Pistons and engines

Abstract

To provide a piston that reduces friction loss which is generated between the piston and a cylinder.SOLUTION: A piston includes: a piston head 1 having an annular cooling channel 12 in which oil flows; a piston skirt portion 2 having a first sliding surface 21 provided on a thrust slide, a second sliding surface 22 provided on an anti-thrust side, and a projecting portion 23 forming a hole 231 to which a piston pin is inserted; a first flow passage 3 for supplying oil flowing in from the cooling channel 12 to the first slide surface 21; and a second flow passage 4 for supplying oil flowing in from the cooling channel 12 to the second slide surface 22. The piston skirt portion 2 includes: a first opening 211 in the first sliding surface 21 out of which the oil flowing in the first flow passage 3 flows; and a second opening 221 in the second sliding surface 22 out of which the oil flowing in the second flow passage 4 flows. The first opening 211 and the second opening 221 are provided on an upper side of a center N of the hole 231.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a piston and an engine. [Background technology]

[0002] Conventionally, a piston is provided in a vehicle engine. Patent Document 1 discloses a piston in which a plurality of openings through which oil in a cooling channel flows out are provided below the center of a boss hole in a first sliding surface on the thrust side and in an upper edge area of ​​a second sliding surface on the anti-thrust side. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2014-511454 Summary of the Invention [Problem to be solved by the invention]

[0004] In the case of the piston shown in Patent Document 1, the opening through which the oil in the cooling channel flows out is located below the center of the boss hole, so there is a risk of oil being insufficient in the area of ​​the piston's sliding surface where the piston is likely to apply force to the cylinder. In this case, the friction loss between the piston and the cylinder increases, causing a problem of worsening fuel efficiency.

[0005] The present invention has been made in consideration of these points, and has an object to provide a piston that can reduce friction loss occurring between the piston and the cylinder. [Means for solving the problem]

[0006] In a first aspect of the present invention, there is provided a piston accommodated in a cylinder of a vehicle engine, the piston comprising: a piston head having an annular cooling channel through which oil flows to cool the piston; and a piston skirt portion connected to an underside of the piston head, the piston skirt portion having a first sliding surface provided on a thrust side, a second sliding surface provided on an anti-thrust side, and a protrusion forming a hole into which a piston pin for connecting the piston to a connecting rod is inserted; a first flow path connected to the cooling channel for supplying the oil flowing in from the cooling channel to the first sliding surface; and a second flow path connected to the cooling channel for supplying the oil flowing in from the cooling channel to the second sliding surface, the piston skirt portion having a first opening through which the oil flowing in through the first flow path flows out to the first sliding surface, and a second opening through which the oil flowing in through the second flow path flows out to the second sliding surface, the first opening and the second opening being provided above the center of the hole.

[0007] The cooling channel may have a first region in which a lower surface slopes downward toward a position where the first flow path in the cooling channel is connected to the cooling channel, and a second region in which a lower surface slopes downward toward a position where the second flow path in the cooling channel is connected to the cooling channel.

[0008] Furthermore, the first opening may be provided in a circumferential direction of the piston within a first range having a central angle of 30° centered on the thrust direction of the first sliding surface toward both sides in the circumferential direction, and the second opening may be provided in a second range having a central angle of 30° centered on the anti-thrust direction of the second sliding surface toward both sides in the circumferential direction.

[0009] The piston head may further include an inlet portion provided on an underside of the piston head through which the oil flows into the cooling channel, and an outlet portion provided on the underside of the piston head through which the oil that has flowed through the cooling channel flows out, and in the circumferential direction, the inlet portion and the outlet portion may be provided outside the first range in which the first opening is provided and the second range in which the second opening is provided.

[0010] In a second aspect of the present invention, there is provided an engine having a piston and a cylinder housing the piston. Effect of the Invention

[0011] According to the present invention, it is possible to reduce friction loss occurring between the piston and the cylinder in the piston. [Brief description of the drawings]

[0012] [Figure 1] 3 shows the structure of a piston according to the present embodiment. [Diagram 2] The piston structure seen from the thrust side is shown. [Diagram 3] The piston structure is shown as seen from the anti-thrust side. [Figure 4] The piston head structure is shown from below. [Diagram 5] The cooling channel structure is shown as seen from the thrust side. [Figure 6] The cooling channel structure seen from the front side is shown. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] [Structure of Piston S] Fig. 1 is a diagram showing the structure of a piston S according to this embodiment. Fig. 1 is a cross-sectional view of the piston S. Fig. 2 is a diagram showing the structure of the piston S as viewed from the thrust side. Fig. 3 is a diagram showing the structure of the piston S as viewed from the anti-thrust side. Fig. 4 is a diagram showing the structure of the piston head 1 as viewed from below.

