Compressor system for puncture repair kit

Abstract

The invention relates to a compressor system for a puncture repair kit, having a piston (3) driven by a motor (8) via a crank mechanism, and a cylinder body (1) with a pump chamber (6) in which the piston (3) is mounted so as to be movable from a bottom dead center to a top dead center for compressing air.

Description

Technical Field

[0001] The invention relates to a compressor system for a puncture repair kit, the compressor system having a piston driven by a motor via a crank mechanism with two gears, and a cylinder body with a pump chamber in which the piston is mounted so as to be movable from bottom dead center to top dead center for compressing air. Furthermore, the invention relates to a puncture repair kit comprising the compressor system and to a method for sealing a vehicle tyre. Background Art

[0002] Compressor systems for puncture repair kits of the type described above are known for use in passenger car tires. Such puncture repair kits are designed to provide the required volume of compressed air at the required pressure for a passenger car tire within a specified time. The known compressor systems for puncture repair kits are not designed for vehicle tires, such as vehicle tires of vans or trucks, which have a larger volume and / or a higher filling pressure. The volume flow provided is too low to fill such vehicle tires within the allotted time. The required long operating times often lead to overheating of the compressor system and the known compressor systems are unable to reach the required filling pressure. This is due to the fact that the known compressor systems are made of plastic in order to achieve low weight and small overall dimensions.

[0003] US 2020 / 0158099 A1 discloses a compressor system made of plastic in which the outlet end piece of the cylinder (which is releasably connected to the outlet unit) has a metal insert to reinforce this area for the high pressures and temperatures prevailing there. Summary of the invention

[0004] Against this background, the invention is based on the object of providing a compressor system for a puncture repair kit of the type mentioned in the opening paragraph, which compressor system has a reliable and cost-effective producible design, has a low weight, has small overall dimensions and is able to achieve higher volume flows and higher filling pressures when filling vehicle tires.

[0005] This object is achieved by a compressor system according to the features of claim 1, a puncture repair kit and a method according to the further independent claims. The dependent claims relate to particularly advantageous developments of the invention.

[0006] Therefore, according to the present invention, a compressor system for a puncture repair kit is provided, which includes a motor, a piston driven by the motor via a crank mechanism, and a one-piece cylinder body, which has a pump chamber and a receiving chamber, wherein the piston is installed in the pump chamber so as to be movable from the bottom dead center to the top dead center to compress the air, and the receiving chamber is used to receive the compressed air compressed in the pump chamber through the outlet valve, wherein the cylinder body is a plastic component, wherein the cylinder body has a metal insert in the area of ​​the outlet valve.

[0007] It has been found that a one-piece cylinder body forming the pump chamber and the receiving chamber is particularly reliable with small dimensions and therefore low weight. Due to the one-piece design of the area exposed to high pressure and temperature, it is not necessary to connect and seal multiple parts in this area. Due to the prevailing pressures and the forces generated thereby, the plastic flange must have larger dimensions at the prevailing temperature in order to achieve a tight connection that is as durable as possible.

[0008] The cylinder body has a metal insert in the area of ​​the outlet valve, because it has been recognized that the highest temperatures and high flow velocities are reached in this area, with the result that there are high thermal loads on the plastic and, at the same time, high mechanical loads due to the high flow velocities and prevailing pressures. Known plastics cannot withstand these loads for a relatively long period of time without being damaged. Known compressors designed for the required pressures and volume flows are made of metal and therefore have larger overall dimensions and are significantly heavier.

[0009] According to the invention, it has been recognized that a one-piece cylinder body made of plastic is suitable for providing a low-weight compressor system which allows higher filling pressures to be achieved at high volume flow rates than known compressor systems of this type if the one-piece cylinder body has a metal insert in a particularly loaded area. The metal insert preferably consists of an iron alloy, a zinc alloy or an aluminum alloy.

[0010] A one-piece cylinder body is understood to mean that the cylinder body is not composed of multiple parts that form sealing surfaces relative to each other or that must be disassembled in the event of maintenance or repair. However, the one-piece cylinder body is composed of multiple materials, such as plastic and a metal insert, and preferably of fiberglass. Preferably, the metal insert is overmoulded with the plastic of the cylinder body. However, the metal insert may alternatively be permanently connected to the plastic using other known means to form a one-piece cylinder body.

[0011] A preferred embodiment provides that at least the plastic of the cylinder body is a glass fiber reinforced plastic, preferably a polyamide, which preferably has a glass fiber content of 40% to 60%, further preferably 45% to 50%. Plastics with a glass fiber content of at least 40% and not more than 60% are particularly suitable for use as the cylinder body due to their high mechanical and thermal load-bearing capacity. Polyamide has proven to be a particularly suitable plastic. Preferably, at least the other highly loaded components also have such a glass fiber content.

