JP4163459B2 - Oil passage structure of engine crankshaft - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  According to the present invention, both ends of a crankpin are press-fitted into both crank arms integrally connected to a pair of first and second journal portions to form a crank portion, and the first and second journal portions are supported by the crankcase. In addition, the present invention relates to an oil passage structure for an engine-assembled crankshaft in which a crank portion is accommodated in a crankcase of a crankcase.
[0002]
[Prior art]
  2. Description of the Related Art Conventionally, in an assembly crankshaft of an engine, in order to connect an axial oil hole provided in a journal part to an oil supply hole opened on the outer peripheral surface of the crankpin, an oblique communication hole is drilled from the journal part to the crankpin. It is known. (For example, refer to Japanese Utility Model Publication No. 56-29204).
[0003]
[Problems to be solved by the invention]
  In an engine-assembled crankshaft, needle bearings and connecting rods are assembled into the crankpin before assembly. Therefore, before assembly, the upstream and downstream portions of the diagonal communication holes are connected to the journal and crankpin sides. If each hole is drilled, it is necessary to align the upstream portion and the downstream portion of the communication hole when assembling the crank pin into the crank arm, which is troublesome. If an oblique communication hole is drilled from the journal portion to the crankpin after assembly, it is necessary to provide troublesome means for preventing chips from adhering to the needle bearing.
[0004]
  The present invention has been made in view of such circumstances, and enables oil to be supplied from the oil hole of the journal portion to the oil supply hole of the crank pin without forming an oblique communication hole. The purpose of the present invention is to provide an oil passage structure for an assembly-type crankshaft of an engine that eliminates the need for alignment of oil passages during assembly and drilling after assembly, and also enables foreign substances to be separated from the passing oil. And
[0005]
[Means for Solving the Problems]
  To achieve the above object, according to the present invention, the crank portion is constructed by press-fitting both end portions of the crank pin into both crank arms integrally connected to the paired first and second journal portions. In an engine-assembled crankshaft in which the journal part is supported by the crankcase and the crank part is housed in the crankcase of the crankcase.An oil reservoir chamber is provided in the crankcase for isolation from the crank chamber;The crank pin is formed with a hollow portion that is open to the crank chamber, and an oil supply hole that communicates with the hollow portion on the outer peripheral surface of the crank pin is formed in the crank pin, so that at least one of the first and second journal portions is formed. IsAboveAn oil hole communicating with the oil sump chamber and opening adjacent to one end surface of the crank portion is formed.A delivery tray that delivers oil from the oil hole to the hollow part is attached to one end of the crank part, andIn this oil hole,Open and close based on the pressure pulsation of the crank chamber acting through the hollow portion;It is equipped with a check valve that allows oil flow in one direction to the crank side.The delivery plate is fitted into an annular positioning recess whose large diameter portion is formed on one end surface of the crank portion, and the small diameter portion elastically contacts the inner end surface of the bearing supporting the one journal portion. And saidA foreign substance reservoir was installed in the delivery tray to hold foreign matter that was centrifuged from oil in the delivery tray during rotation of the crankshaft.SpecialIt is a sign.
[0006]
  ThisSpecialAccording to the feature, a transfer tray that transfers oil from the oil hole of the journal portion to the hollow portion of the crank pin is attached to one end of the crank portion, and oil is contained in the transfer tray in the transfer tray while the crankshaft is rotating. Since a foreign substance reservoir is provided to hold the foreign substances that have been centrifuged from the outside, the oil passing through the inside of the transfer tray that rotates together with the crankshaft is rotated while the engine is running. The foreign matter is centrifuged, and the foreign matter is held in the foreign matter reservoir that spreads radially outward from the hollow portion of the crankpin, and the purified oil can be supplied to the crankpin side.NIt can contribute to improvement of durability.
