KR20100009333A - Piston pin assembly - Google Patents

Abstract

PURPOSE: A piston pin assembly is provided to decrease friction and abrasion by distributing an oil film along a minute gap formed between a bushing and a piston pin. CONSTITUTION: A piston pin assembly comprises a bushing(31) and a piston pin(36). The bushing is press-inserted into a small diameter part of a connecting rod. The piston pin is connected to a piston. The piston pin is inserted into the bushing so that a minute gap is formed between the piston pin and the bushing. The bushing has oil inlets(32a,32b) for flowing oil into the gap. Guide oil pockets(33a,33b) are formed on the inner surface of the bushing. The guide oil pocket is connected to the oil inlet. The oil flowed through the oil inlet is guided to the axial direction parallel to the insertion direction of the piston pin and to the columnar direction of the inner surface by the guide oil pocket. A plurality of first axial direction oil pockets(34a~34g) are extended to the axial direction so that the oil stays. A first columnar direction oil pocket is connected to the first axial direction oil pockets and extended to the columnar direction so that the oil stays.

Description

Piston Pin Assembly {PISTON PIN ASSEMBLY}

The present invention relates to a piston pin assembly for coupling a piston and a connecting rod, and more particularly, oil film is smoothly distributed along a minute gap formed between the piston pin and the bushing to reduce friction and wear. To a piston pin assembly.

Generally, a device for compressing gas in a cylinder, such as an internal combustion engine or a compressor, has a piston that linearly reciprocates within the cylinder. The piston is connected to the crankshaft through a connecting rod, which connects the linear reciprocating motion of the piston to the rotational movement of the crankshaft or, conversely, the rotational movement of the crankshaft to the linear reciprocating motion of the piston. The piston is rotatably coupled to the small diameter portion of the connecting rod, and a piston pin assembly is installed between the piston and the small diameter portion of the connecting rod.

The piston pin assembly consists of a bushing that is pressed into the small diameter portion of the connecting rod and a piston pin that is coupled to the piston and slidably inserted into the bushing. When the piston is linearly reciprocating, the piston pins slide relative to the bushing. Since the friction occurs between the outer circumferential surface of the piston pin and the inner circumferential surface of the bushing when the piston pin moves relative to the bushing, oil for lubrication is supplied between the piston pin and the bushing.

The conventional piston pin assembly has an oil inlet formed at the top of the bushing to supply oil between the piston pin and the bushing, and the oil groove is circumferentially or axially so that the inner circumferential surface of the bushing is adjacent to the oil inlet. Formed. The oil supplied through the oil inlet of the bushing forms an oil film at the gap between the bushing and the piston pin to lubricate and cool the heat generated between the bushing and the piston pin.

However, in the conventional piston pin assembly, even when the oil groove adjacent to the oil inlet is processed circumferentially or axially along the entire inner circumferential surface of the bushing, the supplied oil flows downward along the oil groove by gravity, so that the oil film is applied to the entire microgap. Difficult to form evenly When the piston reaches the top dead center or the bottom dead center, the oil film formed on the upper outer circumferential surface and the lower outer circumferential surface of the piston pin is destroyed by the maximum explosion pressure or inertial force, and the oil escapes in the axial direction, making it difficult to form the oil film. In addition, since most of the oil supplied through the oil inlet exits in the axial direction due to the pressure difference caused by the weight, viscosity, and inertia of the oil itself, it is difficult to form an oil film in the minute gap between the bushing and the piston pin.

Therefore, the conventional piston pin assembly has problems such as thermal wear and seizure due to local frictional heat rise and load concentration due to boundary friction or dry friction rather than fluid friction on the contact movement surface between the bushing and the piston pin. Is generated. And there is a problem that the gap between the bushing and the piston pin is expanded to deepen the occurrence of play, the life of the bushing and the piston pin is shortened, and the degradation of the lubricating oil is encouraged.

In order to solve this problem, a method of manufacturing a piston pin from a hardened heat-resistant material and using a bushing (Pb) having excellent lubricity has been proposed. However, in the case of automobile engines, the use of harmful metals such as lead (Pb) is limited, and low-viscosity engine oils such as SAE 0W-30 are used to reduce mechanical frictional losses of engines. have.

