JPH0786354B2 - Discontinuous contact gear for internal gear type fluid pump - Google Patents

Description

TECHNICAL FIELD The present invention relates to a novel discontinuous contact gear suitable for use in an internal gear type fluid pump.

[Conventional technology]

Among oil motors and oil pumps, there are gear motors and gear pumps that are constructed using special toothed gears.
Among the gears used for these, the trochoid is a representative example of the one in which the difference in the number of teeth between the internal gear and the external gear is 1, and the external gear rotates while continuously contacting the internal gear at multiple points. There are gears.

This is because a plurality of volume fluctuation spaces are always formed between the external gear and the internal gear, and fluid is made to flow into and out of the plurality of volume fluctuation spaces according to the rotation of the gears. It constitutes a motor and an oil pump.

This type of oil pump has a compact structure and is known to be used for supplying engine oil, for example.

However, when an oil pump is configured using the trochoid gear, the external gear and the internal gear make continuous contact at a plurality of points, which requires high precision in manufacturing and mechanical contact due to friction. There was a problem that the decrease in efficiency was unavoidable.

[Problems to be solved by the invention]

The present invention has been made from the above point of view, and the object of the present invention is, for example, when it is used for an oil pump, while there is one volume variation space on the inflow side and one volume variation space on the outflow side. , A new internal gear type fluid pump that can complete a fluid seal, less pulsation at the time of fluid outflow, less rotational friction, and extremely smooth engagement between an internal gear and an external gear To provide a discontinuous contact gear for use.

[Means for solving problems]

Thus, an object of the present invention is to provide an internal gear having a predetermined module and a number of teeth N, and between the internal gear and the internal gear meshing with the internal gear and rotating relative to each other, and the internal surface of the internal gear. It is composed of an external gear with the number of teeth (N-1) that defines the volume fluctuation space, and a tooth profile is formed inside the pitch circles of both gears apart from the pitch circle and outside from the center of the internal gear. A straight line drawn from the center of the external gear toward the center of the internal gear while making the first meshing near the point where the extension line of the straight line drawn toward the center of the tooth gear intersects with the tooth profile curve of both gears. In the non-continuous contact gear for internal gear type fluid pumps, which has the second meshing in the vicinity of the point where the extension line of intersects with the tooth profile curve of both gears, and rotates in other parts without the tooth surfaces contacting each other. , The tip shoulders of the tooth profile curves of the internal gear and the external gear are arcs with radii b and f, respectively. Then, when the two gears satisfy the occlusal conditions and rotate, the other parts of the gear curve defined as the envelopes of the above-mentioned arcs of the mating gears are This is achieved by the above discontinuous contact gear for an internal gear type fluid pump, which is determined by the distance F to the center of the arc forming a part and the radii b and f of the arcs.

Alternatively, the other part of the gear curve is a ratio (b / f) of the distance F from the center of rotation of one of the gears to the center of the arc forming part of the tooth profile curve and the radius of the arcs. ) And the non-continuous contact gear for an internal gear type fluid pump described above.

[Action]

By configuring as described above, on the straight line connecting the center Oa of the internal gear, the external gear, the internal gear, and the center Oa of the external gear, the occlusal ratio of 1 or more at the center Oa side of the external gear One occlusion, and a second occlusion with an occlusion rate of 1 or more on the center O side of the internal gear on the opposite side to the above, and a pair of volume fluctuation spaces are defined between the first occlusion part and the second occlusion part. So, for example,
When used in a fluid pump, the mechanical efficiency is high and the fluid can be transported smoothly.

That is, in the present invention, the external gear and the internal gear are divided into four parts, respectively, and the cutting edge shoulders of the internal gear and the external gear are respectively formed with radii b and f, and the other parts are opposed to each other. By configuring as the envelope of the arc of the gear, the volume variation space of the pair of suction part and discharge part is formed, so that no cusp is generated in the tooth profile of both gears, and there is no disengagement. The occlusal ratio at the first and second occlusal parts can be set to 1 or more, and the internal gear and the external gear mesh with each other very smoothly, so that mechanical efficiency can be improved, pulsation can be prevented, and fluid can be smoothly transported. It will be.

〔Example〕

 Hereinafter, the details of the present invention will be specifically described with reference to the drawings.