[0014] The engine (not shown) of the vehicle has a piston S and a cylinder (not shown). The piston S is housed in the cylinder. The piston S reciprocates up and down within the cylinder. The cylinder houses the piston S.

[0015] The piston S has a piston head 1 , a piston skirt portion 2 , a first flow passage 3 , and a second flow passage 4 .

[0016] The piston head 1 is provided in an upper region of the piston S. A combustion chamber of the engine is formed between the upper surface of the piston head 1 and the inner surface of the cylinder.

[0017] The piston head 1 has a ring portion 11, a cooling channel 12, an inlet portion 13, and an outlet portion 14. The ring portion 11 is a portion having a plurality of recesses in which piston rings (not shown) are housed.

[0018] The cooling channel 12 is a flow path through which oil flows to cool the piston S. As shown in FIG. 4, the cooling channel 12 is provided in an annular shape in the circumferential direction of the piston S, centered on the radial center of the piston S. The cooling channel 12 has a first region 121 and a second region 122. The first region 121 is a region on the thrust side of the annular cooling channel 12. The second region 122 is a region on the anti-thrust side of the annular cooling channel 12. The cooling channel 12 will be described in detail later.

[0019] The inlet section 13 is a portion where oil flows into the cooling channel 12. Specifically, the inlet section 13 is an opening into which the oil flows. The inlet section 13 is provided on the lower surface of the piston head 1. A nozzle (not shown) that sprays oil toward the piston S is provided below the piston S. The oil sprayed from the nozzle flows from the inlet section 13 into the cooling channel 12.

[0020] The outflow portion 14 is a portion where the oil flows out after flowing through the cooling channel 12. More specifically, the outflow portion 14 is an opening through which the oil flows out after flowing through the cooling channel 12. The outflow portion 14 is provided on the lower surface of the piston head 1. The inflow portion 13 and the outflow portion 14 will be described in detail later.

[0021] As shown in FIG. 1, the cooling channel 12 is provided at the same position as the ring portion 11 in the height direction of the piston S.

[0022] The piston skirt portion 2 is connected to the lower surface of the piston head 1. The piston skirt portion 2 has a first sliding surface 21, a second sliding surface 22, and a protruding portion 23, as shown in FIG.

[0023] The first sliding surface 21 is a sliding surface provided on the thrust side. The thrust side is a direction in which a force acts from the piston S to the cylinder as a result of the connecting rod (not shown) tilting when the piston S moves downward during the expansion stroke of the engine.

[0024] The piston skirt portion 2 has a first opening 211 on the first sliding surface 21. The first opening 211 is an opening through which the oil flowing in the cooling channel 12 flows out. Specifically, the first opening 211 is an opening through which the oil flowing in a first flow passage 3 described later flows out.

[0025] The second sliding surface 22 is a sliding surface provided on the anti-thrust side. The anti-thrust side is the side opposite to the thrust side. The piston skirt portion 2 has a second opening 221 on the second sliding surface 22. The second opening 221 is an opening through which the oil flowing in the cooling channel 12 flows out. Specifically, the second opening 221 is an opening through which the oil flowing in the second flow passage 4 described later flows out.

[0026] The protruding portion 23 forms a hole 231. The protruding portion 23 is provided between the first sliding surface 21 and the second sliding surface 22. The hole 231 is a hole into which a piston pin (not shown) is inserted. The piston pin is a component for connecting a piston to a connecting rod.

[0027] The first flow path 3 is a flow path into which oil flows from the cooling channel 12, and is a flow path for supplying the oil from the cooling channel 12 to the first sliding surface 21. The first flow path 3 is connected to the cooling channel 12. Specifically, the first flow path 3 is connected to the first region 121 of the cooling channel 12. The end of the first flow path 3 on the first opening 211 side is located lower than the end of the first flow path 3 on the side connected to the cooling channel 12. The oil that flows through the first flow path 3 flows out from the first opening 211 to the first sliding surface 21.

