Lifter structure

Abstract

To provide a lifter structure capable of suppressing generation of noise by a simple structure.SOLUTION: A lifter structure 1 is equipped with a housing 11 that forms a guide hole 13, and a roller lifter 20 that has a roller 40 and a lifter body 30. The lifter body 30 has a cylindrical shape that rotatably supports the roller 40 and reciprocates in the guide hole 13 according to rotations of a cam 60. The housing 11 has a groove 15 disposing a rotation preventive portion 50 of a roller lifter 20 in an opposing direction of a cam surface 60A of a cam 60 on an inner wall of the guide hole 13. In the groove 15, a space R (allowable space) allowing reciprocating of the rotation preventive portion 50 accompanied with the reciprocating of the lifter body 30 is formed. The housing 11 has a blocking member 80 that fills the groove 15 leaving the space R. The lifter body 30 can slide on a circumferential surface formed on a side on which the groove 15 is located in a circumferential direction of the guide hole 13.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a lifter structure.

Background Art

[0002] Patent Document 1 discloses a conventional lifter structure. This lifter structure includes a roller lifter and a housing. The roller lifter has a roller that rotatably contacts a cam, a cylindrical lifter body, and a detent portion protruding from the outer peripheral surface of the lifter body. The housing forms a guide hole and a detent groove. The guide hole accommodates the lifter body so as to be reciprocally movable. The detent groove is provided along the inner peripheral surface of the guide hole to dispose the detent portion of the roller lifter. Thereby, this roller lifter reciprocally moves in the guide hole in response to the rotation of the cam without rotating around the axis.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In this type of lifter structure, a predetermined gap exists between the outer periphery of the lifter body and the inner wall of the guide hole to ensure a smooth reciprocating movement of the lifter body. In this case, it is known that the roller lifter swings in a nodding motion within the range of the gap with the inner wall of the guide hole due to the force received from the rotating cam, the deviation of the center of gravity caused by the detent piece, etc. When such swinging occurs, the roller lifter collides with the inner wall surface of the cylinder and generates abnormal noise.

[0005] In particular, in lifter structures like the one described in Patent Document 1, the impact point of the lifter on the inner wall of the guide hole is the edge of the opening of the anti-rotation groove, where an oil film is unlikely to form, which tends to increase the noise generated during impact.

[0006] Therefore, the purpose of this disclosure is to provide a lifter structure that can suppress the generation of abnormal noise with a simple configuration. [Means for solving the problem]

[0007] The lifter structure according to this disclosure comprises a roller lifter having a housing formed with a circular cross-section guide hole, a roller that rotatably contacts a cam, and a cylindrical lifter body that rotatably supports the roller at one end and reciprocates within the guide hole in accordance with the rotation of the cam, wherein the housing has a groove extending in the direction opposite to the cam surface of the cam on the inner wall of the guide hole and along the direction of movement of the lifter body, the roller lifter has an anti-rotation portion formed protruding from the outer circumferential surface of the lifter body in the direction opposite to the outer circumferential surface of the roller and positioned within the groove, the groove has a tolerance space that allows the anti-rotation portion to reciprocate in accordance with the reciprocating movement of the lifter body, the housing has a closing member that fills the groove, leaving at least the tolerance space, and the lifter body is slidable on a circumferential surface formed on the side of the groove located in the circumferential direction of the guide hole. [Effects of the Invention]

[0008] According to this disclosure, a lifter structure that can suppress the generation of abnormal noise can be realized with a simple configuration. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a side cross-sectional view showing the lifter structure according to Example 1. [Figure 2] Figure 2 is a cross-sectional view corresponding to line II-II in Figure 1, with some structural elements omitted. [Figure 3] Figure 3 shows a magnified view of the main parts of Figure 2. [Figure 4] Figure 4 is a side cross-sectional view showing the lifter structure according to Example 2. [Figure 5] Figure 5 is a side cross-sectional view showing the lifter structure according to Example 3. [Figure 6] Figure 6 is a side cross-sectional view showing the lifter structure according to Example 4. [Figure 7] Figure 7 is a side cross-sectional view showing a lifter structure according to another embodiment. [Modes for carrying out the invention]

[0010] [Description of Embodiments in this Disclosure] Preferred forms of this disclosure are shown below.

[0011] The groove is formed along the entire length of the guide hole, and the closing member may have an arc-shaped surface that constitutes the circumferential surface. In this case, the groove can be easily formed, and the anti-rotation portion can also be easily placed in the groove.

