Rack-and-pinion device and steering device

Abstract

As shown in fig. 6(b), this rack-and-pinion device comprises a support member (40) in a housing (18). As shown in fig. 6(a), rotation of the support member (40) is inhibited relative to the housing (18) by a caulking part (50) plastically deformed along an orthogonal axis (55) orthogonal to the center axis (54) of the support member (40).

Description

Rack and pinion device and steering device

[0001] The present invention relates to a rack and pinion device and a steering device having as main elements a pinion shaft having pinion teeth and a rack shaft having rack teeth.

[0002] [Terminology] "Central axis": The axis that passes through the center of a part and extends in the longitudinal direction is called the central axis. "Crimping": The plastic processing technique that is also described as caulking or swaging is described as crimping.

[0003] A rack and pinion is a type of gear mechanism that converts rotary motion into linear motion. When one gear is turned, the other gear is turned, but at the same time, the other gear is subjected to a force that moves it away from the first gear. This force is called a repulsion force.

[0004] To counter this separation force, the rack and pinion device is provided with a contact member that comes into contact with the rack shaft and an elastic body that urges the contact member toward the rack shaft, located on the opposite side of the pinion shaft. In other words, the contact member and elastic body limit the movement of the rack shaft.

[0005] Such a structure is known, for example, as disclosed in Patent Document 1 (particularly FIG. 2). As shown in Patent Document 1, a rack shaft, a rack guide (corresponding to a contact member), and a coil spring (corresponding to an elastic body) are housed in a housing, and a rack guide cap (hereinafter referred to as a screw) that prevents the elastic body from coming off is screwed into the housing.

[0006] Increasing the screw thread length reduces the gap between the pinion teeth and the rack teeth, known as backlash. If the backlash is too small, it will affect the rotational movement. On the other hand, if the backlash is too large, strong contact will occur during reverse rotation. As a countermeasure, the screw thread length is adjusted so that the backlash is at the specified value. This adjustment is called backlash adjustment.

[0007] If the screw were to rotate after this backlash adjustment, the backlash would deviate from the predetermined value. This deviation is unacceptable, so it is desirable to take measures to address it.

[0008] Therefore, in Patent Document 1, a lock nut is attached. That is, the lock nut is screwed onto the screw. The lock nut applies axial force to the screw to prevent the screw from rotating.

[0009] However, since the procurement costs of lock nuts are high, from the perspective of reducing costs, a structure that can prevent screw rotation without using a lock nut is desired.

[0010] A known example of such a structure is the crimping method, which is disclosed, for example, in Patent Document 2. The technology disclosed in Patent Document 2 involves punching, or crimping, the periphery of the guide hole in the housing with a punch from a crimping machine (Patent Document 2, paragraph 0013). The crimping prevents the cap (corresponding to a screw) from rotating.

[0011] When this occurs, the punch is driven parallel to the central axis of the guide hole. Part of the force of the punch is transmitted to the screw. As a result, the screw moves slightly along the central axis of the guide hole. This movement changes the backlash value. This change affects the power transmission performance of the rack and pinion device.

[0012] Even if a caulking method is adopted to reduce the number of parts, it is undesirable that the power transmission performance of the rack and pinion device is affected. Therefore, a caulking technique that prevents the screw from moving during caulking is desired.

[0013] JP 2019-209783 A (FIG. 2) JP 2003-182613 A (FIG. 1)

[0014] An object of the present invention is to provide a crimping technique that prevents a support member (a generic concept of a screw) from moving during crimping, and to provide a rack and pinion device obtained by such a crimping technique.

[0015] According to the present disclosure, there is provided a rack and pinion device comprising: a rack shaft accommodated in a housing and having rack teeth; a pinion shaft having pinion teeth that mesh with the rack teeth; a contact member that contacts the rack shaft on the side opposite to the pinion shaft; an elastic body that urges the contact member so that one end abuts against the contact member and presses the rack shaft against the pinion shaft; and a support member that is fixed to the housing and supports the other end of the elastic body, wherein the support member has a crimped portion that is plastically deformed along an orthogonal axis that is perpendicular to the central axis of the support member.

[0016] According to the present disclosure, a crimping technique is provided that prevents the support member from moving during crimping, and a rack and pinion device obtained by such a crimping technique can be provided.

