JP5392559B2 - Rack shaft support device - Google Patents

Description

  The present invention relates to a rack shaft support device.

  The rack shaft support device is used in a rack and pinion type steering device in an automobile to reduce the backlash of the engagement between the pinion and the rack shaft, and to smoothly move the rack shaft in the axial direction. It is. Specifically, the rack shaft support device includes a housing that houses a part of the rack shaft, a rack shaft support member that is housed in a holding hole formed in the housing and that slidably supports the rack shaft, A sealing member fixed to the inlet of the holding hole; and a biasing member supported by the sealing member and biasing the rack shaft support member toward the rack shaft. The rack shaft support member has a cylindrical shape and is slidable with respect to the housing in the depth direction of the holding hole (see, for example, Patent Documents 1 to 5).

In addition, a gap is provided between the outer periphery of the rack shaft support member and the inner periphery of the holding hole so that the rack shaft support member can slide along the holding hole. As a result, the rack shaft support member may be inclined in the holding hole, and the rack shaft support member may not be able to slide smoothly in the depth direction of the holding hole. As a result, for example, abnormal noise may occur.
With respect to such a problem, in Patent Document 1, lubricating oil is accumulated in a groove formed on the outer peripheral surface of the rack shaft support member, thereby suppressing the sliding resistance of the rack shaft support member with respect to the inner surface of the holding hole. I am doing so.

Further, in Patent Documents 2 and 3, the inclination of the rack shaft support member is suppressed by interposing an O-ring between the outer peripheral surface of the rack shaft support member and the inner surface of the holding hole.
Moreover, in patent document 4, the shaft-shaped guide part fixed to the sealing member is fitted in the guide hole formed in the rear surface of the rack shaft support member. Thereby, the movement of the rack shaft support member in the depth direction of the holding hole is guided.

  In Patent Document 5, the fixing position of the sealing member is adjusted by screwing the sealing member into the holding hole, thereby restricting the movement amount of the rack shaft support member in the depth direction of the holding hole. Have been described.

JP 2002-37090 A JP-A-2005-41251 Japanese Patent No. 4135414 Japanese Patent No. 3533281 Japanese Patent No. 3608918

By the way, in the structure of patent document 1, it turned out that prevention of abnormal noise is inadequate. Also, Patent Documents 2 and 3 have similar problems.
In addition, it is conceivable to use the technique of Patent Document 4, but in this case, the rack shaft support member and the sealing member need to be significantly changed. Therefore, the manufacturing cost is increased.
Therefore, an object of the present invention is to provide an inexpensive rack shaft support device that can suppress abnormal noise.

  As a result of earnest research, the inventor of the present application has obtained the following knowledge that has not been conventionally known as a cause of occurrence of abnormal noise. That is, usually, when the meshing reaction force between the rack shaft and the pinion is large (at the time of high load), the rear surface of the rack shaft support member comes into contact with the front surface of the sealing member. Usually, the rear surface of the rack shaft support member comes into contact with the front surface of the sealing member in a state where the axis of the rack shaft support member is parallel to the axis of the holding hole.

  On the other hand, in a state where the axis of the rack shaft support member is inclined with respect to the axis of the holding hole, a part of the outer edge of the rear surface of the rack shaft support member and a part of the front surface of the sealing member are in local contact with each other. It turns out that there may be cases. In this case, when the meshing reaction force acts on the rack shaft support member, a part of the outer edge of the rear surface of the inclined rack shaft support member slides along the front surface of the sealing member. As a result, the rack shaft support member It becomes the above-mentioned normal state where the rear surface hits the front surface of the sealing member.

  However, conventionally, since the space between the rear surface of the rack shaft support member and the front surface of the sealing member has not been lubricated, a part of the outer edge of the rear surface of the rack shaft support member in an inclined state and the front surface of the sealing member High sliding resistance. For this reason, the rack support member cannot move until a considerably large force that exceeds a large static frictional force between the rack shaft support member and the sealing member is applied. Under such a large force, the rack shaft support member moves vigorously in the holding hole so as to return the inclination. As a result, for example, the rear surface of the rack shaft support member and the front surface of the sealing member collide vigorously. Therefore, it is considered that abnormal noise is likely to occur.

In order to solve the above-described problem, the rack shaft support device (28, 28A, 28B, 28C, 28D) of the present invention has a depth direction of the holding hole in the holding hole (31) formed in the housing (30). A rack shaft support member (34, 34A, 34C, 34D) that is slidably accommodated in (Z3) and slidably supports the rack shaft (10, 10D), and fixed to the inlet (311) of the holding hole. And a biasing member (36) that is supported by the sealing member and biases the rack shaft support member toward the rack shaft, and includes a rear surface of the rack shaft support member ( 343, 343A, 343C) and the front surface (352) of the sealing member opposed thereto include annular regions (346; 346A; 346C, 356) opposed to each other, and the rear surface of the rack shaft support member. And at least one of the front surfaces of the sealing member includes a lubricant containing recess (40) containing a lubricant (39) for reducing friction between the rack shaft support member and the annular region of the sealing member. 43), and the lubricant accommodating recess has a plurality of lubricant accommodating grooves (40, 43) formed radially on at least one of the rear surface of the rack shaft support member and the front surface of the sealing member. In addition, the inner end (401) of the lubricant accommodating groove is opposed to the end portion (361) of the biasing member .

