JPS59145311A - Lubricating oil pump of 2-cycle engine - Google Patents

Abstract

PURPOSE:To improve productivity, reduce weight and prevent friction and damage of a cam portion by making a drive body of synthetic resin while making a cam receiving portion of synthetic resin too. CONSTITUTION:Polyacetal resin or the like having excellent oil resistance, self lubricating property, dimensional stability and heat resisting property is synthetic resin for material of a drive body 7. Polyamido resin having small elastic modulus, large effect on absorbing impact and vibration and excellent oil resistance and corrosion resistance is selected for a material constituting a cam receiving portion 45. A cam portion 33 and the cam receiving portion 45 differ from each other in the material to minimize friction and damage in the contact portion.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a so-called separate lubrication type lubricating oil pump that separates fuel and lubricating oil for a two-stroke engine, and particularly includes a worm wheel that meshes with a worm gear that is interlocked with the output shaft of the two-stroke engine. A plunger is constructed by substantially integrating a driving body and a cylinder body having a pump chamber inside, and the plunger is moved in the axial direction by bringing a cam receiving part into contact with a cam part provided on the driving body. The present invention relates to a lubricating oil pump for a two-stroke engine, which sucks and discharges lubricating oil by changing the amount of pumping of the pump into the pump chamber in accordance with its axial movement.

Conventionally, in this type of lubricating oil pump, the cylinder body is
It is formed by cutting and drilling a metal material with excellent dimensional stability, taking into consideration the capacity of the pump chamber, the position of the lubricant intake and discharge holes communicating with the pump chamber, and the lubricity of the sliding surface. . On the other hand, since the drive body includes a worm wheel and a cam portion, cutting a metal material would not only be troublesome but also expensive, so it is formed of sintered metal. However, using sintered metal as the material requires two processing operations: forming and sintering, making the manufacturing process cumbersome. Further, metal grains are generally expensive, and a binder and the like are also required for sintering, which makes the manufacturing process as described above troublesome and relatively expensive.

Therefore, the disadvantages that the molding operation of the driving body is troublesome and expensive still remain unresolved.

The first purpose of the present invention is to solve such conventional technical problems by molding the drive body from synthetic resin, thereby simplifying the manufacturing work, reducing the manufacturing cost, and reducing the weight. It is an object of the present invention to provide a lubricating oil pump for a two-stroke engine that can contribute to

Here, when the drive body is made of synthetic resin as described above, if the cam receiving part that contacts the cam part of the drive body is made of metal, the contact state between the cam part and the cam receiving part may be affected by vibrations, etc. When "slapping" occurs, the cam part may be damaged.

Accordingly, a second object of the present invention is to provide a lubricating oil pump for a two-cycle engine in which the cam receiving part is also made of synthetic resin to prevent such damage to the cam part as much as possible.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.First, in FIG.
By closing the sliding chamber 3, a sliding chamber 3 having a circular cross section perpendicular to the axis is formed inside the pump body 1. A plunger 4 is housed in the sliding chamber 3 so as to be rotatable and movable in the axial direction.

The plunger 4 rotates around the axis in conjunction with the output shaft of a two-cycle engine (not shown), and also reciprocates in the axial direction with a stroke corresponding to the opening degree of the throttle valve (not shown) of the carburetor. An amount of lubricating oil corresponding to the stroke is sucked into the pump chamber 5 and discharged.

Referring also to FIG. 2, the plunger 4 is constructed by concentrically connecting a metal cylindrical cylinder body 6 and a bottomed cylindrical drive body 7 made of synthetic resin with a metal connecting member 8. It is integrated. The synthetic resin used as the material for the driver 7 is, for example, polyacetal resin, which has excellent oil resistance, self-lubricating properties, dimensional stability, and heat resistance.

The drive body 7 is gently inserted into the sliding chamber 3 with its bottom facing toward the right in FIG. 1, and a worm foil 9 is integrally provided on its outer periphery. On the other hand, a worm gear 10 that meshes with the worm wheel 9 is rotatably supported on the pump body 1 with an axis perpendicular to the axis of the drive body T.

This worm gear 10 rotates in conjunction with an output shaft (not shown) of a two-stroke engine.

A bottomed hole 11 is provided in the cylinder body 6 so as to project toward the driver γ side, and the pump chamber 5 is formed by closing the open end of the bottomed hole 11 with the connecting member 8 . That is, the connecting member 8 has a small diameter portion 12, a conical portion 13, and a large diameter portion 14 formed in this order from the cylinder body 6 side toward the drive body γ side, and the small diameter portion 12 is press-fitted into the bottomed hole 11. On the other hand, the surface of the large diameter portion 140 is knurled, and the large diameter portion 14 is press-fitted into the driver T from its open end side. As a result, the cylinder body 6 and the drive body 1 are integrated by the connecting member 8.

A pump rod 15 is fitted into a portion of the cylinder body 6 on the side opposite to the driving body T, so that the pump rod 15 can freely extend into the pump chamber 5, that is, can freely reciprocate relatively in the axial direction.

