JPH0473431A - Hydraulic type power transmission coupling - Google Patents

Abstract

PURPOSE:To prevent the generation of the confined phenomenon by installing a plunger chamber in order to prevent two or more plunger chambers are not connected with each discharge port at the same time and installing a fluid resistance generating means at each discharge port. CONSTITUTION:Each discharge port 14 is constituted so as not to communicate each other so that two or more plunger chambers are not connected to a port 14 at the same time, and each orifice 17 which communicates to a suction passage 13 is formed at each port 14. Accordingly, the oil in the chamber 7 in discharge cycle flows in each independent orifice 17. Accordingly, even if the port 14 and a suction port 12 is short-circuited, at the transition time point from the discharge cycle to the suction cycle, the leak of the oil in other chamber 7 from this short circuit part is prevented, and the operation of each chamber 7 is not given with influence. Accordingly, the interval between the contiguous ports 12 and 14 can be reduced in comparison with the diameter of the suction/discharge hole 10 of a rotor 5, and the confined phenomenon can be avoided from the principle aspect.

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] The present applicant has proposed the following hydraulic power transmission joint in Japanese Patent Application No. 2-40632.

That is, this hydraulic power transmission joint is provided between relatively rotatable input and output shafts, and includes a plunger pump driven by the difference in rotational speed between the two shafts, and a means for generating flow resistance in the discharge path of the pump. A power transmission joint in which transmission torque between the input and output shafts is controlled by the flow resistance, the cam housing being connected to the one shaft and forming a cam surface having two or more ridges on the inner surface; a rotor member connected to the other shaft, rotatably housed in the cam housing, and forming a plurality of plunger chambers; a plurality of plungers that are housed in a reciprocating manner and are driven by the cam surface when the two shafts rotate relative to each other; a suction hole and a discharge hole that are formed in the rotor member and communicate with the plunger chamber; It is in rotatable and sliding contact with the rotor member, and is also positioned rotatably by a predetermined angle between it and the cam housing, and is connected to the suction hole and the discharge hole regardless of whether the relative rotation direction of the two shafts is forward or reverse rotation. a valve body forming a plurality of suction ports and discharge ports that function as suction valves and discharge valves depending on the positional relationship between the two; a high pressure chamber formed by communicating each of the discharge ports with a discharge passage through a communication passage; A flow resistance generating means is provided at the suction passage connecting the port and the low pressure chamber in the joint, and at the outlet section from the high pressure chamber to the low pressure chamber.

[Problems to be Solved by the Invention] However, in such a conventional hydraulic power transmission joint, each discharge port is communicated with each other by a groove provided on the shaft of the rotor or on the surface of the valve body, and the collection chamber is The rotary seal structure formed a high pressure chamber (high pressure chamber) and sealed high pressure oil leakage by a gap between the inner diameter part of the valve body and the outer diameter part of the shaft, which caused the following problems.

(1) In general, axial plunger pumps with a valve body on the thrust surface of the rotor prevent oil leakage from the valve part by causing the hydraulic reaction force in the plunger chamber that acts on the rotor to bring the valve body and rotor into close contact. are doing.

However, since high pressure also acts on the discharge port and the seal land that are open on the surface of the valve, a force is generated that pushes the rotor back against the thrust force and prevents the valve portion from coming into close contact with each other.

If the hydraulic pressure acting on the valve surface is greater than the hydraulic pressure in the plunger chamber, the valve portion will not be able to maintain close contact and the valve will lose its sealing function.

The hydraulic pressure on the valve surface increases as the area of the discharge port opening on the surface and the groove communicating with it increases.If the area of the communication groove is widened, there is a problem in that it becomes difficult for the valve part to fit tightly and no torque is generated. .

As a countermeasure to this, by making the discharge port and communication groove thinner,
Another problem was that the viscous resistance of the oil increases at low temperatures, resulting in increased torque.

It is also possible to maintain close contact between the valve parts by increasing the inner diameter of the valve body and reducing the area of the communication groove, but this causes the problem of increased oil leakage from the gap in the inner diameter of the valve body, as described below. was there.

(2) The amount of oil leaking through a narrow annular gap is generally expressed by the following formula, and is proportional to the diameter and the cube of the gap, and inversely proportional to the viscosity of the oil and the length of the gap.

Q-π*d*ΔP*δ3/(12*μ*L) Q: Leakage amount d ・Diameter of the gap ΔP: Pressure difference before and after the gap δ: Radial gap μ ・Oil viscosity L: Length of the gap In the conventional example, not only the plunger but also the inner diameter portion of the valve body has an annular clearance as described above, and the design is such that a large amount of oil leaks through the clearance.