[0017] 1A and 1B are cross-sectional views of a main portion of a steering device including a rack and pinion device according to the present invention. (a) is a front view of a first crimping jig, and (b) is a cross-sectional view of the first crimping jig. (a) is a cross-sectional view of a support member before crimping, (b) is a front view of the support member, and (c) is a diagram illustrating a jig fitting portion. (a) to (c) are diagrams illustrating a form in which a jig tip portion is fitted into a support member. (a) to (e) are diagrams illustrating the operation of the first crimping jig. (a) is a cross-sectional view illustrating the position of the crimping portion, and (b) is a cross-sectional view taken along line b-b in (a). (a) and (b) are diagrams illustrating a modified example of the support member. (a) and (b) are diagrams illustrating a second crimping jig and its operation. (a) and (b) are diagrams illustrating a third crimping jig and its operation. (a) and (b) are diagrams illustrating a further modified example of the support member. (a) is a cross-sectional view of a fourth crimping jig. 10A and 10B are diagrams illustrating the operation of a fourth crimping jig, and 10A and 10B are diagrams illustrating a further modified example of the support member.

[0018] An embodiment of the present invention will be described below with reference to the accompanying drawings.

[0019] 1, the rack and pinion device 10 includes a rack shaft 14 housed in a housing 18 and having rack teeth 13, a pinion shaft 12 having pinion teeth 11 that mesh with the rack teeth 13, a contact member 15 that contacts the rack shaft 14 on the side opposite the pinion shaft 12, an elastic body 16 that urges the contact member 15 so that one end abuts against the contact member 15 and presses the rack shaft 14 against the pinion shaft 12, and a support member 40 that is fixed to the housing 18 and supports the other end of the elastic body 16. The support member 40 is, for example, a screw, but may have any shape as long as it is a member that supports the other end of the elastic body 16.

[0020] The contact member 15 preferably has O-ring grooves 21 on its outer periphery, and is movably housed in the housing 18 via O-rings 22 fitted into the O-ring grooves 21. The elastic body 16 is preferably a compression coil spring, but may also be elastic rubber. The support member 40 preferably has a central hole 41 in its center, and a dust plug 42 is provided in this central hole 41.

[0021] The end of the support member 40 that is closer to the elastic body 16 will be referred to as the inner end 43, and the end that is farther away will be referred to as the outer end 44. Preferably, a disc spring 23 and a spacer 24 are interposed between the support member 40 and the contact member 15. The disc spring 23 can prevent the contact member 15 from hitting the support member 40 too hard.

[0022] [Materials of Housing and Support Member] The material of the housing 18 is preferably an aluminum alloy, but may be other alloys. Similarly, the material of the support member 40 is preferably an aluminum alloy, but may be other alloys. Aluminum alloys are easy to plastically process and have adequate strength.

[0023] [Steering Device] The rack and pinion device 10 can be used for, but is not limited to, a part of a steering device 30. In the steering device 30, a steering shaft 31 is turned by a steering wheel operated by a driver, and the steering shaft 31 turns the pinion shaft 12, and the pinion shaft 12 moves the rack shaft 14 in the front-to-back direction of the drawing, thereby turning left and right wheels called steering wheels.

[0024] [Multiple Crimping Methods] The crimping method according to the present invention can be selected from a plurality of methods. In order to accommodate the plurality of methods, first to fourth crimping jigs will be illustrated in order.

[0025] [First Crimping Jig] As shown in Figure 2 (b), the first crimping jig 60 includes, for example, a cylinder 61, a lid 62 that closes the rear opening of the cylinder 61, a piston 63 stored in the cylinder 61, a piston rod 63a that extends from the piston 63 in the opposite direction from the lid 62, a compression coil spring 64 that urges the piston 63 toward the lid 62, a jig tip 65 that extends from the front of the cylinder 61 in the opposite direction from the lid 62, a slider 66 that is movably attached to the jig tip 65, and a hemispherical protrusion 69 that extends from the slider 66 along an orthogonal axis 68 that is perpendicular to a central axis 67 of the piston 63.

[0026] Such a first crimping jig 60 may be attached to a robot arm 71. The first crimping jig 60 can be rotated and moved as desired by the robot arm 71.

[0027] 2A, the cylinder 61 has a square shape when viewed from the front, but may have a circular shape. The jig tip 65 has a hexagonal shape when viewed from the front. This hexagonal shape is slightly smaller than the cylinder 61.

