JP4811217B2 - Compressor with torque limit function - Google Patents

Description

  The present invention relates to a compressor for a vehicle air conditioner that is driven by, for example, an engine that is a driving source of a vehicle, and has a torque limit function that interrupts power transmission when the transmission torque exceeds a predetermined torque. It relates to a compressor with a built-in torque limit function.

  In a conventional power transmission device that transmits power to a compressor, a torque limiter is installed to avoid problems such as belt breakage for power transmission when the compressor seizes. In this case, for example, in the torque limiter disclosed in Patent Document 1, a part of the power transmission portion is screw-fitted.

JP 2003-206950 A

In Patent Document 1, a cylindrical limiter mounting portion B ₁ as shown in FIG. 5 is being press-fitted into the rotation axis C of the adapter B extending integrally compressor, the limiter mounting portion B ₁ A female screw B ₂ is engraved on the inner peripheral surface. On the other hand, the torque limiter A fixed to the pulley D is integrally formed by a disc-shaped flange portion A ₁ and a cylindrical connecting portion A _2, and a male screw is provided on the outer peripheral surface of the connecting portion A _2. A ₃ is engraved. Thus, the pulley D is operatively connected to the rotating shaft C via the torque limiter A by screwing the torque limiter A and the adapter B together.
Such a torque limiter method using screw fitting uses an excessive axial force generated in the screw fitting portions A ₃ and B ₂ due to an excessive torque generated when the compressor is seized, and a power In this method, the power transmission path is cut off by breaking a part of the transmission path.

However, since this torque limiter system is screw fastening, the magnitude of the torque generated when the compressor is seized, and the screw parts A ₃ and B ₂ , which are fitting parts, the torque limiter A and the adapter B are matched. The operating accuracy of the torque limiter is affected by the friction coefficient of the seating surface that is the contact surface. As described above, the torque limiter having this configuration is advantageous in that it is not easily affected by material fatigue, but there is a problem that the variation in the operating torque is large. Factors that determine the operating torque are the friction coefficient of the screw surface, the dimensional accuracy of the planned fracture portion, and the material strength of the planned fracture portion. In particular, the material strength of the planned fracture portion depends on the production lot and the manufacturer and varies widely. As a result, the guaranteed range of the operating torque of the torque limiter must be set to a wide range of, for example, 50 to 120 Nm.

Here, the lower limit of the guaranteed operating torque range must be equal to or greater than the maximum torque during normal operation of the compressor, and the upper limit is the torque that the belt slips (belt slip torque) from the viewpoint of protecting the drive belt and preventing engine stall. It is essential that the torque is smaller than the torque at which the engine stalls.
However, recently, in order to reduce the cost of compressors, measures such as reducing the number of pistons have been taken, and fluctuations in operating torque have been increasing. Further, the drive belt has been reduced in tension to reduce fuel consumption, and the belt slip torque tends to decrease.
As described above, since the vehicle cannot be established unless the guaranteed range of the operating torque is small, it is strongly desired to realize a torque limiter with small variations.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a compressor with a torque limit function that incorporates a torque limit function with small variations in operating torque.

The present invention provides a compressor with a torque limit function according to each of the claims as means for solving the above-mentioned problems.
The compressor with a torque limit function according to claim 1 includes a shaft 1, a lug plate 2, a swash plate 3, and a compression mechanism, and includes an outer cylinder portion 21 in which the lug plate 2 is press-fitted and fixed to the shaft 1. The press-fitting allowance is set in the press-fitting portions 1a and 21a between the outer cylinder portion 21 and the shaft 1 so as to slide with a predetermined torque , and the outer cylinder portion 21 is fixed to the shaft 1. A liner layer 23 is provided to stabilize the friction coefficient on the entire surface of the cylinder, so that when an excessive torque is applied due to a lock of the compressor or the like, a press-fitting portion between the outer cylinder portion 21 and the shaft 1 is applied. Torque transmission is interrupted by sliding 1a, 21a. Therefore, it is not necessary to provide a new torque limiter.
Further, it is possible to prevent the three members from adhering to each other due to the sliding heat generated by the shaft 1 and the outer cylinder portion 21 and the lug plate 2 and the outer cylinder portion 21.