The present invention has been made to solve the above problems, by forming a plurality of oil pockets in each of the bushing and the piston pin to perform a limited rotation pendulum motion friction by making the oil film well formed in the gap between the bushing and the piston pin It is an object of the present invention to provide a piston pin assembly that can reduce loss and thermal wear.

Another object of the present invention is to provide a piston pin assembly capable of stably forming an oil film by allowing oil to temporarily stay in a gap between a bushing and a piston pin even when using low viscosity oil.

The piston pin assembly according to the present invention for achieving the above object comprises a bushing press-fitted into the small diameter portion of the connecting rod, and a piston pin is inserted into the bushing is coupled to the piston to form a gap between the bushing and The bushing has an oil inlet for introducing oil into the gap, and an inner circumferential surface of the bushing has the oil flowing through the oil inlet in an axial direction parallel to an insertion direction of the piston pin and around an inner circumferential surface of the bushing. A guide oil pocket connected to the oil inlet for circumferential direction, a plurality of first axial oil pockets axially extending to allow the oil to stay, and connected to the plurality of first axial oil pockets It characterized in that the first circumferential oil pocket is formed extending in the circumferential direction so that it can stay.

In the present invention, the outer peripheral surface of the piston pin is connected to the plurality of second axial oil pocket and the plurality of second axial oil pocket axially extended so that the oil can stay and the oil can stay A second circumferential oil pocket may be formed so as to extend in the circumferential direction.

In the present invention, the oil inlet is formed on the upper portion of the bushing, the guide oil pocket is formed on the upper inner peripheral surface of the bushing, the plurality of first axial oil pocket and the first circumferential oil pocket is And a plurality of second axial oil pockets and the second circumferential oil pockets are formed on the upper circumferential surface of the piston pin.

The piston pin assembly according to the present invention for achieving the above object comprises a bushing press-fitted into the small diameter portion of the connecting rod, and a piston pin is inserted into the bushing is coupled to the piston to form a gap between the bushing and The bushing has an oil inlet for introducing oil into the gap, and an inner circumferential surface of the bushing has the oil flowing through the oil inlet in an axial direction parallel to an insertion direction of the piston pin and around an inner circumferential surface of the bushing. A guide oil pocket connected to the oil inlet for circumferential direction, a first axial oil pocket axially extended to allow the oil to stay, a plurality of obliquely extending along the circumferential direction to allow the oil to stay A first inclined oil pocket is formed.

In the present invention, the outer circumferential surface of the piston pin is a second axial oil pocket axially extended so that the oil can stay and a plurality of second inclined type inclined along the circumferential direction so that the oil can stay An oil pocket may be formed.

The piston pin assembly according to the present invention for achieving the above object comprises a bushing press-fitted into the small diameter portion of the connecting rod, and a piston pin is inserted into the bushing is coupled to the piston to form a gap between the bushing and The bushing has an oil inlet for introducing oil into the gap, and a plurality of axial oil pockets extending in the axial direction to allow the oil to stay in the gap on the upper outer circumferential surface of the piston pin. And a circumferential oil pocket connected to the plurality of axial oil pockets and extending in the circumferential direction so that the oil can stay therein.

The piston pin assembly according to the present invention facilitates the formation of an oil film in the minute gap between the bushing and the piston pin while the oil supplied to the plurality of oil pockets processed on the inner surface of the bushing and the outer surface of the piston pin temporarily stays. Therefore, it is possible to reduce problems such as thermal abrasion at the sliding friction contact surface between the bushing and the piston pin, friction loss due to scissor phenomenon, and shortened life.

In addition, the piston pin assembly according to the present invention has the effect of reducing the friction between the piston and the connecting rod improves the efficiency of the entire apparatus using the same, and the occurrence of noise and vibration.

Hereinafter, a piston pin assembly according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 is a schematic view showing a piston-connecting rod assembly to which a piston pin assembly according to an embodiment of the present invention is applied, and FIG. 2 is a front sectional view schematically showing a piston pin assembly according to an embodiment of the present invention.