[0028] Of the six vertices of the hexagon, a slider 66 and a hemispherical protrusion 69 are arranged at one vertex and another vertex located 180° from the first vertex. That is, two hemispherical protrusions 69 are arranged at a pitch of 180°.

[0029] The slider 66 is guided by the jig tip 65 and cannot swing in a direction perpendicular to the orthogonal axis 68 (left and right in the drawing).

[0030] In this example, two hemispherical protrusions 69 are arranged at 180° intervals, but three may be arranged at 120° intervals, four at 90° intervals, or six at 60° intervals. The hexagonal shape may also be a square or octagon. Therefore, the structure and shape of the first crimping jig 60 described in Figures 2(a) and 2(b) may be modified as appropriate.

[0031] Next, the operation of the first crimping jig 60 will be described. In Fig. 2(b), a pressure oil port 72 is provided in the cylinder 61 near the lid 62, and high-pressure oil is supplied from this port. When this occurs, the piston 63 moves forward while compressing the compression coil spring 64.

[0032] The piston rod 63a is provided with a pointed tapered shaft portion 73. When the tapered shaft portion 73 advances, the slider 66 moves away from the central axis 67. As a result, the hemispherical protrusion 69 protrudes from the jig tip portion 65.

[0033] The slider 66 has an elongated hole 74 extending along the orthogonal axis 68. Two guide pins 75 that pass through the elongated holes 74 are attached to the jig tip 65. These two guide pins 75 are arranged at a predetermined interval along the orthogonal axis 68. As a result, the slider 66 and the hemispherical protrusion 69 move only along the orthogonal axis 68.

[0034] When high-pressure oil is discharged from the pressure oil port 72, the compression coil spring 64 expands and the piston 63 moves backward. This backward movement moves the slider 66 closer to the central axis 67. As a result, the hemispherical protrusion 69 returns to its original position and sinks into the jig tip 65. Preferably, a return spring 76 is disposed between the slider 66 and the cylinder 61. This return spring 76 allows the hemispherical protrusion 69 to move more smoothly from the protruding position to the recessed position.

[0035] [Support Member] The shape of the support member 40 before crimping will be described with reference to Figures 3(a) to 3(c). Figure 3(a) corresponds to a cross-sectional view taken along line a-a in Figure 3(b), and Figure 3(b) corresponds to a view seen from the arrow b in Figure 3(a). Figure 3(c) is a diagram in which the main parts are extracted from Figure 3(b).

[0036] 3A, the support member 40 before crimping has a central hole 41, a male thread portion 45 on the outer periphery, and a large recess 46 on the outer end portion 44 side. The longitudinal axis passing through the center of the central hole 41 is a central axis 54.

[0037] Fig. 3(c) shows only the jig fitting portion 47 extracted from Fig. 3(b). As shown in Fig. 3(c), the jig fitting portion 47 is a collection of straight lines of an appropriate length. For convenience, the center of one jig fitting portion 47 is referred to as the fitting portion center 47a, one end is referred to as the fitting portion one end 47b, and the other end is referred to as the fitting portion other end 47c. The jig tip portion 65 described in Fig. 2 is fitted into such a jig fitting portion 47.

[0038] 3(b), an axis perpendicular to the central axis 54 is an orthogonal axis 55. A circle of any radius centered on the central axis 54 is a circumference 56. Thin portions 48 and thick portions 49 are arranged along this circumference 56. That is, a plurality of thin portions 48 and a plurality of thick portions 49 are formed in the outer end portion 44 by the jig fitting portion 47.

[0039] 4A, the jig tip 65 is fitted into the jig fitting portion 47 so that the hemispherical protrusion 69 coincides with the fitting portion center 47a. Then, the hemispherical protrusion 69 is advanced toward the fitting portion center 47a as indicated by arrows A1 and A2.

[0040] After advancing, the hemispherical protrusion 69 is retracted, the jig tip portion 65 is removed from the jig fitting portion 47, and the jig tip portion 65 is rotated counterclockwise by 30°. Then, as shown in FIG. 4(b), the jig tip portion 65 is fitted into the jig fitting portion 47 so that the hemispherical protrusion 69 matches the fitting portion one end 47b. Then, the hemispherical protrusion 69 is advanced toward the fitting portion one end 47b as shown by arrows B1 and B2.

