JPH04112976A - Reciprocating vacuum pump - Google Patents

Abstract

PURPOSE:To make a reciprocating vacuum pump smaller by forming the lubrication section of a cranking mechanism in an oilless lubrication system to eliminate the need for a conventional wipering box and directly connecting a bellows gland to a cylinder bottom cover to eliminate the need for a conventional distance piece room. CONSTITUTION:Sintered alloys containing solid lubricant are used for a pair of cross head guide bushes 121, cross head pin bushes 131 and crank pin metals 151 in a cranking mechanism 10, sealed bearings are used for a pair of crank shaft bearings 17, and a grease sealed oilseal is used for a crank shaft sealing device 18, in which cases oilless lubrication is allowed. A bellows gland 26 has a valve head frange 261 fitted with a cylinder bottom cover 25 and a block 27 fixed thereto with bolts 271, and a bottom frange 262 inserted therein through a rod through-hole 252 in the cylinder bottom cover 25 and a rod through-hole 270 in the block 27 and fixed with bolts 272 threaded into a cross head 11.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a reciprocating vacuum pump in which the height (length) from the crankcase to the cylinder head cover is greatly shortened.

Problems to be Solved by the Prior Art and the Invention In the conventional reciprocating vacuum pump, as shown in FIG. At this point, an oil stopper 230B is provided on the piston rod 23B to drain oil, and the piston rod 23B connected to the piston 21B in the cylinder 22B is sealed by a shaft sealing device 26B provided with a packing box. Since it had reached the resistance piece chamber 29B, the cylinder head cover 24 was removed from the crankcase 19B.
There is a disadvantage that the height (length) up to B is large,
It was a miniaturized FL book.

The present invention provides a reciprocating vacuum pump that can reduce the height (length) from the crankcase to the cylinder head cover as much as possible, contributing to miniaturization.

Means for Solving the Problems To achieve the above problems, the reciprocating vacuum pump of the present invention has the following features:
As shown in the drawing, the lubricating part of the crank movement mechanism is oil-free, the piston rod shaft sealing device is a bellows gland, the head flange is attached to the cylinder bottom cover, and the bottom flange is attached to the crosshead. This allows the height (length) from the case to the cylinder head cover to be significantly shortened.

In the present invention, the crank movement mechanism includes a crosshead,
The concept includes the cross head guide, connecting rod, cross gear pin, crankshaft, crank pin, crankshaft bearing, crankshaft shaft sealing device, crank case, etc. The lubricating parts are the cross head guide, cross gear pin, crankshaft, etc. There are cylinders, crankshaft bearings, crankshaft shaft seals, etc., and for oil-free lubrication of these parts, sintered alloys with a fixed lubricant, shielded bearings, grease-filled seals, etc. are used.

In addition, the bellows gland as a piston shaft sealing device is
A bellows made of thin metal that is formed or welded into an accordion shape so that it can expand and contract, and seals the piston rod.

EMBODIMENTS The drawings show an actual example of the reciprocating vacuum pump of the present invention.

The vacuum pump of this example includes a crank movement mechanism 10, a piston movement mechanism 20, a flywheel section 30, and a drive motor section 4.
It consists of 0.

The crank movement mechanism 10 includes a crosshead 11 that reciprocates via a pair of crosshead guides 12, a connecting rod 14 rotatably connected to the cross via a radbin 13, and a pair of connecting rods 14. The crankshaft 16 includes a crankshaft 16 rotatably connected via a crank bin 15, a pair of bearings 17 that supports the crankshaft 16, a shaft sealing device 18 that seals the crankshaft 16, and a crankcase 19. There is.

Each of the pair of crossbeds 11 is provided with an air circulation hole 110 that penetrates into the crankcase inner cavity 190 and a space 260 in which a bellows gland type piston rod shaft sealing device 26 described later is provided.

Furthermore, a water jacket 120 is provided around the outer periphery of the crossbed guide 12.

1 pair each of cross head kite bushes 121, radbin push to cross 131, crank pin metal 1
51 is a sintered alloy containing a solid lubricant, the pair of crankshaft bearings 17 is a shield type bearing, and the crankshaft shaft sealing device 18 is a grease-sealed oil ring, so that oil-free lubrication is possible. It has become.

The piston movement mechanism 20 includes two horizontally opposed reciprocating pistons 21.21 (the pistons on the unique side and the left side both move toward the bottom dead center, and both move toward the top dead center).
and a pair of cylinders 22, each with a piston 2 at one end.
A piston rod 23 is connected to the cylinder head cover 24 through a ■-shaped band coupling 28, a piston rod 23 is connected to the rod 11 at the other end, and a cylinder bottom cover 25 is tightly connected to the cylinder head cover 24 via a ■-shaped band coupling 28. A piston rod shaft sealing device 26 and gas communication are provided. A tube (not shown) is provided.