  According to the present invention, the lubricant stored in the lubricant storage recess can be lubricated between the annular regions of the rack shaft support member and the sealing member, so that friction between them can be reduced. Therefore, if the reaction force between the rack shaft and the pinion is large, a part of the outer edge of the rear surface of the rack shaft support member tilted in the holding hole and a part of the front surface of the sealing member are locally in contact with each other. Even if this occurs, the sliding resistance between a part of the outer edge of the rear surface of the rack shaft support member in the inclined state and the front surface of the sealing member is reduced. For this reason, even if the rack shaft support member in the inclined state does not receive a large force, it moves smoothly along the sealing member so as to return the inclination. As a result, abnormal noise due to a collision between the rack shaft support member and the sealing member is hardly generated. In addition, since the lubricant containing recess is simply provided to suppress abnormal noise, the manufacturing cost can be reduced.

Further, the lubricant accommodating recess includes a plurality of lubricant accommodating grooves (40, 43) formed radially on at least one of the rear surface of the rack shaft support member and the front surface of the sealing member . There are advantages.
That is , since the plurality of lubricant accommodating grooves are formed radially, the lubricant can be supplied into the annular region over a wide range in both the circumferential direction and the radial direction of the holding hole. Moreover, if it is a radial groove | channel, the cyclic | annular area | region of the rear surface of a rack shaft support member and the front surface of a sealing member can slide smoothly relatively so that the inclination of the rack shaft support member in a holding hole may be returned. . Further, for example, when adjusting the movable amount of the rack shaft support member by adjusting the screwing amount of the sealing member into the holding hole during assembly, the front surface of the sealing member and the rear surface of the rack shaft support member The annular regions are rotated relative to each other. At this time, the lubricant can be supplied to a wide range in the annular region.
Moreover, since the inner end of the lubricant accommodating groove faces the end of the biasing member, the following advantages can be obtained. For example, when the lubricant accommodating groove is formed in the sealing member, the lubricant stored in the inner end of the lubricant accommodating groove can lubricate between the end of the biasing member and the sealing member. . As a result, the end of the biasing member can slide smoothly with respect to the sealing member. Accordingly, this contributes to smooth relative sliding between the rear surface of the rack shaft support member and the front surface of the sealing member. The same effect can be obtained when the lubricant accommodating groove is formed in the rack shaft support member.

In the present invention, the lubricant accommodating groove includes a plurality of protrusions (42, 42B) formed on the front surface of the sealing member and radially formed on the rear surface of the rack shaft support member, When viewed along the depth direction, the lubricant accommodating grooves and the corresponding protrusions may intersect each other (claim 2 ). In this case, the lubricant can be expanded in the direction in which the protrusions extend as the lubricant accommodating groove and the corresponding protrusions move relative to each other, so that the lubricant is wider in the annular region. Can supply range.

  In addition, although the alphanumeric characters in the parentheses indicate reference signs of corresponding components in the embodiments described later, the scope of the claims is not limited by these reference signs.

1 is a schematic diagram of a schematic configuration of a vehicle steering apparatus including a rack shaft support device according to a first embodiment of the present invention. FIG. 2 is a cross-sectional view of the steering mechanism of the vehicle steering device of FIG. 1 and its peripheral portion. FIG. 3 is an enlarged view of a main part A1 of FIG. 2, in which the center line of the holding hole is illustrated in parallel in the left-right direction, and is shown in a half section with respect to the center line of the holding hole. 4A is a cross-sectional view taken along line IVA-IVA in FIG. 2, and FIG. 4B is an enlarged cross-sectional view taken along line IVB-IVB in FIG. It is a half sectional view of an essential part A1 of the rack shaft support device of the second embodiment of the present invention. FIG. 6 is a cross-sectional view taken along the line VI-VI in FIG. 5, and the protrusion on the rear surface of the rack shaft support member is indicated by a one-dot chain line. It is sectional drawing of the rack shaft support apparatus of the 3rd Embodiment of this invention, and shows the cross section equivalent to FIG. 6 similarly to FIG. It is sectional drawing of the rack shaft support apparatus of the 4th Embodiment of this invention, and shows the cross section corresponded in FIG. It is sectional drawing of the principal part and rack shaft of the rack shaft support apparatus of the 5th Embodiment of this invention. It is a schematic diagram for demonstrating operation | movement, (a) shows the state which the rack axis | shaft support member and the sealing member contact | abutted locally, and shows the state at the normal time which contacted the surface in (b).

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the present embodiment, the rack shaft support device will be described in the case where it is used in an electric power steering device as a vehicle steering device. However, the rack shaft support device is applied to a vehicle steering device for manual steering, for example. May be.
FIG. 1 is a schematic diagram of a schematic configuration of a vehicle steering apparatus having a rack shaft support device according to a first embodiment of the present invention. Referring to FIG. 1, a vehicle steering apparatus 1 includes a steering shaft 3 connected to a steering member 2 such as a steering wheel, an intermediate shaft 5 connected to the steering shaft 3 via a universal joint 4, an intermediate shaft 5 A pinion shaft 7 connected to the shaft 5 via a universal joint 6, and a rack shaft 10 as a steered shaft that has a rack 9 that meshes with a pinion 8 provided on the pinion shaft 7 and extends in the left-right direction of the vehicle. Have.

  The pinion shaft 7 and the rack shaft 10 constitute a steering mechanism 11 composed of a rack and pinion mechanism. The rack shaft 10 is supported in a rack housing 13 fixed to the vehicle body 12 so as to be linearly reciprocable via a plurality of bearings (not shown). A pair of tie rods 14 are coupled to the rack shaft 10. Each tie rod 14 is connected to a corresponding steered wheel 16 via a corresponding knuckle arm (not shown).