[0041] After advancing, the hemispherical protrusion 69 is retracted, the jig tip 65 is removed from the jig fitting portion 47, and the jig tip 65 is rotated clockwise by 60°. Although not shown in the drawing, the hemispherical protrusion 69 is advanced to the other end 47c of the fitting portion.

[0042] By repeating the above steps, it is possible to orient the hemispherical protrusions 69 at a maximum of 12 positions, consisting of arrows A1, A2, A3, A4, B1, B2, B3, B4, B5, B6, B7, and B8, as shown in Figure 4(c). Since this is the maximum, it is possible to freely orient the hemispherical protrusions 69 at four positions, consisting of A1, A2, A3, and A4, eight positions, consisting of B1, B2, B3, B4, B5, B6, B7, and B8, or any other number of positions.

[0043] [First Crimping Method] A crimping method performed using the above-described first crimping jig (FIG. 2, reference numeral 60) will be described with reference to FIGS. 5(a) to 5(e). As shown in FIG. 5(a), the female thread portion 25 and the hemispherical recess 26 are formed in the housing 18. Then, the male thread portion 45 is screwed into the female thread portion 25, and the support member 40 is attached to the housing 18. After attachment, backlash adjustment is performed. This backlash adjustment determines the position of the support member 40.

[0044] As shown in Figure 5(b), the first crimping jig 60 is set on the support member 40. Figure 5(c) is a cross-sectional view taken along line c-c in Figure 5(b). As shown in Figure 5(c), the hemispherical protrusion 69 is advanced. As shown in Figure 5(d), a portion of the support member 40 bites into the hemispherical recess 26 of the housing 18, forming a crimped portion 50 between the support member 40 and the housing 18.

[0045] Fig. 5(e) is an enlarged view of the main part of Fig. 5(d). In Fig. 5(e), it is assumed that an axial force F is applied to the support member 40. The larger the area (area of ​​the circle) Se of the base of the hemispherical crimped portion 50, the greater the axial force F that can be withstood. Furthermore, the more crimped portions 50 there are, the greater the axial force F that can be withstood. Therefore, the anti-rotation force of the support member 40 can be easily set by calculating (area Se x number of crimped portions 50).

[0046] 6A, the support member 40 is crimped to the housing 18 at a maximum of 12 crimp portions 50. That is, the crimp portions 50 are provided at a plurality of locations (12 locations in this example) along a circumference 56 of the support member 40 centered on a central axis 54 thereof.

[0047] Figure 6(b) is a cross-sectional view taken along line b-b in Figure 6(a). As shown in Figure 6(b), the support member 40 is firmly fastened to the housing 18. In this example, the fastening portion 50 includes a male thread portion 45. The inclusion of the male thread portion 45 increases the anti-rotation force of the support member 40.

[0048] However, structurally, the caulking portion 50 may not include the male thread portion 45. A specific example of this case will be described below.

[0049] [Modification of Support Member] As shown in Fig. 7(a), in this support member 40, the male thread portion 45 provided on the outer periphery is not provided at the outer end portion 44. In other words, the outer end portion 44 is an unthreaded portion 51. As shown in Fig. 7(b), the crimped portion 50 is formed in the unthreaded portion 51.

[0050] [Second Crimping Jig] Next, the second crimping jig and the shape of the support member crimped by this second crimping jig will be described. As shown in FIG. 8( a), the second crimping jig 80 comprises a roller 81 inserted into the recess 46 of the support member 40 and a drive unit 82 that moves the roller 81 radially outward while rotating it. A circumferential groove 27 with a hemispherical cross section and an annular shape is formed in the housing 18. As a result, as shown in FIG. 8( b), the crimping portion 50 is provided around the entire circumference 56 centered on the central axis 54. The crimping portion 50 becomes a single annular ring.

[0051] [Third Crimping Jig] Next, the third crimping jig and the shape of the support member crimped by this third crimping jig will be described. As shown in Figure 9(a), the third crimping jig 85 is disposed outside the housing 18 and moves the hemispherical protrusion 69 toward and away from the central axis 54. A thin-walled portion is formed in the housing 18. A hemispherical recess 52 is formed in the support member 40. As shown in Figure 9(b), crimped portions 50 can be formed in multiple locations.