As shown in FIG. 1, the piston pin assembly 30 according to an embodiment of the present invention supports a bushing 31 press-fitted to a small diameter portion 21 of the connecting rod 20 and a piston 10. Or a piston pin 36 fixed and inserted into the inner circumferential surface of the bushing 31. The oil O is supplied between the inner circumferential surface of the bushing 31 and the outer circumferential surface of the piston pin 36 through a pair of oil supply ports 22a and 22b formed in the small diameter portion 21, and the piston 10 is In the linear reciprocating motion, an oil film is formed between the bushing 31 and the piston pin 36 while the bushing 31 and the piston pin 36 have limited rotational friction pendulum motions.

As shown in FIG. 2, a pair of oil inlets 32a and 32b corresponding to the pair of oil inlets 22a and 22b formed in the small diameter portion 21 is formed on the upper portion of the bushing 10. It is. The oil O supplied through the oil inlets 22a and 22b enters the gap 39 between the bushing 31 and the piston pin 36 through these pairs of oil inlets 32a and 32b. do. The oil introduced into the gap 39 is formed with a plurality of first axial oil pockets 34a, 34b, 34c, 34d, 34e, 34f, 34g and piston formed on the lower inner circumferential surface of the bushing 31. Flows into the second axial oil pockets 37a, 37b, 37c, 37d and 37e formed on the upper outer circumferential surface of the fin 36 to temporarily stay and form an oil film.

As shown in FIGS. 3 and 4, the bushing 31 has a ring shape extending in the direction in which the piston pin 36 is inserted, and a pair of oil supply holes 22a of the connecting rod 20 ( It has a pair of oil inlets 32a and 32b corresponding to 22b). A pair of guide oil pockets 33a and 33b connected to the pair of oil supply ports 22a and 22b are formed on the upper inner circumferential surface of the bushing 31. The guide oil pockets 33a and 33b have an X shape, and the oil O flowing through the oil inlets 32a and 32b is axially and bushing parallel to the direction in which the piston pin 36 is inserted. Flow in the circumferential direction around the inner circumferential surface of (31) to be evenly distributed on the inner circumferential surface of the bushing (31). In addition, a plurality of first axial oil pockets 34a, 34b, 34c, 34d, 34e, 34f, 34g are formed on the lower inner circumferential surface of the bushing 31 in parallel with the insertion direction of the piston pin 36. And a pair of first circumferential oil pockets 35a and 35b are formed. The plurality of first axial oil pockets 34a, 34b, 34c, 34d, 34e, 34f, 34g may be arranged at equal or boiling intervals, and each width may be variously changed. have.

The oil flowing into the gap 39 through the pair of oil inlets 32a and 32b flows downward by gravity and is provided with a plurality of first axial oil pockets 34a, 34b, 34c and 34d. The oil film is formed while temporarily staying at (34e) (34f) and (34g). One end and the other end of each of the plurality of first axial oil pockets 34a, 34b, 34c, 34d, 34e, 34f, 34g is a pair of first circumferential oil pockets 35a, 35b. Are connected to each other, whereby the oil O can be evenly distributed in the plurality of first axial oil pockets 34a, 34b, 34c, 34d, 34e, 34f, 34g.

In the present invention, the pair of oil inlets 32a and 32b may be formed at a position other than the top of the bushing 31 according to the oil supply ports 22a and 22b forming position of the connecting rod 20. have. The shape of the guide oil pockets 33a and 33b is not limited to the X-shape, but may be changed into various shapes connected to the oil supply ports 22a and 22b. Also, the number and formation positions of the first axial oil pockets 34a, 34b, 34c, 34d, 34e, 34f, 34g, the number and formation of the first circumferential oil pockets 35a, 35b. The location can also vary.