When the steering member 2 is operated and the steering shaft 3 is rotated, this rotation is caused by the pinion 8 and the rack 9 to linearly move the rack shaft 10 along the left-right direction of the automobile (corresponding to the axial movement of the rack shaft 10). Is converted to Thereby, the turning of the steered wheels 16 is achieved.
The steering shaft 3 is divided into an input shaft 17 connected to the steering member 2 and an output shaft 18 connected to the pinion shaft 7. The input shaft 17 and the output shaft 18 are connected to each other on the same axis via a torsion bar 19. When steering torque is input to the input shaft 17, the torsion bar 19 is elastically torsionally deformed, whereby the input shaft 17 and the output shaft 18 are rotated relative to each other.

  A torque sensor 20 that detects a steering torque based on the amount of relative rotational displacement between the input shaft 17 and the output shaft 18 via the torsion bar 19 is provided. A vehicle speed sensor 21 for detecting the vehicle speed is also provided. An ECU (Electronic Control Unit) 22 is provided as a control device. An electric motor 23 for generating a steering assist force and a speed reducer 24 for reducing the output rotation of the electric motor 23 are provided.

  Detection signals from the torque sensor 20 and the vehicle speed sensor 21 are input to the ECU 22. The ECU 22 controls the steering assisting electric motor 23 based on the torque detection result, the vehicle speed detection result, and the like. The output rotation of the electric motor 23 is decelerated via the speed reducer 24, transmitted to the pinion shaft 7, and converted into a linear motion of the rack shaft 10, thereby assisting in steering.

  FIG. 2 is a cross-sectional view of the steering mechanism 11 and its peripheral portion of the vehicle steering apparatus 1 of FIG. Referring to FIG. 2, the vehicle steering apparatus 1 includes a pair of bearings 26 and 27 that rotatably support the pinion shaft 7, a rack shaft support device 28 that supports the rack shaft 10, and a part of the pinion shaft 7. And a pinion housing 29 that houses the pair of bearings 26 and 27, and a housing 30 that houses at least a part of the rack shaft support device 28.

  Referring to FIGS. 1 and 2, at least a part of rack housing 13, housing 30, and pinion housing 29 are arranged so as to intersect each other and are integrally formed with a single material. That is, the pinion housing 29 has a cylindrical shape and extends in parallel to a direction intersecting with a direction in which the rack housing 13 extends (corresponding to a direction perpendicular to the paper surface of FIG. 2). The housing 30 has a cylindrical shape, and is disposed on the opposite side of the pinion shaft 7 with the rack shaft 10 therebetween. The housing 30 has a holding hole 31.

Both the housing 30 and the holding hole 31 extend in a direction Z3 orthogonal to both the axial direction Z2 of the pinion shaft 7 and the axial direction Z1 of the rack shaft 10. A portion where the pinion shaft 7 and the rack shaft 10 mesh with each other is accommodated by a part of the rack housing 13 formed integrally with each other, the pinion housing 29 and the housing 30.
The rack shaft 10 extends in the direction perpendicular to the paper surface of FIG. The rack 9 is a helical rack. The helical rack meshes with the pinion 8 formed of a helical gear. The rack shaft 10 has a D-shaped cross section. The rack shaft 10 has a back surface formed of a part of a cylindrical surface on the side opposite to the rack 9.

Referring to FIG. 2, the rack shaft support device 28 includes a cylindrical rack shaft support member 34 that slidably supports the rack shaft 10. The rack shaft support member 34 is slidable in the holding hole 31 formed in the housing 30 in the depth direction of the holding hole 31 (corresponding to the direction Z3 in which the housing 30 extends, hereinafter also referred to as depth direction Z3). Is housed in.
The rack shaft support device 28 is fixed to the inlet 311 of the holding hole 31, and the sealing member 35 that seals the inlet 311 and the rack shaft support member 34 that is supported by the sealing member 35 on the rack shaft 10 side. And an urging member 36 for urging the lens.

The holding hole 31 of the housing 30 is a circular hole. The holding hole 31 has an inlet 311. The inner periphery of the holding hole 31 has a holding portion 312 formed by a cylindrical surface that holds the rack shaft support member 34, and a female screw 313 that screws the sealing member 35. The female screw 313 forms the inlet 311 and is formed between the inlet 311 and the holding portion 312.
The sealing member 35 has a cylindrical shape and is formed of an aluminum alloy. A male screw 351 is formed on the outer periphery of the sealing member 35. The male screw 351 is formed by a right screw, and is screwed into the female screw 313 of the holding hole 31. A lock nut 37 is screwed onto the male screw 351. The sealing member 35 is fixed to the housing 30 by the lock nut 37 being pressed against the end surface of the housing 30. On the rear surface 353 of the sealing member 35, a tool engagement hole 354 made of a polygonal hole is provided.

The biasing member 36 is made of a compression coil spring, for example. The compression coil spring is interposed between the sealing member 35 and the rack shaft support member 34 in a state of undergoing elastic compression deformation. The biasing member 36 elastically biases the rack shaft support member 34 toward the rack shaft 10 side.
The rack shaft support member 34 is accommodated in the holding hole 31 and is held in the holding hole 31 so as to be able to advance and retreat in the depth direction Z3 of the holding hole 31. The rack shaft support member 34 is made of an aluminum alloy and has a substantially cylindrical shape. The substantially cylindrical central axis is arranged along the central axis of the holding hole 31.