FIG. 1 is an explanatory view of an end surface perpendicular to the axis showing an embodiment of an internal gear type fluid pump using a discontinuous contact gear according to the present invention, and FIG. 2 is an illustration of the embodiment shown in FIG. FIG. 3 is an explanatory view showing a tooth profile curve of a half pitch portion of an internal gear, FIG. 3 is an explanatory view showing a tooth profile curve of a half pitch portion of an external gear, and FIGS. 4 and 5 are envelopes of an internal gear. It is explanatory drawing which shows the side surface curve of the external gear created from a line.

First, FIG. 1 will be described.

FIG. 1 shows a substantially right-angled end surface of an oil pump configured by using a discontinuous contact gear according to the present invention. In FIGS. 1 to 5, 1 is an internal gear and 2 is an external gear. Reference numeral 3 denotes a casing, and the center of the internal gear 1 is O and the center of the external gear 2 is Oa.

The discontinuous contact gear for an internal gear type fluid pump according to the present invention comprises an internal gear having a number of teeth N and an external gear having a number of teeth (N-1), and as shown in FIG. In this embodiment, N
= 13, module m = 6.13.

Since the number of teeth of the internal gear 1 is 13, the diameter of the pitch circle is PCD = 79.69 mm. The number of teeth of the external gear 2 is 12, and the diameter of its pitch circle is PCD = 73.56 mm. Since the tooth bottom diameter of the internal gear shown in the figure is about 65 mm, the pitch circles of both gears are set outside the contour of the tooth profile curve.

In the oil pump shown in this embodiment, the internal gear 1 and the external gear 2 are housed in a cylindrical casing 3, the internal gear 1 is used as an outer rotor with its center O as the center of rotation, and the external gear 2 is used. It is used as an inner rotor with its center Oa as the center of rotation.

Therefore, the center O of the outer rotor 1 coincides with the center of the casing 3, the center Oa of the inner rotor 2 is eccentric (m / 2) from the center O of the outer rotor 1, and the inner rotor 2 has a rotation shaft (not shown). ) Is attached, and thereby the end face member (not shown) attached to the casing 3
It is rotatably supported by.

In the state shown in FIG. 1, the external gear 2 is in contact with the internal gear 1 at a occlusal rate of 1 or more in the section from the point A to the point B in the clockwise direction. , In the section from the point C to the point D to the point E, the contact between both tooth tip curves is made with a occlusal rate of 1 or more, that is, a second occlusion is made.

Between the external gear 2 and the internal surface of the internal gear 1, a large volume space Sa, Sb, Sc and Sd of four sections and a small volume space existing between AB are defined. When the gear rotates clockwise, for example, a part of the volume space Sa is bisected by a contact point newly generated at the point C due to the rotation of the gear, becomes Sb, moves to the position of Sc, and then merges with Sd. Then, fluid transportation is performed.

Thus, the outer rotor 1 and the inner rotor 2 are housed inside the casing 3, and the end surface members (not shown) attached to the openings at both ends of the outer rotor 1 and the inner rotor 2 flow in and out according to the positions of the volume fluctuation spaces Sa and Sd. An outflow port is provided, which constitutes an oil pump.

Next, referring to the half-pitch tooth profile curves of the internal gear and the external gear shown in FIGS. 2 and 3, the tooth profiles of the internal gear 1 and the external gear 2 in the embodiment shown in FIG. I will explain about curves.

In the tooth profile curve of the internal gear 1, the tip curve between 1a and 1b and 1d to
2a in the root curve between 1e and the tooth profile curve of the external gear 2
The tip curve between ~ 2b and the root curve between 2d ~ 2e will be determined by the well-known Euler-Sabarry formula. Therefore, among the solutions between 1a and 1b and between 2a and 2b,
A radius of curvature ρ = a is adopted.

Next, as a part of the basic tooth profile of the internal gear 1, side curves 1b and 1c
An arc having a radius b forming a gap and a distance F from the arc center e to the rotation center O are given.

In such a case, the tooth profile of both gears should be such that when the above gears rotate as long as they meet the meshing condition, that is, when the pitch circles of both gears make rolling motions without slipping, the tooth profiles of both gears are different from each other. It is formed as an envelope formed on a cross section perpendicular to the axis of one gear.

That is, the portion between the side surface curves 2c to 2d of the external gear 2 is created as an envelope of an arc having a radius b between the side surface curves 1b to 1c of the internal gear 1. In addition, between 2b and 2c is an arc having a radius f.

Thus, the portion between the tooth profile curves 1c to 1d of the internal gear 1 is formed as an envelope of an arc having a radius f on the tooth profile curve of the external gear 2.

