JPH0212277Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a new vacuum pump driven by a camshaft in an internal combustion engine of an automobile, etc. ), and by separating the vacuum pump from the generator, which used to be directly connected to the generator, the amount of work borne by the generator can be reduced, and by using camshaft lubrication, the vacuum pump can be A vacuum pump that simplifies the lubrication of the drive part, prevents lubricating oil from entering the discharged air, reduces the amount of blow-by, and further improves efficiency by using a generator alone. It is.

[Technical background of the invention and its problems] Diesel engines do not have a throttling mechanism when drawing air into the cylinders, so a large negative pressure cannot be expected in the intake manifold. However, brake boosters, air conditioners,
Alternatively, a negative pressure source is required for first idle rotation control, etc., and for this purpose, a vane type vacuum pump integrated with a generator is generally employed. As shown in FIG. 1, this vane type vacuum pump a is integrated with a generator c driven by a belt from a crankshaft b, and is directly connected and driven thereto. Further, as shown in Fig. 2, the vane type vacuum pump a has a roller f that is eccentric in a circular cylinder d and rolls along its inner wall e. A vane g is provided. As the roller f rolls inside the cylinder d, the vane g moves out from the roller f, and while the outer end h of the vane g comes into contact with the inner wall e of the cylinder d, the vane g moves into the cylinder d.
The internal space volume is divided, and each divided space repeatedly contracts and expands to perform a pump function.

By the way, the vane type vacuum pump, which operates as described above, has a large number of sliding parts due to its structure, which creates a large amount of resistance, and requires a large amount of work to drive the parts. An oil pipe must be installed to provide forced lubrication. Furthermore, returning the discharge side into the crankcase also contributes to increasing the amount of blow-by. On the other hand,
Due to the limitations imposed by the vacuum pump, the rotation speed of the generator cannot be increased, which poses a problem in improving efficiency and performance.

Incidentally, the applicant has previously disclosed the related technology as follows:
He proposed a ``vacuum pump driven by a camshaft in internal combustion engines of automobiles'' (Utility Model Application Publication No. 163930/1983).

[Purpose of the invention] The present invention has been devised in view of the above-mentioned problems and to effectively solve them.

The purpose of this invention is to simultaneously supply the required amount of negative pressure to various devices that consume different amounts of negative pressure, such as automobile brake boosters, air conditioners, and first idle speed control devices. To,
To provide a vacuum pump that constantly generates negative pressure that exceeds the total negative pressure of equipment and pools this in a vacuum tank, etc., and to run this vacuum pump by internal combustion without being driven by a generator. It is configured to be driven by the engine's valve drive cam.

[Means for Solving the Problems] In order to solve the above object, the present invention expands and contracts a plurality of pump chambers in which suction ports and discharge ports are sequentially connected in series, and a chamber provided within the pump chambers. The pump includes a diaphragm, a rod member that reciprocates each diaphragm, a biasing means that presses the diaphragm in the contraction direction, and a check valve that is provided at the suction port and the discharge port to prevent backflow of air inside the pump. In order to drive the diaphragms of each of the pump chambers in consecutive phases in the order in which the pump chambers are arranged, each rod member is provided in contact with a valve driving cam of an internal combustion engine that is rotated in consecutive phases.