[0052] 10( a), a folded portion 53 may be formed by extending from the outer end portion 44 of the support member 40 so as to cover the outer peripheral surface of the housing 18. Hemispherical recesses 26 are formed in the outer peripheral surface of the housing 18, and a third crimping jig 85 is placed against these hemispherical recesses 26. As shown in FIG. 10( b), the support member 40 is crimped to the housing 18 by a crimping portion 50.

[0053] [Fourth crimping jig] Figure 11 is a cross-sectional view of a fourth crimping jig 90. In this fourth crimping jig 90, the shape of the tip of the piston rod 63a is changed from that of Figure 2(b), and the slider is changed to a swing piece 91. Since the rest is the same as Figure 2(b), the reference numerals of Figure 2(b) are used for the common parts, and detailed description will be omitted.

[0054] 11, the swing piece 91 is a roughly triangular member rotatably supported by a pin 92 on the cylinder 61. A hemispherical protrusion 69 is provided at one of the three vertices of the roughly triangle, one of the other vertices is pressed by the piston rod 63a, and the remaining vertex is pressed by a return spring 93.

[0055] [Function of the Fourth Crimping Jig] As shown in Figure 12(a) , a hemispherical protrusion 69 is disposed inside the outer end 44 of the support member 40. As shown in Figure 12(b) , the swing piece 91 is rotated in the crimping direction around the pin 92. As a result, the hemispherical protrusion 69 describes an arcuate trajectory 94. The support member 40 is crimped while being pulled along this arcuate trajectory 94 as shown by fx. That is, the crimped portion 50 is formed by pressing the outer end 44 of the support member 40 against the housing 18 while pulling the support member 40 away from the contact member (Figure 1, reference numeral 15).

[0056] [Modification of Crimping Position] A further modification will be described with reference to Figures 13(a) and (b). As shown in Figure 13(a), a hemispherical recess 26 is formed in the inner end 43 of the support member 40, a counterbore 28 is formed in the housing 18, and a third crimping jig 85 faces the counterbore 28. As shown in Figure 13(b), a crimped portion 50 is formed in the inner end 43 of the support member 40.

[0057] The rack and pinion device 10 described above will be summarized below.

[0058] First, as shown in FIG. 1 , the rack and pinion device 10 comprises a pinion shaft 12 having pinion teeth 11, a rack shaft 14 having rack teeth 13 that mesh with the pinion teeth 11, a contact member 15 that contacts the rack shaft 14 on the side opposite to the pinion shaft 12, an elastic body 16 that urges the contact member 15 so that one end abuts against the contact member 15 and presses the rack shaft 14 against the pinion shaft 12, a support member 40 that supports the other end of the elastic body 16, and a housing 18 that houses the pinion shaft 12, the rack shaft 14, the contact member 15, the elastic body 16, and the support member 40.

[0059] As shown in Figures 6(a) and (b), the support member 40 is prevented from rotating relative to the housing 18 by a crimped portion 50 that is plastically deformed along an orthogonal axis 55 that is perpendicular to the central axis 54 of the support member 40.

[0060] Because the crimping portion 50 is plastically deformed along an orthogonal axis 55 that is perpendicular to the central axis 54 of the support member 40, the support member 40 does not move along the central axis 54 (moving to the left or right in FIG. 6(b)) during crimping. As a result, a crimping technique is provided that prevents the support member 40 from moving during crimping, and a rack and pinion device 10 obtained by such a crimping technique can be provided.

[0061] The crimping position (position along the central axis 54) can be provided at the outer end 44 of the support member 40 as shown in FIG. 6(b), or at the inner end 43 of the support member 40 as shown in FIG. 13(b), and can be provided at any position on the support member 40.

[0062] The crimping direction (the direction along an orthogonal axis 55 perpendicular to the central axis 54) may be from the inside to the outside as shown in FIG. 5(c) or from the outside to the inside as shown in FIG. 9(a).

[0063] The crimping portion 50 may be made up of a plurality of pieces arranged along the circumference 56 as shown in FIG. 6(a), or may be made up of a crimping portion 50 extending over the entire circumference as shown in FIG. 7(b).

[0064] Secondly, in the first rack and pinion device 10, when the end of the support member 40 closer to the elastic body 16 is defined as an inner end 43 and the end farther from the elastic body 16 is defined as an outer end 44 as shown in FIG. 1, the crimping portion 50 is provided at the outer end 44 as shown in FIG. 6(b).