In the compressor according to claim 2, the liner layer 23 is formed of a resin coating that melts or softens due to sliding heat generation, whereby torque transmission can be reliably interrupted.

The compressor according to claim 3, melting at an internal temperature above La Inner layer 23 during normal operation the compressor is obtained by so as to soften, thereby, the compressor only when abnormality such as locking, Torque transmission is cut off.

  Hereinafter, a compressor with a torque limit function according to an embodiment of the present invention will be described with reference to the drawings. In the present invention, a swash plate type compressor will be described. However, the present invention is applicable to any type such as a piston type, a scroll type, and a vane type, and the discharge capacity is fixed or variable. Either may be sufficient. Further, the compressor with a torque limit function of the present invention is suitable for a constantly rotating type (electromagnetic clutchless) compressor of a vehicle air conditioner driven by power from an engine that is a travel drive source of the vehicle. However, it can be appropriately used for a compressor for other purposes. FIG. 1 is a cross-sectional view of the front half of the compressor with a torque limit function according to the first embodiment of the present invention.

  In the swash plate type compressor with torque limit function, the front housing 6 is joined to the front end of the cylinder block 7, and the rear end of the cylinder block 7 is rear-mounted via a plate material (not shown) such as a valve plate or a valve forming plate. A housing is formed by joining a housing (not shown). As the front housing 6 and the cylinder block 7 forming the crank chamber 8, the shaft 1 is rotatably supported by a bearing or the like. Power transmitted from an external drive source, for example, a vehicle engine, to a pulley (see FIG. 4) via a belt or the like is transmitted to the shaft 1.

  A lug plate 2 is integrated with the shaft 1 by press fitting or the like, and a swash plate 3 is supported on the shaft 1 so as to be slidable and tiltable in the axial direction. A connecting piece 3a is fixed to the swash plate 3. On the other hand, a guide portion 2a is provided on the lug plate 2, and the connecting piece 3a and the guide portion 2a are slidably connected. Therefore, the swash plate 3 can tilt in the axial direction of the shaft 1 and rotates integrally with the shaft 1 by the linkage of the connecting piece 3a and the guide portion 2a.

  When the center portion of the swash plate 3 moves to the lug plate 2 side, the inclination angle of the swash plate 3 increases, and the maximum inclination angle of the swash plate 3 is regulated by the contact between the lug plate 2 and the swash plate 3. ing. When the central portion of the swash plate 3 moves toward the cylinder block 7, the tilt angle of the swash plate decreases, and the minimum tilt angle of the swash plate 3 is restricted by contact between the swash plate 3 and the circlip provided on the shaft 1. Is done.

  Pistons 4 are accommodated in a plurality of cylinder bores 7 a formed in the cylinder block 7. A pair of shoes 5 are disposed at the rear of the piston 4, and the shoes 5 slidably hold the peripheral end of the swash plate 3. In this way, the rotational movement of the swash plate 3 is converted into the back-and-forth reciprocating movement of the piston 4 via the shoe 5, and the piston 4 slides back and forth in the cylinder bore 7a. That is, the swash plate 3 is connected to the compression mechanism.

  A suction chamber and a discharge chamber are defined in a rear housing (not shown). A suction valve and a discharge valve are formed on plate members such as a valve plate and a valve forming plate that are interposed between the cylinder block 7 and the rear housing. Therefore, the refrigerant gas in the suction chamber flows into the cylinder bore 7a by pushing back the suction valve by the backward movement of the piston 4. The refrigerant gas that has flowed in is pushed out of the discharge valve by the forward movement of the piston 4 and discharged into the discharge chamber.