Further, in the above example, the tooth profile curve of the internal gear 1 and the external gear 2 is the distance F from the rotation center O of the internal gear 1 to the arc center e and the arc radii b and f on both tooth profiles. However, it is also determined by the distance A from the rotation center Oa of the external gear 2 to the arc center of the radius f and the arc radii f and b on both tooth profile curves. Yes, and the values of b and f instead of the values of these arc radii b or f
Both tooth profile curves are uniquely determined even if the ratio of is determined. That is, these parameters, that is, the distance F or A, the radii f and b, or the ratio of those radii, define a part of them as described above, and other parameters are obtained from the meshing condition of the tooth profile curve. And therefore,
The above three methods are mathematically equivalent to each other.

FIG. 4 and FIG. 5 are explanatory diagrams showing side surface curves of the external gear created from the envelope of the internal gear.

In the state shown in FIG. 4, the external gear 2 is fixed here,
It is assumed that the internal gear 1 is revolved counterclockwise about its center Oa as shown by the alternate long and short dash line to rotate on its own axis.

In that case, the tooth profile curve of the external gear 2 is obtained as an envelope formed by an arc on the tooth profile curve of the internal gear 1 on the plane perpendicular to the axis of the external gear.

FIG. 5 is an enlarged explanatory view showing details of creation of the external gear 2 by the above envelope, and the peritrochoid shown in FIG. 5 is a movement curve of the arc center e of the radius b of the internal gear 1. In this way, the tooth profile curve of the external gear 2 shown by the thick solid line is formed.

〔The invention's effect〕

Since the present invention is configured as described above, according to the present invention, the internal gear and the external gear form the first occlusion and the second occlusion at the occlusal rate of 1 or more at the symmetric portions on the center line, respectively.
Further, since a pair of volume fluctuation spaces are defined between the first occlusal portion and the second occlusal portion, for example, when used in a fluid pump, a fluid inflow / outflow port can be easily designed and It is possible to provide a novel discontinuous contact gear for an internal gear type fluid pump that is smoothly transported.

The configuration of the present invention is not limited to the above embodiment, and for example, the number of teeth N of the internal gear is N = 13, but the number of teeth may be appropriately determined. Ports and other components can be widely known ones within the scope of the present invention, and the present invention includes all of them.

[Brief description of drawings]

FIG. 1 is an explanatory view of an end surface perpendicular to an axis shown in an embodiment of an internal gear type fluid pump using a discontinuous contact gear according to the present invention, and FIG. 2 is a view showing the embodiment shown in FIG. FIG. 3 is an explanatory view showing a tooth profile curve of a half pitch portion of an internal gear, FIG. 3 is an explanatory view showing a tooth profile curve of a half pitch portion of an external gear, and FIGS. 4 and 5 are envelopes of an internal gear. It is explanatory drawing which shows the side surface curve of the external gear created from a line. 1 ... Internal gear (outer rotor) 2 ... External gear (inner rotor) 3 ... Casing

Claims (1)

[Claims] 1. An internal gear (1) having a predetermined module and a number of teeth N, and an internal surface of the internal gear (1) which meshes with the internal gear (1) and rotates relatively inside the internal gear (1). And an external gear (2) having a number of teeth (N-1) that defines a volume variation space between the gears, and a tooth profile is formed inside the pitch circle of both gears apart from the pitch circle, and Internal gear (1)
The first bite is made near the point (A to B) where the extension line of the straight line drawn from the center (O) of the gear toward the center (Oa) of the external gear (2) intersects with the tooth profile curve of both gears (AB). , Near the point where the extension line of the straight line drawn from the center (Oa) of the external gear (2) toward the center (O) of the internal gear (1) intersects with the tooth profile curves of both gears (C to D ~ A non-continuous contact gear for an internal gear type fluid pump, which forms a second engagement in E) and rotates in other portions without tooth surfaces contacting each other, wherein the internal gear (1) and the external gear ( The tooth top shoulders (1b to 1c, 2b to 2c) of the tooth profile curve of 2) are given as arcs with radii b and f, respectively, and then, when both gears rotate while satisfying the occlusion condition, the above-mentioned arcs of the mating gears. The other part of the gear curve, which is defined as the envelope of, is the tooth profile curve of either one from the gear rotation center (O, Oa). The arc center (e) the distance F to, the both arc having a radius b and the non-continuous contact gear for an internal gear type fluid pump, characterized in that it is determined by the f forming a part.