JPH0619877Y2 - Sealing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a sealing device having an improved side surface of a seal ring.

(Prior Art) Rotational hydraulic equipment such as transmissions connected to engines of automobiles, construction machinery, etc. are used for the purpose of reducing rotary inertia force, rotational vibration, weight reduction and cost reduction of rotating parts. There is a tendency to adopt soft materials such as aluminum die casting as the material.

An example of such a device will be described with reference to FIGS.

In FIG. 5, a rotary shaft 51 of a conventional rotary hydraulic device is rotatably supported by a casing 52 as a support member,
The seal ring 5 is inserted into the ring groove 53 formed in the rotary shaft 51.
No. 4 is mounted to seal the fitting gap between the rotary shaft 51 and the casing 52, prevent leakage of fluid such as pressure oil flowing from the flow path 55, and prevent decrease in hydraulic pressure of the device.

The pressure P of the fluid flowing in from the flow path 55 acts on the side surface and the inner peripheral surface of the seal ring 54 as shown in FIG. 6, and the side surface 56 of the seal ring 54 and the side surface 57 of the ring groove 53 and the inner surface 58 of the casing 52. Can be pressed against. In this state, the rotary shaft 51 rotates, and relative rotational sliding is performed between the ring groove side surface 57 and the seal ring side surface 56. Further, also in a structure in which the shaft is fixed and the casing rotates, relative rotation slides similarly.

The seal ring used in such hydraulic equipment is a synthetic resin seal ring made by filling carbon powder, copper powder, glass, carbon fiber, etc. into tetrafluoroethylene resin, which has excellent characteristics in relative sliding. Hereinafter, PTFE containing a filler is often used. Further, as the seal ring shape, for example, a normal right-angled opening or an oblique opening having a short cross section is used.

(Problems to be solved by the present invention) When a normal PTFE seal ring containing a filler is used in accordance with higher rotation speed and higher hydraulic pressure for improving the performance of hydraulic equipment, the side surface of the seal ring and the side surface of the ring groove are used. The frictional heat on the sliding contact surface between the and the seal ring abnormally increases, exceeds the heat-resistant temperature of the seal ring material, softens the material, reduces wear resistance, and causes abnormal wear on the side surface of the seal ring, resulting in malfunction.

Further, another problem is that torque loss due to friction between the seal ring side surface and the ring groove side surface is large, a reduction in transmission torque and a decrease in rotation speed are observed, and a loss in engine output results.

Conventionally, in a metal seal ring, as shown in FIG. 7, there are examples of radially arranging grooves penetrating inside and outside, and annular grooves penetrating in the circumferential direction as shown in FIG. 8 are provided. The sealing fluid flows directly to the outside, and the sealing performance deteriorates. The latter has drawbacks such as oil staying in the groove to reduce the cooling efficiency, and fine foreign matters such as abrasion powder flowing in the equipment together with the fluid to accumulate in the groove to accelerate wear on the side surface of the ring groove.

Compared to metal seal rings, synthetic resin seal rings
Since the thermal conductivity is extremely low, the measures in the previous example have not suppressed softening of the seal ring material due to frictional heat.

Further, in the case of forming the groove as in the preceding example, in the case of a metal seal ring, it is possible to fit and fix the cylindrical jig by utilizing the self-expanding force of the seal ring, It was impossible to adopt this kind of processing method with a resin seal ring having low rigidity and softness. In addition, processing burrs are generated when cutting the resin material, which makes it difficult to adopt.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention basically has a cooling groove in the circumferential direction on the side surface and a communication groove communicating from the inner circumferential direction to the cooling groove of the resin material. A seal ring was used in which a mold having a convex groove was pressed against the side surface of the seal ring by utilizing its softness to form a cooling groove and a communication groove on the side surface of the seal ring.

(Operation) As is apparent from FIG. 6, the hydraulic pressure acting on one side surface and the inner peripheral surface of the seal ring presses the seal ring against the ring groove side surface, so that the seal ring side surface and the ring groove side surface face each other. Although it makes rotation, the oil flows from the communication groove into the cooling groove and constantly supplies the lubricating oil to the sliding surface to simultaneously perform the lubrication and the cooling action. As a result, it is possible to prevent abnormal wear of the side surface of the seal ring and reduction of torque transmission efficiency.

Since the cooling groove is located radially inward of the outer peripheral surface of the shaft, there is almost no oil leakage through the cooling groove.

The cooling groove in the circumferential direction and the communication groove in the radial direction supply oil to the sliding surface while circulating the oil and do not allow the oil to stay, so even if foreign matter enters the cooling groove, Foreign matter can be removed before the side surface of the ring groove is scratched. Since the groove is formed by pressing, there is no burring.