The configuration described above is a known general configuration of a swash plate type compressor.
Next, the structure which becomes the characteristic of the compressor with a torque limit function of the first embodiment will be described. An insertion hole 2 b for inserting the shaft 1 is formed at the center of the lug plate 2. The shaft 1 and the lug plate 2 are fixed by press-fitting a cylindrical outer cylinder portion 21 that is a sleeve between the insertion hole 2 b and the shaft 1. A melting member 22 is fixed to the outer peripheral surface of the outer cylinder portion 21. Therefore, as shown in FIG. 1, the outer peripheral surface of the shaft 1 is a shaft-side press-fit portion 1a, and the inner peripheral surface of the outer cylinder portion 21 is a lug plate-side press-fit portion 21a. These press-fitting portions 1a and 21a have a press-fitting allowance (2δ) so as to slide at a predetermined torque. This press-fitting allowance is set so that the transmission torque slides between 30 Nm and 200 Nm. The melting member 22 is made of a material that melts and softens at a temperature equal to or higher than the internal temperature of the compressor during normal operation or in a range of 200 to 400 ° C.

Generally, the transmittable torque T between the inner cylinder A and the outer cylinder B is given by the following equation.
FIG. 2 is a diagram for explaining each symbol in the equation.

In the above formula,
T: transmittable torque p _m: contact pressure was injected p _a: the inner pressure of the inner cylinder A p _b: external pressure r _a of the outer tube B: the inside diameter of the inner cylinder A r _b: outer diameter of the outer tube B r _c: the Outer diameter of cylinder A (inner diameter of outer diameter B)
E ₁ : Young's modulus of inner cylinder A ν ₁ : Poisson's ratio of inner cylinder A E ₂ : Young's modulus of outer cylinder B ν ₂ : Poisson's ratio of outer cylinder B 2δ: Press-fit allowance L: Press-in length μ: Friction coefficient Each is shown. The press fitting allowance (2δ) is obtained from this equation.
In the present embodiment, the inner cylinder A corresponds to the shaft 1, and the outer cylinder B corresponds to the outer cylinder portion 21. Therefore, p _a = 0 and r _a = 0. The press-fitting allowance obtained in this way is set in the press-fitting portions 1a and 21a.

  Although not shown in FIG. 1, as shown in FIG. 4, a pulley, which is a drive side rotation member of the power transmission device, is fixed to the boss portion 6a of the front housing 6 via a bearing. A hub as a driven side rotating member is interposed between the pulley and the shaft 1 so that torque is transmitted. In the compressor with a torque limit function of the present invention, no torque limiter (power cutoff member) is provided between the pulley and the shaft 1. Therefore, the rotational power of the engine rotates the pulley via the belt, and this is transmitted to the shaft 1.

  The operation of the compressor with a torque limit function of the present embodiment having the above-described configuration will be described. When the compressor is locked, the swash plate 3 and the lug plate 2 stop rotating. On the other hand, a pulley (not shown) continues to receive a rotational driving force from the engine via a belt (not shown), and this rotational driving force is transmitted to the shaft 1. At this time, the lug plate 2 (outer cylinder portion 21) and the press-fit portions 1a and 21a of the shaft 1 slide under a predetermined torque. Thereby, torque transmission from the shaft 1 to the lug plate 2 is interrupted. Furthermore, the melting member 23 is melted or softened by receiving heat generated by the sliding portion of the shaft 1 and the lug plate 2 (outer cylinder portion 21), and the torque transmission from the shaft 1 to the lug plate 2 is surely cut off. Can do.

  FIG. 3: has shown sectional drawing and the partial enlarged view of the front half of the compressor with a torque limit function of 2nd Embodiment of this invention. In the second embodiment, instead of the melting member 23 of the first embodiment, a liner layer 23 is provided on the entire circumference of the outer cylinder portion 21 with the aim of stabilizing the friction coefficient. The liner layer 23 is formed, for example, by coating a resin that melts or softens due to sliding heat generation. The temperature at which the liner layer 23 melts and softens is preferably not less than the internal temperature of the compressor during normal operation or not less than 200 ° C and not more than 500 ° C. Since other configurations are the same as those of the first embodiment, the description thereof is omitted.