As shown in FIGS. 5 and 6, a plurality of second axial oil pockets 37a, 37b, 37c and 37d in which oil O may temporarily stay on the upper outer circumferential surface of the piston pin 36. ) 37e and a pair of second circumferential oil pockets 38a and 38b are formed. The plurality of second axial oil pockets 37a, 37b, 37c, 37d, 37e may be arranged at equal intervals or boiling intervals, and the respective widths may be variously changed. In FIG. 2, among the plurality of second axial oil pockets 37a, 37b, 37c, 37d and 37e, the second axial oil pocket 37c positioned at the center of the upper circumferential surface of the piston pin 36 is different. The width of the second axial oil pockets 37a, 37b, 37c, 37d and 37e may be variously changed. The oil O introduced through the oil inlets 32a and 32b of the bushing 31 is provided with a plurality of second axial oil pockets 37a, 37b, 37c, 37d and 37e and a pair of agents. 2 Temporarily stays in the circumferential oil pockets 38a and 38b to form an oil film. One end and the other end of each of the plurality of second axial oil pockets 37a, 37b, 37c, 37d, 37e is connected to each other by a pair of second circumferential oil pockets 38a, 38b, As a result, the oil O may be evenly distributed in each of the plurality of second axial oil pockets 37a, 37b, 37c, 37d, and 37e. In the present invention, the number and forming positions of the second axial oil pockets 37a, 37b, 37c, 37d and 37e, and the number and forming positions of the second circumferential oil pockets 38a and 38b are It can be changed in various ways.

Piston pin assembly 30 according to an embodiment of the present invention having such a configuration as shown in Figure 2, the oil O to the gap 39 through a pair of oil inlets (32a, 32b) When introduced, the introduced oil O flows and spreads in the axial direction and the circumferential direction along the pair of guide oil pockets 33a and 33b. The oil O flowing in the axial direction along the pair of guide oil pockets 33a and 33b does not escape out of the gap 39 but is formed in the plurality of second axial directions on the upper outer circumferential surface of the piston pin 36. Oil pockets 37a, 37b, 37c, 37d, 37e and a pair of second circumferential oil pockets 38a, 38b are filled and filled. Therefore, an oil film is formed in the gap 39 between the upper inner circumferential surface of the bushing 31 and the upper outer circumferential surface of the piston pin 36 to reduce friction between the bushing 31 and the piston pin 36.

In addition, the oil O exiting the second axial oil pockets 37a, 37b, 37c, 37d, 37e and the second circumferential oil pockets 38a, 38b of the piston pin 36. The silver flows down and the first circumferential oil pockets 35a and 35b of the bushing 31 and the first axial oil pockets 34a, 34b, 34c, 34d, 34e and 34f ( 34g) into the filling. Accordingly, an oil film is formed in the gap 39 between the lower inner circumferential surface of the bushing 31 and the lower outer circumferential surface of the piston pin 36 to reduce friction between the bushing 31 and the piston pin 36.

In addition, the piston pin assembly 30 according to an embodiment of the present invention is difficult to escape to the outside even if the oil O introduced into the gap 39 flows along the axial direction. In the upper gap 39, the oil O is blocked by the second circumferential oil pockets 38a and 38b of the piston pin 36, and in the lower gap 39, the oil O is bushing 31. This is because it is blocked by the first circumferential oil pockets 35a and 35b. Therefore, the flow of oil (O) in the fine gap 39 between the bushing 31 and the piston pin 36 is suppressed to facilitate the formation of an oil film. Therefore, the friction between the bushing 31 and the piston pin 36 during the linear reciprocation of the piston 10 is greatly reduced.

7 to 9 show the bushing and the piston pin of the piston pin assembly according to another embodiment of the present invention. As shown in FIGS. 7 and 8, the bushing 40 of the piston pin assembly according to another embodiment of the present invention is a pair corresponding to a pair of oil supply ports 22a and 22b of the connecting rod 20. Oil inlets 32a, 32b. The upper inner circumferential surface of the bushing 40 has a pair of connected to the pair of oil inlets 22a and 22b for guiding the oil flowing through the oil inlets 22a and 22b in the axial and circumferential directions. Guide oil pockets 33a and 33b are formed.

The lower inner circumferential surface of the bushing 40 has a first axial oil pocket 41 and a plurality of first inclined oil pockets 42a along the circumferential direction to the left and right of the first axial oil pocket 41. ) 42b, 42c, 42d, 42e, 42f, 42g and 42h are formed. The plurality of first inclined oil pockets 42a, 42b, 42c, 42d, 42e, 42f, 42g, 42h may be arranged at equal or boiling intervals, and the first axial oil pocket It can be arranged symmetrically or asymmetrically about (41). The plurality of first inclined oil pockets 42a, 42b, 42c, 42d, 42e, 42f, 42g and 42h are oils introduced through the pair of oil inlets 32a and 32b. Partially block O) from leakage in the axial direction. Some of the oil O introduced into the gap 39 is the first axial oil pocket 41 and the plurality of first inclined oil pockets 42a, 42b, 42c, 42d, 42e and 42f. By temporarily staying at (42g) (42h), an oil film is formed between the lower inner peripheral surface of the bushing 40 and the lower outer peripheral surface of the piston pin 43.

