Manufacturing method of an electric power steering apparatus

Abstract

To provide an electric power steering device and a manufacturing method of the same that can prevent reduction of sealing performance and occurrence of noise.SOLUTION: In a state before a rack retainer 28 is inserted into a rack retainer accommodating hole 27 and a state where an O-ring 31 is arrange in an annular groove 28a of the rack retainer 28, an outer diameter D of the O-ring is larger than an inner diameter d of an internal thread 27a of the rack retainer accommodating hole 27. In a state after the rack retainer 28 is inserted into the rack retainer accommodating hole 27, grease 35 adheres to a rear end portion 33 of the rack retainer 28 and does not adhere to an external thread 30a of an adjust plug 30.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a manufacturing method of an electric power steering device. position

Background Art

[0002] Conventionally, in a rack & pinion type electric power steering device, a rack retainer that biases a rack bar toward a pinion shaft is known. The rack retainer is located within a rack retainer housing and presses the rack bar by the biasing force of a coil spring (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a conventional electric power steering device, when a driver starts steering a steering wheel, torque is transmitted from a pinion to rack teeth. At this time, the rack retainer falls, and the front end portion and the rear end portion come into contact with the inner wall of the rack retainer housing. When this is repeated, it wears due to repeated steering, and the friction coefficient increases due to adhesion of wear powder, resulting in a catch during steering. When the catch is released by the driver's steering, the rack retainer may be instantaneously displaced, generating abnormal noise. Here, wear can be suppressed by applying grease to the rear end portion of the rack retainer. However, when applying a sealant to a cap and fastening it with a screw, if the grease adheres to the sealant, there is a risk of deterioration of the sealing performance. One of the objects of the present invention is to provide a manufacturing method of an electric power steering device that can suppress both deterioration of sealing performance and generation of abnormal noise. position ​​

Means for Solving the Problem

[0005] A method for manufacturing an electric power steering apparatus according to an embodiment of the present invention includes a steering shaft that rotates in accordance with a steering operation of a steering wheel, a pinion provided on the steering shaft, rack teeth that mesh with the pinion, and a steering mechanism having a rack bar that converts the rotational motion of the pinion into an axial motion, a pinion housing portion that houses the pinion, a rack bar housing portion that houses the rack bar, and a housing member having a rack retainer housing hole provided on the opposite side of the pinion housing portion with respect to the rack bar, a rack retainer that is slidably disposed inside the rack retainer housing hole and has a tip end portion and a rear end portion in the moving direction, the rear end portion of which abuts against the rack bar, a female screw provided on the inner wall of the rack retainer housing hole, and a male screw having an outer circumference that fastens to the female screw. the rack retainer accommodation hole A cap that closes the [hole], and a biasing member that is disposed between the cap and the rear end portion of the rack retainer and biases the rack retainer toward the rack bar side. A method for manufacturing an electric power steering apparatus includes a first step of pressing the rear end portion of the rack retainer with a jig and inserting the rack retainer into the rack retainer housing hole, and a second step of applying grease to the rear end portion of the rack retainer with the jig in a state where the rack retainer is inserted into the rack retainer housing hole.

Advantages of the Invention

[0006] Therefore, in the present invention, both a decrease in sealing performance and the generation of abnormal noise can be suppressed.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Mode for Carrying Out the Invention

[0008] 〔Embodiment 1〕 FIG. 1 is a schematic diagram of the electric power steering apparatus 1 of Embodiment 1. The electric power steering apparatus 1 includes a steering mechanism 2 and a steering housing 3. The steering mechanism 2 has a steering shaft 4, a rack & pinion mechanism 5, and a rack bar 6. The steering shaft 4 has a steering shaft 4a, an intermediate shaft 4b, and a pinion shaft 4c. Between the steering shaft 4a and the intermediate shaft 4b is connected via a universal joint 4d. Between the intermediate shaft 4b and the pinion shaft 4c is connected via a universal joint 4e. The tip of the steering shaft 4a is connected to the steering wheel 7.