[0065] In Fig. 1, the separating force is applied to the support member 40 via the contact member 15 and the elastic body 16. Then, in Fig. 6(b), the separating force is first applied to the male thread portion 45, and then to the crimped portion 50 provided on the outer end portion 44. In other words, the second configuration reduces the mechanical load on the crimped portion 50.

[0066] Thirdly, in the second rack and pinion device 10, the crimping portion 50 is formed so as to press the outer end portion 44 of the support member 40 against the housing 18, as shown in FIG. 6(b), and the crimping portion 50 is provided at multiple locations along a circumference 56 centered on the central axis 54, as shown in FIG. 6(a).

[0067] 5( e), the anti-rotation force of the support member 40 can be calculated by the formula (area Se × number of crimped portions 50). That is, with the third configuration, the anti-rotation force of the support member 40 can be adjusted as desired by adjusting the number of crimped portions 50 and adjusting the area Se.

[0068] Fourth, in any one of the first to third rack and pinion devices 10, the support member 40 has a male thread portion 45 that is threadably coupled to the housing 18, as shown in FIG. 6(b), and the crimping portion 50 is formed to include the male thread portion 45.

[0069] The crimped portion 50 is formed by plastic deformation. By including the male thread portion 45, more complex plastic deformation becomes possible, and the rotation prevention performance of the support member 40 can be further improved.

[0070] Fifth, in the second or third rack and pinion device 10, the support member 40 further has jig fitting portions 47 at the outer end portion 44 into which a crimping jig is fitted, as shown in Fig. 3(c), and as shown in Fig. 3(b), the crimping portions 50 are aligned along the circumference 56, and as shown in Fig. 6(a), the jig fitting portions 47 are aligned along the circumference 56. In other words, the crimping portions 50 and the jig fitting portions 47 are aligned along the circumference 56.

[0071] By aligning the crimping portion 50 and the jig fitting portion 47, the length of the support member 40 along the central axis 54 can be shortened, and the support member 40 can be made smaller and lighter.

[0072] Sixth, in the fifth rack and pinion device 10, as shown in FIG. 3( b), the outer end portion 44 has a thin-walled portion 48 and a thick-walled portion 49 formed by the jig fitting portion 47, and the crimping portion 50 is formed in the thin-walled portion 48.

[0073] Plastic processing is easier in the thin-walled portions 48 than in the thick-walled portions 49, making it easier to form the crimped portions 50. Furthermore, since the thin-walled portions 48 are formed in multiple locations, any thin-walled portion 48 can be selected and crimped, making it easy to set the crimping position.

[0074] Seventh, in the second or third rack and pinion device 10, the support member 40 has an unthreaded portion 51 at the outer end 44, as shown in FIG. 7( a), and the crimped portion 50 is formed in the unthreaded portion 51, as shown in FIG. 7( b).

[0075] Since the crimped portion 50 does not include a threaded portion, the structure is simple, which increases the accuracy of the calculation shown in FIG.

[0076] Eighth, in the second or third rack and pinion device 10, the crimping portion 50 is formed so as to press the outer end portion 44 of the support member 40 against the housing 18, as shown in Figures 8(a) and 8(b), and the crimping portion 50 is provided around the entire circumference of a circle centered on the central axis 54.

[0077] Since it is the entire circumference, a large shear cross-sectional area (see symbol Se in FIG. 5(e)) can be secured. The shallow, small cross-section of the crimped portion 50 provides sufficient anti-rotation performance. Furthermore, the so-called roll crimping method can be applied. If the roll crimping jig (equivalent to symbol 80 in FIG. 8(a)) is used for another purpose, the eighth configuration allows the existing roll crimping jig to be reused.

[0078] Ninth, in the second or third rack and pinion device 10, the crimping portion 50 is formed so as to press the housing 18 against the outer end portion 44 of the support member 40, as shown in Figures 9(a) and (b), 10(a) and (b), or 13(a) and (b), and the crimping portion 50 is provided at multiple locations along any circumference centered on the central axis 54.

[0079] Even if the outer diameter of the support member 40 is small, the ninth structure does not require the crimping jig to be made unnecessarily small, and the crimped portion 50 can be easily formed.