9 and 10, the upper circumferential surface of the piston pin 43 has a second axial oil pocket 44 formed in the longitudinal direction of the piston pin 43 and a second axial oil pocket 44. A plurality of second inclined oil pockets 45a, 45b, 45c, 45d, 45e, 45f, 45g, 45h formed along the circumferential direction are formed on the left and right sides of. The plurality of second inclined oil pockets 45a, 45b, 45c, 45d, 45e, 45f, 45g, 45h may be arranged at equal or boiling intervals, and the second axial oil pocket It may be arranged symmetrically or asymmetrically about 44. The plurality of second inclined oil pockets 45a, 45b, 45c, 45d, 45e, 45f, 45g, and 45h are oils introduced through a pair of oil inlets 32a and 32b. Shut off some leakage in the axial direction of O). Some of the oil O introduced into the gap 39 is the second axial oil pocket 44 and the plurality of second inclined oil pockets 45a, 45b, 45c, 45d, 45e and 45f. By temporarily staying at 45g and 45h, an oil film is well formed between the upper inner peripheral surface of the bushing 40 and the upper outer peripheral surface of the piston pin 43.

Figure 11 shows a piston pin assembly according to another embodiment of the present invention. As shown in FIG. 11, the piston pin assembly 50 according to another embodiment of the present invention includes a bushing 51 and a piston pin 36. Since the piston pin 36 is the same as that shown in FIGS. 5 and 6, a detailed description of the piston pin 36 is omitted.

The bushing 51 is similar to the bushing 51 shown in FIGS. 3 and 4, but has one oil inlet 52 and one guide oil pocket 53. 12 and 13, a guide oil pocket 53 is formed on the upper inner circumferential surface of the bushing 51 to guide oil introduced into the oil inlet 52 in the axial direction and the circumferential direction. The lower inner circumferential surface of the 51 has a pair of first circumferential oil pockets 35a and 35b and a pair of first circumferential oil pockets 35a and 35b to prevent oil O from escaping along the axial direction. A plurality of first axial oil pockets 34a, 34b, 34c, 34d, 34e, 34f and 34g are formed. Since the operations of the first circumferential oil pockets 35a and 35b and the plurality of first axial oil pockets 34a, 34b, 34c, 34d, 34e, 34f and 34g are the same as described above Detailed description thereof will be omitted.

As described above, the piston pin assembly according to the present invention includes a plurality of oil pockets formed on the outer circumferential surface of the piston pin and a plurality of oil pockets in which oil introduced into the gap between the bushing and the piston pin is formed on the inner circumferential surface of the bushing. By temporarily staying, the amount of oil axially exiting the gap is reduced and oil film is well formed in the gap between the bushing and the piston pin. Therefore, the friction between the bushing and the piston pin is greatly reduced.

The present invention described above is not limited to the configuration and operation as shown and described. That is, the present invention can be variously changed and modified within the spirit and scope of the claims described.

1 schematically shows a piston-connecting rod assembly to which a piston pin assembly according to an embodiment of the present invention is applied.

Figure 2 is a front sectional view schematically showing a piston pin assembly according to an embodiment of the present invention.

Figure 3 is a perspective view schematically showing a bushing of the piston pin assembly according to an embodiment of the present invention.

Figure 4 is a development view showing the inner peripheral surface of the bushing of the piston pin assembly according to an embodiment of the present invention.

Figure 5 is a perspective view schematically showing a piston pin of the piston pin assembly according to an embodiment of the present invention.

6 is an exploded view showing the outer peripheral surface of the piston pin of the piston pin assembly according to an embodiment of the present invention.

7 is a perspective view schematically showing a bushing of a piston pin assembly according to another embodiment of the present invention.