[0007]
  AlsoAn oil reservoir chamber is provided in the crankcase to isolate it from the crank chamber,The crank pin is formed with a hollow portion that is open to the crank chamber, and an oil supply hole that communicates with the hollow portion on the outer peripheral surface of the crank pin is formed in the crank pin, so that at least one of the first and second journal portions is formed. BeforeRecordAn oil hole communicating with the oil storage chamber and opening adjacent to one end face of the crank portion is formed.Open and close based on the pressure pulsation of the crank chamber acting through the hollow portion;Since a check valve that allows unidirectional oil flow to the crank side is installed, the pressure pulsation in the crank chamber acts on the check valve through the hollow part of the crank pin and opens and closes it during engine operation. As a result, the oil stored in the oil reservoir chamber is sucked into the crank chamber intermittently through the oil holes in the journal portion, the transfer tray and the hollow portion of the crank pin in order, and the journal bearings facing the crank chamber are lubricated.TheA part of the oil passing through the hollow portion of the rank pin can be lubricated around the crank pin through the oil supply hole.In other words, by utilizing the pumping action caused by the pulsation of the crank chamber, the oil stored in the oil sump chamber can be circulated to various parts of the engine without using a special oil pump. Can be reduced.
[0008]
  In particular, oil that is intermittently drawn into the crank chamber can be scattered by centrifugal force when leaving the rotating crankshaft to create an oil mist for lubrication, eliminating the need for an oil slinger for oil mist generation. Simplification of the structure can be achieved by reducing the number of parts.
[0009]
  In addition, when the engine is stopped, the check valve closes and the oil hole in the journal section is shut off, so even when the engine is placed at a large angle, such as when the engine is stored, Oil can also be prevented from flowing into the crank chamber.
[0010]
  MaTheThe delivery plate is fitted into an annular positioning recess whose large diameter portion is formed on one end surface of the crank portion, and the small diameter portion elastically contacts the inner end surface of the bearing supporting the one journal portion.Because I tried to, The delivery tray can be easily and accurately attached to one end of the crank portion without using a special fixing member.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
  Embodiments of the present invention will be described below on the basis of preferred embodiments of the present invention shown in the accompanying drawings.
[0012]
  1 is a longitudinal plan view of a 4-cycle engine for a power working machine according to an embodiment of the present invention, FIG. 2 is a sectional view taken along line 2-2 of FIG. 1, FIG. 3 is a sectional view taken along line 3-3 of FIG. 4A is a sectional view taken along line 4A-4A in FIG. 3, FIG. 4B is a sectional view taken along line 4B-4B in FIG. 3, FIG. 5 is a sectional view taken along line 5-5 in FIG. 7 is a cross-sectional view taken along the line 7-7 in FIG. 3, FIG. 8 is a view corresponding to FIG. 1, showing a reference example of the present invention, FIG. 9 is a cross-sectional view taken along the line 9-9 in FIG. 10 is a cross-sectional view taken along line 10-10, and FIG. 11 is a cross-sectional view taken along line 11-11 in FIG.
[0013]
  First, the embodiment of the present invention shown in FIGS. 1 to 7 will be described.
[0014]
  1 to 3, a four-cycle engine E installed on an engine bed B of a power working machine includes a crankcase 1 and a cylinder block 2 coupled to the front end of the crankcase 1 in a forward tilt posture. The cylinder head 3 is integrally formed on the head of the cylinder block 2.
[0015]
  The crankcase 1 is composed of left and right first and second case halves 1a and 1b which are joined at a joint surface P perpendicular to an axis of a crankshaft 5 which will be described later and define a crank chamber 4 therebetween. The crank part 1c of the crankshaft 5 is accommodated in the chamber 4, and the first and second journal parts 5a, 5b at the left and right ends of the crankshaft 5 are formed by opposing side walls of the first and second case halves 1a, 1b. It is supported via first and second ball bearings 6a, 6b. An oil seal 7a that is in close contact with the outer peripheral surface of the first journal portion 5a of the crankshaft 5 is mounted on the side wall of the first case half 1a adjacent to the outside of the first ball bearing 6a. The second ball bearing 6b is configured with a seal.
[0016]
  A side cover 8 is joined to the outer surface of the second case half 1 b, and a first valve operating chamber 9 a is defined between the second case half 1 b and the side cover 8. One end of the crankshaft 5 passes through the side cover 8 across the first valve operating chamber 9a and extends to the outside, and an oil seal 7b that is in close contact with the outer peripheral surface of the one end is attached to the side cover 8. Is done.
[0017]
  A head cover 10 that defines a second valve operating chamber 9b is joined to the front end of the cylinder head 3 so as to communicate with the first and second valve operating chambers 9a and 9b. , 9c are provided in the cylinder block 2.
[0018]
  Crank pin 5 of the crank part 1cp isThe piston 11 sliding in the cylinder bore 1a is connected via a connecting rod 12, and a needle bearing 17 is interposed between the crank pin 5p and the large end of the connecting rod 12.