[0080] Tenth, in the second or third rack and pinion device 10, the crimping portion 50 is formed so as to press the outer end portion 44 of the support member 40 against the housing 18 while pulling the support member 40 away from the contact member 15, as shown in Figures 12(a) and 12(b).

[0081] It is undesirable for the support member 40 to move along the central axis during crimping. According to the tenth configuration, crimping can be performed while compressing the male thread portion 45 onto the female thread portion 25, and movement of the support member 40 can be prevented.

[0082] It is acceptable to add the fifth or sixth configuration to the seventh rack and pinion device 10. It is also acceptable to add the fourth, fifth or seventh configuration to the eighth rack and pinion device 10. It is also acceptable to add the fourth to seventh configurations to the tenth rack and pinion device 10.

[0083] Although the rack and pinion device 10 according to the present invention is suitable for the steering device 30, it may also be applied to devices other than the steering device 30.

[0084] The rack and pinion device of the present invention is suitable for use in a steering device.

[0085] 10...Rack and pinion device 11...Pinion teeth 12...Pinion shaft 13...Rack teeth 14...Rack shaft 15...Contact member 16...Elastic body 18...Housing 30...Steering device 31...Steering shaft 40...Support member 43...Inner end portion 44...Outer end portion 45...External thread portion 47...Jig fitting portion 48...Thin portion 49...Thick portion 50...Crimped portion 51...Unthreaded portion 54...Central axis (central axis of support member) 55...Orthogonal axis (orthogonal axis perpendicular to central axis 54) 56...Circumference 60...Crimped jig (first crimped jig).

Claims

1. A rack and pinion device comprising: a rack shaft housed in a housing and having rack teeth; a pinion shaft having pinion teeth that mesh with the rack teeth; a contact member that contacts the rack shaft on the side opposite the pinion shaft; an elastic body whose one end abuts against the contact member and urges the contact member so as to press the rack shaft against the pinion shaft; and a support member fixed to the housing and supporting the other end of the elastic body, wherein the support member has a crimped portion that is plastically deformed along an orthogonal axis that is perpendicular to the central axis of the support member.

2. A rack and pinion device as set forth in claim 1, wherein the end of said support member closer to said elastic body is defined as the inner end and the end farther from said elastic body is defined as the outer end, and said crimping portion is provided at said outer end.

3. A rack and pinion device as set forth in claim 2, wherein the crimped portion is formed so as to press the outer end of the support member against the housing, and the crimped portion is provided at multiple locations along a circumference centered on the central axis.

4. A rack and pinion device according to claim 1, wherein the support member has a male thread portion that is threadedly coupled to the housing, and the crimped portion is formed to include the male thread portion.

5. A rack and pinion device as set forth in claim 2, wherein the support member further has a jig fitting portion at the outer end into which a crimping jig that moves along the central axis is fitted, and the crimping portion and the jig fitting portion are aligned along the circumference.

6. A rack and pinion device according to claim 5, wherein the outer end portion is formed with a thin-walled portion and a thick-walled portion by the jig fitting portion, and the crimping portion is formed in the thin-walled portion.

7. A rack and pinion device according to claim 3, wherein the support member has an unthreaded portion at the outer end, and the crimped portion is formed in the unthreaded portion.

8. A rack and pinion device as set forth in claim 2, wherein the crimped portion is formed so as to press the outer end of the support member against the housing, and the crimped portion is provided around the entire circumference of a circle centered on the central axis.

9. A rack and pinion device as set forth in claim 2, wherein the crimped portion is formed so as to press the housing against the outer end of the support member, and the crimped portion is provided at a plurality of locations along a circumference centered on the central axis.

10. A rack and pinion device according to claim 2, wherein said crimping portion is formed so as to press said outer end of said support member against said housing while pulling said support member away from said contact member.

11. A steering device comprising: a rack shaft accommodated in a housing and having rack teeth; a pinion shaft having pinion teeth that mesh with the rack teeth; a contact member that contacts the rack shaft on the side opposite to the pinion shaft; an elastic body that urges the contact member so that one end abuts the contact member and presses the rack shaft against the pinion shaft; a support member fixed to the housing and supporting the other end of the elastic body; and a steering shaft that rotates the pinion shaft, wherein the support member has a crimped portion that is plastically deformed along an orthogonal axis that is perpendicular to the central axis of the support member.

Images