The rack shaft support member 34 has a rear surface 343. The rear surface 343 is disposed to face the front surface 352 of the sealing member 35. The rear surface 343 has a recess 345 that accommodates at least a part of the urging member 36 as a region for receiving the urging member 36. The bottom of the recess 345 receives the biasing member 36.
FIG. 3 is an enlarged view of the main part A1 of FIG. 2 and 3, the outer peripheral surface of the rack shaft support member 34 is formed of a cylindrical surface, and has a plurality of (for example, two) peripheral grooves 348. The plurality of circumferential grooves 348 are spaced apart from each other in the depth direction Z3. Each circumferential groove 348 is provided with an annular elastic member, for example, an O-ring 38. The O-ring 38 is interposed between the bottom of the circumferential groove 348 and the inner periphery of the holding hole 31 in a state of being elastically compressed and deformed in the radial direction of the holding hole 31. As a result, the rack shaft support member 34 is elastically supported by the holding hole 31. A lubricant (not shown) is held in a predetermined amount of gap between the outer peripheral surface of the rack shaft support member 34 and the inner peripheral surface of the holding hole 31.

  The rack shaft support member 34 supports the back surface of the rack 9 of the rack shaft 10 so as to be movable in the axial direction Z1 of the rack shaft 10 (corresponding to a direction perpendicular to the paper surface of FIG. 2). The rack shaft support member 34 is disposed to face the back surface of the rack shaft 10 and has a receiving portion 341 that receives the back surface of the rack shaft 10 so as to be slidable in the axial direction Z1. The receiving portion 341 is formed by a concave curved surface and substantially matches the shape of the back surface of the rack shaft 10, and is formed, for example, on a partial cylindrical surface.

  4A is a cross-sectional view taken along line IVA-IVA in FIG. 2, and FIG. 4B is an enlarged cross-sectional view taken along line IVB-IVB in FIG. 3 and 4, the rear surface 343 of the rack shaft support member 34 has an annular region 346 that surrounds the recess 345 when viewed along the depth direction Z3. The annular region 346 forms a plane. On the other hand, the front surface 352 of the sealing member 35 includes a region 355 that receives the biasing member 36 and an annular region 356 that surrounds the region 355.

FIG. 4A shows only a part of the annular region 356 in the circumferential direction. The annular region 356 is a region between the outer peripheral edge 50 and the inner peripheral edge 51. The annular region 355 is a region between the outer peripheral edge 52 and the inner peripheral edge 53.
An annular region 346 of the rack shaft support member 34 and an annular region 356 of the front surface 352 of the sealing member 35 face each other along the depth direction Z3. The interval between the annular regions 346 and 356 is set to a predetermined distance. Since the annular regions 346 and 356 are in contact with each other, the amount of movement of the rack shaft support member 34 is regulated in the depth direction Z3.

  10A and 10B are schematic diagrams for explaining the operation of the rack shaft support device 28. FIG. 10A shows a state in which the rack shaft support member 34 and the sealing member 35 are locally in contact with each other, and FIG. It shows the normal state of contact with each other. Referring to FIGS. 2 and 10 (b), when the meshing reaction force between pinion 8 and rack 9 acts on rack shaft support member 34, rack shaft 10 and The rack shaft support member 34 moves away from the pinion shaft 7. When the meshing reaction force is large, the annular region 346 of the rear surface 343 of the rack shaft support member 34 and the annular region 356 of the front surface 352 of the sealing member 35 come into contact with each other.

Normally, the rear surface 343 of the rack shaft support member 34 contacts the front surface 352 of the sealing member 35 in a state where the center axis of the rack shaft support member 34 is parallel to the center axis of the holding hole 31.
2 and 10A, on the other hand, in the state where the center axis of the rack shaft support member 34 is inclined with respect to the center axis of the holding hole 31, the outer edge of the rear surface 343 of the rack shaft support member 34 is shown. In some cases, the part P1 and the part P2 of the front surface 352 of the sealing member 35 may locally contact each other. In this case, when the meshing reaction force acts on the rack shaft support member 34, a part P1 of the outer edge of the rear surface 343 of the inclined rack shaft support member 34 slides along the front surface 352 of the sealing member 35, As a result, the rear surface 343 of the rack shaft support member 34 comes into contact with the front surface 352 of the sealing member 35 as described above.

  At this time, abnormal noise was generated in the conventional rack shaft support device. That is, since the sliding resistance between a part of the outer edge of the rear surface of the rack shaft support member in an inclined state and the front surface of the sealing member is large, it corresponds to exceed a large static friction force between the rack shaft support member and the sealing member. The rack shaft support member cannot move until a large force is applied. In other words, the rack shaft support member is vigorously moved in the holding hole so as to return to the inclination by receiving a considerable force. As a result, for example, the rear surface of the rack shaft support member and the front surface of the sealing member collided vigorously, and abnormal noise was generated.

With reference to FIGS. 2 and 3, on the other hand, in this embodiment, the rack shaft support device 28 reduces the friction between the annular regions 346 and 356 of the rack shaft support member 34 and the sealing member 35. A plurality of lubricant accommodating grooves 40 formed on the front surface 352 of the sealing member 35 are provided as lubricant accommodating recesses accommodating the lubricant 39.
Since the lubricant 39 accommodated in the lubricant accommodating groove 40 as the lubricant accommodating recess can lubricate the rack shaft support member 34 and the annular regions 346 and 356 of the sealing member 35, friction between them can be reduced. Can do. For example, the static friction coefficient between the annular regions 346 and 356, and hence the static friction force can be reduced.