[0009] The rack & pinion mechanism 5 is composed of a pinion 8 and rack teeth 9 that mesh with this pinion 8. The pinion 8 is provided on a pinion shaft 4c. The rack teeth 9 are provided on a rack bar 6. By means of the rack & pinion mechanism 5, the rotational movement of the pinion shaft 4c is converted into the axial movement of the rack bar 6. Due to the movement of the rack bar 6, the front wheels 11, which are steering wheels, are steered via a link mechanism 10. The pinion shaft 4c is connected to an electric motor 13 via a speed reduction mechanism 12. The speed reduction mechanism 12 is composed of a worm wheel 12a and a worm gear 12b. The worm wheel 12a rotates integrally with the pinion shaft 4c. The worm gear 12b rotates integrally with the motor shaft 13a of the electric motor 13. The electric motor 13 has its operation controlled by a controller 14 and is supplied with power from a battery 15. The controller 14 controls the power supplied to the electric motor 13 based on the steering torque of the driver detected by a torque sensor 16.

[0010] Figure 2 is an enlarged cross-sectional view of the vicinity of the rack & pinion mechanism 5. In Figure 2, a y-axis is set in the direction along the rotation axis line O1 of the pinion shaft 4c, an x-axis is set in the direction of proximity and separation between the rack bar 6 and the pinion shaft 4c and perpendicular to the y-axis, and a z-axis is set in the direction perpendicular to the y-axis and the x-axis respectively. In the y-axis direction, the direction from the lower side to the upper side of the paper surface is defined as the positive y-axis direction. In the x-axis direction, the direction from the rack bar 6 towards the pinion shaft 4c is defined as the positive x-axis direction. In the z-axis direction, the direction from the front side to the back side of the paper surface is defined as the positive z-axis direction.

[0011] The steering housing 3 includes a torque sensor housing 17, a gear housing 18, a worm gear cover 19, and a rack housing (housing member) 20. The torque sensor housing 17 is provided on the most positive y-axis side of the steering housing 3, is formed along the y-axis direction, rotatably accommodates the pinion shaft 4c around the rotation axis O1, and accommodates the torque sensor 16. The pinion shaft 4c is such that the first pinion shaft 21 and the second pinion shaft 22 are connected by a torsion bar 23. The torque sensor 16 detects the driver's steering torque based on the relative angular change between the first pinion shaft 21 and the second pinion shaft 22. The gear housing 18 is provided on the most negative y-axis side of the steering housing 3 and accommodates the reduction mechanism 12. The negative y-axis side of the gear housing 18 is closed by a gear cover 24. The worm gear cover 19 covers the worm gear 12b.

[0012] The rack housing 20 is provided between the torque sensor housing 17 and the gear housing 18 in the y-axis direction and accommodates the rack bar 6 and the pinion 8. The rack housing 20 has a rack bar accommodating portion 25 (see FIG. 1) and a pinion accommodating portion 26. The rack bar accommodating portion 25 extends in the z-axis direction and accommodates the rack bar 6 so as to be movable in the z-axis direction. The pinion accommodating portion 26 faces the positive x-axis side of the rack bar 6 and is formed along the y-axis direction so as to intersect the rack bar accommodating portion 25, and rotatably accommodates the pinion shaft 4c around the rotation axis O1. The rack housing 20 has a rack retainer accommodating hole 27. The rack retainer accommodating hole 27 faces the negative x-axis side of the rack bar 6 and extends in the x-axis direction from the rack bar accommodating portion 25 toward the negative x-axis side of the rack bar 6. That is, the rack retainer accommodating hole 27 is provided on the side opposite to the pinion accommodating portion 26 with respect to the rack bar 6.