[0019]
  The cylinder head 3 is formed with an intake port 14i and an exhaust port 14e that open to the combustion chamber 13 inside thereof, and these ports 14i, 14eAn intake valve 15i and an exhaust valve 15e are attached to open and close the valve, and a valve mechanism 19 for opening and closing the intake and exhaust valves 15e and 15e is provided from the first valve chamber 9a to the second valve chamber 9b. .
[0020]
  That is, the first valve chamber 9a includes a drive timing gear 20 formed on the crankshaft 5, a cam shaft 22 rotatably supported at both ends by the second case half 1b and the side cover 8, and the cam. A driven timing gear 21 formed on the shaft 22 and driven at a reduction ratio of 1/2 from the driving timing gear 20, a cam follower shaft 23 supported at both ends by the first case half 1a and the side cover 8, A pair of cam followers 24i and 24e, which are swingably supported by the cam follower shaft 23 and are slidably engaged with the intake cam 22i and the exhaust cam 22e of the cam shaft 22, are disposed. Further, the second valve chamber 9b is supported by valve springs 25i and 25e for urging the intake valve 15i and the exhaust valve 15e in the valve closing direction and the cylinder head 3, respectively, and each end thereof is connected to the intake valve 15i. And a pair of rocker arms 26i, 26e that are in contact with the upper end of the exhaust valve 15e. A pair of push rods 27i, 27e connecting the other ends of the rocker arms 26i, 26e and the cam followers 24i, 24e are disposed in the rod passages 5c, 5c.
[0021]
  Accordingly, when the crankshaft 5 rotates, the camshaft 22 is driven to decelerate via the drive timing gear 20 and the driven timing gear 21, and the intake cam 22i and the exhaust cam 22e of the camshaft 22 are pushed via the cam followers 24i and 24e. When the rods 27i and 27e are respectively pushed up, the intake valve 15i and the exhaust valve 15e are opened, and when the intake cam 22i and the exhaust cam 22e allow the push rods 27i and 27e to be lowered, the intake valve 15i and the exhaust valve 15e are respectively It closes with the urging | biasing force of valve spring 25i, 25e.
[0022]
  In FIG. 1 to FIG. 4A, the crank chamber 4 in the crankcase 1 is formed in a cylindrical shape with a minimum volume subordinate to the rotation trajectory of the crankshaft 5 so as not to store lubricating oil, and surrounds the crank chamber 4. U-shaped recesses 28a and 28b are formed on the joint surfaces of the first and second case halves 1a and 1b, respectively, and the first oil sump chamber 28 is constituted by these recesses 28a and 28b. The recesses 28a and 28b are formed together with the crank chamber 4 when the first and second case halves 1a and 1b are cast.
[0023]
  Further, the first valve chamber 9a between the second case half 1b and the side cover 8 is also formed to a minimum volume so as not to store lubricating oil, and concave portions 29a and 29b surrounding the first valve chamber 9a are provided. The second oil reservoir chamber 29 is formed by the concave portions 29a and 29b formed on the joint surface of the second case half 1b and the side cover 8. The recesses 29a and 29b are formed together with the first valve operating chamber 9a when the second case half 1b and the side cover 8 are cast.
[0024]
  A plurality of through holes 30 are provided in the second case half 1b so that the first and second oil sump chambers 28 and 29 communicate with each other. The oil reservoirs 28 and 29 store the lubricating oil O up to a level higher than that of the first and second journal portions 5a and 5b of the crankshaft 5.
[0025]
  As shown in FIGS. 3, 4B and 6, the side cover 8 is formed with an annular oil passage 31 surrounding the second journal portion 5b of the crankshaft 5 inside the oil seal 7b. Is communicated via a rising oil passage 34 to a supply small chamber 33 connected to the lower portion of the first oil sump chamber 28 via an outlet hole 32. The outlet hole 32 is formed in the second case half 1 b, and the supply chamber 33 and the rising oil passage 34 are formed between the joint surfaces of the second case half 1 b and the side cover 8.