  Therefore, if the reaction force between the rack 9 and the pinion 8 is large, a part P1 of the outer edge of the rear surface 343 of the rack shaft support member 34 inclined in the holding hole 31 and the front surface 352 of the sealing member 35 Even if there is a local contact with the portion P2 (see FIG. 10A), a part P1 of the outer edge of the rear surface 343 of the rack shaft support member 34 in an inclined state and the front surface 352 of the sealing member 35 The sliding resistance becomes smaller. For this reason, even if the rack shaft support member 34 in the inclined state does not receive a large force, it moves smoothly along the sealing member 35 so as to return the inclination. As a result, abnormal noise due to the collision between the rack shaft support member 34 and the sealing member 35 is less likely to occur.

In addition, since the lubricant containing recess is simply provided to suppress abnormal noise, the manufacturing cost can be reduced. For example, since the lubricant containing recess does not need to be processed with very high accuracy, a manufacturing method using a mold such as plastic working or casting can be employed for manufacturing the lubricant containing recess, resulting in a manufacturing cost as a result. Can be made inexpensively.
Further, the durability of the annular region 346 on the rear surface 343 of the rack shaft support member 34 and the annular region 356 on the front surface 352 of the sealing member 35 is improved.

In addition, as will be described later, the lubricant accommodating recesses may be disposed in at least one annular region 346, 356 of the rear surface 343 of the rack shaft support member 34 and the front surface 352 of the sealing member 35. In the present embodiment, a description will be given in accordance with a case where the lubricant accommodating recess includes a plurality of lubricant accommodating grooves 40 formed only on the front surface 352 of the sealing member 35.
3 and 4A, in the annular regions 346 and 356 between the rear surface 343 of the rack shaft support member 34 and the front surface 352 of the sealing member 35, portions other than the lubricant accommodating groove 40 are It functions as a contactable portion that can contact each other. The amount of movement of the rack shaft support member 34 is restricted by the contactable portions contacting each other.

  The plurality of lubricant accommodating grooves 40 are radial. Accordingly, the lubricant 39 can be supplied into the annular regions 346 and 356 over a wide range in both the circumferential direction and the radial direction of the holding hole 31. Further, if the shape is radial, the rear surface 343 of the rack shaft support member 34 and the front surface 352 of the sealing member 35 are returned so as to return the inclination of the rack shaft support member 34 in the holding hole 31 as compared with the concentric circular shape. The annular regions 346 and 356 can smoothly slide relative to each other.

Further, the plurality of radial lubricant accommodating grooves 40 can supply the lubricant 39 between the annular regions 346 and 356 regardless of the position of the sealing member 35 in the circumferential direction of the holding hole 31.
Further, in the present embodiment, as described later, the movable amount of the rack shaft support member 34 is adjusted by adjusting the screwing amount of the sealing member 35 into the holding hole 31 during assembly. In this case, the annular regions 346 and 356 of the front surface 352 of the sealing member 35 and the rear surface 343 of the rack shaft support member 34 are brought close to each other and relatively rotated. At this time, the plurality of radial lubricant accommodating grooves 40 can supply the lubricant 39 to a wide range in the annular regions 346 and 356.

  The plurality of radial lubricant accommodating grooves 40 for obtaining this effect may be formed on at least one of the rear surface 343 of the rack shaft support member 34 and the front surface 352 of the sealing member 35. Moreover, although the number of the lubricant accommodating grooves 40 that form a radial shape is illustrated as being eight, it may be a number other than eight, for example, three or more. Further, each of the plurality of radial lubricant receiving grooves 40 extends along the radial direction of the holding hole 31 as illustrated in the present embodiment, or is inclined with respect to the radial direction of the holding hole 31. Extending (not shown) is preferable for obtaining the above-described effect.

  Specifically, when viewed along the central axis of the sealing member 35, the plurality of lubricant accommodating grooves 40 have a radial shape centered on the central axis. Each lubricant accommodation groove 40 extends straight along the radial direction of the sealing member 35 by a predetermined length. The lubricant accommodating groove 40 has an inner end 401 disposed relatively inward with respect to the radial direction of the holding hole 31 and an outer end 402 disposed relatively outward with respect to the radial direction.

Inner ends 401 of the plurality of lubricant accommodating grooves 40 are equally spaced from each other in the circumferential direction of the sealing member 35 (corresponding to the circumferential direction of the holding hole 31). The outer ends 402 of the plurality of lubricant accommodating grooves 40 are equally spaced from each other in the circumferential direction of the sealing member 35.
The inner end 401 is closed inward in the radial direction. The outer end 402 is closed outward in the radial direction. By closing the inner end 401 and the outer end 402 of the lubricant accommodating groove 40 in the radial direction of the holding hole 31, it is possible to prevent the lubricant 39 from falling downward due to gravity, thereby preventing the occurrence of poor lubrication. it can.