Since the viscosity of oil changes depending on temperature, when the temperature of the joint changes, the amount of leakage changes, and the oil pressure generated in the plunger chamber, that is, the torque, changes accordingly.

Conventionally, there was a problem in that the amount of leakage was large, resulting in large fluctuations in torque due to temperature changes.

As a countermeasure to this problem, reducing the gaps in each part requires high processing precision, which increases costs, and increasing the length of the gaps increases the length of the joint.

In addition, in the conventional example, if there is a short circuit between the discharge port and the suction port at the time of transition from the discharge stroke to the suction stroke, all the oil in the communicating plunger chamber escapes through this short circuit point, resulting in a drop in oil pressure. There is a problem that the torque decreases, and in order to avoid this, the distance between the discharge port and the suction port is made wider than the diameter of the rotor's suction and discharge hole.

As a result, the discharge valve closes before the end of the discharge stroke, causing a so-called confinement phenomenon in which the pressure in the plunger chamber, which has no oil outlet, suddenly increases, resulting in the generation of shocking torque. Ta.

It is known that this phenomenon can be countered by providing a notch between the discharge port and the suction port to prevent entrapment, but this requires high dimensional accuracy of the notch, which increases processing costs. There was also a problem.

The present invention has been made in view of such conventional problems, and is designed to provide a joint for applications that do not require a variable orifice mechanism without increasing the length of the gap.
By reducing leakage in the valve part without increasing machining accuracy, and by creating a structure that does not, in principle, cause a confinement phenomenon, we have eliminated the notch, making it compact, lightweight, inexpensive, and resistant to torque changes due to temperature. The purpose is to provide a hydraulic power transmission coupling with less power.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a shaft that is provided between relatively rotatable input and output shafts, is connected to the one shaft, and has two or more peaks on the inner surface. a cam housing having a cam surface formed therein; a rotor connected to the other shaft, rotatably housed within the cam housing, and forming a plurality of plunger chambers in the axial direction; and the plurality of plunger chambers. a plurality of plungers, each of which is housed in a reciprocating manner under the pressure of a return spring, and which is driven by the cam surface when the two shafts rotate relative to each other; a suction and discharge hole communicating with the rotor; rotatably slidingly contacts the end surface of the rotor and positioned in a predetermined relationship with the cam housing, and controlling the actions of the suction and discharge valves depending on the positional relationship with the suction and discharge hole; a valve body having a plurality of suction ports and discharge ports formed on its surface, and means for generating flow resistance by the flow of discharged oil caused by the driving of the plunger; In the power transmission joint, the plunger chamber is provided so that two or more plunger chambers are not connected to each of the discharge ports at the same time, and a flow resistance generating means is provided in each of the discharge ports.

[Function] In the present invention, each discharge port is not communicated with each other, two or more plunger chambers are not connected to one discharge port at the same time, and each of the discharge ports is Since the flow resistance generating means is provided, the oil in each plunger chamber during the discharge stroke passes through one independent flow resistance generating means.

Therefore, even if the discharge port and suction port are short-circuited when moving from the discharge stroke to the suction stroke, the oil in other plunger chambers will not escape from this short-circuited point, and the operation of each plunger chamber will not be affected. .

Therefore, the distance between adjacent suction and discharge ports can be made narrower than the diameter of the rotor's suction and discharge holes.
In principle, the trapping phenomenon can be avoided even without providing a trapping prevention notch.

In addition, since the communication groove on the valve surface that communicated each discharge port in the conventional example is eliminated, the only high-pressure part that opens on the surface of the valve body is the discharge port, and the hydraulic pressure that tries to open the close contact between the valve parts is It is smaller than the hydraulic pressure in the plunger chamber that acts on the rotor, and the valve part is kept in close contact.

Therefore, oil leakage from the valve part is reduced, torque fluctuations due to temperature changes can be reduced, and since the seal is made on the surface of the valve body, there is no need for an axial length for sealing, and the length of the joint is reduced. It won't be long either.

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

1 to 3 are diagrams showing one embodiment of the present invention.

First, to explain the configuration, in FIGS. 1 and 2, 1 is a cam with a cam surface 2 having two or more ridges on its inner surface, and the cam 1 is connected to an output shaft 3. 3
It rotates as one. Further, the cam l is fixed to the cam housing 4, and the cam housing 4 rotates integrally with the cam 1.

A rotor 5 is rotatably housed in the cam housing 4. The rotor 5 is coupled to the input shaft 6 and rotates together with the input shaft 6.