[0026]
  The crankshaft 5 is an assembly type in which a crank portion 5c is configured by press-fitting both ends of a hollow crankpin 5p into both crank arms with a balance weight, which are integrally connected to the first and second journal portions 5a and 5b. An oil hole 35 is formed in the second journal portion 5b. One end of the oil hole 35 opens to the annular oil passage 31, and the other end opens to the inner end of the inner race of the second ball bearing 6b. The oil is transferred from the oil hole 35 to the hollow portion 36 of the crank pin 5p. Crank part with delivery weight 37 with balance weight5It is attached to one end of c. That is, when the first and second case halves 1a and 1b are joined, the transfer tray 37 is fitted with a shallow annular positioning recess 43 formed on one end face of the crank portion 5c. The small diameter portion is compressed and deformed in the axial direction and set so as to elastically contact the inner end surface of the inner race of the second ball bearing 5b. In this way, the delivery tray 37 can be easily and accurately attached to one end of the crank portion 5c without using a special fixing member.
[0027]
  An oil supply hole 38 for supplying oil from the hollow portion 36 to the needle bearing 17 between the crankpin 5p and the connecting rod 12 is formed in the crankpin 5p. The oil hole 35 is provided with a check valve 39 that allows a fluid flow in one direction from the annular oil passage 31 to the transfer tray 37 side.
[0028]
  An annular foreign matter reservoir 40 that extends radially outward from the hollow portion 36 of the crankpin 5p is provided inside the delivery tray 37.
[0029]
  Figure14A, the bottom of the crank chamber 4 extends in the axial direction.RuA groove 4a is formed, and a through-hole 41 is formed in the second case half 1b through which the groove 4a communicates with an extension 9a 'extending below the first valve operating chamber 9a. A reed valve 42 is attached to the second case half 1b to allow fluid to flow in one direction from the crank chamber 4 to the first valve operating chamber 9a.
[0030]
  1, 3 and 7, the cylinder block 2 is provided with a recovery hole 45 which opens at the lower part of the second valve chamber 9 b, and the first oil sump chamber 28 extends from the cylinder block 2 to the crankcase 1. An opening return hole 47 is provided, and a bent oil passage 46 connecting between the recovery hole 45 and the return hole 47 is formed on the joint surface of the cylinder block 2 with the crankcase 1 so as to bypass the cylinder bore 1a. At this time, the return hole 47 is disposed behind the recovery hole 45 (on the side opposite to the head cover 10) and above the oil level of the recovery hole 45 and the first oil reservoir chamber 28.
[0031]
  Referring again to FIG. 1, the ceiling wall of the head cover 10 is configured as a double wall comprising an inner wall 10a and an outer wall 10b so as to define a breather chamber 48 in the middle, and the inner wall 10a has a second wall. A through hole 49 communicating between the valve operating chamber 9b and the breather chamber 48 is formed, and a lead allowing fluid to flow in one direction from the second valve operating chamber 9b to the breather chamber 48 through the through hole 49. A valve 50 is attached. Further, a small hole 51 is formed in the inner wall 10a so that the lower part of the breather chamber 48 communicates with the second valve operating chamber 9b.
[0032]
  Also, a breather pipe 52 that connects the breather chamber 48 to an air cleaner (not shown) of the intake system of the engine E is connected to the outer wall 10b.
[0033]
  Next, the operation of this embodiment will be described.
[0034]
  During operation of the engine E, the pressure in the crank chamber 4 pulsates due to the up and down movement of the piston 11, and the pulsation of the pressure acts on the check valve 39 through the hollow portion 36 of the crank pin 5p to open and close it. The pulsation of the pressure also acts on the reed valve 42 through the through hole 30, opens and closes it, and propagates to the first and second valve chambers 9a and 9b.
[0035]
  Thus, when the check valve 39 is opened and closed, the stored oil O in the first oil sump chamber 28 flows into the outlet hole 32, the supply small chamber 33, the rising oil path 34, the annular oil path 31, the oil hole 35, and the delivery tray 37. In addition, the ball bearings 6a and 6b facing the crank chamber 4 are intermittently sucked into the crank chamber 4 sequentially through the hollow portion 36 of the crank pin 5p, and a part of the oil passing through the hollow portion 36 of the rank pin 5p is refueled. The needle bearing 17 between the crankpin 5p and the connecting rod 12 is lubricated through the hole 38.
[0036]
  In the meantime, in the transfer tray 37 that rotates together with the crankshaft 5, the oil passing through the inside is rotated, and foreign matters such as chips and wear powder contained therein are centrifuged, and the foreign matters are contained in the hollow portion 36 of the crank pin 5p. It is held in the foreign substance reservoir 40 that spreads further outward in the radial direction. Therefore, the purified oil can be supplied to the crankpin 5p side, which can contribute to the improvement of the durability of the engine E.