(Embodiment) FIGS. 1-3 show a PTFE seal ring 7 used in the device of the present invention. In the illustrated example, a right angled abutment is used, but the shape of the abutment does not matter. An annular cooling groove 8 and a communication groove 9 extending in the circumferential direction are provided on both side surfaces 2 and 3 of the seal ring 7 by press molding. Seal ring 7
A plurality of communication grooves 9 communicating with the cooling groove 8 from the inner peripheral surface of the above are provided separately. In the illustrated example, four communication grooves 9 are provided at equal intervals.

Although the center of the cooling groove 9 is concentric with the center of the ring, the center of the cooling groove 9 may be decentered from the center of the ring. However, the center of the cooling groove 9 should be located radially inward of the outer peripheral surface of the shaft when the seal ring 7 is used in the hydraulic device as shown in FIG.

(Example) Using the test apparatus shown in FIG. 4, a comparative test was performed between the conventional example and the present invention. The test apparatus 10 has a casing 52 made of aluminum die casting and a shaft 51 made of the same material, and the free end of the shaft 51 is inserted into the casing 52. A pair of ring grooves 53 is provided on the outer peripheral surface of the shaft 51, and a flow passage 55 for oil is provided in the shaft 51.
Open between 3 A sample described later is mounted in the ring groove 53.

The casing 52 includes the motor 1 via the torque meter 11.
The casing 52 is rotated 6000 times per minute by connecting to the motor 2 and operating the motor 11. This is the motor 1
Set the number of rotations to 1. Casing 52 is 6000 rpm
When the hydraulic pressure is not acting on the flow passage 55, the torque meter 11 is set to 0 kg · m.

Oil having an oil temperature of 120 ° C. and an oil pressure of 10 kgf / cm ² is added to the flow passage 55 while rotating the motor 11 at the set rotation speed. Such a hydraulic pressure is applied to the pair of ring grooves 53, the friction torque (kg · m) between the ring side surface and the ring groove side surface for each sample mounted in the ring groove is read by the torque meter 11, and when a load is applied. The actual rotation speed of the motor 12 and the amount of oil leak were measured. The amount of oil leakage (cc / min) and the oil leaked from the hole 13 and the side edge 14 of the casing 52 were measured by the graduated cylinder 15. The test results after 100 hours of continuous operation are shown below.

Each sample had an outer diameter of 70 mm, a width of 2 mm, and a thickness of 2 mm. The groove 8 has a semicircular shape with a radius of 0.3 mm and a depth of 0.3 mm, and the groove 9 has a radius of 0.5 mm and a depth of 0.3 mm. Further, making the cross-sectional area of the communication groove larger than that of the cooling groove is effective for accelerating the oil flow.

(Effect) The seal ring according to the present invention is
It is possible to reduce the friction torque and the wear amount, reduce the friction torque and the wear amount as compared with the comparative examples of Samples 2 and 3, and reduce the oil leak amount. As a result, the durability of the hydraulic equipment can be improved. Further, since the cooling groove and the connecting groove of the seal ring of the present invention allow the oil to circulate, foreign matter entering the groove can be immediately removed from the groove and abnormal wear of the side surface of the ring groove can be prevented. Furthermore, the device according to the invention does not show any reduction in the number of revolutions.

[Brief description of drawings]

FIG. 1 is a partial perspective view of a seal ring used in an example of the present invention, FIG. 2 is a sectional view thereof, FIG. 3 is a plan view thereof, FIG. 4 is a side view of a test apparatus, and FIG. FIG. 6 is a partial sectional view showing the hydraulic pressure acting on the seal ring, and FIGS. 7 and 8 are partial perspective views of a comparative example considered from the conventional example. In the figure: 7 ... Seal ring, 8 ... Cooling groove, 9 ... Radial groove, 51 ... Groove, 52 ... Casing, 53 ... Ring groove.

Claims (1)

[Scope of utility model registration request] 1. A synthetic resin seal ring having circumferentially extending cooling grooves formed on both sides thereof, and a plurality of spaced communication grooves radially extending from the inner circumferential side to the cooling groove. The seal ring is mounted in the ring groove formed on the shaft so that the cooling groove and the communication groove face the side wall of the ring groove and the inner peripheral side opening of the communication groove faces the bottom wall of the ring groove. A sealing device in which the maximum diameter portion of the cooling groove in the circumferential direction of the ring is located radially inward of the outer peripheral surface of the shaft.