A lubricating oil suction chamber 16 is defined between the cylinder body 6 and the lid 2, and a collar 17 is fixed to the end of the pump rod 15 that projects into the lubricating oil suction chamber 16. A return spring 19 is interposed between this collar 17 and a shoulder portion 18 of the cylinder body 6 facing the lubricating oil suction chamber 16. The spring force of the return spring 19 urges the collar 1γ and the cylinder body 6 in a direction away from each other. Therefore, the left end of the pump rod 15 is always in contact with the lid 2.

A suction pipe 2 is connected to the pump body 1 and communicates with the lubricating oil suction chamber 16.
0 is connected. In addition, an oil passage 21 is bored in the pump body 1 in parallel with the sliding chamber 3. One end of this oil passage 21 communicates with the lubricating oil suction chamber 16, and the other end is connected to a cam facing the bottom of the drive body 7. It communicates with room 36. Therefore, the meshing portion between the worm wheel 9 and the worm gear 10 of the drive body 7 is lubricated with lubricating oil.

A suction/discharge hole 22, one end of which communicates with the pump chamber 5, is formed in the cylinder body 6 along one radial direction. On the other hand, a groove 23 is provided on the outer peripheral surface of the cylinder body 6 and extends along the circumferential direction within a certain central angle.
The other end of 2 communicates with the groove 23.

A lubricating oil suction passage 24 that can communicate with the groove 23 is bored in a portion of the pump body 6 between the oil passage 21 and the sliding chamber 3 . In addition, a lubricant-oil discharge passage 25 is bored in the pump body 1 on the opposite side of the lubricant suction passage 24 on one diameter line of the cylinder body 6, and a check valve 26 is connected to the lubricant oil discharge passage 25. A discharge pipe 21 is connected thereto. Check valve 26
is a spherical valve body 28. and the valve body 28 is connected to the lubricating oil discharge passage 2.
The cylinder body 32 has a valve seat 30 at its end, on which the valve body 28 is seated, and forms a valve hole 31.

A cam portion 33 is integrally provided at the bottom of the driver I.

The cam portion 33 includes a small cam 34 that is provided at the center of the drive body 1 and determines the stroke of the plunger 4 by bearing the low-speed rotation of the engine such as an idle link, and a small cam 34 that is provided around the small cam 34 and supports the medium-high speed rotation of the engine. A large cam 35 is provided to determine the stroke of the plunger 4 by applying the load.

Referring also to FIGS. 3, 4, and 5, a rotation shaft 37 is rotatably supported in the pump body 1 in a cam chamber 36, and has an axis perpendicular to the axis of the drive body 7. be done. The rotary shaft 31 is integrated with the arm portion 38 to form an oval-shaped control lever 39, and the control lever 39 is formed by pressing a metal plate. A fitting hole 40 provided at the end of the arm portion 38 is connected to a wire (not shown) for rotating the rotating shaft 37 in accordance with the opening degree of the throttle valve of the carburetor.

The outer surface of the rotating shaft 37 in the control lever 39 is provided with bearing parts 42, 43, 44 for supporting it, and a cam receiving part 45, and is formed by injection molding using a mold with the control lever 39 as an insert. Ru.

The cam receiver 45 includes a small cam receiver 46 having an occluded circular shape that can come into contact with the small cam 34 and a large cylindrical cam receiver 47 that can come into contact with the large cam 35 .

The synthetic resin that is the constituent material of the coating layer 41, that is, the cam receiving part 45, is a resin different from the polyacetal resin that is the material of the drive body 7, such as a resin that has a small elastic modulus, a high impact and vibration absorption effect, and is oil resistant. A polyamide resin with excellent properties and corrosion resistance is selected. This is because, as is generally well known, if the cam part 33 and the cam receiving part 45 are made of the same material, friction damage on the contact surfaces will be severe; By doing so, it is possible to prevent friction damage at the contact portion between the cam portion 33 and the cam receiving portion 45 as much as possible.

Next, to explain the operation of this embodiment, first, when the throttle valve of the air ignition device is in the idle position, the control lever 3
The rotational position of the rotation shaft 37 at 9 is such that the small cam receiver 46 contacts the small cam 34 and the large cam receiver 47 contacts the large cam 35.

When the engine rotates in this state, the rotational driving force is transmitted to the plunger 4 via the worm gear 10 and the worm wheel 9. As the plunger 4 rotates, the small cam 34 comes into sliding contact with the small cam receiver 46, and the large cam 35 comes into sliding contact with a portion of the large cam receiver 47. Along with this, the plunger 4 reciprocates in the axial direction, and when the plunger 4 moves to the right side in FIG. The volume increases, and at this time, lubricating oil is sucked into the pump chamber 5 from the lubricating oil suction path 24 communicating with the suction/discharge hole 22. Furthermore, when the plunger 4 moves the most to the left in FIG.
Lubricating oil is discharged from the pump chamber 5 through a lubricating oil discharge passage 25, a check valve 26, and a discharge pipe 27 that communicate with the pump chamber 5.