A plurality of plunger chambers 7 are formed in the rotor 5 in the axial direction, and a plurality of plungers 8 are formed in the plunger chamber 7.
is slidably housed via a return spring 9. Further, a plurality of suction and discharge holes 10 are formed in the rotor 5 so as to communicate with each plunger chamber 7.

11 is a rotary valve (valve body) on which a suction port 12, a suction passage 13, and a discharge port 14 are formed;
An orifice 17 is formed in each discharge port 14 of the rotary valve 11 as a flow resistance generating means (see FIG. 3). Further, the discharge ports 14 do not communicate with each other, and two or more plunger chambers 7 are not connected to one discharge port 14 at the same time. That is, if the number of cam ridges is N, the number of plunger chambers 7 is configured to be 2N-1 or less. In this embodiment, there are four cam ridges and seven plunger chambers.
There are 7 pieces.

Further, the interval between the adjacent suction port 12 and the discharge port 14 is formed narrower than the diameter of the suction and discharge hole 10 of the rotor 5. Therefore, the entrapment phenomenon can be avoided even without providing an entrapment prevention notch.

Further, the rotary valve 11 has a positioning protrusion 19 that engages with a notch 18 formed on the inner circumference of the cam housing 4.

The rotary valve 11 constitutes a timing member that determines the opening/closing timing of the suction/discharge hole 10, and the notch 18 and the protrusion 19 constitute a positioning mechanism that regulates the phase relationship between the cam 1 and the rotary valve 11.

When the plunger 8 is in the suction stroke, the suction port 12 of the rotary valve 11 and the suction/discharge hole 10 of the rotor 5 communicate with each other, and the suction path 13, suction port 12,
Through the suction and discharge holes 10 of the rotor 5, the plunger chamber 7
The oil can be inhaled.

Further, when the plunger is in the discharge stroke, the relationship is opposite to the suction stroke, and the suction and discharge hole 10 of the rotor 5 is connected to the orifice 17 via the discharge port 14 of the rotary valve 11.
Leads to.

A thrust block 20 rotates integrally with the cam housing 4, and supports the input shaft 6 via a bearing 21. A needle bearing 22 is interposed between the thrust block 20 and the rotary valve 11, and the friction torque on the needle bearing 22 side is transmitted to the rotor 5.
It is set to be smaller than the friction torque between the rotary valve 11 and the rotary valve 11. Therefore, when the direction of differential rotation changes, the rotary valve 11 rotates together with the rotor 5, rotates until the positioning protrusion 19 of the rotary valve 11 hits the notch 18 of the cam housing 4, and then becomes integral with the cam housing 4. Rotate with. Thereby, the suction and discharge holes 10 are forcibly opened and closed at a predetermined timing even during forward rotation or reverse rotation. Further, 16 is a rolling ring for a needle bearing.

23 is an accumulator piston that rotates integrally with the cam housing 4, and the accumulator piston 23 moves according to internal pressure. A return spring 25 is interposed between the accumulator piston 23 and the retainer 24. In addition, 26 is an oil seal, 27 is a stop ring, 28 is a bolt, 29 is an oil hole, and 30 is a bearing.

Next, the effect will be explained.

When there is no difference in rotation between the cam 1 and the rotor 5, the plunger 8 does not operate and no torque is transmitted. Note that at this time, the plunger 8 is pressed against the cam surface 2 by the return spring 9.

Next, when a rotation difference occurs between the cam 1 and the rotor 5, the plunger 8, which is in the discharge stroke, is pushed in the axial direction by the cam surface 2 of the cam 1.

At this time, since the suction and discharge hole 10 communicates with the discharge port 14, the plunger 8 transfers the oil in the plunger chamber 7 from the suction and discharge hole 10 to the discharge port 14 of the rotary valve 11.
push it out.

The oil pushed out to the discharge port 14 flows through the orifice 1
7 and is supplied to the suction passage 13. At this time, the oil pressure in the discharge port 14 and the plunger chamber 7 increases due to the resistance of the orifice 17, and a reaction force is generated in the plunger 8. Torque is generated by rotating the cam 1 against this plunger reaction force, and the torque is transmitted between the cam 1 and the rotor 5.

Furthermore, when the cam 1 rotates, the suction stroke occurs, and the suction and discharge holes 10 communicate with the suction ports 12, so the oil in the suction passage 13 is sucked into the plunger chamber 7 through the suction ports 12 and the suction and discharge holes 10. The plunger 8 returns along the cam surface 2 of the cam 1.

Here, as shown in FIG. 3, the discharge ports 14 are configured so that they do not communicate with each other, and two or more plunger chambers 7 are not connected to one discharge port 14 at the same time. be done. Each discharge port 14 is provided with an orifice 17 that communicates with the suction passage 13.