[0012] One end of the groove can be closed by the closing member, and the other end of the groove, opposite to the one end, can be closed by the portion of the inner wall of the guide hole having the circumferential surface. In this case, the circumferential surface can be easily formed by the inner wall of the guide hole, and the groove after the anti-rotation portion is placed can be closed by the closing member to prevent the assembled roller lifter from falling out of the guide hole.

[0013] The closing member is preferably fixed to the part that closes the guide hole. In this case, when the part that closes the guide hole is assembled to the housing, the closing member can be positioned in the groove at the same time. Therefore, the number of man-hours required for assembling the entire lifter structure can be reduced compared to when the closing member and the part that closes the guide hole are assembled to the housing separately.

[0014] In the groove, a stepped portion in a direction intersecting the extending direction is formed, and it can have a contact portion that contacts the stepped portion in a direction opposite to the insertion direction when inserted into the groove. In this case, the positioning of the closing member in the groove can be easily performed.

[0015] [Details of Embodiments of the Present Disclosure] Embodiments of the present disclosure will be described below with reference to the drawings. In the following description, for convenience, the direction of the reciprocating movement of the roller lifter described later is defined as the vertical direction. That is, for the vertical direction, the directions shown in FIGS. 1 and 4 to 7 are directly defined as upward and downward. However, the directions defined here do not limit the installation direction of the lifter structure according to the present disclosure.

[0016] <Example 1> The lifter structure 1 according to Example 1 of the present embodiment will be described with reference to FIGS. 1 to 3. The lifter structure 1 according to the present embodiment is used in the fuel supply device of the internal combustion engine shown in FIG. 1. The fuel supply device is configured by incorporating a roller lifter 20 into a lifter guide 10. The fuel supply device supplies fuel adjusted to high pressure to a combustion chamber of an engine (not shown) by the reciprocating movement of the roller lifter 20 in the vertical direction.

[0017] As shown in FIG. 1, the lifter guide 10 has a housing 11 and a pump-side housing 12. The housing 11 is formed, for example, by machining a metal sintered body. A guide hole 13 is formed in the housing 11. The guide hole 13 has a circular cross-section and extends in the vertical direction. In the case of the present embodiment, the guide hole 13 penetrates the housing 11 vertically. A roller lifter 20 that reciprocally slides in the vertical direction in accordance with the rotation of the cam 60 is inserted into the guide hole 13. The cam 60 has a cam surface 60A parallel to the rotation axis.

[0018] The pump-side housing 12 is an example of the "component that closes the guide hole" according to the present disclosure. As shown in FIG. 1, the pump-side housing 12 is assembled to the upper end of the housing 11 to close the guide hole 13 from above. A through hole 14 having a circular cross-section penetrating in the vertical direction is formed in the pump-side housing 12. A plunger 16 is inserted into the through hole 14 so as to be reciprocally movable in the vertical direction. The upper end of the plunger 16 is configured to be able to advance and retreat in a pressure chamber (not shown) communicating with the upper end of the through hole 14. When the upper end of the plunger 16 enters the pressure chamber, the fuel in the pressure chamber is pressurized.

[0019] As shown in FIGS. 1 to 3, the housing 11 has a groove 15. The groove 15 extends along the moving direction of a lifter body 30 (to be described later) of the roller lifter 20, that is, along the axial direction of the guide hole 13, on the inner wall of the guide hole 13. The groove 15 is formed in a concave cross-section that is recessed from the inner wall of the guide hole 13 in the outer peripheral direction. The groove 15 extends along the axial direction of the guide hole 13, which is the moving direction of the lifter body 30. In the case of this embodiment, the groove 15 is formed over the entire length of the guide hole 13. That is, the groove 15 penetrates the housing 11 vertically, like the guide hole 13, and the upper end and the lower end are open.

[0020] The groove 15 is formed on the inner wall of the guide hole 13 in a direction orthogonal to the rotation axis of the cam 60 in a plan view when the guide hole 13 is viewed from above, that is, in the direction facing the cam surface 60A of the cam 60. A rotation prevention portion 50 (to be described later) of the roller lifter 20 enters the groove 15 so as to be movable in the vertical direction. The groove 15 forms a space R. The space R is an example of the allowable space according to the present disclosure. The space R allows the reciprocating movement of the rotation prevention portion 50 housed in the groove 15.