[0013] The rack retainer housing hole 27 houses a rack retainer 28, a coil spring (biasing member) 29, and an adjustment plug (cap) 30. The rack retainer 28 is provided so as to be movable in the x-axis direction and supports a convex sliding surface 6a having an arcuate cross-section formed on the negative x-axis side of the rack bar 6. The rack retainer 28 has a substantially circular outer shape when viewed from the x-axis direction. An annular groove 28a is provided on the outer peripheral surface 28f (see FIG. 3) of the rack retainer 28. The annular groove 28a is disposed on the negative x-axis side with respect to the central position of the rack retainer 28 in the x-axis direction. An O-ring 31 slidable with the inner wall of the rack retainer housing hole 27 is provided in the annular groove 28a. The coil spring 29 biases the rack bar 6 toward the pinion 8 via the rack retainer 28. The adjustment plug 30 closes the rack retainer housing hole 27 from the negative X-axis side. The adjustment plug 30 has a substantially cylindrical shape and has an external thread 30a on its outer peripheral surface 30d (see FIG. 3). The external thread 30a is fastened to an internal thread 27a provided on the inner wall of the rack retainer housing hole 27. The adjustment plug 30 is fixed by a lock nut 30e after adjusting the biasing force of the coil spring 29.

[0014] FIG. 3 is an enlarged view of the main part of FIG. 2. A support surface 28b is provided at the end portion (tip portion) 32 on the positive x-axis side of the rack retainer 28. The support surface 28b is formed in an arcuate cross-section so as to follow the convex sliding surface 6a of the rack bar 6 and is in sliding contact with the convex sliding surface 6a. The end portion (rear end portion) 33 on the negative x-axis side of the rack retainer 28 has a cylindrical portion 28c. A spring housing portion 28d is provided inside the cylindrical portion 28c. The spring housing portion 28d is a recess opening toward the negative x-axis side and houses a part of the coil spring 29. A spring housing portion 30b is provided at the end portion (tip portion) 34 on the positive x-axis side of the adjustment plug 30. The spring housing portion 30b is a recess opening toward the positive x-axis side and houses a part of the coil spring 29. In the x-axis direction, the coil spring 29 is housed in a compressed state between the bottom surfaces 28e and 30c of the two spring housing portions 28d and 30b.

[0015] The tip 32 including the support surface 28b of the rack retainer 28, the rear end 33, and the bottom surface 28e of the spring housing portion 28d, and the tip 34 of the adjustment plug 30 and the bottom surface 30c of the spring housing portion 30b are coated with grease 35. The grease 35 on the tip 32 and the rear end 33 of the rack retainer 28 and the tip 34 of the adjustment plug 30 reaches the outer peripheral surfaces 28f, 30d of the rack retainer 28 and the adjustment plug 30, but does not reach the female thread 27a of the rack retainer housing hole 27 and the male thread 30a of the adjustment plug 30. That is, the grease 35 does not adhere to the male thread 30a of the adjustment plug 30. A sealant 36 is applied between the female thread 27a of the rack retainer housing hole 27 and the male thread 30a of the adjustment plug 30. FIG. 4 is a view showing a state immediately before inserting the rack retainer 28 into the rack retainer housing hole 27. As shown in FIG. 4, in a state before inserting the rack retainer 28 into the rack retainer housing hole 27, the outer diameter D of the O-ring 31 in a state where the O-ring 31 is disposed in the annular groove 28a is larger than the inner diameter d of the female thread 27a of the rack retainer housing hole 27.

[0016] Next, among the manufacturing methods of the electric power steering apparatus 1 in Embodiment 1, a step of inserting the rack retainer 28 into the rack retainer housing hole 27 of the rack housing 20 (hereinafter, the first step) and a step of applying the grease 35 to the rear end 33 of the rack retainer 28 (hereinafter, the second step) will be described. FIG. 5 is a cross-sectional view of a main part of the jig 37 used in the first step and the second step. In FIG. 5, a w-axis is set in the vertical direction of the paper surface, and in the w-axis direction, the direction from the upper side to the lower side of the paper surface is defined as the positive direction of the w-axis. The jig 37 includes a base 38, a cylindrical portion 39, a discharge port 40, an adjustment valve 41, and a retainer fitting plug 42.