[0037]
  Thus, the oil that is intermittently sucked into the crank chamber 4 is scattered by the centrifugal force when separated from the rotating crankshaft 5 and becomes oil mist. This oil mist is opened from the through hole 41 by opening and closing the reed valve 42. The pressure is intermittently sent to the first valve operating chamber 9a, and then transferred to the second valve operating chamber 9b through the rod passages 5c and 5c to lubricate each part of the valve operating mechanism 19 therebetween.
[0038]
  When the oil mist that has lubricated the valve mechanism 19 is liquefied, for example, by adhering to the inner wall of the second valve chamber 9b, the oil is returned from the recovery hole 45 below the second valve chamber 9b to the bent oil passage 46. It is returned to the first oil reservoir chamber 28 through the hole 47 by the pressure pulsation of the second valve operating chamber 9b.
[0039]
  The pressure pulsation in the second valve chamber 9b also opens and closes the reed valve 50 in the breather chamber 48. Therefore, when blow-by gas generated in the crank chamber 4 rises to the second valve chamber 9b together with the oil mist, By opening and closing the reed valve 50, the oil mist is intermittently carried to the breather chamber 48 together with a part of the oil mist, and is expanded to perform gas-liquid separation. The liquefied oil returns to the second valve chamber 9b through the small hole 51, and the blow-by gas from which the oil has been separated is sucked into a suction system (not shown) through the breather pipe 52 and subjected to combustion processing.
[0040]
  Thus, by using the pumping action caused by the pulsation of the crank chamber 4, the stored oil O in the first and second oil sump chambers 28 and 29 can be circulated to each part of the engine E without using a special oil pump. Therefore, the lubrication device can be simplified and the cost can be reduced.
[0041]
  Further, the oil O in the first oil sump chamber 28 circulates from the crank chamber 4 to the first valve operating chamber 9 a → the rod passages 5 c and 5 c → the second valve operating chamber 9 b → the first oil sump chamber 28. When the oil O in the first oil reservoir chamber 28 decreases, the oil O in the second oil reservoir chamber 29 is supplied to the first oil reservoir chamber 28 through the through hole 30. Since the total volume of the oil reservoir chambers 28 and 29 is large and a large amount of oil O can be stored, the engine E can be operated for a long time.
[0042]
  Moreover, the first oil sump chamber 28 is formed in the first and second case halves 1a and 1b constituting the crankcase 1 so as to surround the crank chamber 4, and the second oil sump chamber 29 is formed in the first oil sump chamber 29. Since the second case half 1b and the side cover 8 are formed so as to surround the second valve operating chamber 9b, the first and second oil sump chambers 29 are only slightly enlarged in the radial direction of the crankcase 1 and the side cover 8. This can contribute to the compactness of the engine E.
[0043]
  In particular, the oil drawn into the hollow portion 36 of the crankshaft 5 from the first oil sump chamber 28 is scattered by the rotation of the crankshaft 5 to produce oil mist, so that an oil slinger for generating oil mist is no longer necessary. In addition to simplifying the structure, the first and second oil sump chambers 28 and 29 that do not have oil slinger increase the degree of freedom of the shape, and the overall engine E can be made compact. Can be achieved. In addition, the first oil sump chamber 28 is constituted by recesses 28a and 28b formed on the joint surfaces of the first and second case halves 1a and 1b, respectively, and the second oil sump chamber 29 is defined by the second case half. Since the first and second case halves 1a and 1b and the side cover 8 are cast, the crank chamber 4 and the first chamber 1 are formed by the recesses 29a and 29b formed on the joint surfaces of the body 1b and the side cover 8, respectively. It can be formed simultaneously with the valve operating chamber 9a, is easy to manufacture, and can reduce the cost.
[0044]
  The recovery hole 45 that opens to the second valve operating chamber 9b and the return hole 47 that opens to the first oil reservoir chamber 28 are spaced apart from each other in both the horizontal and vertical directions, and communicate with each other via a bent oil passage 46. Therefore, even if the engine E is tilted while the operation is stopped, as long as one of the recovery hole 45 and the return hole 47 is exposed above the oil level of the first oil reservoir chamber 28, the first oil reservoir chamber It is possible to prevent oil from flowing backward from 28 to the second valve operating chamber 9b.