[0021] [[ID=

[0022] The lifter body 30 comprises a circumferential wall 31 and a partition wall 32. The circumferential wall 31 is substantially cylindrical in shape. The circumferential wall 31 constitutes the outer casing of the lifter body 30. The circumferential wall 31 is substantially cylindrical in shape along the vertical direction. The outer circumferential surface of the circumferential wall 31 is positioned along the inner circumferential surface of the guide hole 13. The outer circumferential surface of the circumferential wall 31 slides against the inner circumferential surface of the guide hole 13 via an oil film. At its lower end, the circumferential wall 31 supports both ends of the shaft 70.

[0023] As shown in Figure 1, the partition wall 32 divides the interior of the peripheral wall 31 into upper and lower sections. The partition wall 32 is a flat plate shape along the radial direction and is integrally connected to the inner surface of the peripheral wall 31 in the vertical direction. A roller 40 is housed below the partition wall 32 in the lifter body 30. The lower end of the plunger 16, a retainer 17 (described later), and a biasing member 18 (described later) are housed above the partition wall 32 in the lifter body 30.

[0024] The roller 40 is rotatably supported on the lower end of the peripheral wall 31 via the shaft 70. In this embodiment, the roller 40 is rotatably supported on the shaft 70 via a needle bearing 72. The roller 40 may also be directly supported on the shaft 70 without the needle bearing or the like. The outer circumferential surface of the roller 40 is positioned to contact the cam 60. The cam 60 is provided on the camshaft 61 as shown in Figure 1. The cam 60 rotates counterclockwise around the axis of the camshaft 61 in the direction shown in Figure 1, causing the roller lifter 20 to reciprocate vertically by a predetermined lift amount L.

[0025] As shown in Figure 1, the anti-rotation portion 50 protrudes from the outer circumferential surface of the lifter body 30 in a direction perpendicular to the rotation axis of the roller 40 in a plan view as seen from the axial direction of the lifter body 30, that is, in the direction opposite to the outer circumferential surface of the roller 40. In this embodiment, the anti-rotation portion 50 is provided integrally with the circumferential wall 31 of the lifter body 30, and is formed by bending outward an extended piece that protrudes downward from the lower end of the circumferential wall 31. The anti-rotation portion 50 enters the groove 15 when the lifter body 30 is housed in the guide hole 13. By entering the groove 15 of the housing 11, the anti-rotation portion 50 functions as an anti-rotation device that restricts the rotation of the lifter body 30 within the guide hole 13. The anti-rotation portion 50 is designed to be displaceable in the vertical direction as the lifter body 30 moves in the vertical direction.

[0026] The retainer 17 is disc-shaped along the radial direction of the peripheral wall 31, and the lower end of the plunger 16 is locked and fixed to its center. The biasing member 18 is a spring material made of a compression coil spring, with its lower end in contact with the upper surface of the retainer 17 and its upper end in contact with the pump-side housing 12, and is elastically expandable and contractible in the vertical direction. The biasing member 18 biases the roller lifter 20 toward the cam 60 below, and applies a biasing force that presses the roller 40 against the cam 60.

[0027] As shown in Figure 1, a closing member 80, separate from the housing 11, is positioned within the groove 15. The closing member 80 fills the groove 15, leaving a space R. The closing member 80 is a long, rod-shaped member with a rectangular cross-section. As shown in Figures 2 and 3, the closing member 80 has an arc-shaped surface 81. The arc-shaped surface 81 is an arc-shaped recess on one side of the closing member 80. The curvature of the arc-shaped surface 81 is equivalent to the curvature of the inner circumferential surface of the guide hole 13. As shown in Figure 3, when the closing member 80 is positioned within the groove 15, the arc-shaped surface 81 is substantially flush with the inner circumferential surface of the guide hole 13. In other words, the arc-shaped surface 81, together with the inner circumferential surface of the guide hole 13, forms a circumferential surface on the side of the groove 15 located in the circumferential direction of the guide hole 13. In this embodiment, the closing member 80 is press-fitted and fixed within the groove 15.