8 is an exploded view showing the inner peripheral surface of the bushing of the piston pin assembly according to another embodiment of the present invention.

9 is a perspective view schematically showing the piston pin of the piston pin assembly according to another embodiment of the present invention.

10 is an exploded view showing the outer peripheral surface of the piston pin of the piston pin assembly according to another embodiment of the present invention.

11 is a front sectional view schematically showing a piston pin assembly according to another embodiment of the present invention.

12 is a perspective view schematically showing a bushing of a piston pin assembly according to another embodiment of the present invention.

Figure 13 is an exploded view showing the inner peripheral surface of the bushing of the piston pin assembly according to another embodiment of the present invention.

<Description of the symbols for the main parts of the drawings>

10: piston 20: connecting rod

22a, 22b: oil supply port 30: piston pin assembly

31 bushing 32a, 32b oil inlet

33a, 33b: guide oil pocket

34a, 34b, 34c, 34d, 34e, 34f, 34g: first axial oil pocket

35a, 35b: first circumferential oil pocket

36: piston pin

37a, 37b, 37c, 37d, 37e: second axial oil pocket

38a, 38b: second circumferential oil pocket

39: gap

42a, 42b, 42c, 42d, 42e, 42f, 42g, 42h: first inclined oil pocket

45a, 45b, 45c, 45d, 45e, 45f, 45g, 45h: second inclined oil pocket

Claims (6)

A piston pin assembly comprising a bushing press-fitted into a small diameter portion of a connecting rod, and a piston pin coupled to a piston and inserted into the bushing to form a gap between the bushing. The bushing has an oil inlet for introducing oil into the gap, and the inner circumferential surface of the bushing has the oil flowing through the oil inlet in the axial direction parallel to the insertion direction of the piston pin and the circumference around the inner circumferential surface of the bushing. A guide oil pocket connected to the oil inlet for guiding direction, a plurality of first axial oil pockets extending axially to allow the oil to stay, connected to the plurality of first axial oil pockets and the oil A piston pin assembly, characterized in that the first circumferential oil pocket extending in the circumferential direction so that it can stay. The method of claim 1, The circumferential surface of the piston pin is connected to the plurality of second axial oil pockets and the plurality of second axial oil pockets extending in the axial direction so that the oil can stay and extend in the circumferential direction so that the oil can stay And a second circumferential oil pocket formed therein. The method of claim 2, The oil inlet is formed on the upper portion of the bushing, the guide oil pocket is formed on the upper inner peripheral surface of the bushing, the plurality of first axial oil pocket and the first circumferential oil pocket on the lower inner peripheral surface of the bushing And the plurality of second axial oil pockets and the second circumferential oil pockets are formed on an upper circumferential surface of the piston pin. A piston pin assembly comprising a bushing press-fitted into a small diameter portion of a connecting rod, and a piston pin coupled to a piston and inserted into the bushing to form a gap between the bushing. The bushing has an oil inlet for introducing oil into the gap, and the inner circumferential surface of the bushing has the oil flowing through the oil inlet in the axial direction parallel to the insertion direction of the piston pin and the circumference around the inner circumferential surface of the bushing. A guide oil pocket connected to the oil inlet for guiding in a direction, a first axial oil pocket axially extended to allow the oil to stay, and a plurality of agents that are inclined along the circumferential direction so that the oil can stay Piston pin assembly, characterized in that the inclined oil pocket is formed. The method of claim 4, wherein On the outer circumferential surface of the piston pin is formed a second axial oil pocket extending in the axial direction so that the oil can stay and a plurality of second inclined oil pockets inclined along the circumferential direction so that the oil can stay Piston pin assembly, characterized in that. Piston pin assembly, characterized in that formed. A piston pin assembly comprising a bushing press-fitted into a small diameter portion of a connecting rod, and a piston pin coupled to a piston and inserted into the bushing to form a gap between the bushing. The bushing has an oil inlet for introducing oil into the gap, and a plurality of axially extending on the upper outer circumferential surface of the piston pin so as to allow the oil to stay between the bushing and the piston pin to facilitate oil formation. And a circumferential oil pocket circumferentially extending in the circumferential direction so that the oil can stay in contact with the axial oil pocket and the plurality of axial oil pockets.

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