  The outer end 402 faces the outer peripheral edge portion of the rear surface 343 of the rack shaft support member 34 along the depth direction Z3 of the holding hole 31. The diameter of the circumscribed circle of the outer ends 402 of the plurality of lubricant accommodating grooves 40 is preferably equal to or greater than the outer diameter of the rear surface 343 of the rack shaft support member 34. Thus, the lubricant 39 can be reliably supplied when the annular regions 347 and 356 are in local contact with each other. It is also conceivable that the diameter of the circumscribed circle of the outer ends 402 of the plurality of lubricant accommodating grooves 40 is smaller than the value equal to the outer diameter of the rear surface 343 of the rack shaft support member 34.

  The lubricant accommodating groove 40 continuously extends radially inward from the annular region 356 of the front surface 352 of the sealing member 35. The inner end 401 faces the end portion 361 of the biasing member 36 along the depth direction Z3 of the holding hole 31. For example, the diameter of the inscribed circle of the inner ends 401 of the plurality of lubricant accommodating grooves 40 is smaller than the value equal to the outer diameter of the coil of the urging member 36, for example, the inner diameter of the coil of the urging member 36. Is equal to.

  The lubricant 39 accommodated in the inner end 401 of the lubricant accommodating groove 40 can lubricate between the end 361 of the biasing member 36 and the sealing member 35. As a result, the end 361 of the urging member 36 can slide smoothly with respect to the sealing member 35. Therefore, it contributes to smooth relative sliding between the rear surface 343 of the rack shaft support member 34 and the front surface 352 of the sealing member 35. Even when the lubricant accommodating groove 40 is formed in the rack shaft support member 34, the gap between the end 361 of the biasing member 36 and the rack shaft support member 34 can be lubricated, so that the same effect can be obtained. .

With reference to FIG. 3 and FIG. 4B, the shoulder portion 403 of the lubricant accommodating groove 40 is chamfered. As the chamfering, a convex curved shape may be formed, or a flat shape (not shown) may be used. By chamfering, the lubricant 39 in the lubricant accommodating groove 40 is easily attached to a corresponding annular region, for example, the annular region 346 of the rack shaft support member 34.
2 and 3, the rack shaft support device 28 can be assembled as follows, for example.

First, the lubricant 39, specifically, grease is applied to at least one of the rear surface 343 of the rack shaft support member 34 and the front surface 352 of the sealing member 35. An O-ring 38 is attached to the rack shaft support member 34.
The pinion shaft 7 is assembled to the pinion housing 29, and the rack shaft 10 is assembled to the rack housing 13. Next, the rack shaft support member 34 and the biasing member 36 are incorporated into the housing 30. The sealing member 35 is assembled to the housing 30.

  Next, the fixing position of the sealing member 35 in the holding hole 31 is adjusted. That is, first, the sealing member 35 is screwed to the female screw 313 of the holding hole 31 of the housing 30 clockwise and inserted into the inner side of the holding hole 31. Accordingly, the front surface 352 of the sealing member 35 is brought into contact with the rear surface 343 of the rack shaft support member 34. From this state, the sealing member 35 is rotated counterclockwise, and the sealing member 35 is moved back to the inlet 311 side in the depth direction Z3 of the holding hole 31 by a predetermined distance. Thereby, a predetermined amount of gap can be secured between the annular region 356 of the front surface 352 of the sealing member 35 and the annular region 346 of the rear surface 343 of the rack shaft support member 34. The sealing member 35 is fixed by the lock nut 37 at the fixed position adjusted in this way.

  By screwing the sealing member 35 into the holding hole 31, the space between the annular regions 346 and 356 can be lubricated. That is, when the sealing member 35 is screwed into the holding hole 31, the front surface 352 of the sealing member 35 and the rear surface 343 of the rack shaft support member 34 are relatively rotated around the axis of the holding hole 31. The front surface 352 of the sealing member 35 approaches the rear surface 343 of the rack shaft support member 34 and abuts against each other. During this time, the lubricant 39 adhering to the front surface 352 of the sealing member 35 adheres to the rear surface 343 of the rack shaft support member 34 and is expanded over a wide range, for example, the entire annular regions 346 and 356.

  Thereafter, when the sealing member 35 is retracted in the holding hole 31, the front surface 352 of the sealing member 35 and the rear surface 343 of the rack shaft support member 34 are relatively rotated around the axis of the holding hole 31. The front surface 352 of the sealing member 35 is separated from the rear surface 343 of the rack shaft support member 34. At this time, a part of the lubricant 39 in the lubricant accommodating groove 40 is attached to the rear surface 343 of the rack shaft support member 34. Accordingly, as the sealing member 35 is retracted, a part of the lubricant 39 is drawn out from the lubricant accommodating groove 40 to the periphery thereof and spreads. In this manner, the annular regions 346 and 356 are lubricated by the lubricant 39.

In the present embodiment, in a state in which the front surface 352 of the sealing member 35 is in contact with the rear surface 343 of the rack shaft support member 34, the lubricant 39 is expanded over the entire annular regions 346 and 356 and the lubricant accommodating groove. 40. Therefore, there is no risk of poor lubrication.
On the other hand, conventionally, since the entire surface of the annular region on the front surface of the sealing member and the entire surface of the annular region on the rear surface of the rack shaft support member are each formed by a flat surface, There was a risk that the lubricant would be pushed out, resulting in poor lubrication.

As described above, in the vehicle steering apparatus 1 according to this embodiment, the lubricant housing groove 40 as the lubricant housing recess can prevent the rack shaft support device 28 from generating abnormal noise, and the rack is accompanied by the operation of the steering member 2. The shaft 10 can be operated smoothly. As a result, it is possible to improve the following ability when steering, to smoothly return the steering wheel, and to improve the steering feeling.
Moreover, the following modifications can be considered about this embodiment. In the following description, the points different from the above-described embodiment will be mainly described. In addition, about another structure, it is the same as that of the above-mentioned embodiment.

