JP4041203B2 - Reversible oil pump - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a separate lubricating oil pump that supplies lubricating oil to automobiles, motorcycles, snowmobiles, and the like, and more particularly, to a reversible oil pump suitable for snowmobiles.
[0002]
[Prior art]
Japanese Utility Model Publication No. 61-23668 proposes a reversible oil pump that uses an engine rotation as a pump drive source and can be applied to a small two-cycle engine such as a golf cart without a back gear.
[0003]
In this reversible oil pump proposed in Japanese Utility Model Publication No. 61-23668, a plunger whose axial position is immovable is inserted into a cylinder that rotates while reciprocating a stroke set by a discharge amount setting cam. A suction / discharge path that opens to the peripheral surface of the cylinder communicates with a suction hole and a discharge hole provided in the pump body through a suction stroke and a discharge stroke, respectively. The cylinder rotates 180 ° to a worm wheel that rotates while reciprocating. It is connected with the play of.
[0004]
When the worm wheel rotates in any direction, the suction / discharge path communicates with the suction hole in the suction stroke, and the suction / discharge path communicates with the discharge hole in the discharge stroke. That is, the pump is reversible. However, since this reversible oil pump reciprocates a cylinder having a large diameter, the cylinder is difficult to move when the oil viscosity is high at low temperature, and there is a problem that it is not suitable for a low temperature use type such as a snowmobile.
[0005]
4 to 6 show examples of conventional oil pumps of the type in which the position of the cylinder in the axial direction is fixed and the plunger is reciprocated. FIG. 4 is a cross-sectional view showing the oil pump. The pump body 1 shown in the figure is provided with a cylindrical space into which the cylinder 2 is fitted and an oil chamber 1b connected thereto, and these spaces are fastened with screws 12. It is partitioned from the outside by a lid 9 and a flange 10.
[0006]
Oil is supplied through the nipple 11 integrated with the flange 10 and is discharged from the discharge ports 1a and 1a. As shown in detail in FIG. 5, the cylinder 2 is provided with a pump chamber 2a into which the plunger 3 shown in FIGS. 4 and 6 (b) is fitted. The pump chamber 2a is connected to the plunger 3 by a discharge passage 2b and a suction passage 2c. It communicates with the surrounding surface.
[0007]
The plunger 3 to be fitted into the pump chamber 2a of the cylinder 2 is press-fitted into the worm wheel 4 as shown in FIG. 6 (b). A lead cam 4a is provided on the right end surface of the worm wheel 4, and protrusions 4b and 4b are provided on the left end surface. In the figure, only one lead cam 4a is visible, but two lead cams 4a are provided symmetrically with respect to the central axis.
[0008]
A driving worm 6 to which the rotation of the engine is transmitted is rotatably provided in the oil chamber 1b of the pump body 1, and a discharge amount setting cam 5 is rotatably provided. A compression coil spring 7 interposed between the cylinder 2 and the worm wheel 4 presses the lead cam 4 a against the discharge amount setting cam 5, and presses the retainer 13 fitted to the cylinder 2 against the lid 9. As shown in FIG. 6, the retainer 13 is in contact with the cylinder 2 by the flange plane 13 a, but is in contact with the lid 9, and the apex 13 b is in contact with the lid 9.
[0009]
As shown in FIG. 5C, concave portions 2e and 2e are formed between the convex portions 2d and 2d on the right end surface of the cylinder 2, and the protrusions 4b and 4b of the worm wheel 4 are formed in the concave portions 2e and 2e. It is mated. The cylinder 2 is urged to the left by the compression coil spring 7 and the retainer 13 fitted to the cylinder 2 is kept in pressure contact with the lid 9, and the axial position of the cylinder 2 does not move.
[0010]
The pump body 1 is provided with discharge ports 1a and 1a at intervals of 180 ° at positions where the discharge passage 2b of the cylinder 2 is opened. The suction ports provided at 180 ° intervals at positions shifted from the discharge port 1a in the axial direction communicate with the oil chamber 1b. However, these suction ports and their communication paths are not shown in the cross section shown in FIG. Not.
[0011]
In the above configuration, when the worm wheel 4 is rotated by the driving worm 6, the lead cam 4a of the worm wheel 4 comes into sliding contact with the discharge amount setting cam, and the plunger 2 integrated with the worm wheel 4 reciprocates twice in the axial direction per one rotation. .
