JPH0341230A - Hydraulic power transmission coupling - Google Patents

Abstract

PURPOSE:To reduce size and weight by making the shape of a plunger tip end part and arc or an oval to the slide direction with a cam and by making the straight line shape to the perpendicular direction so as to reduce projecting amount of the plunger. CONSTITUTION:The shape of a tip end part of a plunger 5 is made an arc or an oval to the slide direction with a cam surface 1A of a cam housing 1 and a straight line to its perpendicular direction. The shape of the cam surface 1A is made a shape created by the plunger 5 when the plunger 5 carries out a predetermined stroke action accompanying rotation of the cam 1 so as to reduce projecting amount of the plunger 5. Also, the plunger 5 and the cam surface 1A are brought into contact with each other with a sufficient length all the time, and contact stress is lowered. Thus, size and weight of a hydraulic power transmission coupling can be reduced and durability can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a hydraulic power transmission joint used for distributing driving force in a vehicle.

[Prior art] As a conventional hydraulic power transmission joint, for example,
-286838 and JP-A-63-101567, respectively.

Japanese Patent Laid-Open No. 62-286838 discloses a first rotating member that is formed integrally with one of the input and output shafts and has a cam surface on the inner circumference, and a first rotating member that is formed integrally with the other input and output shaft and has a cam surface on the inner circumference. a second rotating member inserted into the second rotating member; a cam body supported by the second rotating member and adjacent to the cam surface and reciprocating in the radial direction when the rotating member rotates relative to each other; a plurality of liquid chambers whose volume changes accordingly; a fluid path formed in the second rotating member and connecting the respective fluid chambers via an orifice;
A hydraulic power transmission joint is described.

Furthermore, JP-A-63-101567 discloses a first rotating shaft, a second rotating shaft that is rotatable relative to the first rotating shaft,
The rotor is used as a connecting means for the first and second rotating shafts, and has a rotor and a housing that are driven by a difference in rotational speed between the first and second rotating shafts, and discharges an amount of oil according to the difference in rotational speed. In a rotation difference sensitive joint comprising an oil discharge means and an orifice provided in a flow path communicating with a discharge port of the oil discharge means to suppress oil flow, an orifice and an orifice are provided at a central shaft portion of the rotor. A rotation differential sensitive joint is described which is provided with orifice opening degree changing means for changing the opening degree.

[Problem to be solved by the invention] However, in such conventional joints, the first problem is
As shown in Figures 0 and 11, the tip of the plunger is spherical, and the cam cross section perpendicular to the direction of sliding with the plunger has an arc shape that is approximately the same as the spherical radius of the plunger tip. The following problems arose.

In other words, as shown in Figure 10, if the plunger is designed so that the tip of the plunger and the cam surface are in contact for a sufficient length even when the plunger is at the bottom dead center, the plunger will be at the top dead center. In Figure 12, the plunger protrusion amount 1
1 increases.

On the other hand, in Fig. 12, the plunger protrusion amount 1
1 and the length 12 of the portion inserted into the plunger chamber, there is a suitable ratio in design to prevent prying of the plunger.

Therefore, if 11 is increased, 12 must also be increased, which results in an increase in the outer diameter of the joint, which not only increases the weight but also makes it difficult to mount it on a vehicle.

In order to avoid this, the plunger tip and cam surface are in point contact when the plunger reaches the bottom dead center, as shown in Figure 13, which increases the contact stress between the plunger and the cam surface and improves durability. There was a problem that the

Such problems are basically the same even when the plunger reciprocates in the axial direction.

The present invention has been made in view of such conventional problems, and the shape of the tip of the plunger is an arc or an ellipse in the direction of sliding with the cam, and in a direction perpendicular thereto. The cam surface has a linear shape, and the shape of the cam surface is a shape created by the plunger when the plunger makes a predetermined stroke movement as the cam rotates. By reducing the amount and ensuring a sufficient contact length between the plunger and the cam surface, the contact stress can be kept low, and as a result, we can provide a hydraulic power transmission joint that is compact and has sufficient durability. The purpose is

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a system that is provided between relatively rotatable input and output shafts, and allows an amount of fluid to flow in accordance with the rotational speed difference between the two shafts. A power transmission joint comprising: a flow rate generating means; and a means for generating flow resistance of the fluid; the transmission torque between the input and output shafts is controlled by the flow resistance; In the power transmission joint, the member is provided with a plurality of plunger type pumps as a flow rate generating means that reciprocates in the axial direction, and a cam surface for regulating the reciprocating movement of the plunger is formed on the inner surface of the other member, The shape of the tip of the plunger is an arc or an ellipse in the sliding direction with respect to the cam, and a straight shape in the direction perpendicular thereto, and the shape of the cam surface is such that the plunger The shape is created by the plunger when it makes a predetermined stroke movement as it rotates.