[0017] The base 38 has a substantially cylindrical shape extending in the w-axis direction and is movable in the w-axis direction by an actuator (not shown). The cylindrical portion 39 has a substantially cylindrical shape and is provided at the end portion (tip portion) 38a on the positive w-axis side of the base 38. The end portion of the cylindrical portion 39 in the positive w-axis direction is an annular contact portion 39a that contacts the end face of the cylindrical portion 28c of the rack retainer 28 in the first step. The annular contact portion 39a has a tapered shape in which the position in the w-axis direction moves to the negative direction side (the amount of separation from the rear end portion 33 increases) as it goes toward the inner circumference. For this reason, only the outermost peripheral end of the annular contact portion 39a contacts the rear end portion 33 in the first step. The discharge port 40 is an opening through which the grease 35 can be discharged in the second step. The discharge port 40 is provided in a portion of the annular contact portion 39a that is separated from the rear end portion 33, that is, inside the outermost peripheral end of the annular contact portion 39a, and opens toward the positive w-axis side. Four discharge ports 40 are provided at equal intervals (90-degree pitch) in the direction around the w-axis. The discharge port 40 constitutes the positive w-axis end of the grease supply path 43 formed inside the base 38 and the cylindrical portion 39.

[0018] The adjustment valve 41 is provided between a grease supply source (not shown) and each grease supply path 43, and can adjust the amount of grease supplied from the grease supply source to each grease supply path 43, that is, the amount of grease discharged from each discharge port 40. The retainer fitting plug 42 enters the cylindrical portion 28c of the rack retainer 28 in the first step and suppresses the grease 35 discharged from the discharge port 40 from falling into the spring housing portion 28d in the second step. The retainer fitting plug 42 is provided inside the cylindrical portion 39, and a part of it protrudes toward the positive w-axis direction side from the cylindrical portion 39. The retainer fitting plug 42 has large-diameter portions 42a and 42b at both ends of the w-axis, and is formed in an H-shaped cross-section in the w-axis direction having an annular groove portion 42c between both large-diameter portions 42a and 42b. The first large-diameter portion 42a is set to have an outer diameter slightly smaller than the inner diameter of the cylindrical portion 28c of the rack retainer 28. The negative w-axis direction end of the first outer diameter portion 42a is located on the positive w-axis direction side of the annular contact portion 39a. The first outer diameter portion 42a is provided with a concave portion 42d that opens toward the positive w-axis direction side. The second outer diameter portion 42b abuts against the tip portion 38a of the base portion 38. The annular groove portion 42c forms a space portion 44 between it and the inner peripheral surface of the cylindrical portion 39. The grease 35 discharged from the discharge port 40 can enter the space portion 44. A through hole 42e extending in the w-axis direction is provided at the center of the retainer fitting plug 42. A bolt 45 passes through the through hole 42e. The threaded portion 45a of the bolt 45 is screwed into the threaded hole 38b formed in the base portion 38. The head portion 45b of the bolt 45 is located inside the concave portion 42d. The retainer fitting plug 42 can be removed from the base portion 38 by loosening the bolt 45.

[0019] FIG. 6 is a schematic diagram showing the first step and the second step. In FIG. 6, the vertical direction in the drawing plane coincides with the vertical up-and-down direction. In the first step, first, as shown in FIG. 6(a), with the tip portion 32 of the rack retainer 28 inserted into the rack retainer housing hole 27, the rear end portion 33 of the rack retainer 28 is held by the holder 46, and the jig 37 is disposed on the negative w-axis direction side of the rack retainer 28. The holder 46 and the jig 37 have an operating integrated structure. At that time, the annular contact portion 39a is in a state where there is no grease or a state where the grease 35 adheres after the application work of one unit. Next, as shown in FIG. 6(b), the jig 37 is lowered (moved in the positive w-axis direction), and the annular contact portion 39a of the cylindrical portion 39 is brought into contact with the rear end portion 33 of the rack retainer 28. At this time, only the outermost peripheral end of the annular contact portion 39a contacts the rear end portion 33, and the inner peripheral side thereof does not contact the rear end portion 33. Therefore, the excess amount of the grease 35 between the annular contact portion 39a and the rear end portion 33 moves to the inner peripheral side of the jig 37 and accumulates in the upper part of the first outer diameter portion 42a of the retainer fitting plug 42, that is, in the space portion 44. As shown in FIG. 6(c), when the support surface 28b of the rack retainer 28 contacts the convex sliding surface 6a of the rack bar 6, the lowering of the jig 37 is stopped, and the first step is completed.