Therefore, the oil in each plunger chamber 7 during the discharge stroke passes through one independent orifice 17. Therefore, even if the discharge port 14 and suction port 12 are short-circuited at the time of transition from the discharge stroke to the suction stroke, as shown in FIG. It does not escape and does not affect the operation of each plunger chamber 7.

Therefore, as shown in FIG. 4(a), the interval between the adjacent suction port 12 and discharge port 14 can be narrower than the diameter of the suction and discharge hole 10 of the rotor 5, and as shown in FIG. 4(C).
Even without providing a notch 31 for preventing entrapment as shown in FIG. 4, it is possible in principle to avoid the entrapment phenomenon as shown in FIG. 4(b).

In addition, since the communication groove of the rotary valve that communicated with each discharge port in the conventional example is also eliminated, the only high-pressure part that opens on the surface of the rotary valve 11 is the discharge port 14, and the oil that tries to open the close contact between the valve parts The pressure becomes smaller than the hydraulic pressure in the plunger chamber 7 acting on the rotor 5, and the valve portion is kept in close contact.

In addition, in the conventional example, a mechanism is provided to vary the orifice opening degree according to the discharge pressure, but because this mechanism is large, it has to be placed at the center of the shaft, and high-pressure oil is guided to the center of the shaft. A communication groove was provided in the shaft portion out of necessity, but in the case of an application that does not require a variable orifice mechanism, as in this embodiment, there is no need to provide a communication groove in the shaft portion, so the rotary valve 11 is Oil leakage from the inner diameter gap can be prevented.

Therefore, oil leakage from the valve part is reduced, torque fluctuations due to temperature changes can be reduced, and since the seal is formed on the surface of the rotary valve 11, there is no need for an axial length for sealing. , the length of the joint will not increase.

[Effects of the Invention] As explained above, according to the present invention, since the structure is such that the confinement phenomenon does not occur in principle, it is possible to prevent the generation of impactful torque, and also to prevent the occurrence of impact torque. Since it can be abolished, costs can be reduced.

In addition, the hydraulic pressure that tries to open the valve part is smaller than the hydraulic pressure in the plunger chamber that acts on the rotor, which maintains the valve part's tight contact, reduces oil leakage from the valve part, and reduces torque caused by temperature changes. Fluctuations can be reduced, and since sealing is performed on the surface of the valve body, no axial length is required for sealing, and the length of the joint does not become long.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing one embodiment of the present invention, and FIG.
Fig. 3 is a view showing the orifice provided in the discharge port, and Fig. 4 (a-(:) is an explanatory diagram of the entrapment phenomenon. In the figure, 1... cam , 2...Cam surface, 3...Output shaft, 4...Cam housing, 5...Rotor, 6...Input shaft, 7...Plunger chamber, 8...Plunger 9 ... Return spring, 10... Suction and discharge hole, 11... Rotary valve, 12... Suction port, 13... Suction path, 14... Discharge port, 16... Needle bearing diversion Drive wheel 17... Orifice, 18... Notch, 19... Protrusion, 20... Thrust block, 21... Bearing, 22... Needle bearing, 23... Accumulator piston, 24...・Retainer, 25... Return spring, 26... Oil seal, 27... Stop ring, 28... Bolt, 29... Oil hole, 30... Bearing. Fig. 2

Claims (2)

[Claims] (1) A cam housing provided between relatively rotatable input and output shafts, connected to the one shaft, and having a cam surface having two or more ridges on the inner surface; connected to the other shaft. a rotor rotatably housed in the cam housing and having a plurality of plunger chambers formed in the axial direction; and a plurality of plungers driven by the cam surface when the two shafts rotate relative to each other; a suction/discharge hole formed in the rotor and communicating with the plunger chamber; rotatably slidingly contacted with an end surface of the rotor. and a valve body having a plurality of suction ports and discharge ports formed on its surface, which is positioned in a predetermined relationship with the cam housing and acts as a suction valve and a discharge valve depending on the positional relationship with the suction and discharge hole; A power transmission joint that transmits torque according to a rotational speed difference between the two shafts, comprising: means for generating flow resistance by the flow of discharged oil caused by the driving of the plunger; A hydraulic power transmission joint characterized in that the plunger chamber is provided so that the plunger chamber is not connected, and a flow resistance generating means is provided in each of the discharge ports. (2) The hydraulic power transmission joint according to claim 1, wherein the distance between the suction port and the discharge port is narrower than the diameter of the suction and discharge hole.