[0028] The second flow path 4 is a flow path into which oil from the cooling channel 12 flows, and is a flow path for supplying the oil from the cooling channel 12 to the second sliding surface 22. The second flow path 4 is connected to the cooling channel 12. Specifically, the second flow path 4 is connected to the second region 122 of the cooling channel 12. The end of the second flow path 4 on the second opening 221 side is located lower than the end of the second flow path 4 on the side connected to the cooling channel 12. The oil that has flowed through the second flow path 4 flows out from the second opening 221 to the second sliding surface 22.

[0029] 1, the first opening 211 and the second opening 221 are provided above the center N of the hole 231. Specifically, the first opening 211 and the second opening 221 are provided above the upper end of the hole 231. In the height direction of the piston S, the second opening 221 is provided at the same position as the first opening 211.

[0030] In the piston S, since the first opening 211 and the second opening 221 are thus provided above the center N of the hole 231, the oil flowing out from the first opening 211 and the second opening 221 is easily supplied to the vicinity of the position of the piston pin in the height direction of the piston S on the first sliding surface 21 and the second sliding surface 22. As a result, in the piston S, the oil is easily supplied to an area on the sliding surface of the piston S where a force is easily applied from the piston S to the cylinder. Therefore, in the piston S, the friction loss generated between the piston S and the cylinder can be reduced.

[0031] [Shape of Cooling Channel 12] Fig. 5 is a diagram showing the structure of the cooling channel 12 as viewed from the thrust side. Fig. 5(a) is a diagram showing a schematic diagram of the cooling channel 12. Fig. 5(b) is a diagram showing the state of the cooling channel 12 inside the piston S.

[0032] Fig. 6 is a diagram showing the structure of the cooling channel 12 as viewed from the front side. Fig. 6(a) is a diagram showing a schematic view of the cooling channel 12. Fig. 6(b) is a diagram showing the state of the cooling channel 12 inside the piston S.

[0033] The first region 121 is a region whose lower surface slopes downward as it approaches a position where the first flow passage 3 in the cooling channel 12 is connected to the cooling channel 12. Specifically, the first region 121 is a region whose lower surface slopes downward from both sides in the circumferential direction of the piston S as it approaches a position where the first flow passage 3 in the cooling channel 12 is connected to the cooling channel 12 from both sides.

[0034] The second region 122 is a region whose lower surface slopes downward as it approaches a position where the second flow passage 4 in the cooling channel 12 is connected to the cooling channel 12. Specifically, the second region 122 is a region whose lower surface slopes downward from both sides in the circumferential direction of the piston S as it approaches a position where the second flow passage 4 in the cooling channel 12 is connected to the cooling channel 12 from both sides.

[0035] In the piston S, the first region 121 and the second region 122 are thus provided in the cooling channel 12. The first region 121 and the second region 122 are each provided in a shape such that the first flow path 3 and the second flow path 4 are located at the deepest part of each region, so that the oil flowing through the cooling channel 12 easily flows into the first flow path 3 or the second flow path 4. As a result, in the piston S, the oil can be easily supplied to the first sliding surface 21 and the second sliding surface 22.

[0036] [Arrangement of first opening 211, second opening 221, inlet section 13, and outlet section 14] 2 and 4, the first opening 211 is provided within a first range R1 in the circumferential direction of the piston S. The first range R1 is an angular range having a central angle of 30° centered on the thrust direction of the first sliding surface 21 toward both sides in the circumferential direction of the piston S. In FIG. 2, as an example, the first opening 211 is provided at a position in the thrust direction of the first sliding surface 21.

[0037] 3 and 4, the second opening 221 is provided within a second range R2 in the circumferential direction of the piston S. The second range R2 is an angular range having a central angle of 30° from the anti-thrust direction of the second sliding surface 22 toward both sides in the circumferential direction of the piston S. In FIG. 3, as an example, the second opening 221 is provided at a position in the anti-thrust direction of the second sliding surface 22.

[0038] In the piston S, by providing the first opening 211 and the second opening 221 in such a range, oil can be suitably supplied to the vicinity of a position in the thrust direction of the first sliding surface 21 and the vicinity of a position in the anti-thrust direction of the second sliding surface 22. As a result, in the piston S, oil can be supplied to an area in the circumferential direction of the sliding surface of the piston S where force is likely to be applied from the piston S to the cylinder.

[0039] As shown in FIG. 4, in the circumferential direction of the piston S, the inlet portion 13 and the outlet portion 14 are provided outside the first range R1 in which the first opening 211 is provided and the second range R2 in which the second opening 221 is provided.