[0045]
  Further, when the operation of the engine E is stopped, the check valve 39 is closed and the oil hole 35 in the crankshaft 5 is shut off, so that the oil hole 35 in the crankshaft 5 becomes the oil level of the first oil reservoir chamber 28. Even when the engine E is retracted, the oil O in the first oil sump chamber 28 overflows into the crank chamber 4 even when the engine E is disposed at a large inclination even when the engine E is stored. Can also be prevented.
[0046]
  Further, the oil is transferred from the oil hole 35 of the second journal portion 5b to the oil supply hole 38 of the crank pin 5p by a transfer tray 37 attached to one end of the crank portion 5c. In addition, it is possible to eliminate the need for drilling after assembly, and to reduce costs.
[0047]
  Next, reference examples of the present invention shown in FIGS. 8 to 11 will be described.
[0048]
  In this reference example, the first and second ball bearings 6a and 6b supporting the first and second journal portions 5a and 5b of the crankshaft 5 are both sealed, and the first journal is opposite to the previous embodiment. An annular oil passage 31 surrounding the portion 5a is provided in the first case half 1a, and a transfer tray 37 is attached to the crank portion 1c on the first journal portion 5a side. The check valve 39 as in the above embodiment is not provided in the oil hole 35 in the crankshaft 5 that communicates between the annular oil passage 31 and the transfer tray 37. Instead, the annular oil passage 31 includes an oil passage 61 extending forward from the front portion of the annular oil passage 31 through the side wall of the first case half 1a in parallel with the axis of the cylinder bore 1a. An oil passage 62 passing between the joint surfaces of the crankcase 1 and the cylinder block 2 so as to extend upward from the front end of the cylinder bore 1a along the inner peripheral wall of the cylinder bore 1a, and the inside of the upper wall of the crankcase 1 from the upper end of the oil passage 62 The second case half 1b and the side cover 8 are formed so as to bypass the second oil reservoir chamber 9b downward from the oil passage 63 penetrating to the cover 8 side and the opening end of the oil passage 63 toward the side cover 8 side. It communicates with the supply small chamber 33 connected to the lower portion of the first oil sump chamber 28 via an oil passage 64 passing between the joint surfaces.
[0049]
  Thus, the oil passages 61 to 64 communicating with the annular oil passage 31 surrounding the first journal portion 5a of the crankshaft 5 once extend above the oil level of the first and second oil sump chambers 28 and 29, and Since it bends downward and reaches the supply small chamber 33 connected to the lower part of the first oil sump chamber 28, it does not have the check valve 39 in the crankshaft 5 as in the above-described embodiment, but when the operation of the engine E is stopped, In the case of being arranged with a large inclination, it is possible to prevent the oil from flowing into the crank chamber 4 from the first oil reservoir 28 through the annular oil passage 31 to the overflow.
[0050]
  Since the other configuration is the same as that of the above embodiment, in FIG. 8 to FIG.
[0051]
  The present invention is not limited to the above-described embodiments, and various design changes can be made without departing from the scope of the invention.
[0052]
【The invention's effect】
  As described above, the present inventionSpecialAccording to the feature, a transfer tray that transfers oil from the oil hole of the journal portion to the hollow portion of the crank pin is attached to one end of the crank portion, and oil is contained in the transfer tray in the transfer tray while the crankshaft is rotating. Since a foreign substance reservoir is provided to hold the foreign substances that have been centrifuged from the outside, the oil passing through the inside of the transfer tray that rotates together with the crankshaft is rotated while the engine is running. The foreign matter is centrifuged, and the foreign matter is held in the foreign matter reservoir that spreads radially outward from the hollow portion of the crankpin, and the purified oil can be supplied to the crankpin side.NIt can contribute to improvement of durability.
[0053]
  AlsoAn oil reservoir chamber is provided in the crankcase to isolate it from the crank chamber,The crank pin is formed with a hollow portion that is open to the crank chamber, and an oil supply hole that communicates with the hollow portion on the outer peripheral surface of the crank pin is formed in the crank pin, so that at least one of the first and second journal portions is formed. BeforeRecordAn oil hole communicating with the oil storage chamber and opening adjacent to one end face of the crank portion is formed.Open and close based on the pressure pulsation of the crank chamber acting through the hollow portion;Since a check valve that allows unidirectional oil flow to the crank side is installed, the pressure pulsation in the crank chamber acts on the check valve through the hollow part of the crank pin and opens and closes it during engine operation. As a result, the oil stored in the oil reservoir chamber is sucked into the crank chamber intermittently through the oil holes in the journal portion, the transfer tray and the hollow portion of the crank pin in order, and the journal bearings facing the crank chamber are lubricated.TheA part of the oil passing through the hollow portion of the rank pin can be lubricated around the crank pin through the oil supply hole.In other words, by utilizing the pumping action caused by the pulsation of the crank chamber, the oil stored in the oil sump chamber can be circulated to various parts of the engine without using a special oil pump. Can be reduced.