[0012]
The cylinder 2 does not move in the axial direction, but rotates in synchronization with the worm wheel 4, and the suction passage 2c communicates with the suction port of the pump body in the suction stroke in which the plunger 2 moves in the right direction. In the moving discharge stroke, the discharge passage 2b communicates with the discharge port 1a of the pump body. The two discharge ports 1a and 1a supply the same amount of oil to different oil supply ports.
[0013]
The above oil pump only rotates the cylinder 2 with a large diameter and does not move in the axial direction, so it can be used for oil with low viscosity at high temperatures, but the driving worm 6 rotates in the opposite direction to normal rotation. Then, the suction passage 2c communicates with the discharge port 1a of the pump body during the suction stroke, and the discharge passage 2b communicates with the suction port of the pump main body during the discharge stroke, so it cannot be used in reverse rotation.
[0014]
Even if there is some play in the engagement between the concave portion of the cylinder 2 and the convex portion of the worm wheel 4, the timing of communication between the discharge passage 2b and the discharge port 1a and the suction passage 2c and the suction port is adjusted by bidirectional rotation. Further, since the contact between the retainer 13 and the lid 9 is a point contact at the center, the frictional resistance against the rotation of the cylinder 2 is small, and between the worm wheel 4 and the cylinder 2 due to the pressing force of the compression coil spring 7. Since the generated frictional force acts, the cylinder 2 rotates in synchronization with the worm wheel 4 at an intermediate position of the connection with the worm wheel 4, and the discharge passage 2b, the discharge port 1a, the suction passage 2c, and the suction passage. The timing of communication with the mouth could not be synchronized. That is, there has been no reversible oil pump that can be used for oil having a variable discharge amount and high viscosity at low temperatures.
[0015]
[Problems to be solved by the invention]
The present invention has been made in view of the above points, and an object of the present invention is to provide a reversible oil pump that is variable in discharge amount and can be used for low temperature and high viscosity oil. .
[0016]
[Means for Solving the Problems]
In the reversible oil pump of the present invention, a cylinder is rotatably disposed in a cylindrical space provided in a pump body, and a worm wheel that meshes with a driving worm is integrally formed on a plunger that is provided in a pump chamber of the cylinder so as to be freely accessible. A discharge amount setting cam abutting on a lead cam provided on the worm wheel is provided in the pump main body so as to be displaceable, and a suction discharge passage communicating with the pump chamber and opening in a cylinder peripheral surface is provided in the cylinder. A discharge hole and a suction hole whose opening and cylinder axial position coincide with each other are provided in the pump body, and the lead cam and the discharge amount setting cam are pressed against each other by a spring interposed between the worm wheel and the cylinder, and the cylinder is The retainer is pressed against a lid that closes the cylindrical space, and the worm wheel and the cylinder are In the reversible oil pump in which a protrusion provided on one of the facing end faces and a recess provided on the other are engaged with play, the retainer has a plurality of radially extending legs that contact the lid and a vertex at the center. And a leg portion fitted into a concave portion provided in the cylinder so that the apex is brought into contact with an end surface of the cylinder.
[0017]
In the reversible oil pump, the driving worm and the discharge amount setting cam are arranged in an oil suction passage communicating with the suction hole.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
In the following, the reversible oil pump according to the embodiment of the present invention will be described with reference to FIGS. 1 to 3. In FIGS. The part which overlaps description is abbreviate | omitted.
[0019]
In the reversible oil pump of the embodiment, as shown in FIG. 2C, the concave portion 2e that engages with the convex portion 4b of the worm wheel 4 of the cylinder 2 (shown in FIG. 3C) has an angle α. The convex portion 4b of the worm wheel 4 and the concave portion 2e of the cylinder 2 are engaged with play.
[0020]
Further, as shown in FIG. 3, the retainer 8 is formed with four radially extending legs 8a, 8a... And a chevron having a vertex 8b at the center, and flat surfaces 8c, 8c indicated by diagonal lines of the legs 8a. ... is in contact with the lid 9, and the apex 8b is in contact with the end face of the cylinder 2. The legs 8a, 8a... Are engaged with the recesses 2f, 2f... On the end surface of the cylinder 2 shown in FIG.
[0021]
When the cylinder 2 rotates, the retainer 8 also rotates integrally with the cylinder 2, and the flat surfaces 8 c, 8 c. A large frictional resistance is generated in the sliding contact portion, and the cylinder 2 rotates together with the worm wheel 4 in a state where the side surface of the concave portion 2e and the side surface of the convex portion 4b of the worm wheel 4 are in contact with each other. That is, the communication timing between the discharge passage 2b and the discharge port 1a and the suction passage 2c and the suction port can be adjusted by bidirectional rotation.