[0020] In the second step, the adjustment valve 41 is opened for a certain period of time to discharge the grease 35 from the discharge port 40. Since the excess amount of the grease 35 is inhibited from moving to the outer peripheral side due to the contact between the outermost peripheral end of the annular contact portion 39a and the rear end portion 33, it moves to the inner peripheral side of the jig 37 and accumulates in the space portion 44. (FIG. 7) Thereafter, the jig 37 is raised (moved in the negative w-axis direction), the holder 46 is separated from the rack housing 20, and the coating operation is completed. At that time, a certain amount of grease 35 remains in the annular contact portion 39a. FIG. 7 is an enlarged view of the main part of the jig 37 in the second step. Only the outermost peripheral end of the annular contact portion 39a contacts the rear end portion 33, and the inner peripheral side thereof does not contact the rear end portion 33. That is, since the outer periphery of the annular contact portion 39a is sealed, it is possible to suppress the grease 35 discharged from the discharge port 40 from leaking to the inner peripheral side and reaching the female screw 27a. Since the mixing of the sealant 36 and the grease 35 can be suppressed, the loosening of the adjustment plug 30 can be suppressed, and thus the deterioration of the sealing performance and the generation of abnormal noise can be suppressed.

[0021] Next, the operation and effect of Embodiment 1 will be described. Conventionally, in a rack & pinion type electric power steering apparatus, wear of the rack retainer due to the tilting of the rack retainer causes generation of abnormal noise during steering. Although this wear can be suppressed by applying grease to the rear end portion of the rack retainer, when applying a sealant to the cap and fastening it with a screw, there was a risk that the sealing performance would deteriorate if grease adhered to the screw. In particular, when the outer diameter of the O-ring provided between the rack retainer and the rack retainer housing hole is larger than the inner diameter of the screw, it was difficult to apply grease to the rear end portion of the rack retainer so that the grease would not adhere to the screw.

[0022] On the other hand, in the manufacturing method of the electric power steering apparatus 1 according to Embodiment 1, there are a first step of pressing the rear end portion 33 of the rack retainer 28 with a jig 37 and inserting it into the rack retainer housing hole 27, and a second step of applying grease 35 to the rear end portion 33 of the rack retainer 28 with the jig 37 in a state where the rack retainer 28 is inserted into the rack retainer housing hole 27. That is, after inserting the rack retainer 28 into the rack retainer housing hole 27, by applying the grease 35 to the rear end portion 33 of the rack retainer 28 using the jig 37, it is possible to apply the grease 35 to the rear end portion 33 of the rack retainer 28 without causing the grease 35 to adhere to the female screw 27a. As a result, even in a configuration where the outer diameter D of the O-ring 31 is larger than the inner diameter d of the female screw 27a in a state before inserting the rack retainer 28 into the rack retainer housing hole 27, mixing of the sealant 36 and the grease 35 can be suppressed. As a result, loosening of the adjustment plug 30 is suppressed, so that both deterioration of the sealing performance and generation of abnormal noise can be suppressed.

[0023] The jig 37 has an annular contact portion 39a whose outer periphery contacts the rear end portion 33 and whose inner periphery is separated from the rear end portion 33, and has a discharge port 40 capable of discharging the grease 35 at a portion of the annular contact portion 39a that is separated from the rear end portion 33. That is, since the outer periphery of the annular contact portion 39a is sealed, it is possible to suppress the grease 35 discharged from the discharge port 40 from escaping to the inner peripheral side and leaking to the female screw 27a. The rear end portion 33 of the rack retainer 28 has a cylindrical portion 28c, and the annular contact portion 39a has a discharge port 40 at a portion facing the end face of the cylindrical portion 28c. That is, by providing the discharge port 40 facing the end face of the cylindrical portion 28c to which the grease 35 is to be applied, the grease 35 can be applied intensively to the rear end portion 33 of the rack retainer 28. The portion of the annular contact portion 39a away from the rear end portion 33 has a tapered shape in which the amount of separation from the rear end portion 33 increases as it goes toward the inner circumference. Thereby, since the outer circumference of the annular contact portion 39a is sealed, the grease 35 discharged from the discharge port 40 can be allowed to escape to the inner circumferential side, and leakage of the grease 35 to the female screw 27a can be suppressed.