[0054]
  In particular, oil that is intermittently drawn into the crank chamber can be scattered by centrifugal force when leaving the rotating crankshaft to create an oil mist for lubrication, eliminating the need for an oil slinger for oil mist generation. Simplification of the structure can be achieved by reducing the number of parts.
[0055]
  In addition, when the engine is stopped, the check valve closes and the oil hole in the journal section is shut off, so even when the engine is placed at a large angle, such as when the engine is stored, Oil can also be prevented from flowing into the crank chamber.
[0056]
  MaTheThe delivery plate is fitted into an annular positioning recess whose large diameter portion is formed on one end surface of the crank portion, and the small diameter portion elastically contacts the inner end surface of the bearing supporting the one journal portion.LikeTherefore, the delivery tray can be easily and accurately attached to one end of the crank portion without using a special fixing member.
[Brief description of the drawings]
FIG. 1 is a longitudinal plan view of a power work machine engine according to an embodiment of the present invention.
2 is a sectional view taken along line 2-2 in FIG.
3 is a cross-sectional view taken along line 3-3 in FIG.
4A is a cross-sectional view taken along line 4A-4A in FIG.
4B is a cross-sectional view taken along line 4B-4B of FIG.
5 is a cross-sectional view taken along line 5-5 in FIG.
6 is a cross-sectional view taken along line 6-6 in FIG.
7 is a sectional view taken along line 7-7 in FIG.
FIG. 8 is a diagram corresponding to FIG. 1, showing a reference example of the present invention.
9 is a cross-sectional view taken along line 9-9 in FIG.
10 is a sectional view taken along line 10-10 in FIG.
11 is a sectional view taken along line 11-11 in FIG.
[Explanation of symbols]
E ... Engine
1 ... Crankcase
4 ... Crank chamber
5 ... Crankshaft
5a, 5b ... Journal part
28 ... Oil sump chamber
35 ... Oil hole
36 .. Hollow part
37 ··· Delivery plate
38... Refueling hole
39 ··· Check valve
40 ... Foreign matter accumulation
43 ··· Positioning recess

Claims (1)

Both ends of the crank pin (5p) are press-fitted into both crank arms integrally connected to the paired first and second journal portions (5a, 5b) to form the crank portion (5c), and the first and second journals In the assembled crankshaft of the engine, the parts (5a, 5b) are supported by the crankcase (1) and the crank part (5c) is accommodated in the crank chamber (4) of the crankcase (1).
The crankcase (1) is provided with an oil reservoir chamber (28) that is separated from the crank chamber (4), and a hollow portion (36) that is open to the crank chamber (4) is formed in the crank pin (5p). In addition, an oil supply hole (38) communicating the hollow portion (36) with the outer peripheral surface of the crank pin (5p) is formed in the crank pin (5p), and at least one of the first and second journal portions (5a, 5b) is formed. the front crank unit communicates with the Kio yl sump chamber (28) bored oil holes (35) which opens adjacent to one end face of (5c), the hollow portion from the oil gallery (35) mounting (36) to pass oil passing dishes (37) at one end of the crank portion (5c), also in the oil gallery (35), the crank chamber acting through the hollow portion (36) of (4) It opened and closed based on the pressure pulsations, Clan Interposed part (5c) check valve that allows flow in one direction of oil to side (39), said delivery tray (37), the large diameter portion is formed on one end surface of the crank portion (5c) The transfer plate (37) is fitted into the annular positioning recess (43) and the small-diameter portion elastically contacts the inner end surface of the bearing (6b) supporting the one journal portion (5b ). Inside, the crankshaft oil for the engine crankshaft is provided with a foreign matter reservoir (40) for holding foreign matter centrifugally separated from the oil in the transfer tray (37) during rotation of the crankshaft (5). Road structure.

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