[0022]
Since the cylinder 2 processes the small-diameter discharge passage 2b and the like, a material having good cutting properties is used. Although such a material has low wear resistance, the use of a wear-resistant material for the retainer 9 that generates a frictional resistance with the lid 9 prevents a reduction in life due to wear.
[0023]
Since the retainer 9 pushes the cylinder 2 at the central vertex 8b, only axial force is applied to the cylinder 2 so that no contact between the cylinder 2 and the pump body 1 occurs, and the cylinder 2 operates at high speed. Vibration does not occur even when rotating at. If the retainer 9 and the cylinder 2 are brought into surface contact or contacted at a plurality of locations other than the center, if the machining accuracy of the retainer 9 or the cylinder 2 is poor, a force other than the axial direction is applied to the cylinder 2 and high speed rotation is achieved. It comes to vibrate.
[0024]
The stroke of the plunger 3 can be varied depending on the rotation position of the discharge amount setting cam 5. For example, by linking the discharge amount setting cam 5 and the valve shaft of the throttle valve, the oil amount corresponding to the output of the engine is increased. Can be supplied to.
[0025]
The embodiment is configured as described above, but the invention is not limited to this, and for example, the discharge amount setting cam may be displaced in the axial direction.
[0026]
【The invention's effect】
According to the reversible oil pump of the present invention, sufficient oil can be supplied even when used in a low-temperature environment such as a snowmobile, and there is no back gear and the engine can be rotated in the reverse direction. Can be used as a drive source.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a reversible oil pump according to an embodiment of the present invention.
2 (a) is a front view showing a cylinder of the reversible oil pump, FIG. 2 (b) is a cross-sectional view taken along line AA in FIG. 2 (a), and FIG. 2 (c) shows the cylinder. A right side view and FIG. 2 (d) are left side views showing the cylinder.
3 (a) is a bottom view showing the retainer of the reversible oil pump, FIG. 3 (b) is a side view showing the retainer, and FIG. 3 (c) is a plunger and a worm of the reversible oil pump. It is sectional drawing which shows the assembly body of a wheel.
FIG. 4 is a cross-sectional view showing an example of a conventional oil pump.
5A is a front view showing a cylinder of the oil pump, FIG. 5B is a cross-sectional view taken along the line BB in FIG. 5A, and FIG. 5C is a right side view showing the cylinder. FIG.
6 (a) is a side view showing a retainer of the oil pump, and FIG. 6 (b) is a cross-sectional view showing an assembly of a plunger and a worm wheel of the oil pump.
[Explanation of symbols]
1 pump body, 1a discharge port, 1b oil chamber, 2 cylinder, 2a pump chamber, 2b discharge passage, 2c suction passage,
2d convex part, 2e concave part, 2f concave part 3 plunger,
4 Worm wheel, 4a Lead cam, 4b Protrusion 5 Discharge amount setting cam 6 Driving worm 7 Compression coil spring 8 Retainer, 8a Leg, 8b Vertex, 8c Flat surface 9 Lid 10 Flange 11 Nipple 12 Screw 13 Retainer, 13a Flange plane, 13b Vertex

Claims (2)

A cylinder is rotatably arranged in a cylindrical space provided in the pump body, a worm wheel that meshes with a driving worm is integrally formed on a plunger that is provided so as to freely enter and exit the pump chamber of the cylinder, and a lead cam provided on the worm wheel; An abutting discharge amount setting cam is provided in the pump body so as to be displaceable, and a suction discharge passage that communicates with the pump chamber and opens in a cylinder peripheral surface is provided in the cylinder. The opening portion of the suction discharge passage coincides with the cylinder axial position. A discharge hole and a suction hole are provided in the pump body, the lead cam and the discharge amount setting cam are pressed against each other by a spring interposed between the worm wheel and the cylinder, and the cylinder is closed through the retainer. A protrusion provided on one of the end faces where the worm wheel and the cylinder face each other in pressure contact with the lid In the reversible oil pump in which a recess provided on the other side is engaged with play, a plurality of radially extending legs abutting the lid and a chevron having a vertex at the center are formed on the retainer. A reversible oil pump, wherein the reciprocating oil pump is fitted into a recess provided in the cylinder and the apex is brought into contact with an end face of the cylinder. 2. The reversible oil pump according to claim 1, wherein the driving worm and the discharge amount setting cam are arranged in an oil suction passage communicating with the suction hole.

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