In the low-speed rotation state during idle link as described above, the plunger 4 reciprocates with a relatively short stroke depending on the shape of the small cam 34, and as a result, a small amount of lubricating oil is discharged from the discharge pipe 27.

Next, when the throttle valve opening of the carburetor becomes large and the engine speed increases, the rotating shaft 37 rotates and the small cam receiver 46 engages the small cam 3.
4, and only the large cam 35 comes into contact with the large cam receiver 47, as shown in FIG. Therefore, the plunger 4 reciprocates in the axial direction with a relatively long stroke depending on the shape of the large cam 35, and when the plunger 4 moves to the rightmost side as shown in FIG. Oil is inhaled. Further, as shown in FIG. 6, when the plunger 4 moves to the leftmost position, the lubricating oil in the pump chamber 5 is discharged from the discharge pipe 27.

In this way, the stroke of the plunger 4 is determined by the small cam 34 when the engine rotates at low speed, and the stroke of the plunger 40 is determined by the large cam 35 when the engine rotates at medium and high speeds. Therefore, by improving the machining accuracy of the small cam 34, it is possible to precisely control the discharge amount when the engine rotates at low speed, requiring only a small amount of discharge.

As described above, according to the first aspect of the invention, since the drive body is made of synthetic resin, it is possible to manufacture the drive body at a lower cost through simpler processing operations than in the case of conventional sintered metal ones. Furthermore, parts made of synthetic resin can be mass-produced using a single mold, improving productivity. Furthermore, since the weight of the driving body is reduced, it is possible to contribute to the overall weight reduction.

Further, according to the second invention, the driving body is made of synthetic resin and the cam receiving part is also made of synthetic resin.
In addition to the effects of the invention described above, it is possible to prevent the cam portion from being damaged by friction even if “slapping” occurs at the contact portion between the cam portion and the cam receiving portion.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is an overall vertical sectional view, FIG. 2 is an overall side view of the plunger, FIG. 3 is a plan view of the control lever, and FIG. 5 is a sectional view taken along the line v--V in FIG. 3, and FIG. 6 is an overall longitudinal sectional view corresponding to FIG. 1 when the engine rotates at medium and high speeds. DESCRIPTION OF SYMBOLS 1...Pump body, 4...Plunger, 5...Pump chamber, 6...Cylinder body, 1...Driver body, 9...
・Worm wheel, 10- Worm gear, 15...
・Pump rod, 33...Cam part, 31...Rotation shaft, 39...Control lever, 45 River force receiving part Patent applicant Honda Motor Co., Ltd. Figure 1 Figure 2 Figure 5 Figure 6Figure 4

Claims (3)

[Claims] (1) A plunger, in which a driving body is substantially integrated with a metal cylindrical cylinder body, which has a pump chamber and suction/discharge holes that communicate with the pump chamber and open on the outer circumferential surface of the pump body, rotates. The worm wheel is housed so as to be freely and axially movable, and a worm gear interlocked with the output shaft of the two-stroke engine is meshed with the worm wheel provided on the drive body.
The cylinder body is fitted with a pump rod that changes the amount of thrust into the pump chamber according to the amount of axial movement of the cylinder body, and is inserted into the pump body at a position spaced apart in the circumferential direction of the cylinder body. is provided with a lubricant suction passage and a lubricant discharge passage that can communicate with the suction/discharge holes, and further includes a cam in the drive body for regulating the axial movement amount of the plunger and adjusting the pump discharge amount. In the lubricating oil pump for a two-cycle engine, the driving body is formed of synthetic resin. Lubricating oil pump for 2-cycle engine. (2) A plunger in which a driving body is substantially integrated into a metal cylindrical cylinder body that has a pump chamber and suction/discharge holes that communicate with the pump 7° chamber and open on the outer circumferential surface of the pump body. is housed so as to be rotatable and axially movable, a worm gear provided on the drive body is engaged with a worm gear that is interlocked with the output shaft of the two-cycle engine, and the cylinder body has an axial movement amount of the cylinder body. A lubricant suction passage and a lubricant oil are inserted into the pump body at positions spaced apart from each other in the circumferential direction of the cylinder body, and a lubricant oil suction passage that can communicate with the suction/discharge hole is inserted into the pump body to change the amount of intrusion into the pump chamber according to the pump pressure. A discharge passage is perforated in each of the pump bodies, and a cam portion is integrally provided on the drive body to regulate the amount of axial movement of the plunger to adjust the pump discharge amount. In a lubricating oil pump for a two-cycle engine in which a cam receiving part that comes into contact is supported, the driving body is formed of synthetic resin, and the cam receiving part is provided on a rotating shaft of a control lever that is linked to a throttle valve of a carburetor. Moreover, the lubricating oil pump for a two-stroke engine is characterized by being made of synthetic resin. (3) The control lever is made of a metal material and is bent into an abbreviated shape consisting of a rotation shaft and an arm portion, and is insert-coupled to the cam receiving portion. A lubricating oil pump for a two-cycle engine as described in (2).