[Function] In the present invention, the shape of the plunger tip is as follows:
The shape of the cam surface is an arc or an ellipse in the sliding direction with respect to the cam, and the shape is linear in the direction perpendicular to the cam, and the shape of the cam surface is such that the plunger makes a predetermined stroke movement as the cam rotates. The shape is created by the plunger when the plunger is pressed.

Therefore, the amount of protrusion of the plunger can be reduced, and contact stress can be lowered by ensuring that the plunger and cam surface are always in contact with each other over a sufficient length, resulting in a hydraulic power transmission joint that is small, lightweight, and highly durable. It can be done.

[Example] Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a diagram showing an example of the basic structure of a hydraulic power transmission joint to which the present invention is applied.

First, to explain the configuration, Fig. 1(A) and Fig. 1(
In B), 1 is a cam housing having a cam surface IA formed on its inner surface, and the cam housing 1 is connected to an input shaft or an output shaft, and rotates integrally with the input shaft or output shaft.

A rotor 2 is rotatably housed in the cam housing 1. The rotor 2 is connected to an output shaft or an input shaft, and rotates integrally with the output shaft or input shaft. Note that 3 is an oil seal interposed between the cam housing 1 and the rotor 2.

A plurality of plunger chambers 4 are formed in the rotor 2 in the axial direction, and a plurality of plungers 5 are slidably housed in the plunger chamber 4 via a return spring 6.

Further, a main passage 7 is formed in the center of the rotor 2, and the main passage 7 and the plunger chamber 4 communicate with each other via a discharge passage 8. A discharge valve 10 is interposed in the discharge passage 8 by a return spring 9, so that oil flows in one direction. An orifice pulp 14 having an orifice 13 is movably accommodated in the main passage 7 by a spring 11 and a spring 12 which is a temperature-sensitive deformable member. A low pressure chamber 16 is defined on each side.

The orifice pulp 14 moves rightward in the figure when the discharge pressure reaches a predetermined value or the temperature reaches a predetermined value, and the orifice 13 is closed by the needle valve 17.

Further, an oil circulation groove 18 is formed at an intermediate position of the plunger chamber 4 on the outer diameter of the rotor 2 (see FIG. 2), and the low pressure chamber 16 and the suction passage 19 communicate with each other through the oil circulation groove 18. However, the suction passage 19 communicates with the plunger chamber 4 via a suction valve 20.

Therefore, the oil circulates around the outer diameter side of the rotor 2.

21 is a piston, 22 is a holding member, and the piston 21
A return spring 23 is interposed between the holding member 22 and the holding member 22 . Further, a relief pulp 26 for preventing excessive torque is interposed by a spring 25 in a passage 24 that communicates the high pressure chamber 15 and the low pressure chamber 16.

27 is a shutoff valve provided on the rotor 2 to drain oil from the high pressure chamber 15, 28 is a shutoff valve provided on the cam housing 1 for filling oil, and 29 is also provided on the cam housing 1. This is a shutoff valve for draining oil. In addition, 3o is an oil seal, 31 is a stop ring,
32 is a thrust washer, and 33 and 34 are mounting holes for input and output shafts.

A first embodiment of the present invention is shown in FIGS. 2 to 5.

FIG. 2 is a conceptual diagram showing the cam processing method according to the present invention, and the processing end mill 35 in the figure has the same radius as the cylindrical radius of the plunger tip.

The end mill 35 shown in the figure moves up and down with the rotation of the cam, and is positioned at a predetermined stroke and rotor with respect to the rotation angle as shown in FIG. 2(B).

FIG. 2(C) is a sectional view taken along the axis of the end mill 35 when the end mill 35 is at the top dead center.

Here, since the plunger tip has a cylindrical shape with the same radius as the end mill 35 as shown in FIG.
Perform the same stroke movement as in step 5.

FIG. 4 is a plan view showing the cross-sectional shape of the cam and the plunger tip section cut along the sliding direction, which are machined based on such a principle.

In the figure, φDo, φDp, and φDi are the outermost diameters in the plunger arrangement state, respectively, as shown in FIG.
The plunger center pitch diameter is the innermost diameter, and each part of the plunger 5 slides along these pitch circles.

Next, the effect will be explained.

By making the tip of the plunger 5 have a linear shape as described above with respect to the direction perpendicular to the sliding direction with respect to the cam surface IA, the amount of protrusion of the plunger 5 can be reduced.

Further, since the plunger 5 and the cam surface IA are always in contact with the entire width of the plunger 5 and a sufficient contact length can be ensured, contact stress can be reduced.

As a result, a compact and lightweight hydraulic power transmission joint with excellent durability can be obtained.

Incidentally, since the acting force from the cam surface 1A acts so that the plunger 5 always comes into close contact with the cam surface IA, the plunger 5 always faces the sliding direction and does not rotate itself.

Next, a second embodiment of the present invention is shown in FIGS. 6 to 9.

In this example, the shape of the plunger 5 along the sliding direction on the center pitch circle is the same as in the first embodiment, but the shape is continuously shaped so that the degree of ellipse increases as the distance from the center of the plunger 5 increases. changes.