[Operation] When the internal combustion engine is operated, the valve drive cam opens or closes the intake and exhaust valves. The valve drive cams, which rotate in mutually consecutive phases, respectively drive the rod members in consecutive phases in the order in which the pump chambers are arranged. As a result, the diaphragm of each pump expands and contracts in consecutive phases in the order in which the pump chambers are arranged. Here, the pressure changes between the pump chambers in which the intake port and the exhaust port are connected in series are as follows. First, it is assumed that the pressure in the adjacent pump chambers is atmospheric pressure, and that one pump chamber is expanded first by the cam. One pump chamber sucks air from a vacuum tank or the like to reduce the pressure in the chamber as it expands, making it a negative pressure. As a result, the amount of air in one pump chamber increases. When the lift of the valve cam changes from the maximum to the smallest, the diaphragm contracts the volume of one pump chamber due to the biasing force accumulated in the biasing means, opens the check valve, and opens the other pump chamber. Discharges the air stored in the room. As a result of this discharge, one pump chamber waits in a pressure state lower than atmospheric pressure until the next expansion (depressurization) stroke. On the other hand, before the end of the discharge stroke of the other pump chamber, the pump enters an expansion (depressurization) stroke, and the movement of air between both pumps becomes smooth, and an increased amount of air is sucked into the other pump chamber. As a result, the discharge amount of the other pump chamber increases, and the next suction force increases. When the above steps are repeated in each pump chamber, the amount of air suction in the adjacent pump chambers will gradually increase, and as the number of repetitions increases, the suction capacity will become greater.

Furthermore, driving the diaphragms of each pump chamber in consecutive phases in the order in which the pump chambers are arranged was devised from a frequency perspective.
By doing this, the capacity for suction (discharge) and intake of air in a given cycle can be dramatically increased.

Therefore, by adding pump chambers having diaphragms that are driven in consecutive phases in the order of arrangement, the capacity can be dramatically improved.
As suction capacity increases, the burden on each diaphragm pump is reduced and its lifespan is extended, improving the durability and reliability of the vacuum pump, and at the same time ensuring the negative pressure required for each device used. death,
It can be activated when necessary.

As a related technology, a ``fuel supply pump and tachometer for an internal combustion engine'' is provided with a camshaft that drives the intake and exhaust valves of the internal combustion engine via a gear transmission device, and the camshaft drives a fuel injection pump. ``Drive device'' (Utility Model Application Publication No. 56-81127) and ``Fuel injection system'' in which a fuel injection pump and a diaphragm pump that continuously supplies fuel to the fuel injection pump are simultaneously driven by one camshaft. There is a proposal for a fuel supply system for a type engine (Japanese Utility Model Publication No. 54-37714), but these are designed to adjust the amount of fuel introduced and discharged without creating bubbles in the flow of fuel. However, since the suction capacity corresponding to pressure changes is not dramatically improved when the amount of negative pressure required changes sequentially, it cannot be adopted as a vacuum pump.

[Embodiment of the invention] A preferred embodiment of the invention will be described below with reference to the accompanying drawings.

FIG. 3 shows a vacuum pump according to the invention installed in an internal combustion engine of the overhead camshaft type. Intake/exhaust valves 25 and 2 are provided inside the cylinder head cover 1 that partitions the upper part of the internal combustion engine.
On the camshaft 2 that drives the cam 6, cams 3 and 4 are individually provided for the intake and exhaust valves 25 and 26, respectively.

In this example, an in-line 4-cylinder internal combustion engine is used,
The ignition cylinder order is #1, #3, #4, #2
(#n indicates the nth arranged cylinder).
The opening and closing of intake and exhaust valves 25 and 26 provided in each cylinder are controlled by the phases shown in FIG. Vacuum pumps 5 and 6 are connected in series,
The vacuum pump 5 disposed on the upstream side is driven by the cam 3 that drives the intake valve 25 of the #2 cylinder, and the vacuum pump 6 disposed on the downstream side drives the exhaust valve (not shown) of the #3 cylinder. ) is configured so that the respective vacuum pumps 5 and 6 are continuously operated by a cam 4 that drives the vacuum pumps 5 and 6.