  FIG. 4 shows a comparative example of a compressor having a power transmission device, which is basically the same as the prior art of FIG. The power transmission device 9 has power between a pulley 91 that is a driving side rotating member and a hub 92 that is a driven side rotating member fixed to the shaft 1 of the compressor via a torque limiter (power cutoff member) 93. Is communicating. That is, the pulley 91 is rotatably mounted on the boss portion 6 a of the front housing 6 via the bearing 94. A belt (not shown) is wound around the outer peripheral surface of the pulley 91, and is rotated by power from the outside such as an engine.

  On the other hand, a torque limiter 93 is attached to the tip of the shaft 1 by screwing, and a hub 92 is fixed to the torque limiter 93 by fitting. The hub 92 includes an inner hub portion 92a, an elastic cylindrical portion 92b, and an outer hub portion 92c. When the outer hub portion 92c is fitted and fixed to the pulley 91, the pulley 91 and the hub 92 are connected. Yes. Accordingly, the power from the outside is transmitted to the shaft 1 through the power transmission path of the pulley 91, the hub 92 and the torque limiter 93.

  The torque limiter 93 is provided with a cut-to-break portion 93a having a narrow diameter, and when the torque is applied to the shaft 1 as when the compressor is locked, the break-to-break portion 93a is formed. By breaking, the power transmission path is interrupted so that torque is not transmitted.

  Further, in the compressor of the comparative example, the lug plate 2 is directly fixed to the shaft 1 by press fitting or the like without using the outer cylinder portion 21, the melting member 22, or the liner layer 23 as in the present invention.

  As described above, in the comparative example and the prior art, torque transmission is interrupted by using a torque limiter that breaks and breaks the member, whereas in the present invention, between the lug plate and the shaft. Torque transmission is interrupted by setting a pressure margin so as to slide at a predetermined torque at a fixed location, or by providing a melting member or liner layer that melts and softens at a predetermined temperature. Accordingly, the present invention does not require a torque limiter that breaks, so that the variation in material strength that determines the working torque can be canceled, and the guarantee of the working torque is guaranteed compared to a torque limiter that breaks a conventional member. The width can be reduced.

It is sectional drawing of the front half of the compressor with a torque limit function of 1st Embodiment of this invention. It is a figure explaining the code | symbol in the type | formula of the torque which can be transmitted. It is sectional drawing and the partial enlarged view of the front half of the compressor with a torque limit function of 2nd Embodiment of this invention. It is sectional drawing of the front half of the compressor which has a power transmission device which is a comparative example. It is sectional drawing of the torque limiter of a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Shaft 1a Shaft side press-fitting part 2 Lug plate 21 Outer cylinder part 21a Lag plate side press-fitting part 22 Melting member 23 Liner layer 3 Swash plate 5 Piston 6 Front housing 7 Cylinder block 8 Crank chamber 9 Power transmission device 91 Pulley 92 Hub 93 Torque limiter

Claims (3)

A shaft (1) that is supported by a housing via a bearing and that rotates by receiving power from an external power source;
A lug plate (2) that rotates integrally with the shaft;
A swash plate (3) connected to the lug plate, rotating integrally with the shaft, and tiltable with respect to the shaft;
A compression mechanism coupled to the swash plate;
In the compressor with torque limit function equipped with
The lug plate (2) is fixed to the shaft (1) with an outer cylinder part (21) press-fitted and fixed to the shaft (1), and the outer cylinder part (21) and the shaft (1) press-fitting portion of the (1a, 21a) to have been set press-fitting margin to slide at a predetermined torque, also the liner in order to stabilize the coefficient of friction on the entire surface of the outer cylindrical portion (21) A compressor with a torque limit function, wherein a layer (23) is provided. The compressor with a torque limit function according to claim 1 , wherein the liner layer (23) is formed of a resin coating that melts or softens due to sliding heat generation. Before Symbol liner layer (23) is melted at normal internal temperature more compressors during operation, the torque limiting function with compressor according to claim 1 or 2, characterized in that softened.

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