The situation is shown in FIGS. 6 and 7.

φDo, φDp, φD in Figures 6 and 7
i is the same as in the first embodiment.

Here, the developed length for one rotation of the cam along the pitch diameter φD is proportional to the pitch diameter as shown in the following equation, and becomes longer as the pitch diameter becomes larger.

Deployment length L = π×φD Therefore, if the tip of the plunger 5, which was circular on the center pitch circle, is made into an elliptical shape whose deployment length in the sliding direction changes in proportion to the pitch diameter. , a straight line connecting points at the same height intersects the center line of the rotor 2.

Similarly, if the shape of the cam surface IA is made such that its developed length is proportional to the pitch diameter, the point at the same height will intersect with the center line of the cam housing 1, similar to the plunger 5.

By combining the created plunger 5 and cam in this way, if the plunger 5 and cam surface IA are in contact at a certain height on the plunger center pitch diameter, it can also be used on other pitch diameters. They will come into contact at points at the same height, and the line created by connecting the contact points will be a straight line that intersects the center lines of the rotor 2 and the cam housing 1.

Therefore, these contact lines are a collection of line segments extending radially from the center line of the rotor 2.

Conceptual diagrams of the method of machining the cam and plunger 5 described above are shown in FIGS. 8 and 9.

The processing machine in this case is a wire-cut electrical discharge machine, and theoretically the processing is performed using a wire 36 having a zero diameter.

This wire 36 is positioned so as to intersect with the axial centers of the rotor 2 and cam housing 1, and performs predetermined processing by moving up and down in synchronization with the rotation of the rotor 2 and cam housing 1.

Here, if the shapes of the plunger 5 and the cam are the same as those of the first embodiment on the center pitch circle of the plunger 5, the expanded shape of the plunger 5 and the cam will be the seventh.
It will look like the figure.

This embodiment also provides the same effects as the first embodiment.

[Effects of the Invention] As explained above, according to the present invention, the plunger tip has an arc or an elliptical shape in the sliding direction with respect to the cam, and an elliptical shape in the direction perpendicular thereto. The cam surface has a linear shape, and the shape of the cam surface is a shape created by the plunger when the plunger makes a predetermined stroke movement as the cam rotates.

Therefore, the amount of protrusion of the plunger can be reduced, and contact stress can be lowered by ensuring that the plunger and cam surface are always in contact with each other over a sufficient length, resulting in a hydraulic power transmission joint that is small, lightweight, and highly durable. It can be done.

[Brief explanation of drawings]

Figure 1 (A) is a sectional view, Figure 1 (B), Figure 2 (A), and Figure 3 (A) are other sectional views of a joint showing one embodiment of the present invention, and ~ (C) are cams. Processing conceptual diagram, ~(C) is a diagram showing the plunger, Figure 4 is a developed view of the cam and plunger, Figure 5 is a diagram showing the arrangement of the plunger, Figures 6 (A) and (B) are An explanatory diagram of a plunger showing another embodiment of the present invention, FIG. 7 is a developed view of the cam and plunger, FIG. 8 (A),
(B) is a conceptual diagram of cam machining, FIGS. 9(A) and (B) are conceptual diagrams of plunger machining, and FIGS. 10 to 13 are explanatory diagrams for explaining problems. In the figure, 1...Cam housing, IA...Cam surface, 2...Rotor, 3...Oil seal, 4...Plunger chamber, 5...Plunger 6...Return spring , 7... Main passage, 8... Discharge path, 9... Return spring, 10... Discharge valve, 11... Spring, 12... Temperature-sensitive deformable member, 13... Orifice, 14... Orifice valve, 15... High pressure chamber, 16... Low pressure chamber, 17... Needle bearing, 18... Oil circulation groove, 19... Suction path, 20... Suction valve, 21... Piston, 22... Holding member, 23... Return spring, 24... Passage, 25... Spring, 26... Relief valve, 27.28.29... Closing valve, 30...Oil seal, 31...Stop ring, 32...Thrust washer, 33.34...Mounting hole, 35...End mill, 36...Wire 37...Jig.

Claims (1)

[Scope of Claims] A flow rate generating means provided between input and output shafts that are relatively rotatable, and causing a flow of fluid in an amount corresponding to a rotational speed difference between the two shafts, and a means for generating flow resistance of the fluid. , a power transmission joint in which the transmission torque between the input and output shafts is controlled by the flow resistance, wherein one member integrated with the input and output shafts has a plurality of plans as a flow rate generation means that reciprocates in the axial direction. In the power transmission joint, which includes a plunger type pump and has a cam surface formed on the inner surface of another member for regulating the reciprocating movement of the plunger, the shape of the tip of the plunger is adjusted in the sliding direction with respect to the cam. The cam surface has a circular arc or an elliptical shape, and the cam surface has a shape that is created by the plunger when the plunger makes a predetermined stroke movement as the cam rotates. A hydraulic power transmission joint characterized by its shape.