Each piston 21 is fitted with a piston ring 211 whose main component is tetrafluoroethylene resin, and a lighter blade ring 213 whose main component is tetrafluoroethylene resin is fitted to the inner wall of the cylinder 22. It is designed to be able to slide without lubrication. Additionally, each of the pair of pistons 21 is provided with an intake and exhaust valve 214 on its upper surface. Furthermore,
The cylinder head cover 24 is provided with an intake valve 241 at a position corresponding to the intake and exhaust valve 214 of the piston 21. The cylinder bottom cover 25 also includes a piston 2.
A discharge valve 251 is provided at a position corresponding to one intake/exhaust valve 214.

As shown in FIGS. 1 and 2, the bellows gland 26 is constructed by fitting a valve head flange 261 with a cylinder bottom cover 25 and a retaining plate 27 fixed to the cylinder bottom cover 25 by screwing bolts 271 into the bottom cover. The flange 262,
The rod 1 is inserted into the cross through the rod through hole 252 of the cylinder bottom cover 25 and the rod through hole 270 of the holding plate 27.
The piston rod 23 is fixed to the cross by a bolt 272 screwed into the piston rod 1, and the convex portion 231 formed at the rear end of the piston rod 23 is fitted between the bottom flange 262 and the rod 11 to the cross. Rad 11
is connected to.

In addition, in this example, as in the conventional opposed type reciprocating vacuum pump, the weights of the opposing reciprocating parts are made equal, and the unbalanced inertia of the rotating part is balanced.
Furthermore, each cylinder 22 is centered around the crankshaft 16.
are arranged horizontally so that the axis of each cylinder 22 is in a straight line, and the crankshaft 16 has three crank bins 15 adjacent to each other at an angle of 180°, with the central crank bin 15 being straight. Connecting rod 1
Crosshead 1 of one piston rod 23 via 4
1, and the crank bins 15.15 on both sides of the central crank bin 15 are connected to the crosshead 11 of the other piston rod 23 via a bifurcated connecting rod 14.

In the vacuum pump of the present invention, as the right piston 21 moves from the top dead center to the bottom dead center (pull stroke), gas is sucked in from the suction port 240 of the right cylinder head cover 24 and enters the suction chamber 242. , the waste is sucked into the cylinder 22 from the suction valve 241. At this time, since the intake and exhaust valves 214 of the piston 21 are closed, the debris inside the cylinder 22 on the bottom dead center side of the piston 21 is removed from the discharge valve 251 of the cylinder bottom cover 25 as the piston 21 moves toward the bottom dead center. The gas is discharged from the discharge port 250, passes through a gas passage pipe (not shown), and enters the suction port 240 of the left cylinder head cover 24.
It enters the suction chamber 242 from the suction valve 241 (at this time, the left piston 21 moves toward the bottom dead center as the right piston 21 moves toward the bottom dead center), and then enters the cylinder 22 from the suction valve 241. Since the intake and exhaust valves 214 of the piston 21 are closed, the gas in the cylinder 22 on the bottom dead center side of the piston 21 moves toward the bottom dead center of the piston 21.
From the discharge valve 251 of the cylinder bottom cover 25 to the discharge port 2
50 and led to the outside.

When the right and left pistons 21 move from the bottom dead center to the top dead center (push stroke), their intake and exhaust valves 214 act as intake valves. In other words, the right piston is
As shown in Figure 2, as you move from bottom dead center to top dead center,
The intake/exhaust valve 214 of the piston 21 on the right side is closed due to the difference between the gas pressure sucked in during the retraction stroke and the valve plate spring pressure, causing gas to flow into the cylinder 22 on the bottom dead center side of the piston 21. Inhale. At this time, the discharge valve 251 is closed. The left piston 21 also performs the suction operation in the same way as the right piston 21.

Effects of the Invention In the present invention, the lubricated portion 121 .
By making 131, 151, and 17.18 oil-free, the conventional wiper ring box and oil stopper can be abolished, and the bellows gland 2
6 is directly connected to the cylinder bottom cover 25 and cross to the Rad 11, the conventional distance piece chamber can be abolished. As a result, the height (length) from the crankcase 19 to the cylinder cover 24 can be significantly shortened, and this can greatly contribute to downsizing of the reciprocating vacuum pump.

[Brief explanation of the drawing]

1, 2 and 3 show embodiments of the present invention,
FIG. 1 is an overall front view showing a portion in section, FIG. 2 is a sectional view of the main part, and FIG. 3 is a partially enlarged sectional view of the main part. FIG. 4 is an explanatory diagram of a conventional example. 10... Crank movement mechanism 11... Cross head 19... Crank case 24... Cylinder head cover 25... Cylinder bottom cover 26... Bellows gland 261... ...Head flange 262 ...Bottom flange

Claims (1)

[Claims] The lubricating part of the crank movement mechanism is oil-free, the piston rod shaft sealing device is a bellows gland, the head flange is attached to the cylinder bottom cover, the bottom flange is attached to the crosshead, and the height from the crankcase to the cylinder head cover is A reciprocating vacuum pump characterized by being able to greatly shorten its length.