[0024] The jig 37 has an adjustment valve 41 capable of adjusting the amount of the grease 35, and the discharge amount of the grease 35 can be adjusted by the adjustment valve 41. Thereby, since an appropriate amount of the grease 35 can be supplied to the rear end portion 33, it is possible to suppress insufficient lubrication of the rear end portion 33 due to insufficient supply of the grease 35 and a decrease in sealing performance due to excessive supply of the grease 35. The jig 37 has a space portion 44 inside the annular contact portion 39a in the radial direction into which the grease 35 discharged from the discharge port 40 can enter. That is, by providing a space portion 44 for allowing the surplus of the grease 35 to escape on the inner circumferential side of the discharge port 40, it is possible to suppress the grease 35 from overflowing. The jig 37 has a retainer fitting plug 42 that can be inserted into the inside of the cylindrical portion 28c (spring housing portion 28d) inside the annular contact portion 39a in the radial direction. Thereby, it is possible to suppress the grease 35 from falling into the spring housing portion 28d of the rack retainer 28, and waste of the grease 35 can be prevented. In addition, control of the supply amount of the grease 35 can be facilitated. The retainer fitting plug 42 has an annular groove portion 42c formed on the outer circumference, and the annular groove portion 42c constitutes the space portion 44. Thereby, a space for storing the surplus of the grease 35 can be easily formed on the inner circumferential side of the discharge port 40. The retainer fitting plug 42 is removable from the annular contact portion 39a. Therefore, by removing the retainer fitting plug 42 from the annular contact portion 39a, the grease 35 accumulated in the space portion 44 can be easily removed.

[0025] In the state before inserting the rack retainer 28 into the rack retainer housing hole 27 of the electric power steering apparatus 1 according to Embodiment 1, the outer diameter D of the O-ring in the state where the O-ring 31 is disposed in the annular groove 28a of the rack retainer 28 is larger than the inner diameter d of the female thread 27a of the rack retainer housing hole 27. After the rack retainer 28 is inserted into the rack retainer housing hole 27, the grease 35 adheres to the rear end portion 33 of the rack retainer 28 and does not adhere to the male thread 30a of the adjustment plug 30. Thereby, mixing of the sealant 36 and the grease 35 can be suppressed, loosening of the adjustment plug 30 can be suppressed, and thus both a decrease in sealing performance and generation of abnormal noise can be suppressed.

[0026] [Embodiment 2] Since the basic configuration of Embodiment 2 is the same as that of Embodiment 1, only the portions different from Embodiment 1 will be described. FIG. 8 is an enlarged view of a main part of the jig 37 according to Embodiment 2. The annular contact portion 39a of Embodiment 2 has a contact surface 47, a separation surface 48, and a stepped surface 49. The contact surface 47 and the separation surface 48 extend in a direction orthogonal to the w-axis direction. The contact surface 47 is provided on the radially outer side of the separation surface 48. The contact surface 47 is located on the +w-axis direction side of the separation surface 48. Therefore, in the first step, when the rack retainer 28 is pressed by the jig 37, the contact surface 47 contacts the rear end portion 33 of the rack retainer 28, while the separation surface 48 maintains a state of being separated from the rear end portion 33. The stepped surface 49 extends along the w-axis direction and connects between the contact surface 47 and the separation surface 48. Since the jig 37 of Embodiment 2 has the annular contact portion 39a in a stepped shape, manufacturing can be facilitated as compared with the tapered shape of Embodiment 1.