[0040] Specifically, the inlet portion 13 is provided on the anti-thrust side and the front side outside the first range R1 and the second range R2 in the circumferential direction of the piston S. The outlet portion 14 is provided on the thrust side and the rear side outside the first range R1 and the second range R2 in the circumferential direction of the piston S. The outlet portion 14 is provided in a symmetrical position with respect to the inlet portion 13 with respect to the center of the piston S in the radial direction.

[0041] In the piston S, by providing the inlet portion 13 and the outlet portion 14 in this manner, the effect of the flow of oil flowing in from the inlet portion 13 and the flow of oil flowing out from the outlet portion 14 on the flow of oil flowing out from the first opening 211 and the second opening 221 can be reduced.

[0042] [Effects of the piston S according to this embodiment] In the piston S according to this embodiment, the piston skirt portion 2 has a first opening 211 through which the oil that has flowed through the first flow passage 3 flows out on the first sliding surface 21, and a second opening 221 through which the oil that has flowed through the second flow passage 4 flows out on the second sliding surface 22. The first opening 211 and the second opening 221 are provided above the center N of the hole 231.

[0043] In the piston S, since the first opening 211 and the second opening 221 are thus provided above the center N of the hole 231, the oil flowing out from the first opening 211 and the second opening 221 is easily supplied to the vicinity of the position of the piston pin in the height direction of the piston S on the first sliding surface 21 and the second sliding surface 22. As a result, in the piston S, the oil is easily supplied to an area on the sliding surface of the piston S where a force is easily applied from the piston S to the cylinder. Therefore, in the piston S, the friction loss generated between the piston S and the cylinder can be reduced.

[0044] Although the present invention has been described above using the embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments, and various modifications and changes are possible within the scope of the gist of the present invention. For example, all or part of the device can be configured by distributing or integrating functionally or physically in any unit. In addition, new embodiments resulting from any combination of multiple embodiments are also included in the embodiments of the present invention. The effect of the new embodiment resulting from the combination combines the effect of the original embodiment. [Explanation of symbols]

[0045] S...Piston 1. Piston head 11 Ring section 12 Cooling Channel 121...1st area 122...Second area 13...Inflow part 14... Outlet section 2. Piston skirt 21...First sliding surface 211...First opening 22...Second sliding surface 221...Second opening 23...Protrusion 231...hole 3. First flow path 4...Second flow path N...center R1: First range R2: Second range

Claims

1. A piston housed within a cylinder of a vehicle engine, a piston head having an annular cooling channel through which oil flows to cool the piston; a piston skirt portion connected to a lower surface of the piston head, the piston skirt portion having a first sliding surface provided on a thrust side, a second sliding surface provided on an anti-thrust side, and a protruding portion forming a hole into which a piston pin for connecting the piston to a connecting rod is inserted; a first flow passage connected to the cooling channel for supplying the oil flowing from the cooling channel to the first sliding surface; a second flow passage connected to the cooling channel for supplying the oil flowing from the cooling channel to the second sliding surface; having the piston skirt portion has a first opening on the first sliding surface, through which the oil that has flowed through the first flow path flows out, and a second opening on the second sliding surface, through which the oil that has flowed through the second flow path flows out, The first opening and the second opening are provided above a center of the hole, The cooling channel is a first region having a lower surface that slopes downward toward a position where the first flow path in the cooling channel is connected to the cooling channel; a second region having a lower surface that slopes downward toward a position where the second flow path in the cooling channel is connected to the cooling channel; A piston having

2. The first opening is provided within a first range in a circumferential direction of the piston, the first opening being centered on a thrust direction of the first sliding surface and having a central angle of 30° on both sides in the circumferential direction, The second opening is provided within a second range in the circumferential direction, the second range having a central angle of 30° on both sides in the circumferential direction centered on the anti-thrust direction of the second sliding surface. The piston of claim 1.

3. an inlet portion provided on a lower surface of the piston head through which the oil flows into the cooling channel; an outflow portion provided on a lower surface of the piston head, through which the oil flows out after flowing through the cooling channel; and In the circumferential direction, the inlet portion and the outlet portion are provided outside the first range in which the first opening is provided and the second range in which the second opening is provided.

3. The piston of claim 2.

4. A piston according to any one of claims 1 to 3; The cylinder that houses the piston; An engine having

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