the second oil groove 23 has a radial cross section and is inclined in the axial direction. For example, when the rack guide 12 is axially moved to the rack shaft 12 side, as shown in FIG. Since the second oil groove 23 narrows the passage of the lubricant in the axial direction, an oil film pressure is generated in the second oil groove 23, and direct contact between the rack guide 12 and the gear housing 14 can be prevented. On the other hand, when the rack guide 21 is axially moved to the opposite side of the rack shaft 12, the first oil groove 22 has a narrow passage for the lubricant in the axial direction in the depth direction of the radial cross section. As shown in FIG. 5, the oil film pressure of the lubricant is generated by the first oil groove 22 and the direct contact between the rack guide 12 and the gear housing 14 can be prevented.
That is, the first oil groove 22 and the second oil groove 23 are alternately formed, so that the first oil groove 22 and the second oil groove 22 are reciprocated in either direction of the rack guide 21. The passage of the lubricant is narrowed on both the circumferential outer peripheral surface of the oil groove 23 and the radial cross section, and the direct contact between the rack guide 21 and the gear housing 14 can be prevented by the oil film pressure of the lubricant.

  As described above, according to the rack-and-pinion steering device 1, the first oil groove 22 and the second oil groove 23 are formed over the entire circumference of the outer peripheral surface 21a of the rack guide 21, so that the first oil The grooves 22 and the second oil grooves 23 are alternately arranged between the outer peripheral surface 21 a of the rack guide 21 and the inner peripheral surface 22 of the gear housing 14 in addition to the function of retaining the lubricant depending on the reciprocating direction of the rack guide 21. The grease can be efficiently supplied to the sliding gap and the spreading function can be exerted. The grease is always interposed in the sliding gap, and the tooth twist and rack generated by the engagement of the pinion 15 and the rack teeth 12a. A radial load is applied to the rack guide 21 by the action of the wheels at both ends of the bar 12, and the rack guide 21 is strongly pressed against the inner peripheral surface 14 a side of the gear housing 14. Even if the pressing force by the spring 25 acts to produce friction between aluminum or aluminum alloys, so-called “Tomogane”, the grease is interposed between the two, causing an increase in frictional resistance and, consequently, adhesive wear. Therefore, the rack guide 21 can be moved smoothly with respect to the rack bar 12.

  FIG. 9 shows another embodiment of the rack guide 50. In this rack guide 50, a predetermined interval is further provided on the outer peripheral surface 50a of the rack guide 50 in which the oil grooves 53 and 54 described above are formed. Two annular grooves 51 and 52 are formed, and O-rings 61 and 62 made of a rubber elastic body are attached to the annular grooves 51 and 52 so as to slightly protrude from the openings of the annular grooves 51 and 52. ing.

  A rack guide 50 having O-rings 61 and 62 mounted on the outer peripheral surface 50a is disposed in the hollow portion 14a of the gear housing 14 and slidably supports the rack bar 12, whereby the outer peripheral surface 50a of the rack guide 50 is slidably supported. Since the O-rings 61 and 62 are interposed between the cylindrical portion 14 and the inner peripheral surface 14a of the cylindrical portion 14, the lubricant in the oil grooves 53 and 54 is held forever, and wheel vibrations and the like are transmitted to the rack guide 50. However, the rack guide 50 does not rattle, and therefore it is possible to prevent the hitting sound. Further, even if a force is applied to the rack teeth 8 in a direction perpendicular to the moving direction during the operation of the handle, an effect of preventing the vertical vibration of the rack guide 50, i.e., the occurrence of a dance, is provided.

  DESCRIPTION OF SYMBOLS 11 ... Rack housing, 12 ... Rack axis | shaft, 12a ... Rack, 14 ... Gear housing part, 15 ... Pinion, 16 ... Ball bearing, 17 ... Roller bearing, 20 ... Rack bar support apparatus, 21 ... Rack guide, 21a ... Rack guide Peripheral portion, 22 ... first oil groove, 23 ... second oil groove, 24 ... adjustment screw, 25 ... spring

Claims (3)

A housing, a pinion shaft rotatably supported by the housing, a rack shaft meshing with the pinion shaft, a rack guide that slidably supports the rack shaft and is slidably supported by the housing; A spring that presses the rack guide toward the rack shaft, and the rack guide has a cylindrical outer peripheral surface that is slidably in contact with the cylindrical inner peripheral surface of the housing, A first oil groove with a passage narrowing in one of the rack guide shaft directions and a second oil groove with a passage extending in one of the rack guide shaft directions are formed on the outer peripheral surface, and the first oil groove and the first oil groove A rack-and-pinion steering device having a rack guide, wherein two oil grooves are alternately provided in the circumferential direction on the outer peripheral surface. The first oil groove is narrowed in a triangular shape on one side in the rack guide axis direction when viewed from the outer diameter side of the outer peripheral surface, and the second oil groove is widened in a triangular shape on one side in the rack guide axis direction. The rack-and-pinion type steering device according to claim 1, comprising: The first oil groove is shallow in a triangular shape on one side in the rack guide axis direction when viewed in the radial section of the outer peripheral surface, and the second oil groove is deep in a triangle shape on one side in the rack guide axis direction. The rack-and-pinion steering device according to claim 1, wherein the rack-and-pinion steering device is provided.

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