[0012] Another preferred embodiment provides that the metal insert is encapsulated by the plastic of the cylinder body in a strongly locked manner, and further preferably, partial regions of the metal insert extend through the outer surface of the plastic of the cylinder body. The strongly locked encapsulation of the metal insert by the plastic ensures a tight connection between the metal insert and the plastic even under high thermal and mechanical loads. The partial regions of the metal insert protruding from the plastic of the cylinder body into the surroundings allow for an effective heat dissipation to the surroundings. In particular, these partial regions can be designed as cooling fins and be positioned in regions with increased air flow.

[0013] Another preferred embodiment provides that the gas outlet valve is a non-return valve, in particular a reed valve. Non-return valves are reliable, inexpensive to produce and have proven to be suitable (in particular up to medium gas exchange frequencies) gas outlet valves. Reed valves are preferably used because they are particularly efficient, i.e. produce low return losses, and are lightweight. In particular, reed valves enable efficient gas exchange even at higher gas exchange frequencies.

[0014] Another preferred embodiment provides that the crank mechanism comprises a gear, wherein the gear consists of metal at least in some areas, preferably entirely. Plastic gears have a lower durability at the high pressures that occur at high volume flows and therefore at the high powers to be transmitted, with the required compact overall design. It has proven to be advantageous to produce particularly loaded partial areas, such as the teeth of the gear, from metal, since this enables a compact overall design and durable, reliable operation. Gears consisting solely of metal have proven to be particularly durable and inexpensive.

[0015] Another preferred embodiment provides that, in order to limit the maximum pressure in the pump chamber, the pump chamber forms a dead volume, in particular a variable dead volume depending on the pressure in the pump chamber. Limiting the maximum pressure in the pump chamber by means of the dead volume makes it possible to limit the maximum pressure cheaply and reliably. This way of limiting the maximum pressure is still more efficient than blowing out the compressed air via a pressure reducing valve at high pressure. This reduces the temperature load in the pump chamber, especially under the high thermal load and high mechanical load present at high pressure. Under operating conditions where it is not necessary to limit the pressure, the dead volume reduces the efficiency. Therefore, a dead volume that depends on the pressure in the pump chamber (i.e., increases at high pressure) is preferred because it improves the efficiency at lower pressures, thereby achieving a lower heating of the pump chamber, as a result of which the maximum temperature reached when filling the vehicle tire is reduced. For example, the variable dead zone can be formed, for example, by a second spring-loaded piston (the second spring-loaded piston is attached to the pump chamber parallel to the outlet valve), or by means of an elastic sidewall of the pump chamber.

[0016] Another preferred embodiment provides that the cylinder body is suitable for providing a maximum pressure of at least 7 bar, preferably at least 8 bar, further preferably at least 9 bar, most preferably at least 10 bar, wherein the temperature in the region of the cylinder body is at least 150° C., preferably at least 170° C., further preferably at least 190° C., further preferably at least 220° C., most preferably at least 250° C. A cylinder body suitable for providing a maximum pressure of at least 7 bar at a temperature of at least 150° C. enables a compressor system for a puncture repair kit which can generate a higher filling pressure at a high volume flow. If the cylinder body is suitable for even higher pressures and temperatures, even higher filling pressures can be generated at high volume flows. Higher filling pressures are to be understood as meaning, in particular, filling pressures in vehicle tires of at least 3 bar, preferably at least 4 bar, further preferably at least 5 bar.

[0017] According to the invention, a puncture repair kit is provided, comprising a compressor system according to the invention, and a sealant device, wherein the sealant device has a sealant for sealing a vehicle tire, wherein the compressor system can preferably be connected to the sealant device. The puncture repair kit according to the invention is capable of sealing a vehicle tire and of filling the vehicle tire with a higher filling pressure, wherein the compressor system is particularly advantageous in its use as a puncture repair kit, since the puncture repair kit must have a low weight and small overall dimensions.

[0018] According to the invention, there is provided a method for sealing a vehicle tyre using a compressor system according to the invention or a puncture kit according to the invention, the method comprising at least the following steps:

[0019] i) establishing a positive pressure by means of a piston in a compressor system, wherein the positive pressure in the cylinder body is at least 8 bar, preferably at least 9 bar, more preferably at least 10 bar,

[0020] ii) The sealant is delivered into the vehicle tyre by means of the positive pressure established in the compressor system.

[0021] The method for sealing a vehicle tyre with a sealant according to the invention is advantageous because, by virtue of the high pressure that can be generated in the cylinder body, the vehicle tyre can be filled with a higher pressure at a high volume flow and can be preferably sealed. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The present invention allows for many embodiments. To further illustrate its basic principles, one embodiment of these embodiments is shown in the accompanying drawings and will be described below. In the drawings:

[0023] Figure 1 A compressor system for a puncture repair kit is shown.