[0027] [Other Embodiments] As described above, embodiments for carrying out the present invention have been described. However, the specific configuration of the present invention is not limited to the configuration of the embodiments, and design changes and the like within a range not departing from the gist of the invention are also included in the present invention. For example, the number of discharge ports can be arbitrarily set. [Description of Reference Numerals]

[0028] 1 Electric power steering device, 2 Steering mechanism, 4 Steering shaft, 6 Rack bar, 8 Pinion, 9 Rack teeth, 20 Rack housing (housing member), 25 Rack bar housing portion, 26 Pinion housing portion, 27 Rack retainer housing hole, 27a Female thread, 28 Rack retainer, 28a Annular groove, 28c Cylindrical portion, 29 Coil spring (biasing member), 30 Adjustment plug (cap), 30a Male thread, 31 O-ring, 33 Rear end portion, 35 Grease, 36 Sealing agent, 37 Jig, 39a Annular contact portion, 40 Discharge port, 41 Adjustment valve, 42c Annular groove portion, 44 Space portion

Claims

1. A steering mechanism having a steering shaft that rotates with a steering operation of a steering wheel, a pinion provided on the steering shaft, rack teeth that mesh with the pinion, and a rack bar that converts the rotational movement of the pinion into an axial movement, a housing member having a pinion housing portion that houses the pinion, a rack bar housing portion that houses the rack bar, and a rack retainer housing hole provided on the opposite side of the pinion housing portion with respect to the rack bar, a rack retainer that is slidably disposed inside the rack retainer housing hole, has a front end portion and a rear end portion in the moving direction, and the rear end portion abuts against the rack bar, a female screw provided on an inner wall of the rack retainer housing hole, a cap having a male screw that fastens to the female screw on an outer periphery and closes the rack retainer housing hole, a biasing member disposed between the cap and the rear end portion of the rack retainer, and biasing the rack retainer toward the rack bar side, A method for manufacturing an electric power steering apparatus, comprising: a first step of pressing the rear end portion of the rack retainer with a jig and inserting it into the rack retainer housing hole; a second step of applying grease to the rear end portion of the rack retainer with the jig while the rack retainer is inserted into the rack retainer housing hole. A method for manufacturing an electric power steering apparatus having the above steps.

2. A method for manufacturing an electric power steering apparatus according to Claim 1, wherein the jig has an annular contact portion whose outer periphery abuts against the rear end portion and whose inner periphery is separated from the rear end portion, and a discharge port capable of discharging the grease is provided at a portion of the annular contact portion that is separated from the rear end portion. A method for manufacturing an electric power steering apparatus.

3. A method for manufacturing an electric power steering apparatus according to Claim 2, wherein the rear end portion of the rack retainer has a cylindrical portion, and the discharge port is provided at a portion of the annular contact portion that faces an end surface of the cylindrical portion. A method for manufacturing an electric power steering apparatus.

4. A method for manufacturing an electric power steering apparatus according to Claim 3, wherein a portion of the annular contact portion that is separated from the rear end portion has a tapered shape in which the amount of separation from the rear end portion increases as it approaches the inner periphery. A method for manufacturing an electric power steering apparatus.

5. A method for manufacturing an electric power steering apparatus according to Claim 3, A portion of the annular contact portion that is away from the rear end portion has a stepped shape in which the amount of separation from the rear end portion increases as it approaches the inner circumference. A method for manufacturing an electric power steering apparatus.

6. A method for manufacturing an electric power steering apparatus according to claim 3, wherein the jig has an adjustment valve capable of adjusting the discharge amount of the grease, and the discharge amount of the grease can be adjusted by the adjustment valve. A method for manufacturing an electric power steering apparatus.

7. A method for manufacturing an electric power steering apparatus according to claim 2, wherein the jig has a space portion into which the grease discharged from the discharge port can enter inside the radial direction of the annular contact portion. A method for manufacturing an electric power steering apparatus.

8. A method for manufacturing an electric power steering apparatus according to claim 7, wherein the rear end portion of the rack retainer has a cylindrical portion, and the jig has a plug that can be inserted inside the cylindrical portion inside the radial direction of the annular contact portion. A method for manufacturing an electric power steering apparatus.

9. A method for manufacturing an electric power steering according to claim 8, wherein the plug has an annular groove portion formed on the outer circumference, and the annular groove portion is the space portion. A method for manufacturing an electric power steering apparatus.

10. A method for manufacturing an electric power steering apparatus according to claim 9, wherein the plug is removable with respect to the annular contact portion. A method for manufacturing an electric power steering apparatus.

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