The detailed structure of the vacuum pumps 5 and 6 is as shown in FIG. 5. A housing 8 is provided on the cylinder head cover 1 to define a pump chamber 7, and the housing 8 has an inlet for sucking air into the pump chamber 7. 9 and a discharge port 10 for discharging are formed on the side wall 11 thereof. A diaphragm 12 for contracting and expanding the volume of the pump chamber 7 is provided within the housing 8, with its peripheral edge 13 locked to the upper edge 14 of the side wall 11. One end of a rod member 15 for reciprocating the diaphragm 12 is connected to the center of the diaphragm 12. The other end of the rod member 15 is inserted through the bottom 16 of the housing 8 and the cylinder head cover 1, and is connected to the cam 3 via the ball 18, tappet 17, etc.
It is in sliding contact with the cam 4. The peripheral edge 13 of the diaphragm 12 is connected to the side wall 11 in the upper part of the housing 8.
A canopy 19 is placed over the top edge 14 so as to sandwich it, and is fitted onto the top edge 14 from outside. A coil spring is provided as a biasing means 20 between the canopy 19 and the diaphragm 12, and this coil spring is used to push the diaphragm 12 so that the rod member 15 reciprocates following the cam profiles of the cams 3 and 4. The rod member 15 is constantly pressed toward the camshaft 2 through the camshaft 2.
In addition, the above-mentioned suction port 9 and discharge port 10 are provided with reverse directions, respectively, in order to cause the air therein to flow in one direction, that is, from the suction port 9 to the discharge port 10 side, as the volume of the pump chamber 7 changes. Stop valves 21 and 22 are provided.

Note that the canopy 19 is designed so that the air in the space between the diaphragm 12 and the canopy 19 can circulate in and out of the housing 8 as the diaphragm 12 reciprocates.
An air vent hole 23 is formed in the. Further, an oil seal 24 is provided at the sliding portion where the rod member 15 passes through the bottom portion 16 of the housing 8 to prevent the air in the pump chamber 7 from leaking due to the reciprocating movement of the rod member 15. .

Lubrication is performed in the same way as the cams 3 and 4 for intake and exhaust valves, and is carried out either by spray from the bearing part (not shown) of the camshaft 2 or by providing an oil groove (not shown) in the camshaft 2. Let's do it.

Next, the operation of the present invention will be explained.

First, the first feature is that driving force is obtained from the camshaft 2. Therefore, the function can be achieved independently of the generator (not shown), and the constraints on the generator side can be removed.

The camshaft 2 receives driving force from a crankshaft (not shown) and rotates. As the camshaft 2 rotates, the cams 3 and 4 press the rod member 15 upward against its profile. Rod member 15
is constantly pressed toward the camshaft 2 by the coil spring of the biasing means 20, so that it reciprocates along the profiles of the cams 3 and 4. As the rod member 15 reciprocates, the diaphragm 12 reciprocates its central portion, that is, the connection portion with the rod member 15, up and down. The volume inside the pump chamber 7 changes due to the reciprocating movement of the diaphragm 12, and the pump function is exerted. That is, when the diaphragm 12 descends, the volume of the pump chamber 7 contracts, and the air therein is discharged to the discharge port 1.
Send from 0. At this time, the check valve 21 of the inlet 9
is closed, and the check valve 22 of the discharge port 10 is opened. When the diaphragm 12 rises, the volume of the pump chamber 7 expands and the pressure within the pump chamber 7 decreases. Therefore, the check valve 22 of the discharge port 10 is closed, the check valve 21 of the suction port 9 is opened, and air is sucked into the pump chamber 7. This action is repeated between the vacuum pumps 5 and 6 connected in series as the cams 3 and 4 rotate, thereby creating a multi-stage pump function. Further, the cams to be selected may be a combination of cams whose respective phases operate continuously.
(For example, #1 intake cam and #3 intake valve cam, or #1 exhaust valve cam and #3 exhaust valve cam, etc.)
See Figure 4. ) Since an oil seal 24 is provided at the sliding part where the rod member 15 passes through the housing 8 of the pump chamber 7, lubricating oil does not enter into the pump chamber 7, and therefore discharged air can be released to the atmosphere. Also, the discharged air can be connected to an air cleaner (not shown).
Even if it is returned to the side, it will not cause an increase in the amount of blow-by.