[0024] List of Reference Numerals

[0025] 1 Cylinder body

[0026] 2-link

[0027] 3 Piston

[0028] 4 Intake valves

[0029] 5 Sidewall

[0030] 6 Pump chambers

[0031] 7 Exhaust valve

[0032] 8 Receiving chamber

[0033] 9 Motor

[0034] 10 First Gear

[0035] 11 Second Gear

[0036] 12 Metal inserts DETAILED DESCRIPTION

[0037] Figure 1 A compressor system for a puncture repair kit is shown having a one-piece cylinder body 1 receiving a piston 3 driven by a connecting rod 2, the cylinder body having an inlet valve 4 in a side wall 5 of a pump chamber 6. The cylinder body 1 includes an outlet valve 7 which prevents the compressed air from flowing back from a receiving chamber 8.

[0038] If the motor 9 drives the second gear 11 via the first gear 10, the connecting rod 2 moves the piston 3 in the direction of the bottom dead center, as a result of which the outlet valve 7 closes and air flows into the pump chamber 6 through the open inlet valve 4. After passing the bottom dead center, the inlet valve 4 closes, the air in the pump chamber 6 is compressed and delivered through the open outlet valve 7.

[0039] When reaching the top dead center, the air heated by compression reaches its highest temperature, wherein the highest thermal load of the cylinder body 1 is caused by the flow generated in the narrowed pump chamber 6 area located immediately upstream of the outlet valve 7 in the flow direction. Due to the pressure, the highest mechanical loads are also present in this area of ​​the pump chamber 6. In order to withstand such thermal and mechanical loads, the cylinder body 1, which mainly consists of glass fiber reinforced plastic, has a metal insert 12 in this area, which forms the surface of the cylinder body 1 in the high-load area. The metal insert 12 is formed in one piece with the plastic of the cylinder body 1 and is connected to the plastic in a strong locking manner by an injection molding process.

Claims

1. A compressor system for a puncture repair kit, include: - a motor (8), - a piston (3) driven by the motor (8) via a crank mechanism, and a one-piece cylinder body (1) having a pump chamber (6) in which the piston (3) is mounted so as to be movable from the bottom dead center to the top dead center for compressing air, and a receiving chamber (8) for receiving the compressed air compressed in the pump chamber (6) through an outlet valve (7), Wherein, the cylinder body (1) is a plastic component, The cylinder body (1) has a metal insert (12) in the area of ​​the outlet valve (7).

2. The compressor system according to claim 1, characterized in that At least the plastic of the cylinder body (1) is glass fiber reinforced plastic, preferably polyamide, and the glass fiber content of the glass fiber reinforced plastic is preferably 40% to 60%, more preferably 45% to 50%.

3. The compressor system according to claim 1 or 2, characterized in that: The metal insert (12) is encapsulated by the plastic of the cylinder body (1) in a strongly locked manner, and preferably a partial area of ​​the metal insert extends through the outer surface of the plastic of the cylinder body (1).

4. The compressor system according to any one of the preceding claims, characterized in that The outlet valve (7) is a check valve, in particular a reed valve.

5. The compressor system according to any one of the preceding claims, characterized in that The crank mechanism comprises gear wheels (8, 9) which are made of metal at least in some areas, preferably entirely of metal.

6. The compressor system according to any one of the preceding claims, characterized in that In order to limit the maximum pressure in the pump chamber (6), the pump chamber (6) forms a dead volume, in particular a variable dead volume which depends on the pressure in the pump chamber (6).

7. The compressor system according to any one of the preceding claims, characterized in that The cylinder body (1) is suitable for providing a maximum pressure of at least 7 bar, preferably at least 8 bar, further preferably at least 9 bar, most preferably at least 10 bar, wherein the temperature in the area of ​​the cylinder body (1) is at least 150°C, preferably at least 170°C, further preferably at least 190°C, further preferably at least 220°C, most preferably at least 250°C.

8. A puncture repair kit comprising a compressor system as claimed in any one of the preceding claims, and a sealant device, wherein: The sealant device has a sealant for sealing a vehicle tire, wherein the compressor system can preferably be connected to the sealant device.

9. A method for sealing a vehicle tyre using a compressor system according to any one of claims 1 to 7 or a puncture kit according to claim 8, the method comprising at least the following steps: i) establishing a positive pressure by means of a piston (3) in the compressor system, wherein the positive pressure in the cylinder body (1) is at least 8 bar, preferably at least 9 bar, more preferably at least 10 bar, ii) The sealant is delivered into the vehicle tyre by means of the positive pressure established in the compressor system.

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