[0028] The lower end 80B of the closing member 80 demarcates the upper end of space R. Specifically, the length of the closing member 80 is set such that, with its upper end 80A aligned with the upper edge of the groove 15, its lower end 80B is positioned above the reciprocating range of the anti-rotation part 50. In this way, the closing member 80 fills the groove 15, leaving the range of reciprocating movement of the anti-rotation part 50 untouched. As shown in Figure 1, the reciprocating range of the anti-rotation part 50 is the sum of the lift amount L of the cam 60 and the vertical length (thickness) t of the anti-rotation part 50. By positioning the closing member 80 in the groove 15 with its upper end 80A aligned with the upper edge of the groove 15, its lower end 80B is positioned above the reciprocating range of the anti-rotation part 50.

[0029] Next, the operation of the lifter structure 1 of Example 1 will be explained along with the assembly procedure. In the assembly of the lifter structure 1, with the housing 11 assembled to another housing (not shown) on the cam 60 side, the roller lifter 20 is assembled to the housing 11. Specifically, the position of the anti-rotation portion 50 is aligned with the position of the groove 15, and the lifter body 30 is inserted into the guide hole 13 from above the housing 11. This positions the anti-rotation portion 50 within the groove 15. In this state, the roller lifter 20 is temporarily held with the outer circumferential surface of the roller 40 in contact with the outer circumferential surface of the cam 60.

[0030] The groove 15 is formed along the entire length of the guide hole 13. Therefore, before the closing member 80 is placed, the groove 15 is open upwards, just like the guide hole 13. For this reason, in the lifter structure 1, the anti-rotation part 50 can be placed in the groove 15 by inserting it from above at the same time as inserting the roller lifter 20 into the guide hole 13. The assembly of the roller lifter 20 to the housing 11 may be performed before the housing 11 is assembled to the other housing on the cam 60 side. In this case, it is preferable to provide a means to prevent the roller lifter 20 from falling out of the housing 11, for example, by placing another closing member on the lower end side of the groove 15 (see reference numeral 480 in Figure 6).

[0031] Next, the blocking member 80 is press-fitted and fixed into the groove 15. That is, in this embodiment, when assembling the lifter structure 1, the blocking member 80 is assembled after the roller lifter 20 is assembled to the housing 11. The blocking member 80 is inserted into the groove 15 from above the housing 11. The blocking member 80 is inserted until its upper end 80A matches the upper edge of the groove 15, so that it can partition the upper end of the space R at a position above the reciprocating movement range of the anti-rotation part 50. Also, by press-fitting and fixing the blocking member 80 into the groove 15, it is possible to prevent the roller lifter 20 from coming out upward from the guide hole 13. After that, the plunger 16, retainer 17, and biasing member 18 are assembled to the upper part of the roller lifter 20, and the pump-side housing 12 is assembled to the housing 11, thereby completing the assembly of the lifter structure 1.

[0032] As shown in Figure 3, the lifter structure 1 assembled in this manner has the arc-shaped surface 81 of the closing member 80 and the inner circumferential surface of the guide hole 13 continuous and flush in the circumferential direction. As a result, an oil film is formed on the surface of the arc-shaped surface 81 that is continuous with the oil film formed on the inner circumferential surface of the guide hole 13.

[0033] Next, the operation of the lifter structure 1 of this embodiment will be described. When the cam 60 rotates around the axis of the camshaft 61, the roller 40 in the roller lifter 20 rotates in response. During the fuel intake process, the lifter body 30 is pressed by the biasing force of the biasing member 18, and the peripheral wall 31 of the lifter body 30 slides downward along the inner surface of the guide hole 13, while the plunger 16 is similarly displaced downward, causing the upper end of the plunger 16 to retract from the pressure chamber. On the other hand, during the fuel discharge process, the lifter body 30 moves upward against the biasing force of the biasing member 18, with the peripheral wall 31 sliding upward along the inner surface of the guide hole 13, while the plunger 16 is similarly displaced upward, causing the upper end of the plunger 16 to enter the pressure chamber. While the lifter body 30 moves back and forth vertically within the guide hole 13, the anti-rotation part 50 moves back and forth vertically within the groove 15 along with the lifter body 30. During this reciprocating movement, the roller lifter 20 experiences a swaying motion within the gap between it and the inner wall of the guide hole 13 due to the force it receives from the rotating cam 60 and the bias in the center of gravity caused by the anti-rotation part 50.