In addition, its sliding resistance is extremely low compared to vane-type vacuum pumps, and horsepower consumption can be significantly reduced.
Fuel efficiency can be improved. According to experiments, the horsepower required to obtain the required degree of vacuum is approximately 10% of that of a vane-type vacuum pump.

In this embodiment, an overhead camshaft type internal combustion engine has been described, but even in an overhead valve type internal combustion engine, a vacuum pump using the above-mentioned diaphragm is attached to the cylinder body, etc., and the vacuum pump is operated by a camshaft. Of course, similar effects can be obtained by driving. Further, the housing of the vacuum pump may be integrally formed with a mounting portion such as a cylinder head cover. Furthermore, sucking
In addition to the cam for driving the exhaust valve, a dedicated cam for driving only the vacuum pump may be provided on the camshaft.

In the vacuum pumps 5 and 6, the driving parts (balls 17 and tappets 18) are well lubricated by the lubricating oil that lubricates the camshaft 2, and the lubricating oil is not mixed into the pump chamber 7. Only clean air will be exhausted. Furthermore, since the vacuum pumps 5 and 6 are separated from the generator, the load on the generator is greatly reduced, making it possible to downsize the generator and increase its efficiency.

[Effects of the Invention] As is clear from the above explanation, the present invention provides the following excellent effects.

(1) Each pump is designed to simultaneously supply the required amount of negative pressure to various devices that consume different amounts of negative pressure, such as automobile brake boosters, air conditioners, and fast idle speed control devices. The suction capacity is increased by changing the pressure in the chamber, and the suction capacity is increased in terms of frequency (cycle), so it is no longer necessary to constantly generate negative pressure that exceeds the total negative pressure of the equipment. We can provide high-efficiency, high-capacity vacuum pumps.

(2) The load on the generator can be reduced by separating the vacuum pump from the generator.

[Brief explanation of the drawing]

Fig. 1 is a schematic configuration diagram showing the drive system of a conventional vacuum pump, Fig. 2 is a side cross-sectional view showing a vane type vacuum pump, which is a conventional example of a vacuum pump, and Fig. 3 is an illustration of a vacuum pump according to the present invention. FIG. 4 is a side sectional view showing an embodiment; FIG. 4 is a graph showing an embodiment of the opening/closing phase change of the intake and exhaust valves of an internal combustion engine according to the present invention; FIG. 5 is a detailed configuration of the vacuum pump according to the present invention. FIG. 3 is a side sectional view showing one embodiment of the invention. In the figure, 1 is a cylinder head cover, 2 is a camshaft, 3 and 4 are cams for intake and exhaust valves, 5 and 6 are vacuum pumps, 7 is a pump chamber, 9 is an intake port, 10 is a discharge port, 12 is a diaphragm, 15 is a rod member,
20 is a biasing means, and 21 and 22 are check valves.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) A plurality of pump chambers in which suction ports and discharge ports are connected in series, a diaphragm installed in the pump chamber to expand and contract the chamber, and each diaphragm capable of reciprocating motion. a rod member that operates to compress the diaphragm; and a biasing means that presses the diaphragm in the contraction direction.
A check valve is provided at the suction port and the discharge port to prevent backflow of air in the pump chamber, and the rod members are driven in consecutive phases in order to drive the diaphragms of each pump chamber in consecutive phases in the order in which the pump chambers are arranged. 1. A vacuum pump driven by a camshaft in an internal combustion engine of an automobile or the like, characterized in that the vacuum pump is provided in contact with a valve drive cam of an internal combustion engine rotated by a motor vehicle. (2) The pump chamber is driven by a camshaft in an internal combustion engine of an automobile or the like as set forth in claim 1 of the utility model registration claim, wherein the pump chamber is integrally formed on a cylinder head cover that partitions the internal combustion engine. vacuum pump.