For example, FIG. 5 is a half sectional view of the main part A1 of the rack shaft support device 28A according to the second embodiment of the present invention. 6 is a cross-sectional view taken along the line VI-VI in FIG. Referring to FIGS. 5 and 6, the rack shaft support device 28A of the present embodiment is used in place of the rack shaft support device 28 of FIG. 2, and differs in the following points, and the other configurations are the same. Yes.
The rack shaft support device 28A has a rack shaft support member 34A. An annular region 346A (only part of which is shown in FIG. 6) of the rear surface 343A of the rack shaft support member 34A has a plurality of radial ridges 42 (shown by a one-dot chain line in FIG. 6). Each protrusion 42 extends straight and with a predetermined length along a direction that obliquely intersects the radial direction of the rack shaft support member 34A. Except for this point, the arrangement of the plurality of radial protrusions 42 in the annular region 346A is set in the same manner as the arrangement of the plurality of lubricant accommodating grooves 40 in the annular region 356. For example, the number of ridges 42 is equal to the number of lubricant accommodating grooves 40. The inner ends of the plurality of protrusions 42 are equally arranged in the circumferential direction. The outer ends of the plurality of protrusions 42 are evenly arranged in the circumferential direction.

  A plurality of radial lubricant accommodating grooves 40 formed on the front surface 352 of the sealing member 35 and a plurality of protrusions 42 formed radially on the rear surface 343A of the rack shaft support member 34A are along the depth direction Z3. When crossed, they cross each other. Accordingly, the lubricant 39 can be expanded in the direction in which the protrusion 42 extends as the lubricant accommodating groove 40 and the corresponding protrusion 42 move relative to each other. 346A and 356 can be supplied to a wider range.

For example, when the fixing position of the sealing member 35 is adjusted when the sealing member 35 is attached to the housing 30, the lubricant accommodating groove 40 and the protrusion 42 rotate relatively close to each other, and accordingly, the lubricant 39. Can be widely supplied two-dimensionally in both the circumferential direction and the radial direction in the annular regions 346A, 356.
Note that the effect of expanding the lubricant 39 in the direction in which the protrusions 42 extend is only required that the protrusions 42 are inclined obliquely with respect to the radial direction of the holding hole 31. It is obtained irrespective of the inclination direction and the inclination angle of the strip 42 (see the third embodiment).

  Referring to FIGS. 5 and 6, in the annular region 346 </ b> A, the space between the protrusions 42 is relatively recessed, and functions as a lubricant accommodating recess. In addition, the inclination direction of the protrusion 42 is inclined obliquely at a predetermined angle of less than 90 degrees with respect to the radial direction of the rack shaft support member 34 (corresponding to the radial direction of the holding hole 31). When viewed from the inlet 311 side of the holding hole 31 along the depth direction Z3 of the holding hole 31, the ridge 42 is clockwise (clockwise) with respect to the circumferential direction of the holding hole 31 as it goes radially outward. ).

When the sealing member 35 is screwed into the holding hole 31, the lubricant 39 in the lubricant housing groove 40 moves radially inward along the protrusion 42. Further, when the screwing of the sealing member 35 is returned by a predetermined amount in order to adjust the fixing position of the sealing member 35, the lubricant 39 in the lubricant accommodating groove 40 moves radially outward along the protrusion 42. To come.
The protrusion 42 in the annular region 346A on the rear surface 343A of the rack shaft support member 34A and the portion other than the lubricant accommodating groove 40 in the annular region 356 on the front surface 352 of the sealing member 35 can be brought into contact with each other in at least three places. It has become.

  When viewed along the depth direction Z 3 of the holding hole 31, the angle formed by the protrusion 42 with respect to the radial direction of the holding hole 31 and the angle formed by the lubricant accommodating groove 40 with respect to the radial direction of the holding hole 31 Are different from each other. Further, the central angle D1 formed by the lubricant accommodating groove 40 in the annular region 356 of the sealing member 35 is smaller than the central angle D2 formed by the protrusion 42 in the annular region 346A of the rack shaft support member 34A. Thereby, when it sees along the depth direction Z3 of the holding hole 31, a part of protrusion 42 and the lubricant accommodation groove | channel 40 are arrange | positioned so that it may mutually overlap.

FIG. 7 is a cross-sectional view of a rack shaft support device 28B according to the third embodiment of the present invention, and similarly shows a cross-section corresponding to FIG. The rack shaft support device 28B and the ridge 42B of the present embodiment shown in FIG. 7 are used in place of the rack shaft support device 28A and the ridge 42 of the corresponding second embodiment shown in FIG. Unlike other configurations, they are the same.
Referring to FIG. 7, the rack shaft support device 28B has a protrusion 42B. The inclination direction of the protrusion 42B is inclined with respect to the radial direction of the holding hole 31 in the direction opposite to the inclination direction of the protrusion 42 in FIG. As the sealing member 35 is screwed into the holding hole 31, the lubricant 39 moves in the direction opposite to that described in the second embodiment.