[0034] Here, we consider the case where the upper end (end 31A) of the peripheral wall 31 of the lifter body 30, on the side where the anti-rotation portion 50 is provided, pivots in a direction that contacts the inner circumferential surface of the guide hole 13. A groove 15 is formed on the inner circumferential surface of the guide hole 13 corresponding to this end 31A. A closing member 80 is placed in the groove 15. The closing member 80 fills the groove 15, leaving the reciprocating movement range of the anti-rotation portion 50 untouched. The closing member 80 fills the groove 15 within the range of reciprocating movement of the end 31A. On the surface of the closing member 80 on the side of the guide hole 13, an arc-shaped surface 81 is formed that is substantially flush with and continuous with the inner circumferential surface of the guide hole 13. As a result, an oil film is formed on the arc-shaped surface 81 that is continuous with the oil film formed on the inner circumferential surface of the guide hole 13. This oil film mitigates the impact of collisions caused by the pivoting of the roller lifter 20.

[0035] If the blocking member 80 is not provided, an oil film is unlikely to form on the edge of the opening of the groove 15. Therefore, the impact of collision between the roller lifter 20 and the inner circumferential surface of the guide hole 13 is not easily mitigated. In this embodiment, by placing the blocking member 80 in the groove 15, an oil film is formed on the arc-shaped surface 81 of the blocking member 80. The lifter structure 1 of this embodiment is configured to avoid the formation of oil film breaks on the inner circumferential surface of the guide hole 13, thereby mitigating the impact of collision between the roller lifter 20 and the inner circumferential surface of the guide hole 13 and suppressing the generation of abnormal noise.

[0036] As described above, the lifter structure 1 according to Embodiment 1 comprises a housing 11 and a roller lifter 20. The housing 11 forms a guide hole 13 with a circular cross-section. The roller lifter 20 has a roller 40 and a lifter body 30. The roller 40 rotatably contacts the cam 60. The lifter body 30 rotatably supports the roller 40 at one end, the lower end. The lifter body 30 is cylindrical and reciprocates within the guide hole 13 in accordance with the rotation of the cam 60. The housing 11 has a groove 15. The groove 15 extends along the direction of movement of the lifter body 30 in the direction opposite to the cam surface 60A of the cam 60 on the inner wall of the guide hole 13. The roller lifter 20 has an anti-rotation portion 50. The anti-rotation portion 50 is formed protruding from the outer circumferential surface of the lifter body 30 in the direction opposite to the outer circumferential surface of the roller 40 and is positioned within the groove 15. A space R as an allowable space is formed in the groove 15. The space R allows the anti-rotation portion 50 to reciprocate with the reciprocating movement of the lifter body 30. The housing 11 has a closing member 80. The closing member 80 fills the groove 15, leaving space R. The lifter body 30 is slidable on the circumferential surface formed on the side of the guide hole 13 where the groove 15 is located.

[0037] With this configuration, the lifter structure 1 can avoid oil film breakage caused by the groove 15 on the inner circumferential surface of the guide hole 13. Specifically, in this embodiment, an oil film continuous with the inner circumferential surface of the guide hole 13 can be formed on the arc-shaped surface 81 of the closing member 80, which faces the center side of the guide hole 13. Therefore, even if the roller lifter 20 vibrates during reciprocating movement, this oil film can mitigate the impact when the roller lifter 20 collides with the inner wall of the guide hole 13. Thus, the lifter structure 1 can suppress the generation of abnormal noise with a simple configuration.

[0038] Furthermore, the groove 15 is formed along the entire length of the guide hole 13. The closing member 80 has an arc-shaped surface 81. The arc-shaped surface 81 constitutes a circumferential surface formed on the side of the guide hole 13 where the groove 15 is located in the circumferential direction. Therefore, the lifter structure 1 allows for easy formation of the groove 15 and also facilitates the placement of the anti-rotation part 50 in the groove 15. In addition, with the above configuration, the lifter structure 1 can be assembled by inserting the roller lifter 20 into the guide hole 13 from above the housing 11, as in the conventional method. As a result, the lifter structure 1 can suppress the generation of abnormal noise without impairing the ease of assembling the roller lifter 20 to the housing 11.

[0039] <Example 2> Figure 4 shows a lifter structure 201 according to Embodiment 2 of this embodiment. Embodiment 2 differs from Embodiment 1 in that the closing member 280 is assembled to the pump-side housing 212 as a component that closes the guide hole. In the following description, the same reference numerals are used for structures that are the same as or equivalent to those in Embodiment 1, and redundant explanations are omitted.

[0040] As shown in Figure 4, the lifter guide 210 according to Embodiment 2 has a pump-side housing 212. The pump-side housing 212 has a fixing portion 212A for fixing the closure member 280. The closure member 280 is fixed to the fixing portion 212A of the pump-side housing 212 by screws B. The closure member 280 is assembled to the pump-side housing 212 before the pump-side housing 212 is assembled to the housing 11. The closure member 280 is configured such that, when assembled to the pump-side housing 212 and when the pump-side housing 212 is assembled to the housing 11, its lower end 280B can demarcate the upper end of the space R at a position above the reciprocating movement range of the anti-rotation portion 50.

[0041] The lifter structure 201 with the above configuration also provides the same functions and effects as the lifter structure 1 of Example 1. Furthermore, in the lifter structure 201, since the occluding member 280 is assembled to the pump-side housing 212, the occluding member 280 can be placed in the groove 15 at the same time as assembling the pump-side housing 212 to the housing 11. For this reason, the lifter structure 201 can reduce the assembly man-hours for the housing compared to the case where the occluding member and other parts are assembled to the housing separately, as in Example 1.

[0042] <Example 3> Figure 5 shows a lifter structure 301 according to Embodiment 3 of this embodiment. Embodiment 3 differs from Embodiment 1 in that a stepped portion 315A is formed in the groove 315, and the closing member 380 has a contact portion 380C. In the following description, the same reference numerals are used for structures that are the same as or equivalent to those in Embodiment 1, and redundant explanations are omitted.

[0043] As shown in Figure 5, the lifter guide 310 according to Embodiment 3 has a housing 311. The housing 311 forms a groove 315. A stepped portion 315A is formed in the groove 315. The stepped portion 315A is provided in the middle of the groove 315 in the vertical direction. The stepped portion 315A is formed in a stepped shape in a direction intersecting the extending direction of the groove 315. Specifically, the stepped portion 315A is formed in a stepped shape by widening the upper end side of the groove 315 in the depth direction (depth direction) compared to the lower end side. The contact portion 380C contacts the stepped portion 315A in the direction opposite to the insertion direction of the closing member 380 when the closing member 380 is inserted into the groove 315. Specifically, in this embodiment, the contact portion 380C is formed in a stepped shape by making the upper end side of the closing member 380 thicker in the depth direction than the lower end side.

[0044] In the lifter structure 301, when the closing member 380 is assembled into the groove 315, it is press-fitted into the groove 315 from above, similar to the first embodiment. At this time, the closing member 380 is press-fitted until the contact portion 380C contacts the stepped portion 315A in the groove 315. This restricts the downward displacement of the closing member 380. The upward displacement of the closing member 380 is restricted by the pump-side housing 12. Thus, the closing member 380 is positioned in the correct position in the vertical direction. That is, when the closing member 380 is assembled to the housing 311 with the contact portion 380C in contact with the stepped portion 315A in the groove 315, its lower end 380B is configured to define the upper end of the space R at a position above the reciprocating movement range of the anti-rotation portion 50.

[0045] The lifter structure 301 with the above configuration also provides the same functions and effects as the lifter structure 1 of Example 1. Furthermore, in the lifter structure 301, a stepped portion 315A is formed in the groove 315, and the closing member 380 has a contact portion 380C, which allows the closing member 380 to be easily positioned at an appropriate location within the groove 315.

[0046] <Example 4> Figure 6 shows a lifter structure 401 according to Embodiment 4 of this embodiment. Embodiment 4 differs from the above embodiment in that the groove 415 is open only at the lower end, which is one end, and is closed at the upper end, which is the other end, and the closing member 480 is located at the lower end of the groove 415. In the following description, structures that are the same as or equivalent to those in the above embodiments are denoted by the same reference numerals, and redundant explanations are omitted.

[0047] The lifter guide 410 according to Embodiment 4 has a housing 411. The housing 411 has a groove 415. The groove 415 is open only at the lower end of the housing 411, and closed at the upper end. That is, in the lifter structure 401 of Embodiment 4, no groove is formed on the inner circumferential surface of the guide hole 13 corresponding to the end portion 31A in the peripheral wall 31 of the lifter body 30. The groove 415 is closed at the upper end by a portion of the inner wall of the guide hole 13 that has a circumferential surface, and closed at the lower end by a closing member 480. As a result, an oil film is formed over the entire circumference in the circumferential direction on the inner circumferential surface of the guide hole 13 corresponding to the range of reciprocating movement of the end portion 31A, and the impact of collisions due to the swinging of the roller lifter 20 is mitigated.