FIG. 8 is a cross-sectional view of a rack shaft support device 28C according to the fourth embodiment of the present invention, and shows a cross section corresponding to FIG. Referring to FIG. 8, the rack shaft support device 28C of the present embodiment is used in place of the rack shaft support device 28A of the second embodiment shown in FIG. 6, and differs in the following points. It is the same.
The rack shaft support device 28C has a rack shaft support member 34C. An annular region 346C on the rear surface 343C of the rack shaft support member 34C includes a plurality of lubricant containing grooves 43 that are radially formed as lubricant containing recesses. The plurality of lubricant accommodating grooves 43 of the rack shaft support member 34C may extend inclining with respect to the radial direction at the same angle as the protrusion 42 of the second embodiment, or of the third embodiment. You may extend inclining with respect to radial direction at the same angle as the protrusion 42. FIG. Except for the above points, each lubricant accommodating groove 43 is formed in the same manner as the lubricant accommodating groove 40.

The lubricant accommodating groove 43 of the present embodiment has the same effect as the protrusion 42 when combined with the lubricant accommodating groove 40, and the lubricant accommodating grooves 40, 43 approach each other during relative movement, for example, assembly. Alternatively, the lubricant 39 can be widely supplied two-dimensionally in both the circumferential direction and the radial direction when rotating relative to each other while being separated.
FIG. 9 is a cross-sectional view of the main part of the rack shaft support device 28D and the rack shaft 10D according to the fifth embodiment of the present invention. Referring to FIG. 9, the rack shaft 10D and the rack shaft support device 28D of this embodiment are used in place of the rack shaft 10 and the rack shaft support device 28 of the first embodiment shown in FIG. The other configurations are the same.

  The cross-sectional shape of the rack shaft 10D that cuts in the axial direction is a substantially Y-shaped polygon. The rack shaft support device 28 has a rack shaft support member 34D. The receiving portion 341D of the rack shaft support member 34D is formed in a shape that substantially matches the shape of the back surface of the rack shaft 10D, for example, a substantially V-shaped groove shape. Note that the cross-sectional shape of the rack shaft 10D of the fifth embodiment may be applied to other embodiments.

In the first embodiment, the lubricant accommodating groove 40 is formed only on the front surface 352 of the sealing member 35, but may be formed only on the rear surface 343 of the rack shaft support member 34.
In the second embodiment, the lubricant accommodating groove 40 is formed on the front surface 352 of the sealing member 35, and the protrusion 42 is formed on the rear surface 343A of the rack shaft support member 34A. It is also conceivable that the lubricant accommodating groove 40 is formed on the rear surface 343A of the rack shaft support member 34A, and the protrusion 42 is formed on the front surface 352 of the sealing member 35. A similar modification can be considered for the third embodiment.

  In the second embodiment, the lubricant accommodating groove 40 extends in parallel to the radial direction of the holding hole 31, and the protrusion 42 extends in an inclined manner with respect to the radial direction of the holding hole 31. However, the present invention is not limited to this. For example, the lubricant accommodating groove 40 and the protrusion 42 both extend while being inclined with respect to the radial direction of the holding hole 31, and when viewed along the depth direction Z <b> 3 of the holding hole 31, the lubricant accommodating groove 40 and the protrusion 42 may cross each other. Similar modifications can be considered for the lubricant accommodating grooves 40 and 43 of the third embodiment and the fourth embodiment.

Also, in the above embodiment, an example is described in which the present invention is applied to an electric power steering apparatus of a so-called column assist type, not limited to this, and an electric power steering apparatus of a so-called pinion assist type, so-called rack assist The present invention may be applied to an electric power steering device of the type. In addition, various changes can be made within the scope of the matters described in the claims.

DESCRIPTION OF SYMBOLS 10,10D ... Rack shaft, 28, 28A, 28B, 28C, 28D ... Rack shaft support apparatus, 30 ... Housing, 31 ... Holding hole, 34, 34A, 34C, 34D ... Rack shaft support member, 35 ... Sealing member, 36 ... Biasing member, 39 ... Lubricant, 40, 43 ... Lubricant accommodation groove (lubricant accommodation recess), 42, 42B ... Projection, 311 ... Inlet, 343, 343A, 343C ... (of rack shaft support member) Rear surface, 346, 346A, 346C ... annular region (on the rear surface of the rack shaft support member), 352 ... front surface (of the sealing member), 356 ... annular region (on the front surface of the sealing member), 361 ... (biasing) (End of member), 401 ... inner end of lubricant accommodating groove, Z3 ... depth direction.

Claims (2)

A rack shaft support member that is slidably accommodated in a depth direction of the holding hole in a holding hole formed in the housing and slidably supports the rack shaft;
A sealing member fixed to the inlet of the holding hole;
A biasing member supported by the sealing member and biasing the rack shaft support member toward the rack shaft,
The rear surface of the rack shaft support member and the front surface of the sealing member facing the rack shaft include annular regions facing each other,
Lubrication in which at least one of the rear surface of the rack shaft support member and the front surface of the sealing member contains a lubricant for reducing friction between the rack shaft support member and the annular region of the sealing member An agent containing recess ,
The lubricant accommodating recess includes a plurality of lubricant accommodating grooves formed radially on at least one of the rear surface of the rack shaft support member and the front surface of the sealing member,
A rack shaft support device , wherein an inner end of the lubricant accommodating groove is opposed to an end of the urging member . In Claim 1 , the lubricant accommodating groove is formed on the front surface of the sealing member,
A plurality of ridges formed radially on the rear surface of the rack shaft support member;
The rack shaft support device, wherein each of the lubricant accommodating grooves and the corresponding protrusions intersect each other when viewed along the depth direction.

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