[0048] In Embodiment 4, since the upper end of the groove 415 is closed, the roller lifter 20 is assembled to the housing 11 by inserting it into the guide hole 13 from below the housing 411. In this case, the roller lifter 20 must be assembled before the housing 411 is assembled to the other housing on the cam 60 side. The closing member 480 prevents the roller lifter 20 from falling out of the guide hole 13 before the housing 411 is assembled to the other housing on the cam 60 side.

[0049] In other words, the lifter structure 401 according to Example 4, similar to the above embodiments, has a groove 415 formed on the inner circumferential surface of the guide hole 13, with the upper end closed, as a means to avoid oil film breakdown caused by the groove 415. Furthermore, in order to improve ease of assembly in this case, the lifter structure 401 has a closing member 480 placed on the lower end side of the groove 415, which fills the groove 415 while leaving a space R. In this case, the closing member 480 does not have a sliding surface with the roller lifter 20. For this reason, the closing member 480 does not need to have an arc-shaped surface like the closing members in the above embodiments, and it is sufficient if it has a fall prevention function and can simply close the groove 415.

[0050] <Other examples> This disclosure is not limited to the embodiments described above and in the drawings, but also includes, for example, the following embodiments within the technical scope of this disclosure. (1) The material and shape of the closure member relating to this disclosure are not particularly limited. The closure member may be made of a metal similar to the metal used in the lifter body, lifter guide, etc. The closure member may also be made of a material with excellent elasticity such as rubber or resin. In this case, the closure member may be configured to impart elastic force to the peripheral wall of the lifter body and suppress the tilting of the lifter itself. (2) In the lifter structure according to the present disclosure, the closing member may be in the form shown in Figure 7, for example. In the lifter structure 501 shown in Figure 7, the closing member 580 has a length slightly greater in the vertical direction than the lift amount L of the cam 60. The lower end 580B of the closing member 580 is positioned above the lower end 80B of the closing member 80 in Embodiment 1. The closing member 580 is positioned in the groove 15 to fill only the range of reciprocating movement of the end portion 31A in the peripheral wall 31 of the lifter body 30. In this case as well, oil film breakdown caused by the groove 15 can be avoided. (3) The “parts for blocking guide holes” relating to this disclosure are not limited to the pump-side housings exemplified in the above embodiments. [Explanation of Symbols]

[0051] 1,201,301,401,580… Lifter structure 11,311,411… Housing 12,212… Pump-side housing (part that seals the guide hole) 13… Guide hole 15,315,415…Groove 20... Roller Lifter 30... Lifter body 50... Anti-rotation part 80, 280, 380, 480, 580… Closure members 315A...Stepped part 380C…Contact part R...Space (allowable space)

Claims

1. A housing with a circular cross-section guide hole, A roller lifter having a roller that rotatably contacts a cam, and a cylindrical lifter body that rotatably supports the roller at one end and reciprocates within the guide hole in accordance with the rotation of the cam, Equipped with, The housing has a groove in the inner wall of the guide hole that extends in the direction opposite to the cam surface of the cam, along the direction of movement of the lifter body. The roller lifter has an anti-rotation portion that is formed to protrude from the outer circumferential surface of the lifter body in a direction opposite to the outer circumferential surface of the roller and is positioned within the groove. The groove has a tolerance space that allows the anti-rotation portion to reciprocate in conjunction with the reciprocating movement of the lifter body. The housing has a closing member that fills the groove, leaving at least the allowable space, The lifter structure wherein the outer circumferential surface of the lifter body is slidable with a circumferential surface formed in the inner wall of the guide hole in the direction opposite to the cam surface of the cam.

2. The groove is formed along the entire length of the guide hole, The lifter structure according to claim 1, wherein the closing member has an arc-shaped surface that constitutes the circumferential surface.

3. The lifter structure according to claim 1, wherein one end of the groove is closed by the closing member, and the other end of the groove opposite to the one end is closed by the portion of the inner wall of the guide hole having the circumferential surface.

4. The lifter structure according to claim 1 or claim 2, wherein the closing member is fixed to the part that closes the guide hole.

5. The groove has a stepped portion formed in a direction intersecting the direction of movement of the lifter body. The lifter structure according to claim 1 or claim 2, wherein the closing member has a contact portion that abuts the stepped portion in the direction opposite to the insertion direction when inserted into the groove.

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